Solar + Gas Hybrid Turbine
Our friends at WorldChanging have a concise summary of a blog post by Sudarshan P. about a solar & gas hybrid turbine. The post starts out being about how solar production is still more expensive than other methods, and later on a solution is proposed: "Solar concentrators such as parabolic reflectors or fresnel lenses heat oil up to a temperature of 200C which is used to boil water to produce steam at a high pressure. The steam is super heated to temperatures of about 400C to 500C using biogas, wood gas, natural gas etc. [...] Maximum theoretical efficiency of a steam engine at 100 C is 20%. If we are able to increase the temperature of operation of the engine to say 400 C we get efficiencies of the order of 50%. [...] During bright sunlight the hybrid power station would be using 60% solar and 40% bio fuel. During the night the power would come from bio-fuel alone. But the demand during the night would be small. So less bio fuel would suffice during the night."The gas doesn't even have to be of fossil origins; for example, biogas can be produced in great quantity with agricultural waste.
The hybrid turbine sounds like a great idea and we would really like a prototype to be made. If it works are well as predicted, we shouldn't waste any time before starting building a large number of power plants working on that principle!
The picture above is a random solar concentrator, not a solar/gas turbine. Mirrors of that type would probably be part of it if one is ever built, though.