Personally I think thin film solar in conjunction with car or house based batteries will go closer to solving the baseload problem. That's if the price can come way down. The levels of storage envisioned for CSP plants seem to be generally less than 24 hours. Maybe that needs to be extended several times.

Also I'd take the 'comparable to gas fired' price suggestions with a pinch of salt. The gas generator can be switched on or off at random (if it has fuel) and the electrical connection usually already exists, not way out in the desert. It appears CSP promoters cite marginal costs, not average costs of a system that includes backup.

Sidenote: during Adelaide's heatwave some rellies went to Yorke Peninsula to catch the sea air. It too was like an oven despite being in effect way offshore. They sent a phone photo of the wind farm not stirring, the same time that every AC in Adelaide was switched on. CSP would have helped more.

As Prof Goose would say, thanks for your support :

http://reddit.com/info/6edxp/comments/

Because of the recent EROEI discussion, I'd give this link for a CSP estimate: http://www.ases.org/divisions/electric/newsletters/2006-04.html#roi
27 with storage and 44 without with E_out in electricity, not thermal.

By combining CSP district water heating with PV I get a cost estimate for electricity at under a penny per kWh here: http://mdsolar.blogspot.com/2008/03/lux-lucis-tepida.html
The water cools the silicon allowing a much higher concentration of sunlight. Also, the water shields the silicon from cosmic ray induced defects so that it lasts much longer. There may be immediate potential for 3 GW average electric power in the US by this method.

There is a lot of potential for CSP.

Chris

Thanks Big Gav - this is the best summary I have seen on Solar Thermal.

Excellent Article;

Thanks a lot.

An excellent guide to solar thermal power - thanks.

A couple of points, firstly the estimates I have seen are perhaps a bit more conservative on present costs, with figures of around 20-30cents/kwh hour mentioned:
http://www.renewableenergyworld.com/rea/news/story?id=51889

As against that though, you don't really need to compete initially with base-load costs, as in most of the most suitable areas power use tracks very well with solar incidence as it is mainly used for cooling.
There is a lot more flexibility in costing when it is for peak power, so you don't need to hit baseload costs. Increasing costs for natural gas which is the fuel of choice for peaking power should rapidly mean that solar thermal is the preferred option.

Many of the hot areas are also short of water, which makes it easier to use solar thermal than coal or nuclear power with their large cooling requirements. It should be noted though that water use in solar thermal is not negligible, as you need to clean the mirrors.

There is also no free lunch on environmental concerns, as you are using substantial areas of land and affecting the ecology. This would seem to me to be very manageable in most areas though.

There are also possibilities for using solar thermal power in some fuel cycles to replace oil use, for instance in a zinc cycle where the heart for a solar tower directly transforms zinc oxide into zinc, for use in batteries which are very dense in energy terms as they can use air as one of the inputs.
http://www.meridian-int-res.com/Projects/The_Zinc_Air_Solution.pdf
The_Zinc_Air_Solution.pdf

The European SOLZINC project has built and tested a Solar Thermal Reactor in Israel which can reduce Zinc Oxide to Zinc metal by solar power. An array of mirrors focuses sunlight onto a collector which then directs the concentrated light into the reactor chamber containing Zinc Oxide and beech charcoal. The temperature reaches over 1600 deg C. The charcoal reduces the oxide to Zinc metal. If the charcoal is produced from sustainable forests, the net CO2 emissions would be zero.

Many areas of Australia would appear to have the needed sunlight and access to forestry resources - ideally you would not want to transport the timber far.

This is a very advantageous process, as you are not transforming the energy form one form to another, which is always done at a cost.

There is also the possibility of using boron in a fuel cycle, as this fascinating site details:
http://www.eagle.ca/~gcowan/boron_blast.html#TOC

Is the increased complexity worth it? One reason why it actually seems like a pretty good bet is this: it never hurts to make some boron ahead.

Consider two power plants. Each turns 20 or 30 gigawatts of heat into 10 GW of chemical fuel. This is larger than usual for electric power plants today but an ordinary size for oil refineries.

One makes hydrogen, the other makes boron. If the boron plant has no takers for a couple of weeks, it can stack boron outside, perhaps on pallets, 40 acres six feet deep. Rain won't hurt it.

A car running on boron could have cross-continent range!

In either case the chance to turn out a useful portable fuel would seem to mean that perhaps even if solar thermal were around 20c/kwh, then perhaps it would be cost effective.

Could you please clarify whether or not the costs cited for solar thermal includes distribution and all other costs associated with actually transmitting the electricity to the retail customer. I assume this varies, but is there some sort of agreed upon range for comparison purposes.

Or perhaps we only need to be concerned with the marginal distribution costs of producing from the mojave desert.

A project recently in the news is Southern California Edison installing 250 mw on commercial rooftops in Los Angeles. The advantage of this approach is that it can feed into the existing local greed and not require additional transmission lines, etc. to make it all work. Might this approach reduce some of the advantage that solar thermal may have other PV?

Thanks Gav,

Your work and references fill an important gap in the post-carbon toolkit. Now to get it into the hands of those who do the heavy lifting (and jaw-dropping piano-smashing!) in the capital markets. Try cleantech.com and others. Is it not time for solar bonds? Maybe Aussies can configure them if too much of a departure from US energy values/norms.

I like the SciAm piece because it locates its central project in the heart of the US electrical demand beast, across 32,000 km2 of bare-earth right next to the backyards of the most innovative souls on earth, at least per their own self-image! Economic with relatively tiny rate subsidy (under certain potentially reasonable assumptions of course).

Beats bashing bitumen and other innocent tarbabies. We didn't ask to be born near the oilsands or heavy oil and sour gas fairways. From one sick and tired native Albertan...

Just do it.

Big Gav
Thanks for the excellent summary of the status of this technology. A couple of comments about the economics:
- Australian power generators, up until a year ago, were selling in to the grid at average prices of between $25 and $30 per MWhr(2.5c - 3.0c /kWhr). The power stations were still turning a profit at this price level. There has been a bit of a change in the pricing structure over the past year. The reasons are a bit too complex to deal with here. The point is that any competing technology needs to either be subsidised or taxed into competition with coal at these price levels.
- Through my work I have done extensive study into costing of Solar Thermal. My company built one of the only full scale solar troughs in the country. The figures quoted for the construction of a large scale solar thermal facility are pretty accurate. We have estimated it at around A$3100/kW.
- A solar thermal plant utilises the same technology as a coal fired plant for the bulk of the facility i.e. the solar collectors only replace the boiler component of a conventional plant. The boiler constitutes only 40% of the plant costs. You can therefore consider A$1900/kw of the cost fixed and not subject to either volume or technology induced improvement. The claim that the build costs can be reduced to US$1500 is simply wrong. It won't happen.
- Utilising the build cost of $3100/kW and feeding it into a financial model with a few other inputs for operations and maintenance results in a electricity sale price of around $230/MWhr.

I sincerely wish otherwise but the above are the plain economic facts. Either through tax or subsidies the electricity generation price would need to increase 7 fold to make solar thermal viable for stand alone base load operation. On the positive side the retail price of power will "only" have to increase around 150%.

Either Solar thermal or large scale PV will happen, but there will be a lot of screaming and nashing of teeth before it gets there.

Excellent overview of the status of solar thermal power generation projects. There's a bit more to passive solar design, though that could be an article all of it's own.

Great job on this piece.

I just interviewed at Stirling Energy Systems last week, I have a whole packet about the company that they gave me.

I think they have a good chance of dominating the market.

They have signed a 860MW deal with Southern California Edison, and a 900 MW deal with San Diego Gas & Electric, these two projects will require about 70,000 dish units in total. I applied for a High Volume manufacturing engineering position, as they are now ramping up production and hope to have dishes in place by aug of 2010.

A couple key advantages that stiling has is the dishes are modular, and they can track the sun much more effectively.

Modular is big because as they start building the plant as soon as one dish is in, they are putting power to the grid. This is huge for reliability, simplicity and lower startup costs. No cogen unit/boiler/chillers ect. Each dish outputs 3 phase 460 vac.

Tracking: Th tower of power and trough designs have a parabolic efficiency curve, meaning not all mirrors are reaching optimal sun exposure throughout the day, the Stirling dishes can track the sun in both rotation and arc, increasing their efficiency.

Also, they showed me the record received from the from the US Dept of Energy/Sandia National Labs stating an efficiency of 31.25%(sun exposure surface area X radiant energy of sun that day in W/energy output to grid in W)

Hello all,

Great post. I love CSP. I think it will be the solution for large scale power generation. The question is when.

