High altitude wind power: an era of abundance?

The kitegen concept: high altitude wind power based on kites. In this configuration ("stem"), the kite reaches altitudes of the order of 1000 m; pulling on a power generator located on the ground. High altitude wind power promises to be a low cost and widely available technology able, in principle, to provide amounts of energy comparable, and even superior, to the present production based on fossil fuels. (See here an animated representation of how a stem works)

Why should there be an energy problem? After all, there is plenty of energy around us. The sun beams on the earth's surface a daily amount of energy that corresponds to almost ten thousands times the primary energy we generate - mainly - from fossil fuels. And that doesn't include geothermal energy nor the perspectives of nuclear energy, especially in terms of fusion power. Just tap a small fraction of this energy bonanza that surrounds us and we can have more than we need.

But, of course, things are not so simple. We still rely heavily on fossil fuels for our needs and switching to alternative sources is proving to be a very slow and difficult process. Production from traditional nuclear plants is going down (WNA 2009) and fusion power remains far away in the future. Traditional renewable sources, such as wood burning and hydroelectric have very limited possibilities of expansion, while the "new" renewables (mainly photovoltaic and wind power) still produce only a minuscule fraction of the worlds' total primary energy. It was only last year (2008) that for the first time the total power of new renewable plants installed outstripped that of new traditional plants in the US and in Europe (REN21 2009). Renewables are growing fast, but can they grow fast enough to compensate for the depletion of fossil fuels?

We have a problem of cost. That can be intended as monetary costs, but also in terms of energy return of energy invested (EROEI). As shown in Charles Hall's "balloon graph" (2009) the EROEI of renewables can be considered as reasonably good in most cases (with the exception of biofuels). It is around 10 for photovoltaics and around 20 for wind. Similar returns are reported for current nuclear technology. These are good returns on the investment, but not as good as it was for fossil fuels in the golden days. Decades ago, the EROEI of petroleum was of the order of 100 and perhaps even better (Hall 2009). It was this high EROEI that led fossil fuels to acquire the dominance that they have today. Without that kind of EROEI; other energy sources haven't had a possibility to compete. Today, we still need fossil energy to build non-fossil energy plants. But, with fossil fuels starting their decline, it will be more and more difficult to sustain the growth of alternative energies at a rate fast enough to provide a smooth substitution of conventional sources. We can think of an industrialized world that doesn't need fossil fuels, but we don't seem to be able to get there fast enough.

So, we are facing Tantalus' curse: we are surrounded by abundant energy but we can't get it. That is, unless we can develop a technology with a much better EROEI than what we have now. With a very fast energy return on investment, we could free the world's energy system from its dependence on fossil fuels. That is, unfortunately, easier said than done. The internet is full of claims of supposed breakthroughs in energy technologies that promise a lot but turn out to be just dreams; or even outright scams. But there may exist an energy technology that can not only promise, but deliver a high EROEI and that is also based on sound physical principles: high altitude wind power.

The basic idea of high altitude wind power is that wind is more intense as you move up in the atmosphere. The average wind speed increases with height according to an exponent (called "Hellman exponent") which is about 1/7. But the energy contained in a mass of air in movement increases with the cube of speed. From a simple calculation, we see that if we could raise a wind turbine to a height of 800 m, we could increase the power obtained of a factor of 8 in comparison to the same turbine near the ground. Even larger increases are possible at higher altitudes, where winds are also much more constant; easing the intermittency problem of conventional wind turbines. But of course, it is impossible to reach such heights with the current wind technology, limited to about 100 m because of the cost and weight of the tower.

This concept has been clear for a long time and has led to several proposals to tap the wind at higher heights. There are two possible ways for doing that: balloons and wings. You can find a recent summary of the progress in this area in the work by Big Gav (2009) published on TOD . As you can see, there are many ideas in this field, many of which exist only as sketches on paper. In many cases, the energy yield of the proposed systems is only a guess while, for those systems based on aerostats, the need of a non renewable resource (helium) is a considerable limit.

However, a few systems have been studied in depth and some tested in practical experiments. Systems based on rotors are possible and systems based on kites, in particular, do show a lot of promise. Saul Griffith of Makani Power has shown some images of a test done with a three rope kite. Wubbo Ockels, (Delft University of technology) has been also experimenting with a kite , this one using a single rope. In this field, the most advanced system seems to be the "kitegen"; a kite system created by Massimo Ippolito of Sequoia Automation , a company based in Italy. Tests on a prototype system have been completed and a first energy producing plant is being built in Northern Italy.

The Kitegen is a simple aerodynamic system: it uses state of the art kites which create lift dynamically by flying at 70-80 m/sec; this is the speed reached by the tips of the blades of a conventional wind turbine. In the simplest configuration (called "stem"), the system uses a single kite linked to a power generator located on the ground. The kite moves like a yo-yo: when it goes up, it generates energy that is transformed into electric power by the generator. When it reaches its maximum height, it is placed in an aerodynamically non-lifting configuration, so that it can be pulled down at a very small energy cost. Two coupled stems would work like a two-cylinder engine, although the "power" phase would last 90% of the time while the "pull back" phase would be much faster. A single stem could have a maximum power of a few MW. Larger plants could be operated in the "carousel" configuration. In this case, the kites fly at a constant height and at much higher altitudes, pulling a generator that moves on a circular rail. For a large carousel system, the maximum power obtained can be calculated as of the order of 1 GW or even higher.

Since the kitegen has been studied in detail, we can use it to make an estimate of the EROEI involved in high altitude wind generation. Before getting to that, however, let's summarize the known data for the current wind technology. A recent LCA study for a conventional 3 MW wind turbine was reported by Nalukowe et al, (2006). They estimate the total energy input for building and maintaining the turbine as ca. 8000 MWh for 20 years of lifetime. Since the total weight of the above ground part of the turbine is about 400 tons, we can estimate an embodied energy requirement of about 20 kWh/kg. The turbine will produce about 160,000 MWh during its lifetime and hence the final EROEI is ca. 20.

Now, let's see the results of a similar approach for the kitegen. According to Massimo Ippolito (data published on www.kitegen.com), the energy required to make a 3 MW rated power kitegen stem is of 40kWh/kg or 40 MWh/ton. The calculation that leads to this value takes into account all the requirements in terms of the materials needed: steel for the structure, copper for power lines, neodimium and boron for the magnets, machining, transportation, building, etcetera. This value includes also the energy costs involved with having workers at the plant and for the periodic substitution of cables and kites over a 30 year lifespan.

We see that the kitegen requires more energy per kg than a conventional wind turbine; this is expected because it is a more sophisticated machine. But the stem is much lighter: we are talking of about 30 tons in total for a 3MW plant. So, we can estimate the total energy requirement as 30 tons*40 MWh/ton= 1200 MWh. Assuming 5000 hours per year of operation at maximum power, the plant could produce approximately 15,000 MWh per year, or 450,000 MWh in 30 years. The final result is an EROEI = 375 (!!). If we assume a 20 year lifespan, the estimate should be reduced, but it remains large. For larger kitegen plants of the carousel type it would be possible to reach higher heights, tap into stronger winds and increase even more the EROEI. This calculation is valid for the specific case of the kitegen system, but other proposed systems based on kites or rotors would probably be able to attain similar large EROEIs.

Of course, these values have to be taken with a lot of caution, but this calculation should be enough to show us the enormous potential of high altitude wind power. EROEIs higher than 100, perhaps even much higher, bring us back to the golden age of cheap and abundant fossil fuels, without all the troubles and problems that fossil fuels brought. A further advantage of high altitude wind is that plants can be placed almost anywhere; another is that we can obtain a nearly constant output for most of the time (Archer and Caldeira, 2009). Although the cost of energy storage would not be completely eliminated, it would be much reduced. With high altitude wind, we might really have the kind of energy "too cheap to meter" that was prophesied in the optimistic 1950s. Not only we could have cheap energy, but we could also have it fast. Consider a conventional wind turbine, with an EROEI of 20 over a 20 years lifetime. During this period, the energy generated could be used to build 20 more turbines; an average of one per year. A kitegen, with an EROEI > 200 and the same lifespan, could be the "seed" for hundreds more kitegens, an average of more than one per month. With such a high EROEI, high altitude wind energy wouldn't need fossil fuels as energy subsidy. It could grow by itself so fast that it could replace fossil sources well before we arrive to the last drop. That would also ease the climate problem by rapidly reducing the emissions of greenhouse gases from fossil fuels.

Now, of course, all this should be considered still a dream until it is tested and verified. But, at least, it is a dream that has some solid basis in physics and engineering. So, assuming that the promise of low cost and high EROEI can be really fulfilled, we should still remember that the earth is a limited system. So what are the ultimate limits of high altitude wind power?

It is estimated that about 2% of the Sun's energy that arrives on the earth's surface is transformed into wind energy. The atmosphere is not very efficient as a thermal engine, but there is so much energy from the sun that even a mere 2% is a huge amount in comparison to our needs. The total energy stored in form of winds is estimated as of the order of 2000 TW (Hurley 2009) or perhaps higher according to other estimates. In comparison, the total primary energy generated by humans corresponds to an average of just about 16 TW. So, there is no doubt that wind energy is abundant: according to a 2005 study by Archer and Jacobson, already at 80 meters of height there is enough energy in the atmosphere that it could be exploited by means of the conventional wind technologies to provide a total amount corresponding to the present production. But there is much more energy at higher altitudes and we need to exploit just a few percent of it to be able to produce enough for our current needs.

One problem could be the effect of high altitude kites or rotors on the atmospheric wind circulation. This question has been examined by Archer and Caldeira (2009) by means of climate models. The results are that tapping high altitude winds would reduce precipitation. Also, it would have a cooling effect and could affect climate. The problem would be minimal (around 0.1% reduction in precipitation) for amounts of energy tapped corresponding to our present demand. But this effect does pose a limit to the technology. It may not be advisable to use high altitude wind power for generating more than a maximum of around ten times the present production. It is still a huge amount of energy available for free and generating a very small impact on the earth's ecosystems. It could even be further increased, indirectly, by using wind energy to manufacture photovoltaic panels or other kinds of solar plants. In the end, we shouldn't be surprised of these perspectives. After all, as we said, we are surrounded by huge amounts of energy and if we find a way to exploit it, well, why not?

From these data, we could be tempted to see high altitude wind power as a nearly limitless energy technology. But that would be a mistake. Energy production is not static - it goes with the economy and if the economy is powered by a source of cheap and abundant energy it tends to grow exponentially. Exponential growth is treacherously misleading: we could find ourselves bumping into the ceiling of high altitude winds much sooner than we would expect.

But there is a much more serious problem in the fact that energy is not the only parameter that affects the economy. Abundance of something is not abundance of everything. Abundant electric power doesn't necessarily translate into abundant food, although electricity can surely be used in agriculture in place of fossil fuels. That our problem is not just energy is confirmed by the models developed for the "Limits to Growth" series (Meadows 2004). The models can be run for scenarios that assume abundant (or even infinite) energy available, but the result is that the economic system collapses because of the strain on the environment and on agriculture generated by a combination of overpopulation and pollution. To avoid collapse, we need to stabilize both the economy and the population at a stationary level. Even so, the gradual depletion of mineral ores will make us depending on more and more energy if we want to keep the flux of mineral commodities at the present level (Diederen 2008, Bardi, 2008). So, even with abundant energy, we'll still need to recycle materials and reuse what we manufacture.

So, even with abundant energy we still need to come to terms with the fact that the earth is a limited system. However, high altitude wind power offers us a hope of a future of relative abundance, even of prosperity, if we'll be able to keep the economy and the population stable and avoid overexploiting our agricultural and mineral resources.

Acknowledgement: the author thanks Mr. Massimo Ippolito for his comments and input for this paper.

Note: the author is not financially linked to Kitegen Research S.r.l., the company which is developing the kitegen system described in the present article. He has, however, a small financial interest in "Wind Operations Worldwide" (WOW) which is formed of a group of of small investors who intend to finance the development of high altitude wind power, and in particular of the kitegen system.


Archer, C. L., and Jacobson, M.Z., 2005, "Evaluation of global wind power"
Archer, C. L. and Caldeira, K, 2009, "Global assessment of high altitude wind power"
Bardi, U,, 2008, "The universal mining machine"
Big Gav, 2008, "Alternative Wind Power Experiments - SkySails and Airborne Wind Turbines"
Diederen A., 2008 , "Minerals scarcity: A call for managed austerity and the elements of hope"
Hall, C and Lambert, J. G., 2009 (accessed) "The balloon diagram and your future"
Hurley, B. 2009, "How much wind energy is there?" "How much wind energy is there?"
Meadows, D. Randers, J, and Meadows D., 2004 "The Limits to Growth, the 30 years update", # ISBN 1-931498-58-X,
Nalukowe, B. B., Liu J., Damien, W., Lukawski, T., 2006, "Life Cycle Assessment of a Wind Turbine"
REN21, 2009, , "Renewables: global status report"
WNA (World Nuclear Association) 2009, "World Nuclear News 2009."

I would think the potential show stoppers have to do with the potential for semi-catastrophic disruptions (kite crashes). Even at a fairly low rate, they might seriously effect the economics. Obtaining a high capacity factor, while also avoiding generateion during risky weather conditions might be the key. Do you have any insights on this.

Having multiple kites in the air might lead to a risk of entanglement. What implications would this have on the summer of generators per square kilometer? Of course aviation would be in competition for the airspace, so high power generation per amount of restricted airspace needed is probably a requirement. And concerns about the potential damage of kite crashes onto populated areas might also be an issue.

@ enemy: kites are extremely light structures, and so are the cables. the damage that can occur by a kite crashing is truly minimal. The entanglement, instead, is something to be careful about, and so is the interference with aviation. All that has been studied in detail: kites and aviation can live together, but there will be the need of precautions, protocols, etcetera...

Without making much effort to study the concept, I suspect that your comment is not likely to be correct. The drag force on an object also increases as the square of the speed and the area. Larger devices capable of producing MWs of wind poser would also be expected to result in large drag forces which would be transferred to the support structure. The typical kite string would be transformed into a rather heavy rope or cable. Also, the drag force on the tether itself would be rather large, as the drag coefficient on a circular cross section is large.

There's no free lunch in engineering.

E. Swanson

Of course not, an analysis would require a bit of thought and effort...You would rather toss out offhand comments....

OK, looking at Kitegen's multi stem idea, I see a version of a vertical axis wind turbine It has the usual problem of a vertical axis machine, which is, at any one time, half of the kites are moving into the wind and the forces on the ends of those stems result in torques which oppose the rotation of the base. Look at the first image in the linked graphic. What happens on the left side as the kite changes direction, which is actually outside the frame of the graphic? It would appear that the kite would need to make a fast climb to nearly vertical, then dive back down, a situation similar to "jibing" a sail boat, IMHO.

The graphic which shows a comparison of the intercepted area with that of a horizontal axis machine grossly overstates the effective area of the turbine and thus overstates the possible efficiency of energy conversion. The effective area should be the area of the kite(s). Also, the claim that only the tips of a horizontal axis turbine are efficient ignores the effects of both pitch control and proper twist along the blade.

Given the large size and slow rotational speed, it looks to be little more than a drag turbine. And, should the positioning mechanism fail on one kite, the whole thing would crash as the lines would become entangled after one revolution...

E. Swanson

BlackDog, Your points look sound but they apply only to the vertical axis fairground roundabout embodiment which I never much warmed to. The separate yoyo thingys illustrated above seem much the more promising way forward, apart from looking too much like an array of howitzers to ever appear as (relatively!) beautiful as turbines.

Free lunches are getting harder and harder to come by in any area. Average wind around the globe has decreased by about 10% over the last few decades and is likely to decrease more as the temperature differential between the poles and the equator weakens.

Whoa. Send me some links or background on that dohboi. Climate change renders windfarms inoperable. That's poetic.

As long as there is day and night, land and sea, and a spinning globe there will be usable winds.

All climate change will do is change some of the details.


"A third possibility for slower winds is climate change, he said.

"It's simple meteorology that the wind is driven by differences in temperature between the poles and the equator, and those differences have been narrowed by climate change," Takle said."

Yes there are other sources for wind, but this is a major one. In general, also, CC means unpredictability. Some places that had experienced reliably high winds will see much less wind, others will see more. As the article says, the temp differential between land and sea will probably always generate good wind speeds. But then the placement of the coast/depth of the sea will be changing too.

CC makes it harder to plan pretty much anything with the certainty we had before.

I suspect you are in error regarding sources of wind. The primary cause of wind on earth is movement of air from hot equatorial areas to cooler temperate zones, which is, agreed, due to deltaT, but the velocity and thus energy contained in those winds is due to earth surface velocity differences as spherical section diameters on the rotational axis reduce from equator to those temperate zones. It will matter little how much air moves at high altitude from equatorial areas to temperate zones, still the sectional rotational velocity difference remains unchanged and therefore likely the wind velocities (west to east).

I imagine these things fighting it out, buckyball single-molecule threaded cables - the sort that would slice through a body that walked through them unaware. Diamond crusted cables to saw away the other kites from the other corporations competing in the free market.

I can't help but think the emergy of the power delivered by a system like this is an order of magnitude greater than that of a coal plant. Just a gut feeling; these machines will be subject to all sorts of shocks - people, maybe entire city blocks - getting sawed in half by these cables dropping and tightening.

Wouldn't it be easier to take drugs and pretend it worked?

cfm in Gray, ME

No diamond-encrusted saw cables will ever be used to tether a wind-gen kite, nor any single-molecule-wide invisible saws such as you may have seen on some science-fiction kung-fu-figher video game. Even if comprised of the most futuristic single-wall-nanotube composites, any cable capable of holding these kites will be too large to cut, and in order to reduce wind resistance, will be sufficiently smooth surfaced, to be any greater threat than a child's skip-rope.

Drag in energy kite systems in some energy harvesting methods being explored becomes useful. The family of methods using the ground-based lever includes wafting levers, rocker arms, oscillating lifting levers, TipBooms (counter-weighted), stems, carousels, tree trunks, piezo-electric booms, ratchet booms, and tugged-hydro-turbined rafts. Kite-tugging a hydro-turbined-saturated ocean barge could transport freight while making electricity; the electricity could make hydrogen from the available water; at destination ports, the hydrogen could be off-loaded for work-use points night or day.

The KiteGen stem method is a member of a family of lever systems; some members combine reel-in-and-out and others do not use that cycling. The near-vertical TipBoom method oscillates without the reel-in-and-out, especially in always-up formats (some of which involve lifter kites along with oscillating kites or wing-mills). Some working test scale systems are occurring in Ilwaco, Washington, at KiteLab with passive controls.

Recreational kites are light and can fall on one's head. A kite capable of generating power is another story.

These CANNOT be flown where people are underneath.


Airplanes CANNOT be flown where people are underneath!!!....Ugh, the discourse is ABSOLUTELY declining here....

We have a century of experience with airplanes (and many do NOT want to live in the flight path of airports).

We have NO experience with kite gen.

I stand by my statement.


And I stand by the intent of mine....which is to show your statement and counterstatement are silly

It does seem that we forget that there are very heavy and very flammable large objects flying over us all the time...I live near a military base and the amount of aircraft traffic overhead is astounding, and this is over an area where tens of thousands of people live! The placement of the kitegen can be much more limited we can assume.

This post came at an interesting time for, as I have been studying trimaran hydrofoil boats to see what can be learned from them (I have recently posted a YouTube clip of the French hydrofoil that did 47 knots). All indications are that the physical possibilities implied in wind power are HUGE, it is the logistical issues that are the problem. If you had told someone 30 years ago that 50 miles per hour could be done with a sailboat, they would have told you it was absolutley physically not possible.

The strenth to weight of the materials involved in any kite system would be of great importance in determining it's success, but time is on our side on this...nano materials are in the pipeline that will be stunning in their strenth to weight ratio, and there are already various composites that have incredible strenth to weight ratio.

This absolutely has possibilities, but one must be concerned about local opposition. The current cost of wind is being driven back upwards by lawsuits and local laws and zoning rules to effectively ban current generation turbines in many places. The NIMBY and BANANA issues are very real and very daunting in an already risky industry.


Your dismissive acronyms suggest that you don't care what goes into your back yard or perhaps anywhere?

People should be much more concerned about what is in their area and in others' too. The problem with "NIMBY" isn't that people care too much, it's that they don't care enough to see that if they want to use and waste energy at the rates we do in modern society, generation (and transmission...) has to happen somewhere.

But very good lifestyles can be maintained with far lower energy needs and overall lower impacts, locally or elsewhere. And this is where the emphasis needs to be--on reducing demand, and only secondarily (or tertiarily...) on new generation.

Good luck convincing the entire world to follow you back into the stone age there, doboi. Even the laywers you depend on for your tactical manoeuvers should eventually abandon it.

"Good luck convincing the entire world to follow you back into the stone age there, doboi."

Hey, now, cave living is way underrated ;-}

Really, could you have come up with a more cliched response? When anyone questions our mad rush into techno-oblivion they are always immediately equated with the stone age.

Presumably much learning, music, art...could be preserved and enjoyed at a far lower cost to the living world. But if that vision is to frightening to you, please do resort to more cliches.

Presumably much learning, music, art...could be preserved and enjoyed at a far lower cost to the living world.

That is a good start but it should also include things like space telescopes and generation after generation of researchers grinding away at understanding big things like how the universe looks and advancing small things with vast areas of possible knowledge like biology and understanding ourselves.

There is so much that can be possible in the long term if we dont fuck up too much. Some day we can have biotechnology and nanotechnology as understood and usefull tools making todays problems seem easy in hindsight if such tools are used wisely.

But I do not long for infinite generations of people in a static low tech culture telling the same kind of stories around a campfire. If I could choose between that and divergent surprises while figuring out the universe and doing stuff I would choose the later without hesitation but you wont get that if the developments trashes its own ecosystem.

That is a good start but it should also include things like space telescopes and generation after generation of researchers grinding away at understanding big things like how the universe looks and advancing small things with vast areas of possible knowledge like biology and understanding ourselves.

So that we can kill them better when they show up. The aliens. The link is to "Blindsight" by Peter Watts - maybe the best sci-fi novel I've ever read. Derrick Jensen meets The Swarm.

Biology, understanding ourselves. GMO trees. The toxic food chain, etc.... Yeah, we need to study that more.

cfm in Gray, ME

"understanding ourselves"

That's the main project. But the fact that you seem to be willing to broach a mass extinction event to avoid getting bored suggests that you might be a candidate for a bit more self-reflection and self-understanding?


To your reply, I can only say that I was not intended to be dismissive, but it is possible that it came across that way.

Contrary to your remark, I do care very much what is built in my backyard and "anywhere". Remember that here in Kentucky we live in the shadow of "mountaintop removal mining" to extract coal. This is real "in our backyard" catastrophic activity that is virtually ignored by the mass media and even by those folks here on TOD.

I just believe we should play fair: I can come up with objection after objection against every alternative proposed because it will have some kind of "impact" while ignoring impacts that are absolutely catastrophic and that are already occuring.

I ask: Does any of the renewable alternatives to coal production and use(the kite gen, concentrating solar mirror, PV solar, conventional 3 blade wind turbines,ocean wave power...or do ALL of them combined have even the remotest possibility of causing the catastrophic "impacts" that coal extraction and use is already causing?

I am going to be very forthright here, dohboi: I ask, why is that if a PV solar plant opens, there are repeated stories in the news about the fact that it uses "heavy metals" while no mention is made of he micro chip plants just up the road that have used thousands of tons of heavy metals since the 1970's? Why is it that the birds killed by a windmill make headlines, while no one talks about the hundreds of thousands of birds that die every year flying into open oil tanks that look to birds like lakes? Why is not the destruction of rivers and the catch basins for coal sludge ignored, and it makes the back page of a newspaper in the hill country of Kentucky and West Virginia when a cheaply made damm breaks and the slop buries a town killing a few locals, and no where else in the U.S. covered?

Do you want to see massive destruction of birds, plants, animals, eco-structure, soil and rivers, hundreds of thousands of acres of the most diverse eco-structure on the face of the earth turned into lunar landscape? I challange you to put "mountaintop removal mining" into a google search engine and sit back and enjoy the slaughter. But if only the carbon from the coal can be sequestered, all will be okay and we won't need solar or wind or renewable energy the mining and utility companies tell us! But of course, the coal will still have to be extracted and the catastrophic almost unbelievable damage will continue.

It is all too easy to fire up a few local activists groups to the alternatives and create opposition to any alternative based on the most marginal of impacts while the the opponents to mountaintop removal which can be seen from SPACE can get no press coverage. Al Gore screams about a glacier in the arctic while ignoring a catastrophic destruction that is going on in his own backyard in border states of Tennessee. Why?

All the supporters of the alternatives are asking for is a little fairness. Do we need to reduce energy consumption? ABSOLUTELY, we waste energy that goes up the smokestack and out the tailpipe while producing no benefit for anyone except the energy producers.

You say, "People should be much more concerned about what is in their area and in others' too." ABSOLUTELY, but where are the "not in my backyard will I risk being struck on the head by a flying windmill or put up with a small sound from it" instigators to talk about WHAT IS ALREADY HAPPENING? People are willing to attack any change with a bit of instigation and ignore the destruction that has been underway for years. Perhaps we accept the current destruction simply because it is already "well-established". Parhaps we know that we can attack a new start up company much more easily than we can take on a fight with Peabody Coal or Duke Energy.

By thinking that any alternative that brings with it any impact, no matter how slight it may be in comparison to the catastrophic impacts of the entrenched fossil fuel industry, we are supporting our own kind of destruction: The destruction of any path forward except poverty, decline and loss of our intellectual leadership in the world. The alternatives should be questioned and examined closely: But we must do this examination in the context of the damage that is already being done on a much more massive scale than the alternatives have shown any potential to do. We cannot become propaganda pieces for the fossil fuel extraction industry by throwing out meandering attacks on every possible alternative to them.

Thank you for the opportunity to discuss these issues,

Well said, Roger.

Alan and aviator--I suggest the truth lies somewhere between your positions. No way would this be located over a regularly used area such as urban or a village, because as you say these things are (possibly) going to crash down occasionally. But on the other hand the land below could reasonably be used for farming or fishing or a solar thermal farm, with a negligible probability of any significant harm from a crash.

And meanwhile sometimes the precarious can be made unexpectedly reliable. Planes, even helicopters, very rarely fall from the sky. Six people were killed in a major uk tower block fire this week, but hundreds of such blocks have remained consistently unfired for over 40 years (even Ronan Point which was one-quarter demolished by a gas explosion), giving an outstandingly higher safety record than standard height houses with wooden floors.

PS--My thought before working through 201 comments is that this article really does warrant the "excellent" word unlike some recently that it has been dubiously endowed on. Excellent presentation of what looks at firstish sight like excellent engineering (with fine developments of a general concept I was thinking along myself between more pressing chores).
"Yes but don't forget that 20 years back in 2009 people were saying then that we were energy-doomed, and they completely failed to see the kitegen era coming; they were wrong then and they're wrong now."(?!)

the precarious can be made unexpectedly reliable

But only over a considerable period of time. Long term experience is required, unexpected failure modes will be revealed as the experience base expands, equipment near the end of it's service life will have different failures than brand new equipment, operators with differing levels of expertise and maintenance, etc.

In my SWAG, a minimum of ten years, in the best case, to even remotely approach aviation safety standards.


the precarious can be made unexpectedly reliable
But only over a considerable period of time.

Actually not even with time and experience. This kite is fundamentally different from an aircraft, in that it inherently can only be a flap on the end of a cable loop. It can't have engines or steering gear. So there's little scope for self-corrective techs. For this reason I'd agree with my reckoning that it couldn't be acceptable within falling distance of urban or villages, but could be acceptable in land for farming, hiking etc, where any crashes would only rarely hit anyone.

It's not the kite that's the problem. It's the cable it drags. Keep that out of the rigging, please.

A farmer, with his wife and children, might disagree that their lives and home are somehow more expendable than those of the townspeople in the nearest town.

The risk to each individual person is about the same, regardless of location & density, of living under a KiteGen (those that work outside, such as farmers, likely have greater individual risk). It is just that towns have all those individual risks clustered together.

And said farmer owns the air rights over his farm.


Alan, any crash will take a fixed amount of space, the odds of it actually hitting a person relate directly to the odds of a person being in that space.

The farm family is just as likely as any other to be in that space, but since there are fewer farm families per km^2 than village or urban families there is less of a chance that anyone at all will be there.

It isn't a matter of relative value, it is simply a matter of the odds of anyone at all being there.

There is simply no place on earth where you can count on nobody ever being on the ground or water perpetually, there is no completely abandoned space. All you can do is set relative limits.

This applies equally to this technology as to conventional wind, planes, satellites, transmission lines, and myriad other above-ground-level constructions and craft.

And furthermore I wasn't envisaging that the farmers or hikers would be actually living under the thing, just they would have their sparsely-visited fields thereunder. You wander in the country and in a square mile more often than not you never meet anyone anyway. So lower probs all round.

The current standard for wind turbines (ground based) is no permanent human habitation can be within the "falling radius" of a wind turbine.

It appears that the falling radius for KiteGen is a minimum of a mile/1.6 km. Applying the same rule to KiteGen as is currently used for other wind turbines severely reduces the # of sites.

Farmland with a couple of farm houses/mile2 is far too dense. Ranchland, with one ranch house/ 30 miles2 (77 km2) seems to be close to the maximum density *IF* the falling radius is only 1 mile.


This increases transmission problems.

The big problem isn't the kite falling out of the air, despite it's weight it will be moving relatively slowly due to aerodynamics. Any shelter at all should be sufficient. Additionally, since it is only the rigid portions of the kite that are likely to cause damage from impact, the design should minimise rigid kite components (a paraglider style kite would be ideal from a safety perspective).

The big issue is line springback. That would involve a danger area around half the line length in radius. That sort of clearance is available in many more areas.

It is really curious that the main issue emerging here about the KiteGen technology is the falling of the kite hypothesis. I beg your pardon, but from the TODers I was expecting more pregnant commentary.
Let me divide in three main situations, all already experienced in the real tests of the prototype:
If the machine is fully operative the kite cannot fall. Even in the case that the wind stop or suddenly change of direction. The base drums and winches are able to reel in the ropes at various speeds reestablishing the traction that stabilize the flight speed, the lift and the maneuverability of the kite. The control can choose to bring back the kite and stop the machine or move in the new downwind sector
If the KiteGen Stem has one side in mechanical trouble, and only one rope cannot be recovered, with the other rope is easy to start the sideslip procedure and bring back the kite, up to it will be hanged under the arm top, the drawback is that a double rope in half length extension should be recovered from the ground.
The KiteGen Stem is in total default:
If it is an electronic control failure the machine has typically enough time before the falling event to restart the program, or switch the active controller and recover the normal operation, but raising the maintenance alerter flag;
If it is an hardware failure the kite will fall, but an indipendent watchdog automatically cut one of the two rope in order to let flagging the kite avoiding dangerous forces on ropes during the fall.

In my humble opinion and after some machine refining, the latter cases could happen likely with a frequency as the civil aviation, airplanes disasters frequency.

From a technical standpoint there are 3 issues:
1. Will it work at all: I am satisfied from the information that you have made available that it will.
2. Will it be cost effective: Looks promising, but more data is needed. You have plans to collect that data with more tests.
3. Will it be safe: all signs look good there. The safety issue that most concerns me is a break in the line close to the ground. A top of line break has plenty of time for air resistance to slow it down before the line hits the ground.

I realize that the sort of line part that is the most dangerous is also one of the least likely, but if you can show that it has been adequately considered and appropriate precautions taken then it will make siting and permitting that much easier.

The main consideration with a line part is how far the broken end needs to travel for air resistance to slow it down to a safe speed. The actual safety radius for this failure mode will be where a cylinder of that diameter centered on the lines intersects with ground+2m or so. Half the line length on the ground is a very conservative estimate for this, I'm sure that well considered calculations will reveal the actual safe radius to be less than that.

As for the kite itself falling, I see little risk there. In the event of a double line break it appears that you will have a free-gliding/falling mass of cloth. It might get tangled in something...

I see from your comment below that you have considered at least some portion of this in your design. I note that sand can get into almost anything and cause mechanical jams which would impair your tensioner's ability to adjust. If you plan for this sort of failure and nothing happens it still makes people feel better about having one "in their backyard".

[Edit 2] The actual safety radius is even smaller than my original estimate due to the forces being under tension. The actual vector of force is going to be very nearly aligned with the line itself. I suspect that the safety radius will be small enough to be satisfied by the enclosure. Still, calculate it out to be safe.

You overlook downdrafts. Those that you can see (thunderstorms) and those that you cannot (clear air turbulence).

These will force a kite down in seconds. Perhaps to the ground, perhaps just 1 km.

I suspect that after a sudden downdraft, the droop in the cables will hit the ground and become entangled before the kite itself hits the ground.

You fail to understand the over half century of extreme effort (many billions of $ and millions of man-hours) required to get to current civil aviation safety record. I found your statement "...after some machine refining, the latter cases could happen likely with a frequency as the civil aviation, airplanes disasters frequency" quite naive.

Boring (I know) and Airbus (I suspect) hold safety in both deadly seriousness and as the highest priority (*FAR* more important than profits or whether a/c fly or are grounded). Does KiteGen have the same emphasis ?

In any case, it will take a decade of experience, with thousands of KiteGens, in a very wide range of climates, and many different operators (some of whom have tight budgets, and unskilled personnel), to get an inkling of what the risks really are.

I have some other, more esoteric concerns about KiteGen, but safety appears to be the primary one.

The grid must accept whatever KiteGen produces. Conventional wind turbines have large amounts of rotational inertia to even out the variations in wind for short time periods (sub-second to multi-minute) although there is still a pulse (drop) whenever a blade on the down side passes in front of the tower. Large #s of turbines are used to even out this relatively small pulse statistically.

It seems that every time there is an inflection in the path of KiteGen, power production would vary.


Alan--Your second point, about rapidly varying output, looks like a significant problem unless there is an adequate flywheel system built into the base; hopefully someone can turn up to respond here.

As for danger from downdraughts, the suggestion has already been made that the kite can be very rapidly switched to reel-in mode, and perhaps thereby it would escape from the downdraught zone and or promptly re-establish its "flying" mode. It may not take many years to clarify this. Over a non-populated area any crash would be of low risk importance anyway.

To: Alan and other "Kite-crashing"-folks -
This crash-issue is the last challenge this concept will ever face - before this alot of hurdles of functionality shall be checked. And if Kite-Gen so do - then the "crash"-issue will also become ckecked - Why ? Because that one is the easy part ... and I have "10 working proposals ready" already.

The "rope" will become the major-problem, therafter controlling randomness and efficiency...

As a street fighter from the 60's, we used kites to interfere with helicopter blades during riot conditions, with some success.
That said, I love kites, and in the proper environment, why not explore the possibilities?

I think a great deal of scepticism is justified at this point. This is but one more in a long series of ideas for supplying nearly limitless energy. Although you end on a somewhat cautionary note, you are far more optimistic and hopeful than seems prudent to me. If there were even one realistically scaled demo, one could perhaps justify part of your enthusiasm.

I am always on guard whenever I hear about how much energy is out there, if only we could get at it. But that's reality. We can't get at it very easily. If it was really, really easy we wouldn't be here -- we would have destroyed ourselves already. As it is, the imminent decline of FF may indeed save us, or force us to save ourselves by forcing us to ease off on the mayhem we are causing in the surface ecology.

Identification of a potential new source of substantial energy should always focus on the difficulties: how is nature preventng us from accessing this source? The same thing we do telephone marketeers promising easy money. At this point, the claim of a new source of large amounts of accsssible energy is an extraordinary claim, and requires extraordinary proof to be convincing.

None of which detracts from my admiration for the articles on metals and minerals by Mr. Bardi.

Dave, I am known to be an "arch-skeptic" on many things: hydrogen, for instance. But this time I hit into something that I couldn't demolish, no matter how hard I tried. What really pushed me to become a believer was the recent paper by Archer and Caldeira: they showed that the energy is there and that we can get it without unbalancing the ecosystems. It was a little revelation that made me think "hey, we can really do that!"

Of course, we need more proof, we need to see MWh being produced and fed to the grid. But I think it is not too early to claim that we have a chance to get rid once and for all of the fossil fuels, and not having to go back to Middle Ages for that. A chance, I said, just a chance..... but better than no chances at all!

Yes, it seems sound in theory - there are no obvious 'gotchas' in this one.

It would be interesting so see just how dependable these winds are - I'd guess we have some idea from civil aviation. Intermittancy is (IMO) the real gotcha for ground based wind power that stops any major-scale displacement of FF generation.

It would be interesting so see just how dependable these winds are

That should be a pretty straight-forward test at any proposed location. Just like a proposed windmill site can be tested with a anemometer mounted at the proper height and set to record for a year, a kite-generator could be tested with a single tethered kite outfitted with sensors and left to record for a year.

Thanks Ugo for presenting this idea. It is indeed a fairly elegant approach to harvested energy that was previously beyond our earth-bound reach.

