New Ways to Store Solar Energy for Nighttime and Cloudy Days

Storing energy thermally..hmmm….well, if they can insulate it well enough, it should work.

“The difficulty is that electricity is hard to store. Batteries are not up to efficiently storing energy on a large scale. A different approach being tried by the solar power industry could eliminate the problem. The idea is to capture the sun’s heat. Heat, unlike electric current, is something that industry knows how to store cost-effectively. For example, a coffee thermos and a laptop computer’s battery store about the same amount of energy, said John S. O’Donnell, executive vice president of a company in the solar thermal business, Ausra. The thermos costs about $5 and the laptop battery $150, he said, and “that’s why solar thermal is going to be the dominant form.” Solar thermal systems are built to gather heat from the sun, boil water into steam, spin a turbine and make power, as existing solar thermal power plants do — but not immediately. The heat would be stored for hours or even days, like water behind a dam. “You take the energy the sun is putting into the earth that day, store it and capture it, put it into the reservoir, and use it on demand,” said Terry Murphy, president and chief executive of SolarReserve, a company backed in part by United Technologies, the Hartford conglomerate. Power plants are typically designed with a heat production system matched to their electric generators. Mr. Murphy sees no reason why his should. His design is for a power tower that can supply 540 megawatts of heat. At the high temperatures it could achieve, that would produce 250 megawatts of electricity, enough to run a fair-size city. It might make more sense to produce a smaller quantity and run well into the evening or around the clock or for several days when it is cloudy, he said.” - Source