Archive for November 9th, 2010

Article from SFGate.

“A gleaming array of mirrors tucked behind a Sonoma County winery promises a new wrinkle in renewable energy – solar power without all the waste.

Solar panels convert into electricity just a fraction of the energy the sun throws at them, typically 15 to 20 percent. The rest is wasted as heat.

But the solar array nestled next to the Sonoma Wine Co. captures the heat as well. The winery gets electricity for its lights and bottling machinery as well as hot water – up to 165 degrees – for cleaning barrels.

The array is the brainchild of the Mountain View startup Cogenra Solar. Backed by $10.5 million from clean-tech venture capitalist Vinod Khosla, the year-old company aims to make renewable power more cost-competitive with fossil fuels. Cogenra will own the solar arrays it installs, charging its customers for the electricity and hot water rather than the equipment.

“Practically any location we’ve looked at, we can beat their utility rates,” said Chief Executive Officer Gilad Almogy.

Cogenra claims its arrays produce five times the total energy output of comparably sized traditional solar systems, one reason the company can offer attractive rates. The other reason – Cogenra pieces its arrays together using pre-existing solar equipment rather than inventing all its own gear from scratch.

Almogy “said to me, ‘Derek, you could go down to the hardware store and get most of this stuff yourself,’ ” said Derek Benham, who owns the winery in the small town of Graton. “It looks kind of Avatar-like, but you take a close look at it and think, ‘Hey, this looks like siding.’ ”

Benham and Almogy unveiled the system last week at an event packed with curious representatives from other wine-makers such as Bogle Vineyards and Kendall-Jackson. The event also drew former British Prime Minister Tony Blair, an adviser to Khosla Ventures, who praised the technology’s potential for lowering greenhouse gas emissions and fighting global warming. Cogenra arrays cut the amount of natural gas customers burn to heat water, in addition to replacing electricity from fossil-fuel power plants.

“We won’t win this unless business is our ally,” Blair told the crowd. “What is really important right now is that instead of losing interest in this issue or pushing it back, we need to pay attention.”

Cogenra’s arrays combine elements of other, older forms of solar power.

A curved trough of mirrors, similar to those used in large-scale solar power plants, focuses sunlight on a narrow strip of common solar cells. Behind the cells runs a tube filled with a liquid chemical. The liquid absorbs heat from the solar cells and transfers that heat to water. The trough, mounted on a beam about 7 feet off the ground, pivots to track the sun across the sky.”

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