Alternative Wind Power Experiments - SkySails and Airborne Wind Turbines

Wind power is currently the fastest growing renewable energy source (in terms of capacity - solar has a faster percentage growth rate), and looks like remaining so into the next decade. While most attention is focussed on the mainstream approach of generating power using large wind turbines - both onshore and, as Jerome recently looked at, offshore - there are a wide range of alternatives being considered for harvesting energy from the winds. In this post I'll look at 2 approaches that have received some attention in the press recently - attaching kite sails to ships and airborne wind turbines.

SkySails and KiteShips - Using Wind Power To Make Shipping More Fuel Efficient

Shipping is the most energy efficient way of transporting goods around, and it therefore likely to be increasingly important for trade as the availability of fossil fuels decreases and the cost of these increases. According to the Financial Times, it often now costs more to ship a container by road 100km from a port to its final destination than it does to move the container by sea from China to Europe.

One way of increasing the energy efficiency of shipping is to increase the size of the vessel, which big shipping operators like Maersk are already pursuing. Another way to reduce fuel consumption for shipping is being promoted by German company SkySails - attaching a kite the size of a football field to a vessel and using wind power to help save fuel costs.

The SkySails apparatus consists of a towing kite with rope, a launch and recovery system and an automatic control system. Autopilot software monitors data from the sail and makes adjustments to ensure the sail is set at its optimal position. The company also offers a weather-based routing system to help ships sail in optimal wind conditions. The kites usually fly around 1000 feet above sea level where winds can be up to 50% stronger than at deck level.

The first ship using the system, the Beluga Skysail, is expected to set off from Germany this month (The Guardian says it is bound for Venezuela while The Times says it will, fittingly, be hauling windmills from Esbjerg, Denmark to Houston, Texas). Once it is well clear of the land, it will launch a 160 sq metre kite, which wind tunnel tests and sea trials suggest will tug it along and save 10-15% of the oil it would normally burn. In time it will be fitted with a larger kite, possibly saving 30-35% on fuel. One estimate predicts this could save around US$10 million over the lifetime of a vessel.

The Guardian quotes Christine Bornkessel from the Beluga shipping line, which has 52 merchant vessels, as saying "This is a serious attempt to reduce bunker [fuel] costs and polluting emissions. The kite will be used whenever it is possible on the voyage, and we are convinced it will revolutionise cargo shipping. We would consider fitting them to all our ships".

The SkySails company has ambitions to roll out the kites quite rapidly - “About 1100 of the 1900 newly built vessels joining the world’s merchant fleet each year are destined to be outfitted with SkySails propulsion”.

If the Beluga performs well on wind power and if the high-flying kites dramatically cut its fuel consumption, then the age of sail will be back.

“It marks the beginning of a revolution in the way that ships are powered,” said Stephan Wrage, the inventor of the SkySails idea. “We calculate that the sails can reduce fuel consumption by between 30 and 50 per cent, depending on the wind conditions. “The system could be applied to about 60,000 vessels out of the 100,000 or so listed in the Lloyd’s register. Bulk carriers, tankers — they could all benefit from the flying sails.”

Orders are already coming in, ranging from trawlers to a super-yacht. If he realises his dream of re-equipping the world fleet, Mr Wrage calculates that his sails could save 142 million tonnes of CO2 a year, equivalent to about 15 per cent of Germany’s total emissions.

The 35-year-old engineer, who came up with the idea as a teenager when he found himself being dragged by a kite along a blustery North Sea beach, is not the only person brooding about how exactly to reduce the gases released by the world’s shipping fleets.

The problem is huge. Merchant ships, which carry 90 per cent of the world’s merchandise, produce more sulphur dioxide than all the cars and lorries on the planet. And, according to the International Council on Clean Transportation, they also generate about 27 per cent of the world’s nitrogen oxide emissions.

Wallenius Wilhelmsen Logistics, the Norwegian fleet management company, has designed a green flagship, the Orcelle, which will use rigid, rotating sails to capture the strongest winds. When the wind drops the sails can be used as solar panels. But the company admits that it could take 15 years before the ship is developed.

The most straightforward way of reducing sea-borne pollution would be to impose a speed limit on the oceans. Carbon emissions would drop by 23 per cent if ships cut their speed by 10 per cent — but shipping experts say that slower cargo movements would lead to more vessels being deployed, and pollution would return to its former levels. ...

The sails, made of an ultralight synthetic fibre, are shot up as much as 300m (984ft) into the sky. ... Mr Wrage calculates that most ship owners should be able to recoup their £290,000 investment in the kite sails within three years.

Drawbacks associated with this scheme include the additional costs associated with the kites - both with buying, installing and maintaining them, and with training and rostering crew members to tend them.

Skysail isn't the only company investigating the kite sail idea - US company KiteShip is building large kites, mostly for yachts, and plans to expand into the larger cargo and cruise ship markets.

Flying Wind Farms

Airborne wind turbines are an idea that I've always found myself somewhat bemused by - "surely they can't be serious ?" I think to myself, whenever I come across another tale of a company trying to fly kites with wind turbines attached to them.

These sorts of stories have continued to appear with monotonous regularity however, and not just out on the alternative energy fringes - in recent months I've seen articles in places like The New York Times, The Economist, PBS' I, Cringely, The Energy Blog, TreeHugger and WorldChanging - many prompted by's investment in airborne wind company Makani Power (part of their program to make "Renewable Energy Cheaper Than Coal").

The driver for these schemes is that the intermittency issue which reduces the effectiveness of wind turbines operating at ground level is asserted to be much less of a problem at 1000 feet, where the winds tend to blow steadily. Proponents of airborne wind power like Ken Caldeira at the Carnegie Institution's department of global ecology at Stanford University say that if we could tap into 1 percent of the energy in high-altitude winds it would be sufficient to provide all our power needs.

The company that has garnered the most attention in this field is Ottawa-based Magenn Power. Magenn's system is a lighter-than-air wind turbine capable of powering a rural village - the 30 metre wide, helium-filled "Air Rotor System" contains a turbine that spins around a horizontal axis and can produce 10 kilowatts of energy as it floats above the ground while attached to a copper tether. Larger models — ones that might power a skyscraper — are also reportedly in the works. The company claims the governments of India and Pakistan have expressed interest in the first version. Magenn is planning to launch a 1kw prototype (costing around C$1 million) into the air above Ottawa this (northern) spring.

The entrepreneur behind Makani Power is Saul Griffith, originally from my hometown of Sydney but now based in San Francisco. This company is the least transparent of the airborne wind power companies, with very little known about what they are up to.

Another Californian high altitude wind power company is Sky WindPower. This company seems to be the farthest along in its efforts to commercialise their technology and is again directed by an Australian - ex-mechanical engineering professor Bryan Roberts. Jim Fraser at The Energy Blog has a fairly detailed look at what they are proposing:

Sky WindPower is proposing [to] use clusters of Flying Electric Generators (FEGs), on the end of a current carrying tether, in the jet stream at 15,000 to 30,000 feet. The company has done wind tunnel tests and low altitude tests to prove their idea. They are hoping to build a 200 kw model, flying at 15,000 ft, somewhere in a remote area of the U.S. They envision a commercial FEG will have four or eight rotors each generating 2.5 MW. Clusters of FEG's could provide as much power as need for a given site.

