Friday, 18 April 2008

Bagging Some Rays: New Solar Technologies Store Sun's Heat, Not Solar-generated Electricity

The sun is shining brightly as only it can when it’s climbing higher and higher in the sky each day and when there are no leaves on the trees yet. Yesterday it was positively balmy outside, and the snow is finally gone from the front. The big snow piles in back are retreating too.

The power of the sun was underscored in an interesting story in Tuesday’s New York Times Science section. Two new technnolgies for storing energy from the sun show great promise. Both overcome the difficulties of trying to store electricity in batteries by storing solar-genereated heat instead. One uses a sophisticated system of mirrors to focus the sun’s rays on a tower containing salt which can be heated to very high temperatures without reaching high pressure. The molten salt retains heat for long periods. The stored heat energy can be drawn upon to generate electricity with steam turbines. The other method focuses the sun’s rays on miles of black coated tubes which also act as heat sinks.

The Times reports that Google is backing a small start-up, eSolar, which uses the tower model, with the aim of “making renewable electricity for less than the price of coal=fired power.” A similar power tower had been built in the Central Valley of California in the 1990s, but was abandoned even though it was running well because natural gas prices dropped, making the new energy uncompetitive. But, the Times quotes one of the princples involved, “nobody cared about global warming and we weren’t killing people in Iraq” then.

The situation is different today, so solar power may soon have its place in the sun, so to speak.

No comments: