MICROBIAL FUEL CELLS have a very high buzz factor these days. These seemingly magical devices create electricity from hydrogen and oxygen—producing pure water as their only byproduct. Several major cities already have fleets of buses that use fuel cells. Auto manufacturers promise us that within a few years, we’ll be able to buy fuel cell-powered cars that create no pollution at all—thus enabling us to reduce our dependence on oil and slow global warming while saving money with inexpensive hydrogen fuel. Spacecraft have used fuel cells for decades to produce electricity, since the hydrogen and oxygen they need are both conveniently available in onboard tanks. And in the near future, fuel cells may even be put to more prosaic uses, powering notebook computers, cell phones, and other personal electronic devices.