The FEG would fly up into the sky, with its rotors powered by electricity off the grid, pulling up its tether. Once it at its desired altitude it would change the pitch on its rotors and start generating power from the wind. GPS technology would be used to assure that the rotorcraft stays within a few feet both horizontally and vertically of where it is programed to be and a computer would control the rotorcraft's attitude, i.e. pitch, roll and yaw.

The amount of power that you can produce in a wind turbine varies as the cube of the velocity and linearly as the density. So although the density decreases with an increase in altitude, the increase in velocity that you gain with higher altitudes more than makes up for the decrease in density. This further explains the advantage that FEG's have flying at high altitudes and allows the rotors to be smaller in diameter. The wind speed, in addition to being higher, is more uniform.

It is much more steady, blowing at high, useful velocities a much greater percent of the time than do winds at ground level. This gives FEGs the advantage of having a higher capacity factor. Capacity factor is the percentage of energy actually captured relative to what would be captured if the wind turbines were operating at full capacity all the time. Ground based sites that can produce a capacity factor of 35% are hard to find. Capacity factors in the jet stream range from about 70% in the southern parts of the U.S to over 90% in the north. At a capacity factor of 90%, FEGs could become the nation's cheapest source of electricity, with an estimated cost per kilowatt hour of less than 2 cents, about half the price of coal.

Also the wind tends to blow from one direction and when it changes direction it changes slowly. The air is free from turbulence caused by friction and ground protuberances, but is subject to high altitude turbulence. This is moderated by the ability of the FEG to sway on its tether rather than being attached to a ridged tower. The FEG can move up and down on its tether the same way an airplane does to avoid turbulence.

The use of tethers to position objects in the sky is not unknown. Balloons tethered at altitudes up to 15,000 feet exist now at fifteen sites along the southern borders of the United States carrying radar equipment to detect illegal flights from the south trying to smuggle drugs. These sites are shown on all aeronautical charts, as restricted spaces, and are well known to pilots. By reserving less than one four hundredth (0.4%) of U.S. air space, located at relatively remote locations, not on airway routes, all the nations electrical energy needs could be met. The strength to weight ratio of new tether materials has improved over time so much that tethers now available are no longer too heavy to be held up by flying energy generating devices at the needed high altitudes. Tether technology is not simple, but a number of vendors now compete in this field selling primarily to the military and NASA. The FEG would be able to moved up or down on its tether to seek the best wind conditions or to move out of excessively turbulent air space.

WorldChanging has some more details on SkyWindPower, noting some of the main drawbacks with these schemes.

Output would also be less dependent on location than it is on the ground, simply because terrain doesn't matter much when you're at 35,000ft; however, since the jetstream and other "geostrophic" winds don't blow much at latitudes near the equator, it would be useful primarily for middle- and higher-latitudes.

They can't promise uninterrupted power all the time, however. In an electrical storm, the power-carrying tether becomes the biggest lightning rod you've ever seen. (Move over, Ben Franklin!) Their website says this problem is "frequently brought to our attention, and must be addressed." Their plan is to take the flyers down to land before a storm gets bad, and wait for it to end.

The flying windmills would initially get in position under their own power, using their motors to drive the propeller blades and helicopter upwards until they reached altitude. Then the motors would turn off and become generators as wind pushes the propeller blades, and the whirligig would float instead of fall because when tethered, the lift generated by the wind would overcome the craft's weight as it also generates power.

The obvious question is safety. What happens if one of these things falls out of the sky? The proposed design has quadruple-redundancy in the propellers used to hold it up and generate power, and the units could be located away from population centers, so that seems reasonable. What about planes running into them, or more likely, their tethers? They would fly in restricted airspace. Sky Windpower points out that there are already many high-altitude tethered balloons in the US that have not had problems, and that enough installations to generate 100% of the US's power needs could fit in 1/400th of the nation's airspace. What about birds getting killed? They say that the flying windmills could make noise that would keep birds away; this would be prohibitive for ground-based turbines, but at high altitude no people will be around to be annoyed by it.

The prototypes Roberts has been making for the last 25 years have gone from wind tunnel to field trial, and they apparently work, with no new technologies required. However, they have been stalled seeking funding for the last three years. The text on their website shows a woeful lack of marketing savvy, leaning towards crackpottyness, so they may not be getting funding anytime soon. But hopefully they will find someone willing to give them a shot, since they seem the most promising of the three [companies looked at here].

Robert Cringely of "I, Cringely" explains some of the history behind these schemes in "Oh, and We Also Saved the World: Google's Energy Plan".

What's cool about these tethered tensile wings, he explained, is that they can be designed in such a way that no aircraft fuselage is needed and yet they can lift (vertically, straight from the ground, no runway even required!) enormous weights. And I mean ENORMOUS weights, like a thousand tons. A fully loaded Boeing 747-400 weighs about 400 tons, so a THOUSAND tons would change the nature of airfreight.

But there's an even better application for this technology than airfreight, he explained, electric power generation. Build a gigantic tethered tension wing and power it with electric motors mounted in the leading edge of the wing. Send the electricity to run these motors up the tether, itself. The wing will take off vertically and once it is at the end of its rope, so to speak, can be made to circle thousands, or even tens of thousands, of feet off the ground without a pilot or any sort of crew.

Remember from your ground school days that wind tends to increase with altitude. Once aloft, circling in the stiff breeze a few thousand feet in the air, it should be possible during most daylight hours to just turn off the electric motors and get them running as generators, taking energy out of the wind. This would be regenerative air braking.

To my knowledge this idea of using a tethered kite to generate power was first put forth back in 2003 by Pete Lynn, a mechanical engineer and second-generation kite designer from New Zealand. He described his work back then in an extensive post on Google Groups as well as on his own web page. (That page is no longer directly available online, but in this week's links we've managed to recover that page thanks to the Internet Archive's WayBack Machine.)

Lynn's explanations in 2003 and 2004 were very clear and the implications of his work even clearer: this was probably the best way yet to extract energy from the wind — far better than more traditional windmills. ...

The problem with wind power is that much of the time there isn't enough of it available to even justify energizing the alternators attached to the large windmills used in wind farms. Unless the wind speed is over, say, 10 miles per hour, it isn't worth running the windmills at all. And above some speed on the order of 40 mph, it again isn't worth the effort, this time because of fear that high winds will damage the windmills — windmills sometimes costing hundreds of thousands of dollars each.

But power-generating tension kites are different, as Lynn so ably explained: "the numbers strongly infer that such a wind turbine system can produce power for around a fifth to a tenth the cost of current generation systems, depending on site costs. This is roughly US 0.5 cents a kilowatt hour, with the likelihood that this will reduce further with mass production."