About the dependability of winds, see the paper of Archer and Caldeira cited in the post. They have studied exactly that. In practice, high altitude wind does not completely solve the intermittency problem, but greatly eases it

Well, there is one obvious problem - fatigue. Assuming we want each kite to generate 1MW in a 7.2 m/s wind, then the tether force is around 100 kN (or 10 tonnes). That might not seem too much of a problem: offshore we use lightweight polymer ropes which can handle much higher loads than that. In fact, most deepwater riser umbilicals are OK for that sort of load, proving that you could generate the electricity in the sky if you want.

However, the duty cycle looks appallingly severe. The tether rope experiences dramatically varying loads, whilst being constantly spooled on and off a winch, round the clock, every day of the year. Even the most demanding offshore or marine application is nothing like this.

I doubt the kite tethers will last 20 days, never mind 20 years.

the life of the ropes is a function D/d D=diameter of the driving pulley d=diameter of the ropes.
The tether with the design choice we did, will last 6 months, after that a company is ready to recycle the ply to rebuild a new rope.
Let me say, a coal power plant burn 300 tons of coal to produce 1 GWhe. A KiteGen to produce the same amount of energy will wear about 100kg of tether.
Then the rope will be recycled and only the 20% of the ply will be discarded because too short.

The ropes will never experience dramatic variation in load, because the best control algorithm we tested work with constant forces

I hope you're right about the 6 months.

We use advanced polymer ropes for heave-compensated lifting/lowering in deepwater, but reliability is more than just a function of D/d. Each sheave has to rotate at a slightly different speed, for example, because the ropes stretch significantly and would otherwise slide and abrade. Also, load variations cause internal heating due to hysteresis. Abrasion and heating are not good for polymer ropes.

Even if your control algorithm is really efficient at counteracting the effect of turbulence, the tethers inevitably see dramatic load variations, because the force in the traction phase must be as large as possible (to maximise power produced), with the force in the recovery phase as small as possible (to minimise power lost).

Scottish--I think their reasoning is that they will have a constant torque on the windlasses, so "therefore" constant tension in the cables. The idea is that on switching to reel-in mode the same force level produces a whopping acceleration, hence the reel-in being a lot quicker than the reel-out.

However, there is a fallacy in that. School-level theoretical mechanics teaches you to assume that the tension on one end of a "string" must be equal to the tension on the other end. But this breaks down with a very long cable and sudden dynamics. Even if they retain the tension uniform at ground, nevertheless the tension up top is going to experience sudden ups and downs as that kite switches modes. My reckoning is that the area of maximal breakages is liable to be at the top where the cables meet the kite and those repeated stress-changes are imposed, combined with the changes of bending.

If the winches are at constant tension, then no net energy can be generated. Consider my hypothetical 1MW kite. Its two tethers have to spool out at a speed of 5m/s to generate 2 x 100kN x 5 = 1000kW. Say the traction phase lasts 40s, so the winches have spooled out 5 x 40 = 200m, and the energy generated is 40000 kJ. The winches now have to spool in by 200m during the recovery phase, and the energy lost in doing this = force x 200m. If the force is still 2 x 100kN, then the energy lost = 40000 kJ = energy gained in the traction phase. (Even assuming the winch motor/generator is 100% efficient!) I agree that reel-in should be quicker than reel-out, to minimise the time when no power is being generated, but that doesn't alter the fact that overall cycle efficiency is directly proportional to traction force minus recovery force.

The time lag for a 2km catenary to settle into a new configuration after a tension change is indeed another problem, but not I think insoluble, given a sufficiently sophisticated control system. Perhaps Kitegen could adapt the mooring control system of a deepwater catenary-anchored semi-submersible.

Whilst I can't hand out free copies of JIP reports, http://www.dish-jip.com/pubdocs/DISHprp002a.PDF indicates some of the issues to be addressed when using polymer ropes in a dynamic application. And Kitegen's application is as dynamic as they come...

To put your point more simply, if the force x distance (=energy) of reeling-in is equal to the force x distance of reeling-out, then the result is the energy on the in cancels out the energy on the out. (Such is the idiotic blunder of one trying to keep up with too many things while with too much mercury in the brain (and teeth).)

So if the thing is to be a useful generator, it does has to have regularly changing tensions tending to fatigue those cables.

Delete duplicate

"not having to go back to Middle Ages"

Don't go knockin' the Middle Ages, now. We could do worse. You might say we are doing much, much worse, by the earth, at least.

The main thing humanity needs is not a new energy source, renewable or not. The first thing we need is a vision of ourselves living within the limits of the earth. Until we get that collectively, handing us a new source of power is like handing a six year old a live chain saw--dangerous for himself and for everyone and everything around him.

I find it extremely unlikely that all of humanity would agree on any vision. I find it far more likely that regions and countries with a higher degree of environmental awareness and sustainable industry in the medium and long run will fare better economically and those withouth it will have more physical and environmental disasters. Some disasters will be global but there will still be a difference between the regions. For me is the reasonable goal to make the long-term planning regions better in their investments and environmental work, larger and more influential and also able to produce more sustainable goods such as biomas based chemical products or advanced nuclear power. This wont save the world as it is but it saves more of the ecosystems, people and culture then not doing anything. I welcome new energy sources, energy is a very important tool and it is of course possible to do both good and bad with a tool.

"I find it far more likely that regions and countries with a higher degree of environmental awareness and sustainable industry in the medium and long run will fare better economically and those withouth it will have more physical and environmental disasters."

Which regions or countries do you see has having more environmental awareness? I hope you're not going to mention the US the OECD "developed" countries that vastly disproportional amounts of the world's resources and export much of their environmental destruction.

And keep in mind that environmental destruction is now happening on a global scale and will not spare those who contributed least to the problem, particularly the economically poorest.

On the tool issue, do you think the person who develops a powerful tool has no responsibility for how it is used? If a scientist was working for Attila that Hun, should s/he not consider what uses powerful tools s/he develops will likely be put to?

Humans have already brought about the sixth great extinction by their energy-enhanced activity. Are we likely to spend any new energy made available to us on saving what's left? Or will we more likely use it to continue to play power games, provide ourselves with ecologically damaging luxuries, travel that introduces exotics that wipe out native species, developments that flatten ecosystems........

I would agree that a tool is not a good or bad thing. That's why I brought up the live chainsaw--useful in the hands of a skilled adult; almost certainly disastrous in the hands of a young child.

It is, I would suggest, in this case hypothetical case, at least partly the responsibility of the person providing the tool to consider the maturity level of the one s/he is handing it to. And if it is true in this hypothetical case, I would say it is also true in the world today that those working on providing humans with vast new powers have some responsibility to judge how that power is likely to be used, given humans' track record visa vi the rest of the living world.

I find Sweden and several of our neighbours to be among the more environmentaly aware of the industrialized countries with a large part of the industries run in a sustainable manner. Its far from perfect but we are better off then manny overexploited regions where few seems to have cared about the future.

I do know that manny of the problems are global and will hurt everybody, bad for us but we have more options for muddling thru bad times since we have not laid waste to most of the local resources.

Environmental destruction and wastefull use of resouces is deeply unfair, especially to the poorest people who get no benefit and are robbed of their future.

Not solving problems is also a decision with consequences. I find it likely that not developing efficiency and new energy sources will lead to short term desperation that is even more destructive then todays buisness as usual. I am enough of an optimist to find it likely that new technologies can be used wisely. And a new extremey efficint electricity source has to be used in a very dreadfull way to come near the destructiveness of the coal industry wich it would replace.

Good points all. I would just once again remind you that the largest tragedy facing the earth--the loss of most of its complex life forms--has been the result of much more than coal, horrific as that dirty source is.

The WWF a few years ago put out a chart of highest standards of living graphed against lowest footprint. As I recall the Scandinavian countries did quite well, as did many Latin American countries. But Cuba was the only one that past minimal standards for both sustainability and standards of human well being.

Not solving problems is also a decision with consequences. I find it likely that not developing efficiency and new energy sources will lead to short term desperation that is even more destructive then todays buisness as usual.

I went to what may become a new farm today. The tractor is churning the clay - it's been raining here in Maine for most of the past month. The goats are pooping galinsoga. This on some prime river bottom right at the city limits of Portland, Maine. The new farmers are promising a CSA and to help train a lot of kids and the town council wants that to happen. Good people, good intentions.

That new farm will become a desert, hardpan clay and galinsoga. And this is not short term desperation. Yet.

Dohboi's comment about average wind speed (power?) dropping by 10% over recent history set me back. Maybe we are doing that now by burning fossil energy. But if we converted our fossil energy to wind, we would suck at least that much out of the wind. Probably much, much, much more because of the transformity issues.

We keep focusing on how-do-we-get-more out of Gaia. While Gaia is bleed white.

cfm in Gray, ME

Dohboi's comment about average wind speed (power?) dropping by 10% over recent history set me back. Maybe we are doing that now by burning fossil energy. But if we converted our fossil energy to wind, we would suck at least that much out of the wind. Probably much, much, much more because of the transformity issues.

No, I don't think tapping it would be likely to have a detectable effect, while global warming from fossil fuels certainly will affect the wind speed.

But count me as onboard philosophically with dohboi. I like giant kites, but the fact remains that what the planet actually needs is less human screwing around, and the sooner the better.

Still, to the extent it might be coal or kites, I'll take kites. Without something large crashing from time to time there would be less flavor to life. Indeed, having things randomly fall out of the sky onto people might be perceived as sufficiently unpredictable to be an acceptable way of thinning the herd. I'd be fine with living under one if it meant less CO2 released.

just saying...

Dear davebygolly,
we are at third generation of scaled demo now is arrived the moment to build the industrial scale machine, currently we are dealing with the site authorisations for this reason we have some spare time to try to inform you about this development, I still hope it will be appreciated.

Could be helpful to ideally include the kitegen among the other technologies to be tested and evaluated, we do not ask much more.
Please read some references before put down so quicky.

Massimo Ippolito

Where is the calculation to represent the drop in air density at kite height? I would think that all of the EROEI's are wrong.


How wind power is calculated?
Wind power is measured in W/m² (Watt per square meter) of swept area and is equal to ½ ρ v³ (where ρ is air density in kg/m³ and v is wind speed in m/s).

How wind power changes with altitude?
Leaving the ground, as altitude increases, wind speed on average increases (and wind power grows with the cube of wind speed) and air density decreases (but wind power decreases linearly with air density, and at 1 000 m air density is reduced by approx. 10% only). Wind power therefore always tends to grow from ground to approx. 10 000 m of altitude, see Wind data page.

thanks..should have read this before commenting.

Good point.
The force on the surface of the kite is related to not only the velocity but the mass of air that is traveling at that velocity.
Air density decreases with altitude.

Ah yes!!!!....THE favorite word in all of the Oil Drum kingdom....EROEI!!!!....I really wonder about the EROEI of a good night of sleep or an afternoon of making love...or just a good bowel movement??!!!?

Because this is a place for discussion about energy sources, the Term is completely applicable.

I don't hear advocates of 'Net Energy' or EROEI trying to apply it to such unrelated aspects of life, while they DO commonly describe the great and sometimes immeasurable benefits of Nutrition, Sleep, Love, and other quality of life issues, etc.. EROEI is purely about the measurable aspects of Energy Production.

There's a difference between Skepticism and Obstinacy, and I think you're crossing the line, there.

And all of you miscalculate that formula CONSTANTLY...by what you leave out of the EROEI of oil for example...Do any of you EVER add in the huge amount of waste from dry holes...and the cost of exploration...Bah!!!
Nope, you just think oil is in the ground and we just pump it out...By Jove...It's free!!!!! Right????????

Oh really, and now you ASSIGN these characteristics to ME???....And what is that LINE of which you speak?...Perhaps the one now creasing your forehead?

Of course drilling dry holes would be part of Oil or Gas EROEI, as is the Herculean military effort we have invested in protecting oil producing Neighborhoods .. They are all fair game, as far as I'm concerned.

You don't seem to know what the EROEI calc's include. Some (not me) will insist that they must include everything within eyesight of an energy process, the paving of the roads, the Lunchmeat for the guy who paved those roads, the farmer who raised the lunchmeat, etc.. at some point, you have to decide that the pro-rated fractions are hardly worth detailing, and you just toss in a contingency number.. but no, you don't ignore clearly relevant processes.

The 'Line' would be where you tried to include the unappreciated valuations of Lovemaking and Bowel Movements into some version of the subject. Unless you show how they are part of deriving energy, they are, of course irrelevant, and you'd have been 'obstinate' (or possibly just seriously misinformed), but not 'Skeptical'.

You know, Robin Williams once famously quipped about the human body...."Why did God place an amusement park right next to a sewage treatment plant???!??"

The point I was making that the majority of folks here seem to think of the EROEI of oil is unassailable...It is NOT!!!...Undercounting of EROEI of oil is HUGE!!!..(i.e. exploration costs)...And then when we look at the EROEI of any substitutes, the EROEI calculations of so many at the Oil Drum BEND OVER BACKWARD to account for EVERYTHING! This makes the GAP between conventional oil and any substitute (i.e. algae and methane hydrates) appear impossible to bridge. Thus what I call the Oil Drum distortion machine!!! If ALL fabrication, transportation, human labors, exploration failures and on and on were considered...the EROEI of oil would be far worse than commonly supposed...It's called distortion...and the Oil Drum revels in this misconception as a POLITICAL philosophy...It is dishonest and a bit fradulent.

You're using scattershot. You need to show an example where on TOD this has been foisted this way.

The articles on EROEI have never shown that they champion undercounting the costs of Oil production. The inclination would be the opposite, to show how UNeconomical it has become to produce oil compared to the alternatives.

I have to say though, with the number of exclamation marks you are placing in your writing today, that it's hard to imagine you're interested in nailing this point to actual references. But please prove me wrong. Enough spitting and fussing already.. do some homework and make a case.

The numbers R.Rapier used somewhat recently were that oil production went from roughly 100:1 in the Mid-20th century down to something in the range of 8-10:1 today. What would you say?

Dishonest and Fraudulent? Back it up, please. Or just say what you have found Oil's EROEI to be, if you have put in numbers that you think are more complete. I would really like to know how different types of project fit in, to tell the truth. and Then, I'd also love to see some EROEI calcs on the simplest, cheapest recycled Solar Hot Water systems as well, which I have to think could have just outrageous Returns, especially if they get some discounting for the amount that the core materials (Glass and Copper most likely) were used in their 'first lives'..

Ok....Look at ANY discussion of algae on this site...Again and again the topic of EROEI comes up...and many of the commentators claim algae is lacking...To this I say, we don't have to explore the bowels of the Earth to FIND it...as we have with petroleum for a century and a half...Surely all the dry holes and wasted effort highly impact the EROEI...As well as the fabricated machines necessary to drill, lift, transport and refine it?...But no, algae will never work....So what EROEI is the gold standard?....Petroleum!!!....And yet it's EROEI is waaaayyyyy impacted by the unending wild goose chases to find it...And we agree on one thing...The diminishing returns of looking but not finding IS reducing its EROEI even more than is commonly acknowledged...

Also another example, hybrid cars...Why the manufacture of such items uses more energy than will ever be saved....or so it is said...The same argument have been advanced about wind turbines and the manufacture of PV...it has been said that EROEI won't work for ANY of these...

Trouble is the way the EROEI accounting is currently manipulated it is just the sleight of hand of statistics...To quote Mark Twain......."...Lies, damned lies and statistics"

As soon as any substitute is advanced as even a PARTIAL solution to the inevitable depletion of oil, it is pooh poohed...because, well only oil can do the job and we've burned it all up so the only thing left to do is all go live as the Amish do...It's the EROEI and well, you know ONLY oil ever satisfied EROEI...Bah and hogwash!!!!

And no, I'm NOT a librarian...These articles are CLEARLY posted in their entirety on the Oil Drum...Do your OWN research...


Give it up. I tried over a year ago (at least) to have the same discussion and was dissed immediately. The one thing that no one in the oil trade wants to talk about is the over century of embedded human labor, thought and development, not to mention the embedded materials already invested in the oil and gas industry. In other words, oil and gas gets a century plus head start in EROEI that is "discharged, debt free" by the "oil is god" crowd. Imagine if the alternatives got the first century free, an EROEI "get out of jail free" card as it were! That would sort of have an effect on the EROEI bean counters calculations, don't ya' think?


Wow, I don't know what site you folks have been reading. But most of the discussion I've seen on EROEI around here is how close to 1:1 it is getting for oil.

Of course people apply this measure to other proposed alternatives. Do you think this site should just be a cheer-leading section for every new technology that comes up? If not, on what basis do you think it is reasonable to critique energy proposals rather than how much net energy they provide?

Oil didn't get a Head Start as much as it use to come just flying out of the ground with a relatively shallow hole. The huge energy density of this material that was just handed to us had a comparably incredible return on the modest investment of energy that it took to retrieve. The rest of the materials that were built WITH that wasting resource are not a Head Start, they are entirely the beneficiaries OF that high excess of energy that Oil made available.

I don't say this to say 'hurray for Oil!', as Aviator seems to suggest, but to say that we will have to be working a good bit harder with our alternatives, because we DID get a free lunch with Oil, but it doesn't look like we'll get one with any of the alternates. Many will work, and I am pushing Solar Heat and PV because I see them as some of the most helpful and simple technologies we've come up with, but we'll also have to live with less energy, probably a lot less. I think not getting spoiled by such cheap overabundant power can be good for us in many ways. But it will also force our population to contract, which will maybe be seen in devastating episodes. I hope I can avoid them.

But there were large, mirrored Solar Boilers a century ago, there were electric cars and trains, hot water SunHeaters .. and then someone opened up the Free C&C Candy Store, and that stuff suddenly looked like Tofu next to Toblerone. It just didn't have the Pizzazz of a loud, strong ICE motor. That's not 'Head Start'.. it's energy density, arriving almost for free.

So the oil just gushed out of shallow holes...okay...and one assumes then that it transported itself? That it refined itself? That the finished products transported themselves to markets around the world? That the conversion devices (piston and turbine engines and furnaces) designed and built themselves?

We have been through this over and over again: I often ask people, if you accept that the only way the alternatives can be accepted is if they use their own energy to create the industry (i.e., only wind can be used to create more wind, only solar to create more solar, etc.) then how was the first oil transported? Are we to assume that oil was used to build the first oil burning engine? That no other form of energy was used in the earliest days of oil to transport, refine, and distribute the oil?

I don't say this as a way of being insulting, but the concept that the first oil somehow as EROEI self sufficient is idiotic on the face of it. Huge amounts of human and animal labor was used, huge amounts of coal in steam engines was burned to move the oil about, in the earliest days even wood was used to move oil in the earliest steam engines.