So, I'm wondering when it will be cost competitive? If $3000-3100/kW remains fixed for CSP then how long will it be before electricity from FF is more expensive? Excluding any taxes, subsidies, carbon credits, or legislation, how long before depletion pushes up the cost of coal and gas to make CSP competitive?

Thanks in advance,
Tim

PS for bonus points give TheOilDrum.com a Defcon rating

This begs the question of if the homebuilders start giving land away in the desert is that land basically a speculation on solar power in the future?

Stirling Engines

Another variant on the solar thermal power theme are Stirling engine based power plants, which generate electricity directly rather than first storing the energy as heat.

I had a similar idea to the Infinia engine and drew up plans in January. Mine may be better... Any engineers want to take a look and get it to a workable stage? Mine is quite crude.

Hmmm... if TOD community were to develop my idea (assuming it's practicable), we could call it the TOD engine and use it to fund a whole new world!

;)

Cheers

I like this idea.

http://www.news.com/2300-11392_3-6207903-1.html

http://www.news.com/2300-11392_3-6207903-2.html?tag=ne.gall.pg

Eventually I predict we'll have a DIY local way of dealing with peak oil problems.

Sixty Six Bottles of Beer on the Wall Provide Hot Water
http://www.treehugger.com/files/2007/06/sixty_six_bottl.php

Soda Can Solar Panel
http://www.treehugger.com/files/2007/04/pop_can_solar_p.php

That 5,800 MW number is old (relatively)--Novemeber 2007. It's really exploded since then, even though before then it was picking up speed, so it should be significantly higher than that. I consider myself very up to date on nearly all things regarding alternative energy, but solar has really come out of left field and hit the seen big in basically less than a year. It seems like every week they announce another >100 MW plant is put into the works somewhere. I read recently that one company is building a 700 MW/year fabrication plant in (I think) Nevada--and that's just one company, and 1 MW of solar thermal produces more than the 1 MW PV on average because utilities only really put solar thermal plants in prime locations, while PV is more often than not used in sub-optimal areas (like Germany, who installed something like 1/2 the world's PV last year).

If they can really get the prices down to what they say they can (<$.15/kwh), this will be absolutely huge. Since the demand profile of the places that it is best used in (unlike wind), and the electricity profile isn't unmanageably variable (unlike PV, especially distributed PV), this is really manageable from an infrastructure standpoint.

Also, this tech isn't only aplicable to the US. This shows promise in high power demand areas with population centers reasonably close to open desert, including China, Australia, and the Middle East. Could you imagine what this could do in Dubai--I would imagine their peak-load natural gas consumption is nothing short of horriffic (I've read stories that Dubaians think nothing of having their homes wide open while cranking the A/C).

Great post! The advantage of CSP over PV is that it takes less fossil fuel energy to produce the materials and doesn't require expensive materials like silicon. Nevertheless, the same rules apply: no power at night, very little in the morning & evening, very little in Autumn & Winter. So even in the Mojave Desert, this is no silver bullet. And even the molten-salt storage won't work in the winter, so it is incorrect to call it base-load, since it isn't year round. Nevertheless, this is a promising technology. But when they say they're installing 5,800 MW, we won't actually get that much most of the time. We'll only get close to that around 20% of the time, even in the desert.

Is there any information on the resources needed for CSP, including any new infrastructure? How much steel, concrete, glass, etc, per MW, or whatever? Any exotic minerals needed? What are the ongoing resources needed? I'd just like to get an idea of whether the scales mentioned are actually doable or if something else needs to make way for it. Also, is there much research on the environmental consequences, if any, of producing the resources needed and of the setup itself?

GIven that you get sunburned worse if you swim in water, rather than simply tan by a pool, is there a way to harness all that reflected sunlight??

Thanks for synthesizing all this info!

(And yes, what is right/fair/sensible is not usually the chosen path.)

THE FUTURE RECIPE: SUN, AND A SMALL DASH OF GAS

Excellent article Big Gav! This article now joins the great previous article on the subject on TOD Europe.
http://europe.theoildrum.com/node/2583
This article and the previous one linked above give an excellent comprehensive overview of the state of the CSP (Concentrating Solar Power) art.
The TOD Europe article also gave us a link to what an integrated CSP system could look like in combination with wind and biomass:
http://www.trecers.net/
It has been fascinating to watch the great minds of the TOD group, Stuart Staniford and Robert Rapier come over to the solar alternative. They now join an earlier generation of great minds, such as M. King Hubbert, R. Buckminster Fuller, and Thomas Edison, among others.

One of the earlier posts I placed on TOD in reply to the anti-hydrogen camp described my own growing belief that solar was the route to take, and now, not later.

I had in prior years considered both solar and hydrogen as somewhat “pie in the sky”, but the more I studied, the more I came to believe that the myriad other alternative energy schemes (ethanol, coal to liquid, coal to gas, gas to liquid, tar sands to liquid, shale oil, etc.) were basically what I called “death by 1000 conversions. Basically, they required the creation of multiple new industries layered one upon the other to do one job: Extract hydrogen, and then get rid of the carbon. The hydrogen was of course bound by nature in the form of fossil fuels. The depletion treadmill never ended, the procedure was basically a “fuel swapping” operation, and the carbon problem would not go away.

At some point, it became apparent that only solar could provide the high intensity heat and energy needed without the carbon cargo. The appeal of solar is that it “cuts out the middleman” of multiple conversions, and releases one of the constant carbon burden.

Now for the first time, solar is being seen as not just a fringe marginal player in future energy production. For the first time, people are beginning to understand that if your stated goal is to reduce carbon release, you simply have to find an energy source that does not contain carbon. For the first time, we are seeing the outline forming of a sustainable and clean energy future.

Solar energy is fascinating in another respect: The more you learn about it, the more reasonable it becomes. This is the opposite of coal to liquids or ethanol, wherein the more it is studied, the less appealing it becomes. Solar and it’s kindred brother wind are the energy sources with the Midas touch: the more they are developed and cultivated the cheaper they get. No matter how much is extracted, the supply never diminishes.

I would make the argument that if the cost of carbon release were factored in, solar has been cheaper than fossil energy for some time.
Above, I mentioned hydrogen. Use of hydrogen as energy storage and transport method is still very unpopular to discuss here at TOD, so I won’t discuss it except to say that application of hydrogen from solar would still pose many challenges. The development of very high quality batteries, or other chemical options such as boron may make hydrogen economically non-viable in all but only a few special cases. As is often pointed out, hydrogen is only a carrier of energy and not a source. Of course in the greater scheme of things this is true of oil, natural gas and coal,in fact any fossil hydrocarbon fuel. It has simply taken us a while to realize that only the sun is a source (laying aside the atom for the moment, because even there the suitable fuel depletes with current generation nuclear power).

I would propose something very similar in arrangement to the TVA (Tennessee Valley Authority) to be established in the U.S. Southwest to organize and finance a large scale CSP system. This could be chartered by a consortium of Western states who need clean non carbon fuel, or by the federal government. Bonds could be underwritten that would pay for initial development, and then paid by outlying years of power sales. In a world of market generated paper based wealth or "fiat" wealth based on nothing, could there be a safer bond? Anyone who TRULY believes in "peak oil" and "peak gas" should be willing to buy all of them they could get!

In combination with Texas and Midwest wind resources, the Western CSP Authority could provide clean grid power to all citizens west of the Mississippi. Efficient electrified rail for cargo transport and modern comfortable rail complete with telecommunications services for inter-city passenger transportation, one can seen a continental energy/transportation system of astonishing efficiency and cleanliness. Private vehicles would consist of grid based plug hybrids, for those who still needed, or felt they needed a private vehicle. Given the economics, many people would probably rent those only for special occasions, however. This system could offer the “spine” baseline energy system in combination with currently existing nuclear plants, so that baseline energy would never be a concern. Smaller private PV solar systems and Distributed Generation systems could feed into and extract from this system, using methane recapture from sewers, landfills and agriculture byproduct. Of course natural gas, propane, and coal bed methane would be available for many decades in some quantity (albeit perhaps small amounts and expensive) and used sparingly and efficiently where it is most economic to do so (the Rockies or areas that still have areas of large stranded gas reserves for example)

Burt Rutan of Voyager aircraft fame once said the weakness of hybrid cars of the Toyota Prius type was that they are mostly heat engine cars with a little bit of electric thrown in. Rutan maintained that the viable hybrid option was a mostly electric car, with a little bit of heat engine thrown in.

This is exactly the case with current thinking on renewable energy. Everyone pictures a basically fossil fuel energy system with a small dash of renewable thrown in. That is not viable if we accept a true post peak fossil fuel scenario. The only viable option would be a mostly renewable energy system with a small dash of remaining fossil fuel and methane thrown in.
Thank you.
Roger Conner Jr.

Yes.
This is definitely one of the ways forward.
On a personal scale, it is fairly inexpensive to cut down on your heating bill by building solar air heaters and likewise solar hot water heating.

Also: since there is effectively a free tank of sunlight every morning, we don't need to worry about declining EROEI. The more we build, the more energy we have.

Solar thermal district heating:

The Drake Landing Solar Community in Okotoks, AB Canada is a joint venture to seasonally store thermal energy for home heating for a subdivision of 52 R-2000 rated energy efficient homes.
In the summer, solar heat is collected from solar thermal panels mounted on the garage roofs.
The heat is stored seasonally in a central borehole thermal storage system. In the winter the heat is transferred from the storage system to provide heating for the homes.

Hi Guys,

No question that Solar is one of the solutions. We have been talking about it for more than 30 years now. We keep finding "cost" excuses. Cost is a false indicator. I think it has always had a slightly positive long term EROI, even in the old days, because it has no moving parts.

The 'Olduvai Theory" absolutely defines our energy problem, which in turn defines the only possible solution.

The Problem is defined as: Per Capita Energy Consumption. (At just over 6 billion people)the graph has gone negative. The solution is a No-brainer. In the absence of Plague, SARS, Bird Flu, Ebola, and a declining AIDS, we had better get real.

We all have pet theories for solutions, but we all conveniently avoid the reality of the Human Condition. "The dilemma of the Commons" is what we are fighting. Who wins, who loses, and who voluntarily steps back so another can take his/her place.

Most of us who read this column are at least middle aged and educated. Most live in a few thousand square foot house, drive at least a 3 liter engined car (probably more than one) We have pets, gardens, and we commute hundreds of miles a month.

Not one of us is going to live within the limits, required by Sanity, to save mankind. The truth is that we have structured our lives so that it would be impossible.

In the 1960's I had a little Morris 8, (8HP) and thought I was a king.

My children now drive nothing less than a Chevy Truck with the 400 series cubic inch engines. (They are still single and earn good money)

We are doubly trapped. We keep talking about the "Self Correcting" Free market system. the North American Free Market System has made the world insane. The Free market system absolutely insures that we always remain psychologically and emotionally trapped in a totally controlled and un-free system. With National Pressures, Social Pressures, Peer Pressures and Advertising, "They" manipulate us in profound and subtle ways, all our waking lives. Was it Kunstler who coined the term "Sheeple"?

My point is that we could actually really solve some of our problems right now, instead of playing for time. We really could at this point still save our Oil, Coal, and Gas supplies for another 1000 years if we had not taught the Chinese, Indians, and other Asians to aspire to the North American Insanity.

They have taken Per Capita Energy Consumption out of our hands and we are still acting like Prima Donna's with our heads in the sand by thinking we still have some say in the matter.

This Very week Ford, GM, and Toyota are crying in their beer because they were not able to find sufficient Idiots to buy their humanity destroying vehicles.

This very year the Fed is trying to get even bigger Idiots to keep buying houses which need massive Heating and Air conditioning energy inputs, and are miles from anywhere.

Our Free Market system will make sure that not one of us ever succeeds in changing our Profligate Energy lifestyle.

The "Real Patriot Act" tells us that we consumers are a National Treasure. It is "we" who have to save the US by blindly consuming more and more (and Energy) all the time.

This is not about me but I mention in passing, My total monthly energy bill is less than $50.00 per month.I again have an 800cc car, I spend only $20.00 per month on gasoline. My total electric bill is less than $25.00. My two bedroom house cost me less than $3000. (built it myself)I am 80% self sufficient with a few sheep, pigs and chickens and lots of fruit trees.

I retired on a small pension, so it was survival. I live better now than I ever have, and am I happier now than I have ever been in my entire life.

We still keep "Talking" about solutions. Maybe its time to get serious.

We think of solar as a diffuse power source and electricity as dense power power. The following quote from Edison shows that at the time electricity was being engineered into useful form, it was viewed as a diffused source.

1910, Source: Interview in Elbert Hubbard's Little Journeys to the Homes of the Great:
"Some day some fellow will invent a way of concentrating and storing up sunshine to use instead of this old, absurd Prometheus scheme of fire. I'll do the trick myself if some one else doesn't get at it. Why, that is all there is about my work in electricity--you know, I never claimed to have invented electricity--that is a campaign lie--nail it!"

"Sunshine is spread out thin and so is electricity. Perhaps they are the same, but we will take that up later. Now the trick was, you see, to concentrate the juice and liberate it as you needed it. The old-fashioned way inaugurated by Jove, of letting it off in a clap of thunder, is dangerous, disconcerting and wasteful. It doesn't fetch up anywhere. My task was to subdivide the current and use it in a great number of little lights, and to do this I had to store it. And we haven't really found out how to store it yet and let it off real easy-like and cheap. Why, we have just begun to commence to get ready to find out about electricity. This scheme of combustion to get power makes me sick to think of--it is so wasteful. It is just the old, foolish Prometheus idea, and the father of Prometheus was a baboon."

"When we learn how to store electricity, we will cease being apes ourselves; until then we are tailless orangutans. You see, we should utilize natural forces and thus get all of our power. Sunshine is a form of energy, and the winds and the tides are manifestations of energy."

"Do we use them? Oh, no! We burn up wood and coal, as renters burn up the front fence for fuel. We live like squatters, not as if we owned the property.

"There must surely come a time when heat and power will be stored in unlimited quantities in every community, all gathered by natural forces. Electricity ought to be as cheap as oxygen, for it can not be destroyed.

"Now, I am not sure but that my new storage-battery is the thing. I'd tell you about that, but I don't want to bore you..."

Once we work the engineering, we will find that sunshine is quite adequate. We are planning to power JPods transportation networks with solar. The distributed nature of the transportation network can be used to harvest the energy needed to power it.

Transporting a pallet of cargo or up to 4 people requires about 200 watt-hours a mile. Solar collectors mounted over that mile of rail gathers about 2.5 million watt-hours in a typical day, 12,500 vehicle-miles of power. The following image shows PV panels. It is likely Sterling Engines will also prove very effective. Solar is very potent when used where it is gathered.

Big Gav - Thanks for a nice article on solar thermal. A couple of thoughts on it that I didn't see: The problem of theft in the future is hardly ever mentioned. With solar thermal your possible theft vulnerability is small. Only pieces of the operation could be taken and then only sold for scrap. You couldn't take the turbine portion of the plant, nor the solar storage. If molten salts were the heat medium just dismantling the CSP panels would be extremely dangerous for the thief. Other thermal system designs have similar built-in theft deterrents. This theft for scrap problem could be a significant problem in its own right, but would be much less then the theft potential of PV panels. The panels could be stolen and then sold as complete working units to other users. Their market would be large and their value much higher than solar thermal scrap. Dismantling would be much easier, the main threat being electrocution. The copper wiring would also be a real target for thieves. It is already becoming a problem for our society, and our current electric distribution network is built right into our neighborhoods where we can watch it all the time. Square miles of PV panels and wires out in the desert will be prime pickings for organized crime or the fly-by-night thief.

Also not mentioned was the use of personal solar thermal systems. I have used a batch water heater since 1999 and, being located in Florida, enjoy free hot water year-round. No maintenance has been required, as the system has no moving parts. The life expectancy of the unit is a least 25 years, with the unit paying for itself after about 7 years. Being a point-of-use system with no moving parts, it just doesn't get any better. Maybe TODers could spend their tax rebates on purchasing a system like this, or something solar or insulation related. That would be better than a flat panel TV for the kids.

I looked at that 250 km X 250 km desert example and thought about how far from a cooling water source can a CSP plant be built. We are talking about 62,500 sq km. How long is the Mediterranean coast of Africa? The coast of Baja California? Could CSP be built in such a way as to not need water for cooling? Would an open loop Brayton cycle be cost effective? The Stirling and PV systems don't need water but quit working when the sun goes down. Storing energy in batteries is much more expensive than a big tank of hot salt or oil.
As for the cost of solar electricity just consider what the percentage of household income would 20c per kwh be? Here in Iowa it wouldn't be much of a financial burden but for folks in Pheonix it might be a budget buster.

The place to go for heliostats (as that is what this post is all about):
http://www.redrok.com You can find him every year at the Midwest Renewable Energy Fair hawk'n his wares

From my info page here.
Use of a large heliostat for cooking:
http://www.dfg-vk.de/SolareBruecke/info_e.htm
http://www.geocities.com/%7Edmdelaney/scheffler-precis/scheffler-precis....

THE UNQUANTIFIABLE

On the dictionary.com website, unquantifiable is defined as
"unable to be counted or to have a value assigned: impossible to determine the quantity of."

In discussing solar energy and it's potential to reduce natural gas and coal consumption, many of the advantages of solar energy are hard to quantify. We have seen this in the string of discussion above, in which costs for construction of CSP plants and solar towers are compared to wind, to conventional fossil fuels, to competing forms of solar such as PV and to nuclear. The math can become overwhelming.

And exactly how do you compare the advantage of solar to fossil energy in terms of carbon release? If the darkest of scenarios depicting the outcome of climate change (ala Hansen) are to be believed, the cost of solar would be worth it at any price. However, if one is a climate change skeptic, the cost of solar may be considered very high, perhaps making it non-viable.

If peak oil is to be accepted as valid, we likewise see that the cost of solar may be worth it because it can be viewed as the only viable long term renewable that has any chance of helping us maintain a modern society. If that scenario is accepted, then solar will have to be built in large scale no matter the cost.

One other aspect of solar not often discussed is the geo-political aspect. We know that the United States, Japan and Europe consume great quantities of natural gas, even though these areas have marginal amounts of natural gas reserves in comparison to total worldwide reserves. This must mean that those with large volumes of natural gas reserves would have a geo-political advantage. Solar would be a huge national security tool in attempting to blunt that advantage.

I would like to offer for your observation the type of "argument" being put forth by those engaged in the ongoing effort to persuade the American investor that they MUST invest in commodities, especially natural gas, precious and strategic minerals commodities.
The nations with natural gas and strategic minerals reserves are now being posited as major threats to our national securtiy and future.
I could not provide a web link to the text below that would show only the sales pitch, as it comes to the prospective customer in the form of an e-mail, so I posted the text of the e-mail in it's entirity below.
My point is that if we accept as factual the content of what is being said here, then the strategic advantage of solar energy becomes great, almost impossible to quantify. One in fact would quanitify it on this basis based purely on the percieved reality of the threat. If the reality of the threat below is seen as small, the quantifiable advantage would be seen as small on a geo-political basis. However if one accepts the percieved threat to be as grave as that depicted below, the geo-political advantage of solar energy produced in volume and inside the borders of an nation would be huge, so huge as to be unquantifiable:
----------------------------------
The World’s Most Dangerous Man

Putin Plunges Red Dagger Into America's Financial Heart!

As Russia plays a deadly game of "Resource Roulette," you can now safeguard your money with a little-known investment plan that could return 493% in the next 12 months…

Dear Reader,

I’ve just returned from an extensive fact-finding mission throughout Russia with some shocking news.

At this very moment, the country’s ruthless, power-hungry president, Vladimir Putin, is taking bold steps toward becoming a very real, very dangerous threat to your well-being -- financial or otherwise.

Do a little digging, and you’ll find that word has already begun to spread…

The New York Times has reported that U.S. officials "have growing doubts about the nature of [Putin’s] leadership."

USA Today confirms and says that Putin "is now showing his true - and very Soviet - colors."

Inside Russia, The Moscow Times states,"Russia is full of fear. Businessmen and politicians are afraid of Vladimir Putin. [Putin] relishes the fear. The greater the fear, the stronger his power."

And the U.K.'s oldest and most-respected newspaper, The Daily Mail, goes so far as to call Putin a "brutal despot who is dragging the West into a new Cold War."

Bottom line: Vladimir Putin is not the friend to the U.S. that we once thought he was.

And, as much as I wish these reports were sensationalizing the situation, they're not!

In fact, it's actually much worse.

You see, Putin is already in the early stages of a strategic strike on the United States economy, the likes of which could cripple our nation for decades.

That’s right, even as you read this, the attack is underway; and, sadly, most won’t realize it until it’s too late.

Putin’s playing it smart and hitting our weak spots -- taking aim at our struggling dollar, our growing energy crisis and our crumbling healthcare industry.

And with his warhorses racing toward us at full speed, all of these things are going to get a lot worse, real fast.

Now, when I say Putin has begun an "attack," it’s important to realize that we’re not talking about cruise missiles or machine guns.