Five tenths of a cent per kilowatt-hour is VASTLY cheaper than the average retail price was for electricity anywhere in the U.S. in 2005, where electricity costs ran as high as 12 cents per kilowatt-hour in California and 14 cents per kilowatt-hour in the state of New York. So even though the kits would have to be all new construction and the old coal, gas, and oil-fired power plants mothballed or dismantled, the payback period for doing so would be measured in months, not years or decades as most such capital expenses are today. Today, with energy costs even higher, the payback would be even quicker.

Getting the cost of wind-power production so low depends on a couple of factors — building kites that cost very little for the power they generate and allowing them to harvest energy from a larger slug of airspace than is used by the big ground-based windmills employed in most wind farms.

"The trick is that the propeller is operating at the speed of the airplane, which is many times greater than that of the true wind speed," wrote Lynn. "At an overall lift to drag ratio of ten the air plane speed is ten times that of the true wind, with power proportional to wind speed cubed, the propeller can have a thousandth the swept area of a comparable wind turbine for the same power. This makes for a very compact and effective unit, it is important to exploit this apparent wind directly as it allows for much higher specific speed of the propeller and generating unit, (no gearing)... Line length can actually scale with size, somewhat, a 100MW unit might optimally have around a 1000m line. "

Such wind kites would be cheaper to build than current windmills because their structural efficiency is so high, according to Lynn. In fact the weight of such a kite turbine might be only one percent that of a comparable windmill.

According to Lynn's figures, then, to completely replace the one million megawatts of electricity generated in the U.S. annually by a total of 16,000 generators of various types would require 10,000 of those 100-megawatt tethered flying wings. ...

Pete Lynn no longer works in New Zealand. Today he works in Emeryville, CA at a company called Makani Power, which is developing exactly the sort of power-generating kites Lynn envisioned six years ago. Go to the people section of Makani's website and you'll see the healthiest bunch of windsurfer/engineers imaginable, including Pete Lynn, who actually seems to play a minor role in the company.

The only other initiative in this area is a Dutch effort out of the Delft University of Technology, described by The Economist:

Wubbo Ockels of the Delft University of Technology in the Netherlands has been developing another approach to airborne wind generation at lower altitude, with backing from Royal Dutch Shell and Nederlandse Gasunie, a natural-gas company. Dr Ockels’s idea is that a kite (without rotor blades) be launched from a ground station, turning a generator as it rises to an altitude of several hundred metres. When it reaches its full height, it alters its shape to catch less wind, and can thus be reeled back in using much less power than it produced when it was being paid out.

An arrangement of two or more of these kites could act together to produce a steady supply of power. When one kite was being released, part of the electricity produced would reel the other kite back in, and vice versa. The whole system would thus remain in surplus, and if well designed could deliver a constant current. This system has the advantage that it requires only simple parts—generators, kites and cables—and should thus be much cheaper to build than a conventional turbine.

Controlling it, however, would be a different matter. Dr Ockels is working on kites with wings and rudders, which look much more like a plane than anything you might see flying in the park. The wings and rudders themselves would be under computer control—a technology already well established for flying aircraft without too much interference from a human pilot.

To test the idea, Dr Ockels’s team is building a 100kW prototype. He hopes to start testing a full-scale device, which would generate 10MW, within five years. That would be large enough to power around 10,000 homes. He believes the system should be capable of generating electricity at a cost of just 1 cent a kilowatt hour.

Any promise of such cheap energy has to be treated with scepticism, and all these projects are still a long way from the full-scale test rigs needed to prove they will succeed. No-one denies that it will be hard to build a flying generator that can make money. However, the political impetus behind renewable energy is growing and space is limited at ground level. Perhaps it is time for the wind power industry to reach for the sky.

There are other efforts efforts, including an Italian one, Kitegen:
Check out the video on the site for the flight of the prototype.
And there is this:
Check out also the increase in average wind speed as you go higher, and in constancy of wind - the increase in power generated is not a linear progression, but rises as a much higher function of windspeed.
This all boils down to the fact that you transform windpower by harvesting at at altitudes above 800 meters from something which is intermittent, and doesn't happen at any strengths for a lot of the year, to one of the most concentrated and reliable sources of renewable power, which can be accessed almost anywhere.
You throw away the huge structure needed for windmills, and greatly multiply the power, both from the higher average windspeeds at altitude and from the way you can steer the kites to generate virtual wind - the computer control systems for an automated system have already been developed by Skysails, and contrary to what is written here they say that they will need no extra members of staff on board the ships, as it is a fully automated system.
Of course that is yet to prove itself in practise.
Makani is backed by Google.
This could provide ample power for an industrial lifestyle for everyone in the world, and at hugely lower cost than present generation

they will need no extra members of staff on board the ships, as it is a fully automated system

Hopefully that is true - though I suspect there are some cases where crew intervention will be required, so people will need some training at the least.

Thanks for the Kitegen link - I'd never heard of those guys.

Back on earth (and out of the sky...)--

There's the Turby, and this is being implemented as an affordable, small-scale option and one that is needed for PV backup..

It is very nice that this sail will save something south of 30% in fuel costs on what appear to be otherwise a conventional ship.

A century ago, the largest "all sail" ships ever built is the "Preussen" which had 5 masts and was 438 ft. long with a displacement of 5,081 tons, or the "France", 418 ft. long and 5,600 tons displacement.

The largest all sail ship-of-the-line is the French Valmy which displaced 5,826 tons and had a length of 64 meters.

All of these ships used sails rigged from the deck. A kite system that makes use of stronger winds higher up should be able to pull a much larger ship entirely on sail, with the on-board engine plant only used when it is entering / leaving port and the prop feathered the rest of the time. Even better, let the prop rotate and use the energy to generate electricity to carry the ship's hotel load.

An engine that is only used in such a limited fashion can be made much more powerful for a given size than a typical marine engine that is expected to operate 24/7 for the life of the ship.

Why not go for 99% sail powered?

Many trade goods like coal are bulky, low value, and would hardly matter if it spent more time in transit of the fuel savings were large enough.

That is, of course, assuming that such a sailing ship can have a small, inexpensive crew like an oil fired ship.

That monster ship from Maersk I show above apparently has a crew of 13 people - so crew sizes seem to be pretty small.

On a simpler note...I see sails in our future...maybe a "new occupation/industry...once again clipperships set sail...

150 MPG plug-in SUV. it's a start. I can see car-pooling in a 150 mpg car from the suburbs. kunstler's worst nightmare.

A little off-topic for this thread, but I like the "Kunstler's worst nightmare" tag (so much so I'll steal it for a Peak Energy post).

The 150mpg claim is a furphy as is cogently argued by 'mind' at MetaEfficient:

I love these ideas, despite any shortcomings. It's an aesthetically cool way to power a civilization. Then again, I admit to a fondness for putting things up into the sky, which I've been doing since I was about 6. Being bored in the Indiana far-suburbs, my younger brothers and I made all manner of unlikely things.

