Probably one of the best layman articles on the subject from a contemporary perspective except for one major problem. Nevertheless it’s worth a good read. Check it out: http://www.sciam.com/article.cfm?id=a-solar-grand-plan
The problem: Once again it places more emphasis on Solar PV than Solar thermal. It pretends to justify this by throwing around some magical numbers that at this point are pure theory and highly unlikely. Compare that to Solar thermal where the numbers are even better and are proven.
Case in point: It says Cadmium Telluride (nanosolar film) will be able to produce electricity for $0.05/kWh by 2020. This is based on the theory that they can get efficiencies up to 14%. I’m sorry, but I’m quite convinced that in order to do that they’ll have to enable some technologies that will up the price of the manufacturing enough to blow that number out of the water. They think they can improve the efficiency by 40%, based on what? Silicon solar efficiencies have improved maybe 10% in the last 20 years? Sure Cadmium Telluride went from 8% to 9% in the last year, but they’re approaching a ceiling that will get extremely hard to raise. My guess is that it will top out at 12%, which leaves solar PV maxing out at $0.06/kWh assuming all other costs stay the same, which they won’t. Add to that $0.04 /kWh for storage and you get 0.10/kWh, AND YOU HAVE TO WAIT UNTIL 2020 TO SEE THAT RESULT.
Compare that to Ausra’s Solar thermal technology which by 2013 should produce electricity, including storage, at $0.07 /kWh.
HELLO!? Am I the only one running these numbers? Solar Thermal is so superior. Nothing, I repeat: NOTHING should go toward the development of something that will cost more near term and long term than Solar Thermal will.
Two more reasons Solar thermal is better:
TIME TO MARKET: Unlike any kind of Solar PV solar thermal uses no fancy technology. It uses no special materials that require special processing. The materials and the parts and pieces that make solar thermal plants are found all throughout existing industrial parks across America -and at bargain prices. All you need is the money to buy them (tons cheaper than what Solar PV factories cost), and people to build them (requires no special training or science). All these things are in stark contrast to the supply problems that have plagued the Solar PV industry. Solar PV, whether it’s thin film or otherwise, will never be able to scale up at the rate that the Scientific American author suggests. The materials and processing equipment demands are just too great even if the money was there … can’t be done.
LIFETIME: A solar thermal plant lasts almost forever if cared for correctly. Sure parts of the turbine needs replacing as with any turbine including the ones used by SolarPV to reconvert pressurized gas to electricity, but thats about it. No solar cells to replace. The mirrors last forever. The dewar tubes containing the molten salt or H2O (Ausra’s technology) should last a very long time if maintained right. Compare that to SolarPV where the life of the Solar Cells is 20-30 years at the most. Also you’ll have to replace the compressors as well as the turbines parts in the Solar PV plant (incidentally solar thermal needs no compressors – another bonys). Can you imagine that? With a Solar PV plant you’re replacing practically the whole plant every 20-30 years. Not so with Solar Thermal.
In short, media bias favoring Solar PV once again garners unworthy support, thereby siphoning off the funds from Solar Thermal, possibly in order to fatten the wallets of those who invest in Solar PV (Al Gore) or work for the industry. Solar PV, even in Cadmium Telluride thin films will forever be inferior, less efficient, and a more expensive technology than Solar thermal. Articles like this that have some fantastic information and promote the use of the Sun’s rays almost do more bad than good by obfuscating the issue and guaranteeing that our hard earned tax dollars will be taken away from Solar Thermal and reinvested in Solar PV assuming that Solar PV will someday meet the magic numbers that it was supposed to achieve 20-30 years ago, and neither will we solve our energy problems as quickly as we could if all the funds went to something like what Ausra does (www.ausra.com).