Homes could be powered by sand

KR Sridhar: Expects models to cost US $3000 within a decade.

The latest fuel-cell technology uses low-cost materials such as sand, and can power everything from small office complexes to apartment buildings and housing developments.

Silicon Valley start-up Bloom Energy has unveiled a fuel cell known as a Bloom Box, with CEO KR Sridhar expecting home models within a decade that cost less than US $3000.

With Bloom’s fuel cell, air and fuel — such as natural gas, ethanol or biogas — are fed into the cell. The oxygen ions react with the fuel to produce electricity. There is no burning, so the fuel cell is two-thirds cleaner than coal-fired plants, said Bloom.

Bloom’s technology is said to be cheaper and more efficient than others because of proprietary technology that enables it to use low-cost materials such as sand in four-inch-by-four-inch fuel cells as thick as business cards. One cell powers a lightbulb; these are then stacked together to produce more power.

Bloom’s big breakthrough was reducing breakage by figuring out how to get the cells and the metal plates that go between them in the stacks to expand and shrink at the same rate at temperatures up to 800 degrees Celsius.

The high heat makes the fuel more reactive and the cell more efficient. The heat also enables use of different fuels, making the technology easier and cheaper to deploy.

US company eBay started using five Bloom boxes in July 2009. They produce electricity to power space for 2000 to 3000 employees and shaved US $100,000 off the company’s power bill, said Amy Skoczlas Cole, director of eBay’s Green Team.

Bloom’s lead venture-capital backer, John Doerr, who also helped fund Netscape and Google, cautioned that technology will not solve the world’s clean-energy needs.

“It is not a silver bullet, but a piece of an emerging clean-energy economy. Everybody wants clean, reliable, affordable electricity,” said Doerr.

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