Among these things was putting a small generator and fan blade beheath a 12-foot standard-design kite to power the flashlight bulbs on it. Worked until it broke. This would have been in about 1967, in the unlikely event nobody did it before... though we didn't run power down the wire. We did use wire once on a stable kite about 100m in altitude in a thunderstorm to see if we could direct a lightning bolt to some stuff on the ground we wanted to fuse together, but the results were ambiguous as we weren't nuts enough to stand at the base of it, and it was gone after the storm.

We also built enormous translucent hot-air things out of 10-cent plastic dropcloths stapled together, but these had to be "release and watch" devices with the occasional side-effect of sometimes dropping chunks of burning sterno on rooftops like blue napalm... a pretty effect, though, and the things looked like invading martian sandworms or something. But I digress....

Similarly, back in the 60's you could get large surplus military parachutes through mailorder ads in comic books, and we used these for motive power on a number of garage-made vehicles. These would not only propel a human at significant speeds downwind, but would actually go over any buildings in their way. We never did figure a way around the power-line drawback other than to use expendable passengers; and our test-pilot quit riding the things when he had to bail out 20 feet in the air when the 'rocket sled' headed over the Fall Creek School gymnasium. He was still on the rise when he hit the side of it. There was definitely power involved.

Later in life, I suggested kites for the Greenpeace vessel RW, but it was refitted with large fairly-conventional sails instead.

Tensile strength rocks for construction, and hanging things up in the wind to generate electicity is great. Dozens of ways spring to mind, and they should probably all be tried.

Like greenish, I love these ideas.

How far can it go? I see one number of 10 to 15% fuel saving. Why not 99% as D111 suggests? I think the answer must depend on operating cost of bunker oil fuel relative to capital cost of the kites. If the idea succeeds at all, the percent saving will be determined by the drift of prices over time.

Also, I note in the Briza PDF they talk about placing their blimps in the wind shade of their wind turbines. This wind kite idea is the first idea that I've seen that has, I think, some chance of success. It makes me wonder what is the total size of the wind resource. There is wind shade for each one of these things. They must therefore be placed at some minimum spacing. All the different kite designs must have different minimum spacings. Has anyone seen serious engineering / scientific calculations of this resource?

As soon as you get above around 800 meters, 8 times the height of the tallest windmill, or 300 meters at sea, the wind power resource is both vast and reliable.
It contains many hundreds of times as much energy as is needed by, say, 15billion people in a technological society.
It is also one of the most concentrated forms of renewable energy, far more than solar.
Effectively, the only part of a windmill which generates power is the area towards the tips of the rotors, so all the rest of the structure, the base, and the tower and most of the blades, are not generating power.
Kites cut out all this waste.
If you look at the pdf's on the kitegen site I linked, much of what you wanted to know is there.
By sweeping the airspace above a nuclear plant, which is restricted anyway, a kitegen system is calculated to generate as much area as the plant!
The control system for the multiple kites on this system is probably the difficult bit.
You will find most of the rest here:
Makani looks to be going for a system where you have the generator on the kite, you power up using an electrical lead of high-performance materials, and fly it to the required altitude.
The propellers then stop being driven, and start collecting wind energy.
The kites would be larger than on the Kitegen system, and controls simpler.
If you think in terms of using around 1% of the airspace in the States, you are in the right ball-park.
The exact amounts depend on all sorts of variables, including the height that is chosen - winds get stronger as you go higher, but obviously affect air traffic control more.
High altitude wind is one of only two technologies I am aware of which might actually greatly reduce energy costs as against current levels, the other being mass-produced nuclear plants.
Hot rock Geothermal could provide a lot of power almost everywhere, but getting it is probably relatively espensive.

The voyage of Emma Maerks, worlds largest cargo ship:

Pick up from China 11,000 20ft containers full of:

    Martini glasses, sports bags, shower gel, shampoo and bath foam, pinball machines, toothpicks, chopsticks, electric guitars, tool boxes, drum kits, lamp shades, silver and wooden photo frames, wooden trouser hangers, candles, books, laptop computers, singing and dancing gorilla toys, poker tables, bingo sets, lunchboxes, cuddly toys, make-up, dolls, toy motorcycles, christmas decorations, sofas, puzzles, televisions, frozen mussles, computer parts, CD players, fax machines, key rings, jam, noodles, biscuits, pumpkins (frozen), more than 1000 bales of carpet, 117 boxes of girls jeans, 40 boxes of brass, 2000 pairs of mens shoes, 9000 pairs of trainers, three boxes of spectacle frames and more than 1500 frozen cooked chickens.

Return from Europe with:

    Plastic scrap, waste paper and card, waste electronic components, repairable electrical goods and scap metal.


ransu -

Well that just about perfectly illustrates what globilization is all about circa 2008, doesn't it?

The Chinese make stuff and sell it to the West, whereas what the West sells to China consists mainly of bulk waste material and junk goods ... that are in turn made back into stuff to be sold to the West.

Goods flow from east to west; but money flows from west to east.

It doesn't take a genius to see where this is leading.

How about renaming the ship "Chinese Junk"?

Carrying the products of our crass consumer society. How much of that stuff do we actually need?

"How much of that stuff do we actually need?"

What, you want to cut me off from my supply of "singing and dancing gorilla toys"?

What are you, some kind of Luddite? :-)


I couldnt live without my solar powered halogen rockery lights!

In one of Herman Daly's books he estimates that at least 40% of global trade is simply exchanging the same stuff--e.g., shortbread cookies crossing the mid-Atlantic.

I have seen other studies suggesting that France and Great Britain exchange roughly equal amounts of dairy products.

The kite ideas are nifty, but much more could be saved by simply sharing recipes.

And with food, we spend an enormous amount shipping water at high-speed from one place on the planet to another. Water is a high percentage of the weight of many shipped foods....

Um, the idea that people are swapping the same stuff back and forth is simply nonsense. It is true that some countries import and export oil, but that is simply that the oil they export is different from the oil they import. Australia used to export waxy oil and import asphaltic oil to get enough oil to make it's roads. Perhaps it still does.

This wasn't a comment about oil, but about the basket of goods on container ships. For example, go into a grocery store where you live and look at a section of cooking oils, wines, beers, cheese, baked goods, fruit vegetables, pasta products, etc. and count the countries of origin.

In my town much of the olive oil market is dominated by European imports, though olives grow great here. Wines are usually local, but we can get plenty of French, Italian, Australian and Chilean too. Beers from Europe and Mexico are abundant. Cheese from Europe is easy to get. Hard crackers and cookies from Europe, no problem. Vegetables and fruits come from all over the world! Italian pasta is on our shelves.

Somebody do the same in another country and compare notes.

I haven't read the primary literature on this, but I believe the book was Beyond Growth by Herman Daly were read it. Richard Douthwaite in the bood The Growth Illusion has similar discussion I think.

Much of the cheap Chinese made clothes Americans buy are made of cotton grown in the U.S. south. So the cotton is shipped from the US to China. China makes into clothes and ships it back. So by the time the average American buys the clothes in a Walmart, the item has essentially gone half-way round the world twice. Makes you realize how inconsequential the cost of shipping really is for many products.

And that in turn makes you realize how little actual oil it takes. It's perfectly possible that it saves energy shipping something to China, do stuff with it there, and shipping it back, because shipping containers on ships is so extremely energy-efficient.

That was exactly my point - shipping stuff around is already very efficient (vastly more so than trucking it from port to big box store) and likely to become more so.

This means that coastal areas will be under much less pressure to "relocalise" their economies, as their transport costs aren't the limiting factor - its the cost of the "stuff" itself.

Cities in the hinterland however (especially without good rail connections) are going to be the ones hardest hit by rising transport fuel costs.

Exactly. You can ship ore from Brazil to China for $100 a tonne, and most of that price is due to competition for bulk carriers. A few dollars a kilogram.

The "half-way across the world" argument is just emotional. Once you get it floating, distance isn't that important.

It makes sense to import dairy into London from Brittanny instead of from Scotland. States are not point entities. Though I agree that cheap fuels make all need for efficiency vanish.

With the power kites and ballons the one design factor that is not talked about is the weight of the power lines. To get to the alitude that they want to operate at the power lines will be way too heavy to be held up by the generating unit itself. Maybe there will have to be kite units that attach to the power lines just to support them. I beleive the world record for a kite is around 20,000 ft. It was done with several kites strung out along the line just to support it. I'm sure something similar will have to be done here.
Also the generators will have to be very high voltage to keep the diameter of the power lines small and yet be able to transmitt the nessary power.

Not all of the possible designs use power lines. The Kitegen, for instance, operates at around 800-1000 meters and pulls around a central rotating generator, rather like a clothes drier.
This should be well within current materials technology.
There are a number of other designs which do not include power lines, for instance the Laddermill
They fly at rather higher altitude but again do not use power lines:
They are planning on using a material called Dyneema.
For some of the other designs I agree that the power line design will be challenging.

Wind can power a human civilization of quite adequate size.

I have discovered a truly marvelous demonstration of this proposition that this margin is too narrow to contain.

Look for a possible future keypost.

I actually went out a few years ago and learned to be a "licensed" windsurfer. That means I have a little card that allows me to rent a windsurfer from anywhere in the world, and it also means I've learned more than the average tyro. I spent some time hanging out with the windsurfers and kite sailors.

I learned two things:

(1) I have windsurfing! Feh! You guys can have it! Phooey!
(2) Windsurfing is losing ground to kite surfing and the reasons why are fascinating. You need a lot of different rigs, different sail sizes and board sizes to match conditions in windsurfing. Meanwhile a kite sailor can cover most conditions with one kite, and may have two. The kiters can sail close to the wind, and it's essentially a fairly simple setup. If things get hairy, you can just let go and the kite dumps and that's that - kite-sailing ships would have a system like this, no more of the rolling and losing your mast business regular sailboats do sometimes. The kite is pretty easy to understand, probably easier to understand than a sail is, really. Aspiring kite sailors are sold a DVD and toy kite, and go through a set of lessons and maneuvers with that. When they learn how the kite works and how to maneuver it, they start lessons with the real thing.

I can see this possibly really taking off, lol. It takes modern fabrics and cordage to make something like this work which is why people weren't doing it 1000's of years ago, but at least for now we have that stuff.

It also takes a sophisticated computer system to control the kite, unless you want to flu it by hand!
Watching the kite deploy and furl back into it's telescopic tube which contains it is fascinating, not to mention the interest of watching it fly under computer control in figure 8's to generate virtual wind!
Here's the video:

I would think the Chinese would really go for this stuff, kite flying being a part of the cultural. That and having invented kites a long time ago.

Some comments:

Kite Sails -

Seems like a great idea for giving large cargo ships a wind 'boost' and thereby saving on fuel consumption. However, let us be sure to understand that such devices were never intended to, and never will, turn power ships into sailing ships. The reasons should be obvious: i) the modern cargo ship has a hull form that is hardly conducive to true sailing,, tacking at an angle to the wind, and ii) modern nautical commerce is based on direct point-to-point courses and extremely well-planned tight schedules. Having to go off course because of the necessity of tacking and thus lose perhaps days or weeks of schedule would be costly and not tolerated. It just ain't gonna happen.

Airborne Turbines -

There is no doubt that if a wind turbine could be placed at high altitude it would enjoy a much greater power density and a much greater uniformity of wind availability and thus a greater 'capacity factor'. However, the question then becomes: overall, do we gain or lose something by attempting to put wind turbines up in the sky?

On the plus side, the turbines can be considerably smaller for a given amount of rated power and will operate much more steadily.

But on the negative side, we have the prospect of trying to keep several hundred tons of hardware up in the sky 24/7 and having to contend with all the stresses and strains of doing so. Then we have to think about whether such would be acceptable to the people living under and near an array of such airborne wind turbines.

If you think the NIMBY effect is bad regarding offshore wind, just watch what will happen when you try to put these things over someone's home! The other thing is that the higher these things are placed the wider the radius of tether swing and the more widley placed they will have to be situated. So, even though they would be very high up, they would still occupy or dominate a very large plot of land.

Then, the question of how you go about maintenance and repair isn't even addressed.

This concept is a perfect example of confusing efficiency with effectiveness. While an airborne wind turbine might have superior efficiency, its effectiveness in the real world is highly dubious.

You are absolutely correct that wind power will not power the ship totally - Skysail have no plans to do so, although as they gain experience they plan to increase the area of the kites substantially.
As for your strictures on generating power, it seems to me that these only apply to some of the proposals - not all of them are at very high altitude.
As for their being over someone's home - so are aeroplanes.
However, most proposals allow for their siting well away from houses, and indeed the power density leads to rather compact land use patterns, certainly in comparison to windmills.
So, for instance, the Kitegen proposal would generate 1Gw of power in around the same airspace as the controlled space over a nuclear power station.
In the UK should there be concerns over land use in the particular configuration chosen, then you could certainly site them in shallow water offshore.
For the US the lower population density means that for most areas siting considerations would hardly be a show-stopper.
Many of the proposals do not have the generators in the air, but on the ground, minimising weight concerns.
Of course though, the concerns you raise are amoungst the real engineering issues that the various approaches try to address.
The prize is turning wind power from an intermittent, expensive hobby into a massive resource, accessible at most temperate latitudes and without emissions.

1. I wonder what the upper limit to kite sails on ships is? What are the issues with just increasing the size/tether?

2. The NIMBY issue: I bet when there are intermittent power outages and brownouts, people will be glad that the kite generators are nearby.

