Bloom Energy, a Silicon Valley start-up, will unveiling a fuel-cell product today (Feb 24) that promises cheap and clean power.

Bloom's technology gives users the ability to produce electricity — as opposed to buying it from utilities — and has the potential to extend electricity to parts of the world lacking traditional power systems and lines, the company was quoted as saying in a USA Today report.

Twenty companies, including Wal-Mart, Google, eBay, FedEx, Staples, Coca-Cola, Bank of America and Cox Enterprises have already bought Bloom's fuel-cell boxes. The commercial-scale boxes are about the size of a parking space and cost $700,000 to $800,000 now, the report said.

Bloom CEO KR Sridhar expects home models, about the size of a loaf of bread, within 10 years that cost less than $3,000. He says consumers could see the so-called Bloom boxes powering apartment buildings and housing developments before that.

Sridhar, a professor of aerospace engineering who once led a team developing technology to sustain life on Mars for Nasa, says utilities could buy the boxes, too, to power neighborhoods.

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's no burning, so the fuel cell is two-thirds cleaner than coal-fired plants, the company says.

Automakers have been working on fuel cells for vehicles for years. A few companies also sell commercial systems. The big challenge is cost.

Sridhar says Bloom's technology is cheaper and more efficient than others because of proprietary technology that enables it to use low-cost materials — sand and ink — in 4-inch-by-4-inch fuel cells as thick as business cards. One cell powers a light bulb. Bloom stacks them 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 (1,472 degrees Fahrenheit). The high heat makes the fuel more reactive and the cell more efficient, Sridhar says. The heat also enables use of different fuels, making the tech easier and cheaper to deploy, he says.

EBay started using five Bloom boxes in July. They produce electricity to power space for 2,000 to 3,000 employees and shaved $100,000 off eBay's power bill, says Amy Skoczlas Cole, director of eBay's Green Team. EBay uses natural gas in the boxes but will switch to methane gas from an Oklahoma landfill this spring.

Bank of America plans to use Bloom boxes to power a California call center. Coca-Cola is deploying Bloom boxes at a plant in California. They're expected to provide 30 per cent of the plant's power while reducing its carbon footprint by 35 per cent, a Bloom press release said.

EBay's Cole expects Bloom boxes to pay for themselves within three years, given a 30 per cent federal tax credit and a 20 per cent subsidy from the state of California. "In a few years, we won't require subsidies to become the most affordable energy," Sridhar says.