Sometimes high tech can start out low tech. Fuel cells are an old and basic technology; they generate electricity within a cell through the reaction of a fuel and an oxidant. Essentially they're a kind of chemical battery, and your average high school chemistry class can make one. Unlike batteries, however, they can't store electricity; you need an outside fuel source that has to be replenished over time. But their simplicity has also made them useful for certain purposes; NASA has long used hydrogen fuel cells to power its spacecraft.
Inventors have tried to use hydrogen fuel cells as a cleaner way to create electricity commercially. Honda and other car companies have made hydrogen fuel cell-powered cars, for example, but they've always been limited by the cost. That's beginning to change, however, thanks to a California startup called Bloom Energy. The company exploded onto the public scene earlier this year with the release of its Bloom Box, a system that uses fuel cell technology to provide off-the-grid power. The Bloom Boxes about half the size of a shipping container use solid oxide fuel cells, which generate electricity by oxidizing natural gas. The technology has existed for awhile, but Bloom figured out how to carry out the reaction at a relatively low temperature, making the Bloom Boxes safe to use in corporate offices which is exactly where they're being put to work now, by companies like Google and eBay that can use the lower carbon power as an off-the-grid back up to conventional grid electricity and as a way to reduce their own carbon footprint.
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