The first kite has a design load of 16 tons and is 160sq meters.
They have plans to build up to a 128 ton system and 1280 sq meters
All the information is on their website
As regards nibyism, it might help to be a little less judgemental of others motivations, if you don't happen to agree.
Windmills provide comparatively little power and are a considerable nuisance.
Any high altitude wind system is likely to be much more compact and generate a lot more power, so there should be less who are upset by them

:-) well, the MARE Initiative platform (offshore) might just be the perfect place for airborne turbines ... (?) lol

Hi can anybody clear three pionys for meregarding aii bourne generators
1/ How is the Torque reaction of the generator over come,
2/ how do the make allowance for the drop in air density as the power developed by a areofoil is directly related to airdensity and this drops exponentialy with hight.
3/ Generators/transformers are heavy to my mind a trade off will need to be made in lift/drag to keep them up versus potential, power to be developed

Seems to me that if kites and airborne turbines were used on a large scale it would spell the end of safe air transportation. Maybe just as well, there isn't likely to be enough fuel for airplanes anyway. I sure wouldn't want to take an air trip to any place with moving air cables all over the place or even stationary ones. But then I never fly anyway.

Check back to the original article. We are only talking of around 1/400th of the airspace of the US.
There are already a lot of weather balloons and such with cables.
The problem is very minor, and air travel would be quite safe assuming minimal regulation and precaution.

None of the high altitude turbine stuff sounds like rocket science, so why are there no working prototypes? So many of these great ideas simply remain ideas because they are not quite do-able.

Funding is darn difficult for really new ideas - uncounted billions are thrown at things like corn ethanol, or guarantees for windmills, where there is a constituency and votes, but really new ideas by definition are small.
Government funding often misses them, as the amounts are too small - they like things like ITER, which cost billions - incidentally, it appears to me that has no chance of actually producing fusion at an economic price, whereas the much more hopeful Bussard process
has struggled for years to get tiny amounts of funds:
The problem is that there are around 5 people in the world who understand it, and 4 of those work for ITER!
All the guys involved in high-altitude wind have struggled for years for any level of funding, when what they need is pocket change compared to the subsidy-machine for PV and windmills.
Never underestimate the power of human stupidity!

Thanks for the memories.

Nice romp down memory lane.

This has been in development for ever.

I used to live on a 40' kettenburg 15 years ago and BELIEVED that this tech was the future of shipping.

I developed a retro-fit sail rig for Zodiac and contracted with West Marine for almost 2 years.

Discussed this concept with many top designers of the last 20 years.

The potential for loosing the entire rig (which is real and constant) on these kites is IMO the real deal breaker second only to the complexity of deploying and retrieving.

The only thing that has gotten even close to commercial application are the tubine towers like on the Cousteau research vessel Alycone.

I am a bit supprised TOD is dragging up this Waterworld fantasy bologna as well as mpg enhancing gimmics.

I am not condeming kite power, in fact I have seen it work in theory and in practice. However it has less chance of being applied than all of the EXISTING tech that could make the ICE vehicles twice as efficent as they now are.

Next you will be reposting my original post on Steorn.

Lets reel in that kite and get back down to earth with stranded wind, solar, electrified rail, etc.

Best hopes for doing what we already know is doable.

If nothing had changed in the intervening years you might have a point.
It would not have been easy to design the computer controlled system to guide the Skysail 15 years ago.
Materials for things like power cables and tethers have also advanced, as has computer modelling of aerodynamics.
What is a challenging project today would have been impossible or impractical 20 years ago.
Of course though you are correct in the main hurdles that Skysail has to overcome to prove itself - deploying, furling and avoiding loosing the kites.
That is what the trials on the cargo ship will test.
you do know that full trials have already been carried out on a smaller vessel including computer control, flying, deploying and furling the kite?
See the video I linked to earlier in this thread for the system in action.

Materials for things like power cables and tethers have also advanced .... What is a challenging project today would have been impossible or impractical 20 years ago

Really? The "new" materials for the tethers (ultra high molecular weight polyethylenes) have been around for a long while. Dyneema was invented in 1979.

So if it does the job, why change? :-)
Of course you don't have to use any new materials, but they are more likely to be available now than 20 years ago if you have a particular requirement.
We certainly know a great deal more about flying guided by a computer than 20years ago, which is an enabling technology for these ideas.

nothing of significance HAS changed.

the spooling, cannon launch, computer control, wind tracking, tension sensors, etc.

All 20 years old. A pipe dream that will never be realised.

Why is this stuff being floated here on what has been the primary source for debunking pie (kite?) in the sky BS?

and ilargi with tons of pertinent info is censored.

Hello ello ello ello, anybody out there at TOD?

yeah, look at all the UAV's that were flying around the battlefields 20 years ago!
Oh, hang on...
You obviously just have an axe to grind.
In principle it is usually pretty difficult to prove that something cannot be done.
If you know to the contrary why don't you present your precise proof, instead of just making flat statements?
Otherwise, if you think it is a waste of time, what are you doing here?

Well, parachute canopies have advanced a lot in the last 20 years, as skydiving took off in the 70s and 80s it provided a good test-bed for the evolution of rigs,wings and high-performance fabrics.

Kite-surfing didn't exist 20 years ago - it was made possible by lessons learnt in parachuting and paragliding.

Ask a sailor if sails and lines have improved at all in the last 2 decades.

Go Dave go! You really are a fine addition to this site (really).

I find this stuff exciting, even if I give it less than a fifty percent chance of coming to pass. Look at the risk reward ratio. Risk, a high probability that any particular high altitude wind project being backed will not be a winner. Reward, potentially huge. If we can't figure out how to give these sorts of ideas a reasonable chance at development, what does that say about us?

The reason I like high altitude wind-power is that I'm cheap!
And so should high altitude windpower be if it can be made to work at all.
The alternatives are mostly pricier, the exception being the Bussard fusion machine I referenced earlier in this thread, and it's cousin focus fusion.
Mind you, if I didn't have greens to bother about I could reduce the cost of nuclear power hugely.
I would build them underneath cities - safe from sabotage, and still more secure with perhaps 100meters of earth on top of them as well as their containment vessel.
In a separate system which didn't enter the reactor I would send the coolant water.
After building the piping was paid off you would have hot water free with your electric, bar maintenance.
Green roofs would reduce heat island effects.
You might also be able to make geothermal dry-rock power work, but I suspect it would be pretty expensive.
You are right high-altitude wind is regarded as a long shot, but unlike most renewable resources it is concentrated, and it seems to me that we SHOULD be able to make it work, if we gave it a bit of a go - resources so far have been tiny.
Further south where most of humanity live solar should work well in many applications, especially in places like Africa with a limited grid.
It is just that PV is a really, really silly idea in Germany, where they have spent a fortune on it, and a 1kw system will produce you a magnificent 3watts or so during Dec, Jan and Feb
50c feed in tarriffs, forsooth!

The good stuff is quite expensive ( like Cuben Fiber). and as was pointed out, one mistake can be disastrous. I have been a kite flyer and sailor for quite some time, and the feedback loops dealing with wind are immense.
But I'm willing to be proven wrong, as kites always bring elegance and beauty to anything they touch.

Thanks for the comment. That gives me some insight into what the problems are.
It certainly sounds from your comment as though this would have been impossible in previous years, due to computational difficulties, and difficult even now.
I take it the Cuben Fiber is material for the cable?
If so, how fast does the cost of these materials normally drop?