In a post I did here on TOD over a year and a half ago I linked to one of those historically magnificant photographs that was so ironic it was beautiful: It showed the last sailing oil transport ship used just before it was scuttled. There had been many of them at the birth of the petroleum industry. Think about that, wind used to transport oil, and this over a century ago! One wonders what the EROEI calculators would do with that today...what about the human labor of the timbermen and lumber yard and shipyard workers that went into the building of the sailing ship...and the textile workers who made the massive sails...ohh, and the textile mill driven by waterwheels in New England used to make the canvas to make the sails...and the labor of the dock workers who loaded and unloaded the barrels (wooden barrels, from which we still get the name "barrel" of oil...their labor would be in their, along with the farmers and the horse drawn and then later steam drawn farm machinery to feed them...and we have not even gotten to the iron and steel in the first refineries, produced in those giant coking plants...the coal consumed in one of those plants...are any of the EROEI calculators doing the calcs on all this as I go along, keeping track of what this "free" oil was consuming to ever come into existance as a useable product? And these imputs from other industries went on for DECADES.

Oil does indeed have a positive EROEI, but not nearly to the point of being "almost free". The EROEI of oil has indeed declined from the earliest days, but not nearly to the extent that some would lead us to believe. Only by completely discounting all the original externalities can one come to the conclusion that oil was "almost free". The amount of material, labor and perhaps most important of all, intellectual labor that went into birthing and expanding the original oil industry is staggering. The original giants of the industry would laugh at us for being daunted by the amount of material and labor needed to build a large concentrating mirror station or windfarm, which would seem to them to be a venture of STAGGERING potential return for the energy invested.

Real EROEI calculations are extremely valuable. I have said that the understanding of the EROEI issue is one of the things that has been most educational to me here on TOD. I had been familiar with it in my younger years, but had not given it proper credit as a useful tool in calculating one alternative against the other (where it is most useful) But I am not referring to this EROEI myth of a great utopian time of "almost" free oil. That "almost" becomes a crucial factor once one begins to try to calculate in the externalities of the birth of the oil industry.

So I have wasted the better part of a page repeating what should be obvious to anyone who has ever bothered to do even a brief study of the birth of the oil industry, to make again an argument that should have long been over. Oh well, once more around the track, I didn't have much else to do. And a few days from now, this post will be buried, and the newcomers here will get the same old creation myth, the myth of "almost free" oil against which no alternative can possibly compete. (sigh) :-(

Some fascinating old woodcut type photos, click on them to expand:


The oil export trade to the orient:

In the latter part of the 19th century, Americans exported kerosene, also called case oil or illuminating oil, to China, Japan, and India. Kerosene was first refined about 1850 from asphalt and shale extracts. After 1859 oil wells in Pennsylvania became the primary source.
Caption to beautiful sailing ship photo reads:
"The Bangalore is shown above loading 65,000 cases of oil for Calcutta. In the early twentieth century she was commanded by Captain Phineas Banning Blanchard of Searsport. The Belle of Bath, at right, was owned in Searsport and was destroyed by fire in 1897 while bound from New York to Hong Kong loaded with case oil."

Wonderful painting of another ship in the "case oil" trade, the Belle of Bath:
(Case oil was in a 5 gallon can, two cans to a wooden case, usually kerosene used in lamps. In the example given above for the Bangalore, this would be 650,000 gallons!)

Lastly, a link to a great set of photos from the early California oil industry, not the number of men, horses and steam engines:


ALL of that Human thought and energy, all the sailing vessels, the cloth.. to build a boat with a great crew to carry 65,000 cases of oil across the sea.. and yet once the Oil regime took over, what built the supertanker the fleet of them, each run by a crew of what, 10, 20? to carry an impossibly larger volume of oil over the sea? It was built from and driven with the massive excess power in this energy-dense fluid. What makes you think I am celebrating this back-handed gift of 'Unlimited Power' when I say that? I'm saying we've gotten drunk on the stuff, and have to clean up.

For the number of 'slaves at the lash', this energy has been incredibly cheap. (Not 'Free', but there is so much 'profit' in that energy, that it came with a lot of freebies) Look, I don't point that out to dismiss the renewables, but I DO say that the ability to command so many hundreds of obedient pawns when you get your first GTO at 17 is a very powerful drug to fight against when trying to tell people that Solar and Wind etc can and should be added in with all haste before that Pontiac finally sputters out..

You point to the birth of the industry, which OF COURSE is going to be running on the labor-intense tools of the preceeding era. Look at what was doing the same work 4 decades down the line. OIL, not muscle, not sails. It was the energy available FROM OIL that turned it into the behemoth that it is, and left us accustomed to a lifestyle which we will soon discover cannot be continued as is.

Well, peace, Roger. I suspect that whatever the point we're talking past each other on is less important than the fact that we both see oil as yesterday, and renewables as one of our best hopes going forward.

Maybe we'll see where that schizm lies another day..


" I suspect that whatever the point we're talking past each other on is less important than the fact that we both see oil as yesterday, and renewables as one of our best hopes going forward."

AMEN. We are just arguing details, I think we are both on the same side in this fight. I am just thinking that if we actually build a few of these alternatives (hopefully, we carefully choose the best of the best) we are going to be pleasantly surprised by the returns!


Roger that and Out.

the problem is less one of EROI of what replaces oil and more one of the time lag of changing non liquid fuel intensive infrastructure. Net energy for society is highly relevant - we only have so much of societies harnessed energy to invest while keeping the natives from getting too restless. There are lots of problems with EROI analysis but at the very least it has people discussing things in energy (as opposed to dollar) terms (even though many still conflate many aspects of the concept)

I have been through the TOD "meat grinder" (as I call it) and it has been generally accepted that all components of efficient Non-Oil Transportation; electrified rail (Urban & inter-city), bicycles and walkable neighborhoods "work" under a variety of scenarios. The next issue is making the investment.

The brutal truth is that MOST "solutions" will not work. Sorry if you have trouble accepting that. Reality sucks sometimes.

We CAN reorganize our society (USA) around efficient Non-Oil Transportation largely powered by renewable & nuclear energy (wind, geothermal in the Western USA, solar in lower latitudes/clear skies, small biomass, pumped storage, HV DC, and nukes).

Best Hopes for Workable Changes to BAU,


Or Sandia's "Sunshine to Petrol" project http://www.sandia.gov/news/resources/releases/2007/sunshine.html proposes to convert 2 CO2 into 2 CO + O2 using only solar energy. From there they propose using the CO to produce either liquid fuels (methanol etc) or H2 ? Proposing initially to capture the CO2 from fossil fuel electrical generation, later directly from the atmosphere. Last news Dec 2007.

Hello Ugo,

Thxs for this keypost. After my viewing of the included video: these kites could be quite the dopamine thrill-ride, too.

I could easily see a person [or more?] paying to be strapped to the kite at launch-time, then swooping around while high aloft and sight-seeing for a few hours [or until you start running out of oxygen at the high altitude]. Then when you have had enough:

1. You can be reeled back in [during the periodic slack kite refresh-gencycle].
2. Just jettison yourself, freefall for awhile, then parachute back down.
3. Or maybe ride the cable backdown on some kind of free-wheeling pulley wheel with a built-in brake to safely slow your final approach to the ground base-station stem.

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

The only thing I see is the 'prefect and universal lightening rod' - Ben Franklin could not have done it better. A few of these hovering above London / Paris / NYC and the firebrigades could start to sack workers.(/snark)

I did not understand how they were supposed to make these 'stretching random wave-patterns' turn into rotational movements- and in particular EFFICIENT rotational movements.
In watching the video I could only envision "a maximum stretch amplitude"-situation .... sort of, well what do I now? I was eager to see what happende inside that fancy glass house - but that was Prohibited-Area, only thing i noticed was that the MegaWatt-metering display was all Up n' Go . :-)

No way Jose - I'll put this in the same basket as I earlier put the Space-Solar-fantacy
My 2 cents.

Well, uh, the prototipe, the smallish ksu1, ( about 50 KW top power) works quite good.
Of course it is NOT so easy, otherwise it would have been done before.
For thi new first prodution prototype we'l have to wait until September, more or less, to see if it works.

Alright Pietro, you have a prototype : good.

Q1- Now ,did you have a thunderstorm during trials ? You understand that this construction will "ground" a large spherical volume of airspace , no ?

Q2- The ideal flying-pattern for Kite-gen is a perfect 8-shape and laminar wind - that is "perfect" 180 degrees clock/countercclockwise days, weeks and months on end ... Do You believe in this yourself ? What if a 360 with twist and snag happend ? or a 720 maybe ?

Q3- What kind of generator / mechanical device does this Kite-Gen use ? It has to be "some sort of" spring-loaded piston working on the wobbeling-jerks fron the kite (I guess) - but I suffer with efficiency here. Will you enlighten us?

When these many Q's are answered convingsingly - I will maybe start to pay heed - but probably not since there are to many 'issues' with this I still suffer with.
B/C laboratory/smallscale "proofs" are one thing - the BIG reality always beg you for more..

You want to try reading his answer to you before you stick your finger in his eye?

He'll get to launch some practical tests in September. You gunning for a job, by assuming that they will somehow forget that they might have imperfect or stormy weather to contend with?

Really! There's nothing wrong with challenging, but you're just being rude about it.

Well jokul not so sensible please,but if you substitute rude with frank I concur.
I browsed the article and watched the video - but didn't see any og my 3 Q's adressed.
I see my Q's as pivotal to such a concept - live or let die so to speak - so I did a inquiry for answers - and I phrased them my way. Rude (?) that's in the eye of the beholder.

If they are not able to adress the "thunderstorm" issue as a theoretical problem at this stage - well then I doom the project right here and now, you see thunderstorms occur all over the planet - every so often and sometimes suddenly .


Q1) the ropes are in polymeric material without a galvanic continuity, the lightings will not find a preferred path through the 1 miles ropes, we adopted this different approach respect the other troposphere generator projects that plan to put the generators directly on the wings and transfer the electrical energy to the ground through the cable.

Q2) the control is able and free to twist and untwist the ropes and to fly the kite against the wind around the arm in a zenital position to reset the neutral position/rotation.

Q3) the ropes unwind a drum and some fast winches, and are linked to alternators with optimal efficiency, the cable friction loss was an issue that we meet in the early experiments, so we did the math, redesigned the interface and now is a negligible phenomena.

Thanks for responding here, it truly is great to have principal investigators (or managers or ???) respond.

I would still be suspicious of your answer to Q1. Can the line still form a preferred path to ground? Even if dry, charges might build upon it and create some locally higher voltage fields, leading to breakdown on or near the line?
Then if it is raining the line might be wet, and that might create a preferred path for lightening. You might almost be better off with a highly conductive line. Lastly, you'll have to avoid conditions where either the kite -or its line could ice up. All of these might be overcome by conservative choice of flying weather. But that would decrease the capacity factor. And I suspect launch and recovery might not be the easiest thing in the world.

thanks for reply Massimo -
As for my Q2 and Q3 I rest my case for now, as in 'I believe you'.

But Q1 (lightening) hangs still in the balance , even if you use cords without galvanic continuity it will (most of the time) have ground-charge as a reference. Anyway the charge is "always" different from whatever charge builds high up in the air - so the setup for a discharge is permanent, IMO. (Well, If not the cord is made from a substance that can NOT hold a charge of course - a total insulator)
This tree is no more galvanic than your cord - but you see what lightning did to it. It's about this 'highest point / enough difference in charge' that ignites the lighhtening ...
Thunderstorms always look for an opportunity to discharge - and KiteGen looks like a good starting point to do so (IMHO)

*** EDIT
Enemy helps me here , thx : Then if it is raining the line might be wet Yes, what then Massimo ?

To Jokul : Ok Jokul.

This sounds more than plausible.
I guess a grounding wire could be incorporated into the design.
Maybe the electric potential difference could be harnessed.
I have to agree with the other commenter in that this was thought out early on.

Enemy helps me here , thx : Then if it is raining the line might be wet

That was what I meant. But even if it isn't raining, but the line is in a cloud, it might also get wet.

Hopefully, they have done some experiments with high voltages, and know what they may be up against. I misspent my youth playing with high voltage electricity -but never incorporated any of that into a career. It is amazing how the stuff likes to flow along the surface of insulators. Ever look at a high voltage insulator. They have this very elaborate topography. Among other things the shape is designed to greatly increase the length of the shortest possible surface path, so as to make it much tougher for current leakage (or worse formation of an ionized channel (spark)). I suspect the breakdown electric field (volts per meter) is several times lower on the surface, than it is in free air, or within the solid insulator. It is probably going to come down to how conservative they need to be wrt flying weather. Obviously the economic incentives will cause them to want to push the envelope.

first of all, I cannot exclude that a lightning could hit the tether, our analysis is on a probabilistic level.
One of my previous work was focused on EHV and insulators for the national grid company, I've designed machines suitable to operate on the potential gap of 500kV gaining some experience on the topic.
I can say you that a mile long rope, even if it is wet, will not provide a preferred ignition path to lightning.
in case of pollution like acid rain I definitively agree with you, but typically the distilled water (rainwater) is a perfect insulator.
In this case the most important parameter is the length of the object between the ground and the ionized layer.

In anyway we can accept the caution, then if I try to summarize the hours in a year with lightning risk, we can program to retract the kite reducing the availability of what? 50-80 hours?

maybe somebody remember the Japanese experiment to catch the energy of lightings with ionizing lasers? It is not an easy job to impose or suggest a path to a bolt

It is good to see that you are able to respond to our attempts to shoot down your concept. Clearly you have thought through a lot of the issues.

How easy is it to launch/retrieve the kites? In many cases, say just after a storm I can imagine having decent wind aloft, but perhaps not enough low level wind to get the kite up. Do you have a way to get the kite up beyond a sluggish boundary layer, or do you have to wait for better conditions.

If you have all these potential problems solved, then I suppose the issue becomes intermittency. Essentially you need customers who will accept cheap and green -but unreliable power.

Enemy, I agree very much to this sentiment - Massimo is on top of the situation ... bravo ! And the best of luck on this effort to him and KiteGen.

As you point out the next step - a larger scale prototype due in September -will give more answers and posibilities for more focused Q's on various topics mentioned in this list.

Essentially you need customers who will accept cheap and green -but unreliable power

I think Mr Future knows that this reality of 'more unreliable power' will force it's way through ..... there is no way around it IMO.

... unreliable power or NO power , the pick is easy.

But let it be clear - I still have my doubts on KiteGen - and TODer Joules (July 6, 2009 - 9:05pm) take near the bottom of the threads illustrates my overall 'gut feeling' quite well.

And of course, we'll find out sooner or later how Oil will be unreliable, but basically only ONCE, while wind and the others get to be unreliable over and over again.

As you said. Easy Choice.

(and I DO appreciate your insisting on answers to pressing questions. Thanks. Just to remember as Joker said in the Original Batman Movie, 'Be careful, each of these boys has a mother!' http://www.youtube.com/watch?v=HoUpF7rvfnk right movie, wrong clip, but makes the point.. )

Hi jokul , thx. There is often a thin line between being frank or rude, and I'm aware that I sometimes can come near that line - in particular regarding matters that matter much to me. So, I understood what you were aiming at ....

New and promising concepts like, in this case KiteGen, need a serious "spanking" here on TOD and other informal fora - because if they can't pass the litmus test here .... they can't do it anywere e.g get investors to put money on their idea/product. I could have continnued my "spanking" here (like ask about snow and frozen rain for instance) , but as both yourself and Joule down the thread hints - let them make their "next level" KiteGen and save some ink till then. But wish them all the best, cuz' if successfull it will 'kick positively back on us all..'

Obviously KiteGen is in very early stages - but they seem to have been through some 'trial and errors' already - and rectified the weaknesses accordingly. Also the concept has a skilled man like Massimo on their side- promissing.

It's rude when your questions are so obvious that you treat them like fools.

It seems clear they've done enough practical work to show they are not idiots. (UNLIKE what we were shown and NOT shown around the Satellite Power post a few weeks back.)

Lightning? It's like the Solar Skeptics having to 'remind' us about nighttime. Come on.

Hear hear, the idea that the engineers would not have considered such an ridiculously obvious problem is simply insulting. People still bring up the fact that things rust in marine energy discussions! I mean seriously!

It's like before getting into a car for a driving lesson the instructor gives you a half hour lecture on how you have to face the same direction the car is moving for safety.

"on the order of 1000m"

few people have any Oxygen issues below 4000m.

Well, this one of kites having passengers, I think not even Massimo Ippolito had imagined!

During WWI, humans were put up on kites for observation of enemy lines.
Not a job for me---

I just discovered that people DID fly on kites much before WWI, and even much before planes. Read this reference; it is amazing. This George Pocock had flown his son and his daugther on (rather, under) a kite, and invented a kite powered cart named, correctly, "charvolant"!


In VERY isolated & unpopulated regions (far from electrical demand & transmission) this MIGHT be viable. But too many years to develop & debug to be of help "in time".

Today, residences must be far enough away from wind turbines are a falling WT not to hit homes, etc. Apply that same safety standard to kite gen and there are very few areas in West Texas without an isolated ranch house.

Sea based, perhaps, but this restricts fishing and commerce. Again as issue.


I was wondering if a dispersed, remote placement might not work like my preferred CSP scheme in deserts and remote stretches, where they could be strung out along an HVDC line with a corresponding Elec-Rail line, so that they have a respectable distance between Kites, as well as access and grid links in a system that doubles/triples as the Grid ROW, and a Transportation link.

Such a string of generators could include various types of wind, CSP and PV Solar, and this KiteWind idea, if it proves workable.

Railroads had an annoying habit of promoting small towns and villages along their ROW. (Not an issue in areas w/o water).

I could see some, but not that many, kite gens along RR ROWs.

Less than the just announced 20 GW (by 2020, 40 GW later) Chinese wind farm.



That's my reaction too. Kind of an interesting idea, I guess. I suppose parts of Montana or Canada might be sufficiently sparsely populated that one could make it work, but I would expect that you would need an onsite person there to maintain the thing, and paying people to live in isolated areas is always a little tough (not impossible - lighthouse keepers were isolated too).

(far from electrical demand & transmission)

I would imagine that part of the installation of a kite-generator would be the burial (or re-location) of any above ground electric transmission lines in the kite's range...

Bit of a red herring, that one.

There's quite a bit of difference between a conventional wind turbine tower/blades/etc. and a kite. Mass, aerodynamics, energy - they are quite different. Proper comparison would be between one of these kites and an aircraft, and we have those flying overhead all the time. Given the low impact of a worst case scenario (breaking lose and travelling with the wind) I'd guess that it would be quite possible to get lawmakers to OK such kites over farmland, etc. The risk profile is lower than aircraft after all.

No, the main issue will be making the kites transparent. If you can't see it against the sky then the main problem of Nimbys goes away. A good match for aircraft traffic declining as it gets too expensive to fly.

