Monday, August 31, 2009

Will Solar Ever Live Up to the Hype? Paul Allen, Vinod Khosla Bet On Infinia’s Engines of the Sun

Sitton, the CEO of Kennewick, WA-based Infinia, showed me a device resembling a satellite dish that has attracted some deep-pocketed investors, including Paul Allen and Vinod Khosla. Their hope is that Infinia’s dishes will finally turn solar energy into a workhorse for meeting more of the world’s electricity demand. If Sitton and his backers are right, he’ll be running a multi-billion dollar company five years from now. If he’s wrong, Infinia will be written off as just another costly pipe dream.

Here’s how this is supposed to work. That satellite dish I mentioned earlier? It has a little motor attached to it that keeps it in the right position to capture as many direct rays of sun as possible during daylight hours. Like any dish, it uses mirrors to reflect something, in this case, sunlight, back up to a focal point. That’s where Infinia has the business end of its device.

It’s a Stirling engine, made to convert that concentrated heat from the sun into mechanical work. It’s like a steam engine, except it doesn’t need water—it powers its internal piston through the expansion and contraction of helium. The heat moves the piston, which generates electricity. These engines are thought to be attractive for this kind of work, partly because they are highly efficient at converting heat into electricity, and they don’t require water, or oil. They are supposed to be able to last 25 years with zero maintenance, Sitton says.

Balance of article: xeconomy

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