Cuben is incredibly strong and light sail and kite fabric, also has made inroads into the lightweight backpacking field. Magical stuff, but often times doubles the price of a item.
It has been around for a while, but unless you are a sponsored racer or obsessed backpacker, it is generally out of range.

Interesting! I am usually a bit suspicious of arguments which go: 'It may be ludicrously expensive now, but you wait until we get it into mass-production, prices will drop like a stone!'
It really all depends on the reasons why it is expensive - some technologies don't drop too much with economies of scale, technology is not a magic wand.
However, perhaps with the huge demand for the material from windpower generation, this or something similar would indeed see large cost reductions.
Particularly in the case of very high altitude ideas rather than the comparatively low sea-going vessel kites of Kitegen, this might be worth it for the stronger winds encountered at very high altitude and the weight savings.

Several of the posts on this thread have asked, to paraphrase, "If its so great, then why hasn't it been done? It's been touted for 20 or 30 years!"

Ahh, there's the rub. Many of the most promising alternative energy ideas were indeed touted and in some cases even pilot tested about 30 years ago. What happened to them?

Thirty years ago....1977-78, what a time it was...oil crisis, the Iran crisis, oil was to hit an all time high in 1980 that in inflation adjusted terms STILL has not been surpassed (in wage adjusted terms, we still have not even gotten close to it).

This pushed alternative energy thinking to the absolute edge of what was technically do-able with the then current technology, often far beyond what was then do-able. Briggs Stratton Corp. built a plug hybrid automobile in those days that was conceptually brilliant, but simply exceeded what any battery could have delivered at that time!

Then, 1982:

I ask readers of this post to look at the section of the chart from 1982 to approx. 1998.

I ask readers to ask themselves: How interested do you think bankers, investors, managers, politicians and leaders were in "alternatives" to oil and gas in this period?

Many who had given the early part of their careers to alternative energy research and investing were wiped out in this period. In this they shared the fate of those in the oil patch working in fossil fuels.
Energy production, energy research, and even oil E&P (Exploration and Production) were terribly underfunded in what were some of the darkest days for the energy industry in it's history. The alternative energy producers and the fossil fuels producers were brothers in misery.

Even now, as Matt Simmons reminds us repeatedly, oil and gas are CHEAP. But many alternatives are able to reach grid parity and compete even at this relatively cheap oil price.

If oil were to go to say $180 per barrel, which many in the peak community (and even Simmons himself) believes is possible, the alternatives would be EVEN MORE able to compete. If one considers the implications of carbon release by coal and petroleum, the alternatives could be viewed as the only enlightened and modern way to go. Fossil fuels would be seen as the dirty, expensive primitive laggard of the industry.

But oil and other fossil fuels do still have that one great advantage: They are cheap, even at today's historic high prices.
And anyone investing or developing alternatives to petroleum or coal can still feel the ghost of 1982 breathing down over thier shoulder: Could it happen again? Just at the moment of making the alternatives to oil and gas competitive, could the petro producers flood the market with cheap oil and drive petroleum prices through the floor?

The peakers say no, it can't happen, those days are over for good, the oil is just not out there in volume. And even if it were, it would be too expensive to get out of the ground or sub sea.

But of course, those in the alternative energy industry were told with absolute assurance in 1978-79 that the days of cheap oil were the 1990's, it was said, $5.00 per gallon gasoline would be considered a steal, and by 2000, gasoline would be so expensive no would be using it..... The North Sea? Of course, it will delver a little, but never enough to make a real difference, and the expense of drilling in heavy seas and terrible weather will make it too expensive to be a real factor....

But now, the time may have finally come that oil is truly as cheap as it will ever be. Since the start of this year, oil is higher than it has ever been with one 4 year exception in the late 1970's, when so many of these alternative ideas we are again seeing now were being dreamed up, designed, touted. The price of petroleum is again near a historic high point.

This time however, the technology of the alternatives is MUCH better, having finally caught up with many of the concepts dreamed of in the 1970's. Computers, nano technology, batteries, PV panels are operating at levels of efficiency unheard of even a decade ago.

But one thing has not changed. For any of the alternatives to really take hold and expand, the petroleum price must remain high, even if it is "cheap" in the larger sense that Simmons is referring to.
It absolutely MUST not decline quickly, as it did in 1982. The developers and investors in the alternative energy technologies are banking on the price of petroleum remaining sustainable at the current levels for the foeseeable future.

If they are wrong, again, they, and possibly we as modern technical societies lose everything.


Spot on, ThatsitImout!
Just as an addendum noting one other technology which uses a big enough resource to really make a difference, in the seventies in Britain they were looking into Geothermal energy, using hot dry rocks.
You could theoretically generate energy from this in most places , although practicalities and costs vary.
They stopped the project, partly because the technology relies on bring vertical tubes to force water down, and then horizontally to fraction the rock and produce steam, and fractioning did not occur as well as they had hoped. But the real reason was the cheap price of energy - at the time it had no chance of being competitive.
The technology has moved on a long way since those days, due to experience in drilling in the oil and gas industry, and experiments are underway to develop it anew.
In one place in Switzerland I believe they chose a daft place to drill, near a zone subject to earthquakes, and duly set off a small shock, which has delayed things nut experiments in other regions continue, in France.
With the change in Government Australia is also moving to exploit it's truly exceptional resources.
Here is a link to a recent MIT study indicating the vary large size and the economics of exploiting the resource in the States:

Dave - I did a post on geothermal energy (particularly hot rock) here a few months back :

The change of government hasn't really made any difference one way or the other - there was lots of enthusiasm before the government changed, and still is (see today's "Bullroarer" for a report from Tasmania).

Gav - your article is a very interesting read, and I enjoyed catching up on 'Peak Energy' again too!
Outstanding work, but I will mention the reason why I hadn't put your blog into my 'favs'
Linking to an individual story is difficult, and sad ggek that I am, I always reference energy posts.
I wonder if there is an easy fix for that?


When you say linking is difficult, do you mean you can't find the permalink for each post ? Or that the omnibus style posts with 20 different things in them aren't partcularly amenable to linking to as its hard for people to find the relevant item ?

If its the first one, the permalink is at the bottom of the post....

I didn't know what a Permalink was! 'blush!'

At first, I thought that this was an April Fool's joke, but then I realized that it's not April. Especially unbelievable was the kite attached to the ship. Maybe it's just that the longest I've been able to keep a kite in the air is around 10 seconds, so I thought that everyone was like that... Anyway, I think that these are some great ideas that some governments should start throwing a little money at. I mean, if we just used 10% (or even 1%) of the money we used subsidizing things that are harming us in the long run and instead threw it at various projects that might or might not work, but had the possibility of generating as much power as a nuclear power plant in just as much space and without the radioactivity, then I think we'd be a lot better off.