I think that there really is no need to worry about falling kites.
If it actually is a problem than design kites with barometrically deployed parachutes to reduce the velocity at which they free fall.
This is not a hard problem to solve if it is a problem at all.

I think that there really is no need to worry about falling kites.

Murphy's Law my friend ... always Murphy's Law

Otherwise known as entropy.
Big sky little plane theory on this topic.
If this concept indeed has legs than I think locating them in areas that have low density and also designing them to have low speed when they do break free and fall will be easy.
I just think that the scale required makes this a nonviable idea either way.
Having said all that I am not worried about getting hit on the head by a kite.

I think the main problem is the cable. There is a tremendous amount of energy stored in the cable. You don't want to be in its way when it snaps; it could cut you in half.

Good point. I see this now.

Hermann, I doubt it. Few people are going to be "in the way" (IF/ ) when a cable up in the air snaps. It would mostly snap right up top (where it flexes between modes) or at the bottom (on the windlass). Violinists regularly have their strings break, always while playing with face/fingers right by. I've never heard of it considered a danger except to the musical performance. Violin bellies aren't exactly noted for string-break damage. Ditto piano strings prior to the last 120 yrs. And operators could if necessary usually pre-emptively replace cables before snapping occurs anyway.

Nautical mooring lines part on occasion. This has been known to kill people.

One of the most important safety rules is "don't straddle the line". If you are standing next to the line it might hit you in the event of a break, if you straddle the line it will hit you and if you are lucky you will only lose a leg.

Imagine a quarter ton of rope moving at or past the speed of sound.

The Kitegen lines have more in common with nautical mooring lines (size, strength, forces) than they do with violin strings.

On a side note, guitarists being injured by string breaks is not uncommon. Such injuries are usually minor, but to assert that musical instrument string breaks are harmless just ain't true.

And operators could if necessary usually pre-emptively replace cables before snapping occurs anyway

exactly and the lines will never experience forces that overcome the design specifications, because it is a force feedback full controlled machine.
The winches reel out the lines in time, thank to some additional spring behavior, in order to clip accidental peak forces under tollerable level.

"I think that there really is no need to worry about falling kites."

Well, it is a very big issue in one way: We have seen the hysteria already generated here on this board around this one issue, and this is a crowd that can for the most part be expected to do the math.

Can you imagine the hysteria that would be whipped up among the general public against the kites if they are attempted to be implemented on any scale worth using? Do you actually believe the fossil fuel providers would not help fan the flames by funding a few "concerned citizens" groups anywhere the kites were proposed?

With the litigation environment the way it is today, a firm trying to install the kites anywhere within hundreds of miles of anyone would face lawsuits, local ordinances and legal challenges that would cost the firm millions, possibly more than the cost of the kite system itself. And after all, if a kite broke loose, it could sail for miles before coming to the ground...any good lawyer could create a legal environment wherein no where would be far enough from the kites to be "safe". With a few choice slides and some "expert testimony" shown on CNN and Larry King Live, an environment would be created wherein a housewife in Atlanta would be terrified out of her wits of kites in Montana!

This is one reason that for the most part I have abandoned wind as a viable business opportunity for anyone but the most powerful big players (such as Pickens or General Electric). I and some partners once worked up a set of concepts for low level slow turning windmills that would compress or liquify air as storage (I still have a semi-abandoned website that was part of the original program that I will soon be using for more lucrative and promising opportunities) but even though the technical concept showed no real weakness, the legal and political "activist" environment has gotten more and more hostile with each passing year.

I am now convinced (and market testing has shown this) that any alternative must be "transparent", that is to say all but invisible to the public. An example of this would be solar shingles that blend into the look of a house, or solar film that is integrated into the roofing of malls or big box stores and warehouses, or geo-thermal power production using the difference in tempeture between the surface and the depth below ground. The alternative energy systems will not be accepted by the opponents of any change if it can be seen at all.

Transparency is why hybrid cars have been relatively successful. electic only cars are just too "radical", too "different", even though for most uses they are probably as useful as a gas-electric hybrid.

The kite gen system, while seeming to be technically very good, is about as radical in appearance and design as most people have ever seen. It will not be an easy sell, if it can be sold at all, no matter how good (or bad) the "EROEI" is, and no one knows how good or bad it will be without building one of at least considerable size, which will be allowed to be built almost nowhere.


qaryp, the kites are so high up that you barely see them by naked eye. The visual impact is really minimal. No need to make them transparent.

Hello Ugo,

Has the inventor Ippolitto [sp?] done any research on these steerable kites being used to help move and/or spread I-NPK or O-NPK over vast farming areas underneath?

I am trying to imagine a design whereby the kite could have a motorized descending tail--for pulling a 'manure surfboard' a reasonable distance [a mile or more?] to a suitable area first--then the tail would unlock from the surfboard, and then the kite could then continue upward to its usual powergen-operational altitude.

It might be an easy way to help reduce/eliminate tractor fert-application with much less soil compaction due to less weight/sqfoot or sqmeter for you. Then have Ippolitto work on the kite with tail steering wheat or corn combines across the fields at harvest time. Recall that I proposed something along these design lines in earlier posting, but I am not enough of an engineer to bring them to fruition.

Totonella, I never heard Ippolito discussing about something like that. It might be done, perhaps, but I don't see it as very practical. In the stem configuration, the length of the ropes can be controlled, but it is difficult to control the direction - that depends on where the wind blows. So, kites are not a good means of transportation; except when coupled to ships (See Big Gav's post)

Assuming this arrangement could be made to work at a large scale it could be added to offshore wind turbines or places currently using 'low level' wind energy. These sites are already 'wired up' to the grid and the the kite would not interfere with the main rotor...


Thanks for this post Ugo - excellent work.

Thanks Ugo for sharing this update.

Are the high altitude wind folks looking at anchors in ocean? (ships or generator buoys)?

hello Nate,

thank you very much for the question.
pls. have a look at:


Right...why not test fly off Hawaii, and see if we can make Hawaii and make Hawaii self sufficient on electricity...what a showpiece for the world that would be!


well it could be VERY nice, as there is a tradition, on the big island for top knotch research project, aka in totally different fields ( i am thinkin about astronomy).
Probably there would be no big issues about deploying some of these stems, waiting for the carousel version ( that could arrive at HUNDREDS of MW.

Hawaii is good idea, but to make it work, there would have to be a very considerable grid upgrade (among other things).

At this point, there is geothermal on one end of the Big Island, but not good enough transmission to share it to the distant end of The Big Island. Sharing the electricity across islands would require even more transmission upgrades.

So are you going to ground all the airplane traffic. I don't see how this is at all compatible with aviation.

Aviation is already guided by maps of restricted areas, specified altitudes and routes, etc.

Turning your skepticism into saying 'Ground All Airplane Traffic' is an unhelpful snark that moves these discussions towards becoming sarcastic and adolescent.

I hope you're helping to keep this site from getting mired in that tone.

Bizarre assumption...Ever LOOK at an aviation chart???....Ever HEAR of restricted or prohibited areas?...Another kneejerk reaction from one who has NOTHING to contribute but nonetheless wishes to be heard....Bah!

...We ALREADY have anchored balloons soaring to heights WELL ABOVE 10000MSL in at least two locations in Florida..They lift look down radar to reveal illegal crossing of US borders (i.e. drug runners)...The sites are well depicted on aviation charts and are easily avoided.

See above? QED.

An interesting thought. In NC, we have a ridgeline protection law which would prevent WTs from being placed there. However, I could see the ground stations being placed below the ridgeline zone, with the kites then flying high above the ridgeline. This would circumvent the legal restrictions. It might also be a more visually acceptable approach than would be WTs on the ridgetops. I suspect that the kites would just barely be visible from a distance, and might often be shrouded by clouds; the cables would not be visible at all from a distance. This could be an ideal arrangement. The Southern Appalachians have very good wind potential, especially along the ridgelines; I would imagine that the winds 1000 m above them would be even stronger and more steady. Most of these mountains are in forested areas, so the downing of a kite would be of minimal hazard to people or property. The only potential downside I see is that there might be some turbulence as winds pass over the mountains; I don't know if that would be so severe as to preclude implementation here.

If the same system could also be used for broadcast and cell phone antennas, thus allowing the removal of radio and cell towers on the mountains, then this might very well be an attractive enough proposition to actually fly (both figuratively and literally).

No Birds were killed in the making of this discussion thread ;)

Thanks for the post, I can see some great potential here.

If the design was coupled with a flywheel to smooth out the power strokes then it comes with the benefit of a small amount of energy storage too.

I have a smallish "power kite" a 4 line kite used for pulling me around on a board or a buggy, and I can tell you its amazing how much power is available in only slight breezes. One limitation of such devices is going to be designing them to survive extreme weather. Either that or they will need to be reeled in when severe weather is detected.

Great post. I had been following Makani and the skywindpower site, but was unaware of the more recent research and of kitegen. In terms of production of electricity at today's scale, this technology has a shot.

The objections to high altitude windpower related to airspace, entanglement, weather and so forth appear manageable, well short of 'fatal flaws.' They are more likely to be unexpected drivers of cost, which could increase cost/drop EROEI.

I think that a technology that can generate large amounts of electricity with little overall water use deserves attention, more than it is getting today. What little I have been able to piece together from press accounts suggests Google has put $10-20 million into Makani. By comparison, First Solar needed $150 million and a guaranteed market via feed in tariffs in Germany simply to refine manufacturing processes of a proven technology and get to the point of commercial viability. We're well short of that on high altitude windpower.

On all of these new ideas, adequate investment dollars and an available market (at a high enough price) for electricity generated will be critical.

Neither of these are likely to be easy to obtain in our current world. In particular, if demand is falling because of recession or because of conservation, it will be hard to get utilities to commit to a relatively high price for new production, if utilities have declining demand and are still obliged to repay the debt on their existing facilities.

Neither of these are likely to be easy to obtain in our current world

What sort of world would they likely to be easy to obtain?

if utilities have declining demand and are still obliged to repay the debt on their existing facilities.

Natural gas power plants have quite low capital costs (1/5th coal from memory) and we have built little else (except wind recently) for the last 12-15 years in the USA,

Standard depreciation for power plants in the USA is 30 years, inflation has eroded the nominal value of most existing coal fired power plants (16 to 30 years) and many coal plants are fully depreciated, or will be before anything significant is done.

This is even more true of nuclear power plants. Among the very newest nukes are Palo Verde (3 nukes) which came on-line in 1986, 1986 & 1988, South Texas in 1988 and 1989 and Comanche Peak 1990 and 1993. Although no nukes are likely to be shut down because of renewables.

So just scrap coal fired plants when they are fully depreciated (30 years), build VERY few new ones and all be fine. Older plants are inefficient (more coal/carbon per MWh) and we are well rid of them.

So your concern is misplaced.


USA may never need new coal and nuclear power plants, says FERC head


I guess I'm not alone in reckoning that few if any new energy source ideas have even remotely as much promise as this one here (the "yoyo"s more than the "merry-go-round"). Subject to any death-blows emerging further down this page, rather than hanging around for the next prototype in September this should be given urgent priority war-scale research investment in multiple prototypes. With a look towards rapid scaleing up. It could even restore some justified faith to the credit market. The only downside would be that those d'm'd powers-that-be and their greedist system would have their downfall put off till a later crisis (probably food limits).

I suggest looking around for a national government that would see this as in its strategic interests (e.g. not KSA?)--and get them seriously on board supporting it.

Energy production is not static - it goes with the economy and if the economy is powered by a source of cheap and abundant energy it tends to grow exponentially. Exponential growth is treacherously misleading: we could find ourselves bumping into the ceiling of high altitude winds much sooner than we would expect.

I'm never entirely sure which scares me more, running out of a virtually limitless cheap energy source (oil), or finding another one.

As should be painfully obvious to almost everybody, our first shot at dealing in a responsible way with the the availability of a seemingly limitless cheap energy source hasn't necessarily been a smashing success. I'm not certain I see a whole lot of convincing evidence that we (humans) are mature enough to do better with another bite at the apple. I'd like to think we are, but virtually all current (and, for that matter, past) events seem to argue otherwise. Given abundant energy, all evidence supports the conclusion that humans would grow their consumption of other resources (or their emissions/pollution) beyond the breaking point.

In the end, this is why peak oil (or energy or water or pick your limited resource of choice) cannot be separated from the wider environmental/economic growth issues. Addressing the various limits and constraints tends, at best, only to shift the problem to the next limit in line. Addressing the growth issue potentially helps all the other problems. This is not to say that we should stop looking for clean abundant energy or trying to improve efficiency or any of the other things we try to do that make sense. It simply means that these things should all be done in the context of (and subordinate to) finding a solution to the larger overarching problem of redefining our existence in some way that does not assume that our species can have essentially infinite growth on a finite rock.


Brian -- Excellent comment on this point.

In particular, most of these 'magic bullet' solutions have in common a high build cost and low incremental cost of production. That cheap long-term energy only increases the temptation of future generations to exploit it (assuming it can be got at in the first place).

Energy for the sake of growth will simply put us in a similar predicament to where we are today. What is needed, IMHO, is a type of grand bargain for humanity: energy for subsistence as a basic right for all, in exchange for a limit on rights to have children.

Would enough of us take that deal? There is plenty of reason to be skeptical....

Brian, read my post, please. What you are saying is exactly the point I have been trying to make: solving just ONE problem is useless. Abundant energy can be a good thing, but it will make things worse if we don't manage it correctly

Brian--we have a less urgent problem, namely the continuation of the growthism dogma. And we have a more urgent problem, namely the immediate crunch of energy, which if not solved will make the first problem merely academic.

I cannot agree with your relative prioritization of the importance of dealing with the growth paradigm and finding new sources of energy. There is not a shred of evidence that anything short of a major society rending economic crisis will allow us to come to grips with the reality of limits to growth. In Bolivia where a large native population exists who view the capitalist system as having failed miserably to provide for their welfare and who have a cultural memory of a communitarian society, the amount of progress made toward a major revision of the social contract is still relatively small. The miserably inadquate response to the threat of global warming is another example of our inability to act with ecological intelligence.

I realize that hoping for a major episode of pain and suffering as means of acheiving long term health is a sad situation to be in. Unfortunately, sometimes no other option presents itself. It is as if you had friend with a high hereditary risk of heart disease who eats too much rich food and exercises too little, and who, at the same time, refuses to listen to any advice about changing his lifestyle. His best hope for a long and healthy life may be a non-fatal heart attack which is severe enough to get his attention and force him to change his way of living. Yes, it would be far better if he had the wisdom and foresight to act intelligently without such an inducement, but generally speaking wisdom is purchased at a high price.

None of which is to say that I am opposed to developing this or any other energy source. I am not really that worried about high altitude kites enabling decades more of BAU economic growth. I would guess that it would be two decades at a minimum before such an energy source could provide a significant fraction of the current global demand. Our most severe immediate problem is a liquid fuels crisis which electricity does not directly address. Even with free electricity, electricity to liquid fuels will not be a cheap option, and complete electrification of our transportation system has other large costs besides electricity at the generator output.

Roger, I agree with the notion that the sooner the collapse comes the less damage the system will have caused. But it would be good if more people have a few more years to prepare in light of the transition concept which has only recently developed. I myself in particular would like more time to escape my no-health-no-wealth vicious circle and be in position to start some preparations a la www.energyark.blogspot.com , along with others.

I agree this does not generate liquid fuels, but it would go a long way to filling some major gaps. And a lot faster than 20 years. These things could be scaled out very quickly given the will and the profiteering credibility for investors. Ugo made the key point that these things could rapidly provide the energy to make more of themselves, unlike so many other concepts. Exponential growth therefrom (for benefit for a change!).

"Wind Operations Worldwide SRL" not "World Operations Worldwide"
(SRL means Ltd)

A financial holding that reaches its "target by buying shares of Kite Gen Research S.r.l., thus allowing small investors to take part in this industrial project for the exploitation of high altitude wind to produce electrical energy.buys shares of KiteWind SRL"

from http://www.windoperationsworldwide.eu/en/

When I was a kid we used to fly kites-mostly the simple dimestore variety- nearly every Sunday afternoon from the yard at my paternal grandfathers house from late April til early
June .My Daddy's part time job at "the plastic plant"(forty hours three to elevenpm) did come with two incredible benefits for all the nieghborhood kids.We had hulahoops(no doubt illegal patent wise but the plant was one of the ones that manufactured the tubing,which was not originally used for hulahoops ) the first week they were seen on tv,and we had kite string-lovely bobbin style spools of three to five pound of nylon (?) thread thin enough to use as dental floss and strong enough to hold up probably fifty pounds.

We put the kites "out of sight" on many occasions --they were so far away and high up that only those with very good eyesight could after looking for a while spot a bright colored four foot long kite in strong sunshine and crystal clear skies. Once your kite was well up you could put the spool on a stick and she would WHISTLE as she unwound.Getting that kite back ,IF you got it back,took hours of winding the line up again.And when she was way up it took a considerable effort to just hold the string.Winding it up required gloves-even if you were a horny callused farmer.

Sometimes we just tied the string and some of them stayed up for at least two or three days but none was ever still flying the next Sunday.I guess we must have polluted the woods with a thousand miles or more of that string that somehow failed QC.

It was rare for a kite to fall due to a lack of wind but it did happen.Almost every one that was not retrieved -half of them I guess-fell due to broken sticks or ripped sails- they weren't strong enough to withstand the wind.

Somehow I think that power generating kites are a real world possibility.Much more likely to work in our life times than a lot of other schemes,and much cheaper to r&d.

Thanks, Oldfarmer, I see that you are a real expert on kites. Maybe you could give a hand to Massimo Ippolito with his kitegen!


He has my moral support but alas I have no money to invest in this or any other scheme.:-(

But if I did,I would be inline for a few grand.This could pay off like Microsoft in the early days.

But even favorable comments by bloggers may help if there are enough of them and potential investors read our comments.This looks a thousand times more likely to succeed than fusion power,space based solar, or some other cockeyed schemes we see promoted.

As I see it,it will probably work if the ultralight ultrastrong materials such as carbon fiber now available in small quantities scale up and become cheap.

There are tens of thousands of square miles where there would be no property damage to consider,and computers and avionics are fast moving fields.

At the hieghts proposed it seems that a small percent of the energy could be cannibalized to power a propeller that acts on the kite frame -which could be shaped like an airfoil-and the whole thing could fly like a stationery airplane,no ballons etc necessary,even in erratic winds.

This idea occurs to my because my canoe when traveling up stream loses forward motion in proportion to the current in the river.

Sometimes when I aim into a fast riffle going upstream she crawls to a halt,stationary at full throttle,when the current speed equals the canoes maximum engine driven speed.

I have even traveled down stream while pointed up stream with the engine revving on occasion.

Once a design is standardized and mass produced,the kites could be built to glide down with perhaps a power assist sent back up the cables by an operator on the ground,so getting them down for storms or maintainence would not necessarily be that big a problem.

Actually they could probably be made to drop thier tethers and power cables and glide onto a runway,or fly themselves to a runway,if very close by,by using a small but powerful on board battery.I have seen people fly radio controlled toy airplanes that cost only a few hundred dollars in mock dogfights,and we know that the military are flying unmanned aircraft on a regular basis.

And it might be possible to get them up to altitude by hoisting them with a very large tethered dirigible and a winch.

I have also read about a system whereby men can be snatched up from the ground by a tether dropped to them from a circling fixed wing aircraft-not a helicopter- in military rescue situations.

This leads me to speculate about a very fast and powerful truck hauling a power kite down a long runway and a heavy lifter type aircraft grabbing it off the truck at maybe eighty to a hundred mph or more-whatever the kite can withstand and hauling her the rest of the way up.The plane could probably get a dozen or two kites up in one flight once the system is debugged.

I don't see any reason at all why a sophisticated computer program should not be able to operate rudders and flaps under normal conditions to hold the kites reasonably stable.A few thousand acres of prairie kept planted in a very low growing variety of wheat could do double duty as a farm and also as a landing field ,especially if the kites can glide in on thier bellies in an emergency.

If the kites work,they can be mass produced and not much infrastructure ,other than transmission lines and kite plants, will need to be built on the ground.

Mass production is an underrated,often overlooked miracle.If we had to engineer a car from scratch,and haul all the parts on trains and giant trucks out into the middle of nowhere to the top of a mountian,and assemble them with a giant crane,and we were going to build them only by the hundreds or in the low thousands ,cars would probably cost twenty or thirty or forty times as much as they do.

If these things CAN be built,the odds against building them cheaply enough to actually fly them do not appear to be astronomical.

This COULD be a Black Swan of the good kind.

This is most definitely not agriculture,but electrons ARE still dirt cheap.

Oldfarmer, I didn't mean financial support; I meant mostly moral support from someone who really has experience on kites. For most of us, kites are something that we never had a chance to try. Too many power lines, buildings, things; too dangerous to fly a kite. I have flown kites, long ago, along the sea shore, but that went rapidly out of fashion. Too many people on the beach, they didn't want to have things flying over their heads. But, apparently, you live in an area were you had time to experiment at leisure and I was very interested to read that even a very simple kite can stay in air for days without the need of doing anything to it. So, that supports Ippolito's idea. Kites are robust and fly reliably. We can try.

I can at attest that kites can be very stable as Mac says; in middle-teen years in Indiana my brother and I would make good-sized "normal" style kites sometimes about 8-10' tall and wind them out until they weren't easily visible. It was odd to go out days after launching and on an overcast day just see a piece of rope hooked to the sky, heading up through the overcast as though we'd tied it to the moon or something, unmoving and stable and entirely impossible to pull down. They were not sophisticated constructions. They wouldn't handle a thunderstorm, though; which was a shame as we were hoping to melt our mailbox, and various things we wanted to fuse together with lightning.

good fun. We also had a fair bit of success with sterno-powered hot air balloons made out of 10-cent dropcloths stapled together, but the tendency of these to rain blue napalm on houses caused us to return to kites.


We never made our own kites,but just flew the dimestore variety as a family activity.

I would be willing to place a fairy large bet that if we had used strong custom made kites they would have stayed up concieveably for weeks at a time.Certainly for a week easily in most cases.

I've read everything on this site for a long long time but this is my first post. I have a couple questions. 1: Is this an attempt by the company to get a government research grant? 2: Due to the urbanization of the planet I don't see how this could be economically feasable or practical.

I don't want my tax dollars used on such a scheme. There are many simple things we can do and should be doing. Increasing complexity will not help. Technology will not save us. I don't want to offend anyone but it just seems delusional.

A few comments:

1. The company is not behind the post. It is Ugo's post, and he points out in the post that even if it did work, it would be constrained by limits to growth issues.

2. The comments to the post present a pretty good laundry list of anything that might go wrong. If a company wanted publicity, they probably wouldn't want such a long list of potential problems that might need to be solved.

3. Which country subsidize? The Oil Drum is read around the world. Ugo writes from Italy. Kitgen also seems to be Italian. Your bio is says you are from the South Central US. It seems like a pretty remote stretch that the US would subsidize an Italian company.

Thank You Gail.
1: good point
2: good point
3: "It seems like a pretty remote stretch that the US would subsidize an Italian company."
Our govt just gave away 20%+ of Chrysler plus dealer network access to Fiat even though it won't be the case with this.

20% of zero is zero, didn't you hear chrysler went bankrupt?

I'm quite sure that Ugo, a friend of Ippolito's, knows if the company (which one precisely?) was funded by taxpayers' money and how much they got.

In 2005 there where rumours of about one million Euros from the European Union.
I remember very well that the italian Partito Radicale helped advertise the KiteGen project in 2005.

I might be wrong, as there's no trasparency on where precisely the taxpayers' money is thrown at.
For example I cannot find anywhere how much RAMSES project No. 32447 got itself.

Geppetto, you keep making the same point over and over, but I can't see what's wrong with governments subsidizing research. And government's money can only come from the taxpayers. All governments do that, it is an investment in the future. We need to do research with a minimum of vision for the future - otherwise we would still be perfecting the square wheel. So, if Ippolito can get some money from my taxes to pursue a vision that is useful to everyone, I am happy about that.

Governments spend their money in much, much worse ways and I think I don't have to harp on this point. About RAMSES, it "got itself" exactly where it is: with a working prototype being shipped right now to the intended test site in Lebanon. Read the post I write on TOD and you'll see exactly where we stand and what we did.

Ugo, please just tell if, when and how much.

It's a simple matter of transparency, and as a taxpayer it is my very right to know.

Thank you in advance for the figures.

Geppetto, for some reason you have singled out a project that you don't like and you want from ME the figures (??). What do you think I am? I am not a politician, I am not an officer of the European Union. I am not here to justify policy choices on the part of the European Union or of any government. Go ask them to justify their choices in matters of policy. I am just a modest researcher and I do what I can to make things work.

While there are always things that can go wrong with converting from theory to practice (especially the cost of wear of those cables), I think there can be few things more suitable for taxpayers' money to be subsidising than this. Rather than yet more cars (scrappage scheme in uk now), roads, airports, Olympic Dinosaurs, wars.

Why don't you write to your local representitive for this information if you care so much? In future if you don't like it you can vote for the other guy.

Can't find a flaw? Ugo, I assume you've flown kites before, and therefore know the extreme variability of the results, as well as the quite narrow window of optimum conditions for sustained good results. And that's not even to mention the simple eyeball test -- that contraption in the picture is going to take a boatload of up-front resources to build. And it will malfunction frequently.

This reminds me of how elegant wave generators are -- on paper.

Life doesn't happen on paper. In reality, one fly can spoil the loveliest ointment.

As a regular kite flyer for sports (kite rider in fact), I'm always amazed how much the kite technology has improved in the past 10 years. Nowadays, you can easily fly a kite (and be dragged fast enough for surfing) from 5 to 40 kt wind... and this with only 30 meters of lines! So high altitude kites coupled to current kite technology definitely widen the window of optimum conditions!
Finally, I can spend hours staring at the hundreds of kites swooping in the air in the most frequented kitespots, and find it very elegant!

Ugo Bardi is one of my favorite TOD contributors--always interesting and well thought out. Although the concepts of high-altitude wind energy dealt with may be implemented with "minimal damage to ecosystems," I shudder at the thought of how energy too cheap to meter would be used. We have not solved our most desperate problems--population and consumption, which pose grave threats to natural ecosystems--and neither will be helped if we succeed in "democratizing" energy. I feel much more comfortable with declining energy supply.

My gut feeling tells me this tecnology finally is a "green shot". Just compare a kite surfer with an ordinary windsurfer and you will understand the potential of this system compared to conventional wind turbines. And it's basically simple - a must for fast spreading efficient tecnology IMO. As simple and convincing like solar termal energy. Nor does it need a big upfront investment, the worst example here probably would be fusion. You can start with small units using available tecnology and scale it step by step - in the best case, if it proves to be viable and cheap, simply pushed by market force.

It also looks like a good solution here in the Caribbeans. The former cuban commander in chief Fidel Castro (a convinced peak oiler by the way) just wrote a couple of years ago about wind turbines that would be horizontally tilted to the ground in case of a hurricane. Much easier to do so with kites.

howardw--The declining energy supply you feel more comfortable with is liable to involve most of the world's trees being chopped down for heating, and loads of coal being burned adding to the Climate Catastrophe already bad enough without also those treeburners adding co2.

My thoughts always drift off to unintended consequences. If you reduce the wind velocity by extracting energy from it it probably has some ripple effect we can't even imagine.
Whenever I read about the idea to power Florida by putting turbines into the gulfstream I always wonder how much that would slow down the current, and what the effects on the North East and Europe are.
TANSTAAFL - There Ain't No Such Thing As A Free Lunch.


Unintended consequences can be huge.

So saying, it is extremely unlikely that the miniscule amount of extra wind drag would have any effect at all, particularly compared with the other ways we now "get" energy. The amount of wind drag from changes in tree cover is probably much greater.

I think Heinlein would endorse these.

Everything and anything to keep the toys. What's next?

'Rubber band electric generators!'

Main cathedral (community center) in Florence - Santa Maria del Fiore. Tower by Giotto. Dome by Brunelleschi. Bronze doors by Cimabue. No cars. No electricity. No petroleum. No coal. All work by hand and simple - albeit clever - machines. Thousands employed in a small town for decades. No pollution. No resource wars.

Even corrupt politicians were gainfully employed.

Does the entire world have to be turned into an industrial site? For what?

As the question about fuel consumption in general. Why are you driving today? To save a life? To cure cancer? To waste some time?

When I went to Florence back in 1989 I was suitably impressed. Florence was a small town a little larger in population in its heyday than Charlottesville, Virginia. Unlike Charlottesville, Florence was populated with a large percentage of brilliant minds ... in all of human history! Consider; all those who built the cathedral and many others just like it ... and Michaelangelo, Leonardo DaVinci, Rafael, Giotto, Botticelli, Boccaccio, Macciavelli, etc.

Maybe it was the water.

Their 'stuff' is still around, today.

The Duomo was built in the 14- 15th centuries. What of stuff of today's will last that long? What will be as satisfying?

Maybe the best thing to do is forget for a bit the endless search for creature comforts. It's futile. Any new 'energy sources' will simply line the pockets of the current bank robbers. How do they make the world a better place?

I realize this is outside the ambit of technology and engineering. It's more important; it is how the end product interfaces with how people actually live. We live badly, today. Yes, we have stuff and more stuff and lots of fake religion and pretend democracy - and the Disney cartoon 'kulture' to rationalize it. We have money. We have ... a legacy of waste, fraud and abuse.

Can't we try something else that we know works?

BTW, despite my positive post about this tech just below, I do in fact agree with what Steve says.

My support of this type of tech is in the context that humans will try SOMEthing to keep power happening, and this is more benign than most.

Steve -- I appreciate your commentary, but this post is so riddled with ironies it is hard to separate them from your substantive points. My favorite:

When I went to Florence back in 1989 I was suitably impressed.

May I assume you didn't get there via adze-carved dugout canoe? I hope you found the experience 'satisfying' and not at all 'futile'.

IIRC, Da Vinci was fascinated with windpower and flying apparatus.

I'm left to wonder what you advocate here -- that we all build sturdy and aesthetic cathedrals? I think I'd rather pursue potential schemes to improve energy availability (may/may not be possible). That way, maybe everyone who wanted to could visit Florence, or at least check out YouTube travelogues of those that have (in your case, not much Internet in 1989...).


My interpretation of his post is that we have lost our taste for quality.

Fair enough, then. My apologies to Steve for over-interpreting.

I think the first line sort of got me. Many of these discussions revolve around the useful question of 'would we make better choices if we had abundant energy or scarce energy'? When the discussion breaks down, those who favor limited energy are labeled 'doomers' while those who favor abundant energy are labeled 'wasteful materialists.' A workaround for that would be nice.

Yeah, I know what you mean.
We are forever trapped in the path of least resistance mindset.
That is what makes abundant energy dangerous.
Self control is what we need.

Call me ... Mr. Irony ...

Of course, silly, I flew there on an airplane. It was a matter of diversion. I was wasting time. I could do it again if I wanted to!

Da Vinci was smart but he couldn't have imagined the implications of industrialization. Darwin didn't either. Neither did Adam Smith. Planetary death didn't arrive as a concept until after WWI. It was biblical, prior; Noah's flood and the parting of the Red Sea. Artillery equaled Sodom and Gomorrah. 'Progress' gave us the tools to destroy ourselves. I suspect progress arrived on the mind sometime after James Watt invented the condensor. Progress and short term thinking.

There is the good and the bad and all are enmeshed. I have a car. I drive it occasionally. I don't like cars, I hate them in fact. I am counting the days until I get rid of the one I have now and not get another one. I will likely move someplace that allows for walking. I like to walk. If I go somewhere I am usually required now to leap out of the way of cars at least once.

Just one reason to hate cars ...

Is doing something - anything - futile? Yes! What I have done for most of my adult life has been futile. There is always tomorrow. Life admits opportunities and when these arrive there is the choice to not do something futile or not do anything at all. This opportunity may strike later today or tomorrow or ... it might not happen, ever. One cannot know until the end whether something truly useful has been acheived. Unfortunately, I cannot build any useful cathedrals, even though I would like to.

It is important to question the futility quotient of everything including energy availability. It is an assumption that energy availability is useful. Maybe it is and maybe not. Energy seems to make things worse. No matter the form, it is always making a mess. People accept the mess because they usually cannot see it from their houses.

Everyone has to change. The dollars and cents cost of our familiar lifestyle is pricing normalcy out of reach. The quantity of change is large, probably too large to effect with leverage, particularly the sort that is given to us by machines. We either sink with our machines or abandon them and try something else. A lot of people here and elsewhere embrace subsistence agriculture. Why not try another form, a more intricate form of culture/civilization?

The attempt to reconfigure industry is not something new. I know that someone ele - some company or companies - will build these things. How do you interact with them ... and all the rast of industrial detritus? As a consumer?

Anyone - I presume you can yourself - walk somewhere close to where you live and see the tools and outcomes of our industrial endeavors in action. Consider these endeavors have been with us as humans for the past hundreds of years. We are supposed to add more and more of them ... at what point do we acknowledge the obvious and accept the limitations of this approach and say enough?

I imagine the cost to someone like myself in an alternative future without fuel- driven - and 'progress' obsessed - society will be the inability to fly to Italy from America when I please. I can accept that. That would make the challenge to make some Italy here or where ever I happen to be or to sail to Italy on a boat I make myself.

A long time ago the human race learned how to do complex and engaging tasks and wound up doing them extraordinarily well. The outcome allowed humans lucky enough to be in certain places - or ambitious enough to travel there - satisfying and rewarding lives. I suspect a lot of people were this lucky, seeing the populations were smaller and distances closer. Now, business does things for everyone and nobody knows how to do anything but buy the product or complain.

I think a more comprehensive thinking about what this energy will do ... is required before any more improvements are made. Americans can cut their energy use in half and would not notice the difference in their lives.

Cut in half means no kite power mega- projects cluttering up the landscape. Certainly tens of thousands of these would be needed for business as usual and ever more would be demanded. There is no end to 'comfort', 'convenience' or 'luxury'.

What I am trying to drive at here is the source of our dilemmas is largely cultural. I know Nate Hagens and a surprisingly large number of thinkers are examining the role of brain- waves in our behavior. Culture is another pathway to behavior and unlike the rigid confines of animal/limbic cause and effect, culture can be changed, there are varieties. It is possible to look back and find successful non- energy- centric civilizations.

The pathway to cultural change is by philosophy rather than psychiatry or applied psyschology.

We need a culture that can give people something useful - non futile - to do. Right now the choice seems to be consumer or subsistence farmer. Let's think of some other choices.

I do not find it wise to postpone producing more energy untill we achive
some kind of collective wisdom. The real world is a great furball of
interdependencies and our culture and technology is more like a comlex
ecosystem then a nice understandable clockwork where some parts can be
stopped to be worked on and then restared. The problems need to be solved
in a parallell process that provides as manny pathways as possible to
solutions or duct-tape cludgeds that allows parts of it to survive to the
next day to allow something new to be tested.

I try to grook this from a resource viewpoint and I know about lots of
solutions that work in some places for some problems and I would very much
like such ideas to be implemented and not wait for a new philosophy to
emerge before trying to do things that has a reasonable chance of doing
good. I suggest people choose to try to do something usefull.

Oh goody...An erudite screed that basically says..."Life sucks and then you die"...Good work mate!!!!!

I normally ignore rude comments, but please keep comments civil and respectful of those whose viewpoints differ from yours.. Post a thoughtful contrary view if you want - insults don't strengthen your support.

No resource wars.


Very short quotes can be very unfair but your glasses have som pink in them.

Florence is indeed very nice to visit but its fortune were made by skillfull handling of fierce resource competition and then a significant percentage of the surplus were invested in employing brilliant people.

Continued scietific advances and creation of artwork require a surplus to run schools etc and keep indirectly productive people fed and sheltered. Much of the scientifical advances require very specialised tools that are work and resource intensive and artwork and architecture that lasts require good materials.

But you are very much right that the resource use could be lot wiser. And to last the things we build will have to be worth maintaining, the cathedral etc have been continously maintained. If its not worth mantaining the only things left intact after 600 years will be the underground nuclear waste storages.

Thank you, I rest my case, your Honor!

This cathedral, while elegant and inspiring also stands to represent the greatest power-player of the day. Could our descendents be looking at the Pentagon with such Awe?

This construction made Florence into an 'Industrial Town' for those decades, and DaVinci, whom I do greatly admire, was designing tools of war as much as anything a modern lover of art and architecture would fawn over..

They might look at the Pentagon with the same awe as the Ufizi if the greatest power players start collecting art or other highly advanced artifacts to show of their wealth and power in their offices.

Maybe, but probably not. The Pentagon is simply an office building. The Secretary of Defense and the service chiefs have their offices there but no real power players like there are at the Treasury or nearby the White House.

The building is too big and the enormous parking lots packed with cars are a real put- off.

Plus, it's under the approach path for National Airport so there is the sound of jets taking off or landing every 60 seconds.

Plus, the Pentagon is surrounded by high speed roads that are clogged with traffic all the time, even on Saturdays and Sundays. It's hard to walk to the Pentagon although you can take the subway/Metro or the bus.

Aside from the parking lots, the area surrounding the Pentagon is filled with numerous outbuildings, sheds, garages and other conmmercial- style detritus. There is a berm and a memorial park where the 9/11 aircraft hit the building. The whole affair is pretty awkward, nobody would confuse it with the Ufizi.

The Ufizi (office) is not pretty but it is spacious and has windows that open. It would be pleasant to work in. Now, it's filled with tourists, not much office work is done there at all. Adding artworks to the Pentagon would not change its character at all. The Pentagon is not awe inspiring, it's just the Pentagon. It's ugly and banal.

The Pentagon used to be open to the public. The building was originally five concentric rings of offices. It was built by Gen. Leslie Groves (later to command the Manhattan Project) in 16 months in 1941 - 43. Since renovation the rings are gone and the spaces are just flat office 'plates' on five levels.

Most of the wealthy today have no idea about anything about anything. Education is wasted on some people. It is depressing. Houses of the rich - there are quite a few extremely wealthy here - are wood and vinyl fake- chateaus built right up against the sides of busy state roads! Designs by Home Depot. Someone over here called them 'biodegradeable'. John Thain's $15,000 trash can comes to mind.

I know JH Kunstler rails about this all the time. I'm old enough to remember when the good ol' USA was a beautiful country, but sprawl and cheap, garbage development has pretty much ruined it.

'Ballistically Ugly' is a good way to put it. 'Compounds' for the wealthy are the worst. Gauche is a consumer category. Next to worst are the industrial developments; feedlots that you can smell twenty miles away, power stations with the piles of coal and waste pits, garbage transfer stations, landfills, strip mines/mountaintops removed, warehouse and transshipment stations ... goddamned wires and transformers looping everywhere ... abandoned houses with rows of 'For Sale' signs, the houses that never should have been built in the first place ... malls of every sort with the acres of free parking, some abandoned but the rest soon to be.

Most on what was good farmland, too.

I'm a huge skeptic of most energy proposals in general, as those who have seen my posts on TOD know. Reality places much tighter constraints on our options than most people seem to conceive.

So saying, I think the direction this article is describing is one of the very best. Indeed, many of my own draft (doodle) concepts are exactly along these lines. The circular-track deal is, in fact, one of those doodles, I hadn't realized others had taken that up... good show. It's not my favorite, though.

I share the ambivalence of many posters here about providing more power as the answer - the world will be better off when humans are making do with less. But certainly this would be preferable to many ways to most alternatives. I tend to think that one could maintain a civilization around it. (In theory, that is, if we had more foresight than we actually do).

As another kid who built scary giant kites and balloons in his misspent youth, I find this aesthetically "cool" as well. I like big flying things, and I like structures which mostly rely on tensile strength.

If humans are to hang around, this is one of the ways they should harvest power.

Indeed, one could envisiion an electrified railroad between some points that hauled cargo and people as well as powering the trains both ways (and probably supplying extra power) with high-altitude kites. (This in ADDITION to Alan's plans, not instead of...)

There are many other variations on this theme, and I hope they get serious attention. Thanks for this post.

Think "rotating balloon generators" rather than kites ..
Solves several of the objections raised in this thread ..


Triff ..

Cool as kinetic art, but I think very limited by the design, I've seen these before.

If I thought getting power to humans was the biggest priority, I'd probably start up a company to flesh out some of my other notions.

As a note, I do think that going back to hydrogen as a lifting gas rather than using scarce helium is more rational, and of course it can be regenerated onsite.

yes - I'd put my monies on this any day before KiteGen. It can achieve some efficiency and not the least predictability due to it's revolving way of harnessing the power. But it still has to cope with that pesky thunderstorm and other random stuff. I'm afraid that one also is a ..........

Better but the heavy generation aparatus has to float with the baloon. Simpler still, a small hydrogen weather baloon to lift a cross shaped paragliding canopy into the sky. The result simply rotates on it's 4 stays.

The generator remains on the ground and is very simple.
The wing is cheap to produce and light.

Interesting article, a comment about EROEI in Nalukowe et al 2006 paper,for Vestas V90(3MW) turbine, this is assuming that 25% of electricity is from NG, 50% coal and 25% renewable/nuclear(this was for C02 accounting). The correct comparison would be if energy came from renewable or nuclear so that input and output(MWh) are directly comparable. Doing this, you get 1000MWh/MW capacity and an EROEI of 58,000MWh/790MWh or about 60:1 rather than 20:1(20year lifetime).

This agrees more with Cutler Cleveland's estimates of much smaller turbines(10-20:1 for <350KW, 20-35:1 for 350-750KW sized turbines) used by Hall &Lambert in now out of date balloon diagram. Extrapolating that data to 3MW would give 60-100:1

A better way would be to consider the cost per MW capacity and use energy/$or euro GDP.

Neil, you may be right, but it is not clear from the paper how they accounted for different sources of electricity in terms of total energy cost. I had understood that the different sources were considered only in terms of pollution estimates. Could you explain your point a little more in detail? Thanks

The information is from the Vestas web site for the V90.
Down load on V90-3.0

For example if the output is 58,000MWh/MW(1MWx0.35x8760x20) of electric energy, and 1000MWh were used in the construction and producing steel etc, it would seem sensible to say the EROEI =58,000/1000=58:1.
However for the environmental impact statement they have to use an estimate for the way the 1000MWh was generated, so 250MWh from nuclear, hydro and wind( no CO2; counts as 250MWh x3600MJ), 500MWh from coal (uses 250tonnes coal and generates 600 tones C02; counts as 500 x3600 MJx 100/3 ie the energy content in 250tonnes coal to generate 500MWh at 33% efficiency) and NG 250 MWh (250x3600 MJx100/2, ie the energy content of X? MJ gas used to generate 250 MWh at 50% efficiency ) which works out at 2250MWh equivalent energy( ie X2.25).

For C02 accounting this is correct, but for EROEI we need to compare the energy(MJ) in 1000 MWh with the output of the wind turbine which is in MWhs.
For a coal mine using 1MWh of electricity/tonne of production you would directly compare the amount of coal(tonnes) used to generate 1MWh as the input, and as the output the tonnes produced(tonnes/MWh).

Mmmmm.... the problem is the usual one. The concept of EROEI is not defined in a completely univocal manner. It depends on how deep we go in the chain. But, as a relative measure of efficiency, we can always compare different technologies

I don't see helium even being necessary for balloon based wind power. As long as there are static dissipaters there is no legal prohibition against using hydrogen as the lifting gas.

First, at this stage of the game it is way premature to be even talking about comparative EROEIs. So, I don't think it useful to expend further effort along those lines until Kitegen actually builds and operates a demonstration unit at a reasonably large scale.

The whole selling point of the Kitegen scheme is that the wind at high altitude has about 4 times the power per unit area as does the wind at the typical altitude of the rotors of a large land-based turbine. However, on the other side of the balance sheet are a whole bunch of negative features. Here are the ones that immediately come to mind:

1) It is one thing to successfully fly a large kite, but something else again to have a huge kite pulsing up and down and/or moving in a large circle 24 hours a day, 365 days a year.

2) Extracting power from an intermittent pulsing movement is inherently problematic and poses extremely high wear and tear on mechanical components (which is exactly one of the major drawbacks of many ocean wave energy schemes).

3) Related to 2), it is not obvious that the type of ground-based energy extraction system would be any less costly or less difficult to maintain than a large pulsing tethering system for multiple large kites. (Cables or large ropes subjected to long periods of cyclical stresses generally do not last very long, a problem well recognized by sailors having to tow large ships over long distances.)

4) While individual kites might be less heavy than a comparable wind turbine rotor blade, at the sizes required, they will still probably have to weigh several thousand pounds. If one of them breaks loose and takes off, it would pose a definite safety hazard. This feature alone would further restrict the number of suitable sites for building such a system.

It is hardly obvious to me that the drawbacks compensate for the single advantage of higher power density at altitude.

I predict that if and when Kitegen builds and operates a large demonstration unit, these problems will become manifest. For all it's innovative aspects, taken as a whole, I find this a rather inelegant concept in that complications abound.

I of course could be entirely wrong.

"The whole selling point of the Kitegen scheme is that the wind at high altitude has about 4 times the power per unit area as does the wind at the typical altitude of the rotors of a large land-based turbine."

The best selling point is instead the much greater area that the KiteGen can sweep, about 1km^2 for the stem configuration, and much more for the carousel.

"2) Extracting power from an intermittent pulsing movement is inherently problematic and poses extremely high wear and tear on mechanical components (which is exactly one of the major drawbacks of many ocean wave energy schemes). "

You are right, but this wear can be accounted for in a correct dimensioning of the system, and this is what the engineering equipe is doing.

"4) While individual kites might be less heavy than a comparable wind turbine rotor blade, at the sizes required, they will still probably have to weigh several thousand pounds. If one of them breaks loose and takes off, it would pose a definite safety hazard. This feature alone would further restrict the number of suitable sites for building such a system. "

You have to look at the the density weight, that is however very very low compared with the iron

"I predict that if and when Kitegen builds and operates a large demonstration unit, these problems will become manifest."

A demonstrator has been already built

"I of course could be entirely wrong."

Not entirely, but enough wrong

It's really great having the guys from KiteGen participating in this discussion.

Especially since they have been patient and polite in countering the negative "It will never work" attitude we often resort to here on TOD.

Hopefully KiteGen gets a clue or two of potential problems that they can design out of existence before their next prototype. I'm sure they are getting some good experience dealing with skepticism :)

Go KiteGen! I hope your idea flys (literally). We need every silver BB we can get...

If one of them breaks loose and takes off, it would pose a definite safety hazard. This feature alone would further restrict the number of suitable sites for building such a system. "

[Response]You have to look at the the density weight, that is however very very low compared with the iron

Simply wrong !

[Elsewhere] The kites will weight several thousand kg

As a metric of public safety, the issue is *NOT* if something is less dense than steel, but if it falls on a small child (or frail elderly person) will they be killed or significantly injured. This why no permanent habitation (home, store, factory, warehouse) is allowed within "falling distance" of wind turbines today. Why should Kitegen not be held to the same safety standard ?

A 100 kg balsa wood log falling from a height can obviously kill. A 400 gram child's kite will not.

Kitegen will not, and should not, be allowed to be deployed where there is any permanent human habitation with range of a kite falling after a cable breaks. This constraint severely reduces possible applications, but does not eliminate them.

The kites need to be designed to plummet as soon as the cable breaks to reduce the size of the "safety zone".


It might be less of a problem to find such sites than some might think. As I type this I am sitting in a building on the western slope of the ridge that defines the Eastern Continental Divide. To the east is the vast expanse of the Pisgah National Forest. A set of ground stations could be erected on the east side of mountains, just below the ridgeline. There is usually a good steady wind 1000m above the ridgeline. Should a kite come down, it would come down in the woods; very unlikely to hit anybody, unless someone just happens to be there hunting or cutting firewood at just the wrong time.

Of course, you could also place these along the sea shore. Along the whole Atlantic coast, the prevailing winds blow to the east, which means that a downed kite would fall harmlessly into the water. Only if a boat just happened to be in the wrong place at the wrong time would they be in harm's way.

I suspect that we have enough good sites here in WNC to enable us to produce 100% of our electricity from these kites alone, and maybe even some to export to other surounding areas.

Kitegen will not, and should not, be allowed to be deployed where there is any permanent human habitation with range of a kite falling after a cable breaks.

Alternatively, if the technology works/scales and if fossil depletion will be as steep as some suspect, then perhaps 'permanent human habitation' will not and should not be in range of such kite power systems...? Many roads are possible...

Kitegen will not, and should not, be allowed to be deployed where there is any permanent human habitation with range of a kite falling after a cable breaks.

I think you are going a little too far here. Sparsely inhabited farmland (a couple of farms per square mile) could be perfectly adequate. If there is some small increase in danger, the farmers need to be compensated. The added risk is much smaller than those that farm the edges of airport runways incur. Nearly everything we do entails some degree of risk. The trick is to use science based, rather than emotion based thinking to make the appropriate compromises. I'm sure you've encountered the no-nukes ever near anyone mentality, for some people 99.999997% safety is never going to be enough, as long as a theoretical risk can be imagined it is unacceptable.

If we get into the situation where we have to choose between a smallish risk from kitegen failures versus catastrophic climate change, I hope we as a society are able to make the right choice.

Sparsely inhabited farmland (a couple of farms per square mile) could be perfectly adequate.

I disagree.

First, ALL affected farmers have to agree, voluntarily, to accepting the increased risk for a negotiated compensation. Telling someone that they HAVE TO accept some unknown risk (true for first decade of KiteGen commercial operation) for $X/month is simply wrong.

My SWAG, the maximum viable "real world" density for KiteGen deployment is somewhere around one permanent habitation /30 mile2 (77 km2). King Ranch in South Texas, some areas of West Texas, New Mexico, Montana, Wyoming, large forests (northern Maine & national forests for example) and over bodies of water.

A related issue is air rights. A KiteGen operator has no right to generate power over *MY* land without my agreement and just compensation to me. If KiteGen operates over 1, 2 or maybe 3 landowners, the land man deals are not too large a hurdle. But the costs to assemble parcels with 20 land owners may exceed the capital costs for hardware.



Perhaps no permanent habitation.. should be allowed within the crash area of motor vehicles or trains just in case they have an accident? how about the danger to health caused by burning coal?

As a train nut i thought you would see the problems caused by trying to engineer out remote dangers such as train crashes which kill far fewer people than say cars or guns.

Trains are a 179 year old technology and the risks are very well known. The risks (MUCH higher in 1800s) are one reason that 95% of US RR ROWs are 100' (30 m) wide. Few derailments go off RR property.

One standard of Urban Rail design is that derailments will not impact human habitations.

KiteGen is brand new technology with unknowable risk % until extensive (say 10 years) of commercial operation.

And there is plenty of low-risk building area to put them in while the technology is proven.

I personally understand your point, Alan, but you are strangely emphatic about it. It seems a bit out of character for you to be so strongly negative about something that looks rather promising and could tie in nicely with your own plans if it pans out OK.

I try to be dispassionate. I never had toy trains, I am not a "rail fan" per se, I advocate them because they work, they need not use oil and they are efficient.

I do not see where I am doing a dis-service by pointing out limitations that are apparent to me with KiteGen. Reality is reality.

Best Hopes for Properly Vetted Plans,


It was an excellent point, it was just the language you used to make it that caught me by surprise.

I definitely hope that kite landing area and line spring-back zones are taken into account when siting these. Line spring-back is nasty when dealing with long lines under high tension, and can kill people if they are standing in the wrong spot when it happens (not to mention the potential damage to equipment).

The huge dangers of cars and their support systems have never been much obstacle to "progress". I asked my MP if she agreed that my (proven harmless and life-saving!) vitamin B6 pills should be banned till proven safe (precautionary principle)..."Yes". So she must also agree that cars should also be banned until proven safe. One reader observed he had never seen such a rude reply as I got, the more printable essence of which was "don't be ridiculous". Cars are still allowed to race around in near-invisible grey/black colours, terrorising our public spaces.
Add on the oil spills, particulate deaths and climate catastrophe. Once the big money sees something as profitable there's no stopping it other than Nature intervening with a closeout order.

Everything that is in this world is doing something. Wind, water, air, tides, sunlight etc are not sitting around just waiting to be tapped for human use. They are an integral part of how the world works at present. How the world works at present is in a way that allows humans to exist. Other ways the world worked in the past would not have allowed humans to exist. When we appropriate something like wind that is currently doing something else we change things. If we appropriate it in small amounts we mostly likely change the current state of the world in such small ways that it is not noticed.

We are no longer looking to occasional windmills to power pumps or mills. We are looking to windmills to replace all the ancient sunlight we are currently using. If successful we will appropriate a large amount of wind energy. Where are the studies that will tell us how we will change our environment if we do that????

The answer is not in more technology to allow us pampered first and second worlders to maintain our lifestyle. The answer is to Power Down and reduce population ASAP

I would rather aim to continue to power UP he local society with non fossil energy sources and biomass based industry and increase the population by making it easier to move over here and integrate into the local culture. We got an abundance of resources and could ease the global preassure a tiny litte bit withouth breaking our country by welcomming more people.

Every person that cease to consume in the developed world contributes far more to reducing environmental footprint of mankind on earth than a person in the "least developed" or "lesser developed" places.

By that logic... the fastest way to ramp down would be to....

I agree OG - I don't believe I have seen much work on the impact of removing energy (solar, wind, tide) from natural systems. I wonder if it is even possible to get such measurements before scaling up the extraction?
I hate to start the birds vs energy argument but.... I have to ask - what has been the experience with bird strikes and the kitegen system?


I am disappointed that so many participants on this site are so quick to say no to an idea that has only been in front of them for a few hours. As Wordsworth said in explaining his "Lyrical Ballads," people think by habit which prevents them from seeing virtue in something new.

That may be the case here.

Another great thinker, Howard T. Odum, said as fossil fuel declines as a source of energy, we are going to have to move toward "environmental fit" working with the forces of nature instead of environmental opposition working against them. In that sense, the idea of Kitegen, could be a step in the right direction.

But we aren't going to know that at this moment today or even in the coming days on this website.

Or as Einstein supposedly declared,

"I refuse to believe I KNOW something, because then I will stop thinking about it."

Stem (hybrid method within the larger family of wafting levers, rotating levers, rocking arms, oscillating lever, shaking handle, and TipBoom or Tipping Boom. The Stem method involves some out and in with some period of non-energy production.) . . KiteGen moves into stem tech And blow starts, and 3-D onboard sensor.

All interestested in related matters have a web home at
and related group continuing discussions:

Scores of methods are being explored in rapid development.

Someone needs to build a prototype or proof of concept.

It shouldn't be too expensive to build one. Often the devil is in the details for new technology. It would be neat if this concept worked. The question being, how automated could this system be made?

After we got one flying, we could determine it's productivity.

A mobile demonstrator has been built. See http://files.meetup.com/870405/2008.04.06-mobilegen_scheda.pdf

A fixed plant is not cheap as you would think. There are first of all the development costs that are very high. It has to be studied the behaviour of the ropes, that have to be light, resistant, and with low drag. New kites have to be produced that will have very high efficiency, and that will be flexible in one dimension and rigid in the other. There are the generator-motor , the electronic, the controllability...

However, the plant at the end of the industrialization process, will be much cheaper then the traditional wind turbine, with comparable power.