No, instead this fight is being led with commodities such as nickel, oil and liquid natural gas. The very commodities Americans use to fuel their cars, heat their homes, maintain their health and more.

That’s right. Russia’s abundant natural resources are also its absolute deadliest secret weapons.

That’s why now it’s more important than ever for you to protect yourself from the dangerous game Putin is playing with the rest of the world.

And that’s what I’ve spent the past 17 days throughout Eastern Europe working on for you.

My name is Andrew Mickey, and I’ve created what I believe to be an ironclad protection plan for you and your portfolio against Putin’s upcoming attack.

But this isn’t just about preserving your assets.

No, in fact, this protection plan I’ve devised actually utilizes several little-known investments that could actually hand you up to 493% in gains over the next year.

These are stocks that have managed to either fly under Putin’s radar or have figured out exactly how to hit the Russian czar where it hurts the most -- his wallet.

And in the process, they’re raking up healthy gains that any investor would be thrilled to have maximizing his or her portfolio.

I can tell you with 100% confidence that this could be your one and only chance to immunize yourself from this insidious threat and actually BUILD your wealth, to boot!

Believe me, I’ve seen what’s taking place over in Russia firsthand, and I can safely say that we haven’t seen a threat like this since the darkest days of the Cold War.

Now is the time to make your move. If you wait even a few short weeks, it could already be too late.

All I ask is that you take the next few moments to read through this urgent report. Inside, I’ll spell out in precise detail how Vladimir Putin - the most dangerous man alive - is working to destroy your wealth and well-being.

Not only that, but I’ll show you exactly what you need to do to protect your portfolio from this threat, plus how you could rack up 493% in gains in the next 12 months in the process.

So, let’s not waste another second.

Read on to learn more...

http://www1.youreletters.com/t/1463227/15647857/845745/5824/
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So is this a "boogy man" put forth simply to sell commodities futures, or is the threat real? You be the judge, but in relation to our discussion, it adds a very real national security or strategic aspect to the discussion of large scale solar power. In a nation that spends trillions of dollars on national security, this aspect could be interesting to attempt to quantify. If it is quantifiable at all.

RC

Greetings to all,

This is my first post. Just to introduce myself, I am an expatriate, non-land-owning, automotive engineer. Also a previously diagnosed depressive. :-) You can probably imagine my state of mind as peak oil awareness really kicked in over Christmas. Laugh and a half.

But I'd like to mention a crazy idea and hopefully get some comments back from what seems to be one of the most intelligent sites on the subject.
I read the post about solar thermal, and had also thought it to be the best renewable option. But when I see the enormous amount of it we'd need to build and started looking up raw materials production rates for metals and glass, it's pretty shocking.

So (and I'm not saying this is a new idea, but I didn't yet come across it around any peak oil debates), why not place solar collection on reflective balloons in the stratosphere, somewhere around 80,000ft where winds are low?

The advantages are

1. Far cheaper than a space-based solution
2. Guaranteed solar power in all weathers/locations
3. Low usage of resources (reflective balloons - yes, oil derived, are much less energy intensive than all that glass etc.).
4. Scaleability
5. EFFICIENCY - The possible efficiency of any mechanism would improve with a -50C heat sink instead of ground temperature.

Regarding the mechanism of capture it needs to be massively scaleable and very simple, some kind of seebeck effect device?
The scaleability would work as follows - you need to put up one "base station", probably a very large helium/hydrogen balloon. Following this, solar concentrating balloons are "floated up" and tethered to the base station, at any rate desired by "the market". Floating balloons up also provides transport of personnel and other equipment to the base station.

So here are what I consider to be the main problems :

1. Tethering the station
2. Returning the power to terra firma

These problems can be linked, in that 25000m of power cable would certainly weigh something more than any feasible balloon could carry, which suggests to me that we'd have to leave the station untethered to float around, and ship the energy back by dropping lumps of hydrogen from the base station, or a microwave power transfer system to ground. The hydrogen scheme would mean that the raw materials for buoyancy control would also be available in-situ.

So, lots of problems with it and I would prefer to float the idea incomplete, and maybe someone will point out more fatal flaws, or come up with helpful suggestions. Incidentally, a company in California is already producing such balloons as low cost solar collectors, though it's a concentrated PV system at the moment.

So let me know, cheers.