But even if this works, every form of energy has a downside. I can imagine it now. "August 14, 2134: Our ubiquitous kite technology that was first put into use just over a century ago could be involved in 'Rotational Speeding'. Since the year 2000, a full rotation of the earth has gone from 24 hours to the present 23 hours 36 minutes. Some scientists now attribute this to humans, with the kites of the Northern Hemisphere pulling the earth ever faster with them. On the other side of the issue, 2133 saw the Jet Stream's average speed decline to an all-time low." Or something, hehe...

You raise something that I have been wondering about.
Of course, to provide all the windpower needed by ten billion or so of us should only take a tiny fraction of the available resource, so real effects should be localised and limited.
However, since the function of wind is to transfer heat energy from the tropics to the arctic, I wondered if you would in fact 'use' some of this resource, leading to cooler temperatures in the arctic, or if in some way you would have to move the energy anyway, so that temperatures would remain constant, and if so, where the energy would come from.
You raise one possibility, some incredibly small slowing of the rotation rate of the earth, but I really have no idea!
I wonder what others think?

There is no chance of slowing the earths rotation, as the earth/atmosphere is a closed system. Increasing planetary wind drag significantly could have an impact on the weather, although I dodbt we will exploit enough high energy wind for that to matter. Generally the corriolis effect from the earths rotation causes wind to travel at right angles to the pressure gradient. Putting in wind resistance I think tends to allow those winds to slow down, and allow a bit more drift towards lower pressure. It is possible that adding drag would increase pole/equator heat transport rather then slow it. In general, decreasing transport would tend to cool the earth a bit, as cooler polar regions would have more snow/ice to reflect sunlight. Over tens of thousands of years, it is those periods where the tilt of the earths axis is lower than average that are ice ages.

Tidal power, on the other hand, increases the drag of the earth/moon system, transferring angular momentum from the earth to the moon. I doubt we could have much effect on the rate of retreat of the moon, which is currently a few cm/year.

The kite wind generator

Is already in the advanced test phase. The first 5kWp mobile generator (Mobilgen) has already been successfully testd. A second, bigger, 50kWp generator is under construction.

The final goal design is a 500 MWp wind generator. It will cost about 1/10 of an equivalent gas plant, with no externalities, except for a 5 km no-fly zone (the same existing for a nuclear plant).
Foundamentally, it will be a reliable (non intermittant) renewable energy plant with the same concentrated power of a fossil one.
It can be also downscaled or upscaled, and even put offshore.

Too good to be real?
The problem, for me, is that a similar source could be too good for us, freeing us to take care of energy waste, and enabling us to continue our BAU attitude, and consequently destroy the environment using its own energy.

As far as energy savings go, could cargo ships achieve further energy savings by using a hydrofoil configuration, or are they too big/heavy to accommodate that?

"Slow steaming" would save more $$$ in reduced fuel
consumption than any of these kite schemes ..

The ship would of course take longer per voyage to
reach it's destination ..

Potash ( guano ), coal, iron ore and bauxite could be
shipped this way ..

The 'last' cost effective cargoes in the age of sail
were potash, wool, lumber ..

Triff ..

Carbon emissions would drop by 23 per cent if ships cut their speed by 10 per cent — but shipping experts say that slower cargo movements would lead to more vessels being deployed, and pollution would return to its former levels.

It seems to me that you enforce a 10% speed reduction, add 10% more shipping capacity, and your still saving 13% emissions. I know the numbers don't work out exactly like that, but it's got to be close.

They have probably optimized speed versus costs. Those major costs: capital expense of the ship, cost of the crew, possibly lower revenue/trip because customers will probably pay a bit less for slower delivery, fuel cost, ship & engine maintainance costs.
I suspect as fuel grows more expensive that a newer optimization would be to slow down the speed. But schedules, are likely made at pretty rare intervals, and customers are probably used to Nday delivery. So rebalanacing probably ocurrs at rare intervals.

I read somewhere that the increase in world trade of recent years has been primarily absorbed by increasing cruise speeds rather than adding to the world merchant fleet. In the event of economic turndown / rising costs I suppose this can be absorbed by slowing back down again.

Long term all this high speed cruising - peak shipping / shipping crunch perhaps!

I live amongst the southern Appalachian mountains. In theory, we have the best wind energy potential in the SE US. None of that potential can be realized, however, because North Carolina has very strong ridgeline protection laws prohibiting development. WTs are simply not permitted at the places they would need to be to harvest that wind.

I wonder if these "flying wind farms" might not be a viable solution for us? Would a machine flying 1000+ft above the ridgeline (and often invisible above the clouds), attached by a barely-visible teather, be nearly as objectionable as a row of WTs along a ridgeline? The teather would not even need to be attached at the ridgeline, they could be attached at a point below the protection zone, thus offering a way around the restrictions.

If getting 1000ft above flat land gets one into more steady and stronger winds, what does getting 1000 ft above mountains that are over 6000 ft above sea level do for you? On the other hand, would there be too much turbulence?

The thought occurs to me that many of our mountains are within national park and forest lands. If one of these things came down, they would crash into uninhabited territory, which is a good thing.

Here's a discussion of the benefits of placing one high-altitude power system on mountaintops:
More generally though, the visual and so on impact of high altitude wind systems tends to be very much less than windmills, because you can generate much more power from one site.
An individual windmill is limited to around 5MW, and in practise for land installations they tend to be around 1.5-3MW due to noise issues and so on.
Many of the high-altitude wind systems vary form 50MW or so up to 5,000MW for one installation, so you obviously need many fewer of them.
There is the additional point that since they are way up in the air, they don't have the same noise and visual impact, with only a comparatively small ground installation.
For the ladder kite concept, for example, you are talking in terms of 200ladder kites to power the whole of the Netherlands, against umpteen thousands of windmills, even ignoring the fact that the more intermittent nature of the windmill power production means that you could not in practise power everything from that source - the more constant nature of high altitude wind means that you could power a much higher fraction of societies needs from that source.

You are describing technical details of hypothetical systems that exist as drawings. The odds of a commercial installation at anywhere close to economic production cosst in the next decade or two are extremely small (<1% ?).

In other words, an interesting but unrealistic dream.

Just build what works, 3 bladed horizontal axis WTs on tall towers and tell the NIMBYs that they are beautiful. Do offer the NIMBYs a choice of colors.


What about using an airborne wind turbine as part of a hybrid electric ship propulsion system? We already know how to do diesel-electric propulsion. An airborne wind turbine could contribute to the output of a diesel gen-set, helping to turn the drive shafts. Even if the wind at altitude was blowing in a direction divergent from the ship's course, you could still make headway. This seems simpler to me than performing alot of fancy kite manipulations in order to tack against the wind.
I think the wind turbines would be more versatile than kites, since the altitude of the turbines could be controlled by sending power up to the turbines and using the generators as motors. A wind turbine could hunt for a favorable or strong wind by borrowing power from the diesel gen-set, raising or lowering itself until it finds an optimal wind condition.
Using high-flying wind turbines on ships could contribute alot of useful meteorological knowledge. Just think of all the temperature, humidity, and wind velocity data a ship could collect if it had sensors regularly spaced along the tether to its wind turbine.