On reading this, my first reaction was that it could not be applied on a massive scale, because of such things as severe thunderstorms (which could tear an airplane to pieces), but it might be ideal for small islands which rely on imported coal or oil to generate electricity. And which really don't use much electricity. Hawaii was mentioned in the comments, but there are many more, smaller, islands that might be far more ideal. Non-mountainous islands would have much more constant wind speeds, and only large, infrequent storms, which can be easily predicted, so precautions could be taken to prevent damage. It would be a shame for a good idea like this to fail because it was first done in the wrong place.

Well, you could just land the kites during the storm and restart later. I hear this happens with planes too.

Small scale distributed micro systems (e.g. solar or micro-hydro to power individual households, neighbourhoods, or small communities) seem to me to have potential to address some key issues (e.g. NIMBY-ism might diminish if infrastructure is for one's own benefit rather than a corporation; less reliance on centralized production and the grid for distribution; more direct linkage between production and consumption could increase awareness of limits and encourage conservation). This, of course, needs to be combined with drastic reduction in energy consumption (powerdown).

While claims of potential to create 10x current energy production raises the eyebrows of the skeptic in me, high altitude wind does seem to have some potential to at least provide significant affordable energy, and is certainly more encouraging than many other proposals I've read about. As such, it is definitely worth exploring, and I look forward to seeing how larger scale tests turn out.

Most of the Kitegen proposal seems to focus towards creating large scale generators (for obvious financial and energy efficiencies of scale). I would be interested to know if there are "micro scale" concepts being explored. Although the EROEI may be lower for a smaller system, if might be easier to mass produce and adoption rates might increase since they would cost less in an absolute sense and perhaps be within range for communities or small groups of people (especially in a credit constrained economy).

Well, I have spoken about the "downscaling" of the prototype with Massimo Ippolito.
I was thinking to small sail boats and single house generators.
The problem is the finite amount of time and energy people has, at this point in the Kitegen Group.
They are giong for the big target.
Next, with cash flow flooding in ( hopefully) they will think also to downscaling.
I am pretty shure it will work quite well.

Micro hydro is a great concept but there are so few sites it can actually be deployed it can be of no real interest to anyone not willing to move specifically to enjoy it,except a tiny handful(relative to the population) of "lottery winners"who live adjacent to suitable streams.

And anyone who thinks you can just go out and monkey around near a stream these days without a permit imposing some very stringent and expensive conditions -if it can be obtained at all-is likely to find himself in front of a judge,pronto.

Not so in the USA. The rule-of-thumb is that an EXISTING, operating small hydropower plant < 3 to 5 MW is not worth the paperwork costs to renew it's 50 year license.

Result, few US hydropower plants <8 MW.

USGS estimated an upper limit of 17 GW of small hydro potential in the USA (reality is likely ~5 GW).


We know of people who have micro hydro generators that produce less than 1kW (sometimes only enough for a couple lights and perhaps a laptop). It doesn't necessarily require a large stream (I've seem them work on a ditch or small dug pond that captures winter runoff). The key for making micro-hydro feasible for larger numbers of people is powerdown - reducing needs dramatically so that one only uses a few kilowatt hours per day.

I'm surprised it's taken this long to get another high-altitude pilot wind project afloat. A growing number of people I respect put their faith in fast breeders and high-altitude wind power to continue our exponentially-advancing society, so it's nice to see one of these getting some more work.

There are dozens of solutions to deal with high-charge clouds and safely overseeing their discharge or letting that charge go elsewhere, so it makes me sad to see some folks putting this idea down for that reason.

I personally put more faith in flying motors. Nevertheless, kites are great and $200 oil is all we need to give them serious attention. When the money flows in, and this idea or a similar one works, many will become millionaires, some billionaires, and a new revolution will come about. When the time comes, a lot of ECE professionals will move from semiconductors/vlsi to wind.

It is interesting, thought provoking. Yesterday this post gave me about 47 crazy new ideas, I forgot 46 of them but one has been nagging me, and now I have a cartoon in my head. I do like the idea of the kite rising and pulling the cable out, but I don't like the idea of the kite falling and the cable being reeled in. I was thinking about a ski chair lift. Here comes the chair, just aim your tush and up you go, when you get to the turnaround just ski off the chair. Could a kite system have a lot of controlled kites on a never-ending loop of cable? Wind pulls kites up as before, they fly/pull the cable out into a loop, and fly the downhill side of the cable back to the generator, where the downhill kite nearest the ground disengages and glides itself over to a loading rack, where it takes its turn to grab the uphill cable.

Here is a refined version of your "ski-lift" .... TIDAL SAILS

I believe an air-in-motion based "hill-sail" version would beg to much troubles and 'lack of efficiency on the money'- I mean after all Windturbines do exist.

I like that one too, Paal. But the sails pull out and push back when the tide changes, for the wind/kite comparison you should think about tapping into something like the Gulf Stream, or a river. A loop of sails would work in a stream driving a couple of big wheels. The water sail example is nice because the sails can be passive. In the wind example, I think a loop of kites would work, and now that I have thought about it some more, there is no need for them to uncouple and re-hook to the cable, just make the loop at the generator like a big Ferris wheel.

I agree with you here.
The water-sail system should be a continuous neverending loop where the "sail" collapses and takes a low profile against the waterflow -- but I reckon they will end up as such, if commercialised.
The good part with water sails is : They know exactly where the force (current) is comming from, and can thus plan accordingly.

Say, the Kite-Gen in this article needs vast 360-expanses , where the rope length is the radius, this bode for some area/entangelment challenges.

You are not the first one to come up with this idea:

Interestingly enough the prototype is pretty similar to the KiteGen:

There are dozens of solutions to deal with high-charge clouds and safely overseeing their discharge or letting that charge go elsewhere, so it makes me sad to see some folks putting this idea down for that reason.

I hope you aren't getting the wrong message. At least in my case (I probably made about half the lightening posts), I love the idea, and want to raise the issues, just incase the designers haven't properly considered them. It never hurts to have some extra reveiw of your project, just in case you missed something. From the quality of the responses, it sounds to me like they have done their homework. Demonstrating that they have indeed thought seriously about the issues is one way they can build credibility.

In my case, I also hope to learn more about the concept, the potential gotchas, and the strategies to overcome/minimize them.

I hope the kites work better than that link did. It repeatedly crashes my browser, no matter which one I use. Please boycott quicktime, since it is garbage anyway.

Same problem on my (preinsalled) garbage, pardon, Vista

Is it better now? :)

if wind speed and power generated increase with altitude, I guess that the weight of the lines also does. Any figures about the optimum? At which height do the lines become too heavy? Does this already affect the kite at 1'000 m altitude, or is it neglectable? would it then make sense to build kitegens in high altitude (e.g. on the top of mountains)?

Nice thinking but then it would be so much more bother doing the installing and operating up in a mountain, would probably cancel out the advantages. My bet is most will be over the seacoasts, and on smaller 'mountains'/hills.

I think that this concept has potential.

However, I think that generating electricity is only one possibility. The energy transmitted through the cables and that ends as rotation can be used to compress air. Compressing air turns this mechanical energy into heat - useful. As for the compressed air, it can be released elsewhere to create cooling.

Certainly, when the overall picture is looked at, it would make a lot more sense than making electricity which is then used to compress gases (HCFCs) that are then decompressed (after cooling). Much electricity is used for cooling in summer.

We're pushing motors at > 95% efficiency (both directions), so it would probably make more sense to use electricity as the energy carrier between this power system and the electric machines that would do any useful work.

The exception I'm thinking of is making fertilizer on-site because this could be the sole sink for these systems. Nat gas is too cheap right now in N.America however, but Europe? It would be pretty romantic to have high-altitude wind feeding the world more than it can eat.

A friend of mine, Magnus Landberg, has for more then two years worked on a very similar system for extracting energy out of fairly slow moving tidal flows. Its a fixed hydrofoil "flying" in 8:s in an underwater flow with an ancor to the sea bottom and it extracts the energy by carrying a small water turbine round and round in the 8:s.

Today I got an ok to post about it but their web page has very little technical information:

Magnus, it seems like your friend has to improve his home-page quite a lot - with pictures and videos and more to get my (and others?) attention, but of course his idea continue to stay quite secret "this way" . This is 2009 , I am not reading a lot of text to understand a technical principle.


Its a fixed hydrofoil "flying" in 8:s in an underwater flow with an ancor to the sea bottom and it extracts the energy by carrying a small water turbine round and round in the 8:s.

I read this one more time , and understood this flying in 8:s just right now --- and obviously it is almost a hydro version of this Kite-Gen - I get the point - use the hydro-wing to increase the waterflow. But these "living and physically moving" constructions beg for an array of challenges IMO. It all boils down to (cost of investment+operational cost) / energy returned or cost of energy if you like. The expenditures for the hydro-wing could be used to make a larger water-turbine handling lower water flow - in the end yielding maybe the same amount of energy out. This would make it break-even, but the latter is a fixed and known item leaving little left for imagination ...my 5 cents worth !

A here-and-now application of kite technology can be seen here. This technology took the world's record for the largest kite to ever pull anything in 2004.

The fact that Ugo is an investor in a VC firm that intends to capitalize Kitegen is a clear conflict of interest and completely dismisses any possible validity associated with this supposedly un-biased 'paper'.

Shame on TOD for publishing such a blatantly biased puerile piece of nonsense.

I will not bother to address the obvious practical, engineering, and ecological shortfalls of the proposed Kitegen systems.


He clearly stated his involvement with the project. How is that in conflict with sharing these thoughts?

Acknowledging financial ties to Kitegen and friendship with company principals does not and cannot remove his bias on the subject.

Akin to telling someone that 'sticks and stones may break your bones but words will never hurt you.' and the ridiculing them and walking away expecting no repercussions.

Or letting a student write their own report card...

There would only be a conflict if he had pretended to be completely neutral, which he did not.

He's not lobbying congress for money for a company he's secretly going to gain from. He's offering up an idea with some admitted level of advocacy, but into a forum where it is merely evaluated and criticized. While there is an understood rule about direct promotion, this would seem to be a more than acceptable gray area where people looking at new energy tech will want to hear a range of thoughtful perspectives on ideas, and some of these will invariably be businesses they have 'some' stake or interest in.

Chitowncarl--Your objection of bias and profitmaking abuse (and "puerile nonsense") is miles out, completely unsound. If Ugo wanted to make money from a dodgy idea the last place he would want to present it is here where it would get torn to shreds as regularly happens with most crackpot ideas presented (most notably one last month).

As usual, the same old same old anti-technology stuff being posed against a worthwhile concept. It's started me thinking about some questions. Why is it acceptable to demand an arbitrary power-down of society even though sources of energy may be available which use renewable natural energy sources, renew their own construction, and pose no significant threat to long-term sustainable society? The primary rational presented is "because it will encourage population growth", but that argument is clearly false to anyone who has spent even two minutes studying world demographic trends. A secondary argument presented is "because such access to additional energy will simply enable humanity to bump into some other limit", with no proof presented that given simple access to energy all other limits can be dealt with, which appears to me to be true.

It appears that the real reason is that such people are hoping for a dramatic life-support-system crash which will "take out" all the people which the downers don't happen to like (different races in poorer countries, city-dwellers or especially suburb-dwellers in their own countries, liberals, etc. etc.) I can find no counter-argument for this position and will hencforth begin to raise it every time a "radical-arbitrary-power-down" (RAPD)comes on here or elsewhere. eg. You can expect to start seeing me posting "That's an unsupported RAPD position" on this site.

I wholeheartedly agree with that. After having read some of the replies in this post I have come to the conclusion that some people are not looking for a solution that can prevent a peak oil collapse.

My interpretation is that these "radical-arbitrary-power-down" proponents simply feel that industrialized human society has spoiled the beauty and perfection of nature. Forests have been cut down; the air, rivers and lakes have been polluted; many species have gone extinct because of hunting or loss of habitat. These people believe that human societies outside of hunter-gatherer tribes or primitive agricultural societies are inherently evil. In their mind humans have turned a Garden of Eden into a garbage dump.

Peak oil for them is not a problem to be dreaded, rather it is a welcome catharsis that stops industrialization and restores the supremacy of ‘nature’. Therefore any technological progress that delays or avoids the collapse of civilization is not welcome.

My answer to Len's question is similar to yours, while I would consider this PD reaction as a completely understandable 'equal and opposite' to the industrial ravages we continue to perpetrate on the planet.

It's not my own response, that we 'Have to Just Power-Down'.. but it's fair enough to keep a very cautious eye on our current habit of HyperManufacturing any solution we come across, in order to get it up to the scale of things it is supposed to replace. We like to replicate our precious creations like they were little bunnies.. and end up with a second-tier population crisis.

Nature was never perfect, but we have certainly created a staggering number of garbage dumps across the garden, haven't we? I don't see modern man as Evil.. just largely alienated and distracted from the harm we are creating. Hungry for power, which feels like security, I suspect.

As with Violence, it takes a lot of inner strength to let go of power, and to realize that you don't depend on it nearly as much as you had supposed. Power/Energy carries the implied promise that it will easily solve your problems for you, when often enough it causes additional problems that cost even more energy to grapple with.

McDonough's motto of the Industrial Revolution "If brute force doesn't work, you need to use more."

I never comment on the ‘new’ proposals for harvesting E as I sometimes don’t understand some of the technical details, well they are often missing anyway, and am on the whole extremely skeptical, and then after some superficial thought, dismissive. The last one was so far out -literally!- it was hilarious, I thought someone could lift it to use in a Sci-Fi novel.

So, knowing my opinion is not worth much, but wanting to counter the negativity I read so far, I think this is a really grand idea. It makes sense - the basics seem to be reasonable. Of course next come 100s of problems...

The discourse about falling kites seems absurd, sort of kindergarten stuff.

The general position that humans thrash the planet and would do so even more vigorously if offered yet more so to speak cheap energy is another debate entirely.

At no point did I take an anti technology or arbitrary power down stance, that is your prestidigitation.

The point in debate is the worthiness of a white paper written by a person with a financial and personal interest in the technology being touted.

I would appreciate the retraction of your inappropriate comment.

Dude, chill out. Len wasn't even addressing your post directly, but the many others asserting the 'impossibility' of a field demonstrated technology.

Len --

I agree with you, and see a problem with any viewpoint that does not try to integrate new information. The RAPD mindset you have identified is the most pernicious of these types of viewpoints appearing in this forum.

Have you ever flown a traction kite? Try it, you'll see what I mean.

Since the topic is wind, here is another concept that I believe has potential to raise living standards where it matters most, in the developing countries.

Windbelt, Cheap Generator Alternative, Set to Power Third World

As the Kitegen website makes clear, the Yo-Yo or Stem configuration shown in the video is not the most efficient way to capture high-altitude wind energy.

What is required is a configuration that can be scaled up easily to generate large amounts of electrical power (hundreds of megawatts or more). The best way to achieve that is to have a circular level railway track, on which runs a train of wagons equal in length to the circumference of the circle. Each wagon or car is coupled to one in front and one behind, so that the train has no beginning and no end.

At regular intervals along the train, for example every fourth car, there is a rotating turret (similar to that on a battleship) with a pair of winches and cables up to a mile long connected to a power kite. Dozens of such kites pull the train around the track and the motion of the train produces electrical power via linear induction motors operating in regenerative mode. (Current could be supplied to the train to start it and launch the kites.)

Cables one mile long at an angle of 30 degrees to the horizontal mean a kite altitude of half a mile. Even at this relatively shallow angle, there would be a large vertical force component acting against gravity. This upward force would have the beneficial effect of reducing wheel and rail wear (important for a continuous train that normally never stops), but could lead to a serious risk of derailment. To avoid this possibility, the railcars could have ballast tanks filled with water.

In terms of construction, the KiteTrain Power Station would consist of little more than a single-track electric railway and associated electrical transformers. (Contrast that to a nuclear power plant.) The power rating could be made larger or smaller by increasing or decreasing the circumference of the track in integer multiples of the railcar length. Land enclosed by the track could be used for agriculture, recreation or by wildlife, with access via underbridges.

High altitude wind power: an era of abundance? Yes!

I have said little that is not on the KiteGen website (with which I have no connection at all), but perhaps I have said it in a slightly different way.

Impressive comment, Tony. Though you said you are not connected to KiteGen, you've understood many ideas. :) Another thing which could reduce the "risk of derailment" is magnetic levitation: I don't remember if it's described on the website but I'm pretty sure they know this hint. :)


For the same specific power, the structural weight on ground of the stem farm is much heavier than that of the carousel configuration. I tried to explain that in some notes that can be found at http://www.geocities.com/ceccato3/Confronto_carosello_yoyo.pdf


Yes, the carousel project is oriented to the magnetic levitation.

I for one will be all the happier if the future does indeed look like merry-go-rounds rather than batteries of howitzers!

I'm wondering what are the implications of discussions such as these on the patenting of ideas expressed. This is potentially a very serious point. Without a supportible patent (/application) an idea can be impossible to find commercial funding for. (Hard enough anyway, even for great ideas.) I have already thought of some ideas from this page, but if I mention them here first, then any patent application subsequently filed in UK/Europe will automatically fail the criterion of novelty. And that could kill a project regardless of how brilliant in all other terms.

You are absolutely right, I can see you are used to deal with patents and with investors.
About the KiteGen we patented the ideas, the tecnology approaches and the different possible detalis and we extended them worldwide.
I think we reach the level of more than 20 indipendent good patents on the concept, with a mean of 100 claims each.
that became several hundred patents if we consider the translations in different languages and the local deposit with again local taxes. :-(
My personal feeling about the current patent international policy is really very bad, the cost to make marketable an idea that could help the economy or even the umanity is huge.
Missing to make marketable the technology through the patents is harmful, the idea will be wasted because nobody will invest.
The patents cost is in concurrency with the expense for the phisical day by day development.
The answer from the PO to be certified to have not intellectually protected the "hot water" takes years.
So in few year the applicants will have a million $ expense in taxes without having completed yet a comprehensive packet of validated patents.
It is an absurd risk and a goddamn for the applicant scientists or technologues, that are per definition with the head in the clouds assorted in their technical problems without any money feeling.
The problem do not change if you are hired in a big reserch centre, they istitutionally love to produce a lot of patents, but nobody at the top of the organisation understand what is really being discovered or disclosed or the different value of the various patents produced by the people of the centre, so the good work will be wasted anyways.
I have a lot of direct or indirect examples, one of the most famous was the Fiat multijet for the diesel cars.

Absolutely agree. As presently set up, the patent system is merely a huge barrier to small-company innovations. It seems entirely designed to consolidate the power of large corporations.

Those 20 patents must be costing a small fortune. I hope you will have some money left over to pay for the actual engineering! I noticed in the piano field that many corporate patents (Y*m*ha etc) are rubbish published just to make it look like their researchers are doing something.

More likely hoping to catch some competitor in an infringement lawsuit. Nowdays the most valuable inventors for corporations are lawyers who invent claims language interpretations.