Wired News: Algae: Power Plant of the Future?:
"Researchers seeking another energy source to ease the world's dependency on fossil fuels may have found a small answer to a big problem.
A microscopic green algae -- known to scientists as Chlamydomonas reinhardtii, and to regular folk as pond scum -- was discovered more than 60 years ago to split water into hydrogen and oxygen under controlled conditions. A recent breakthrough in controlling the algae's hydrogen yield has prompted a Berkeley, California, company to try to be first to commercialize production.
Energy experts -- who disagree on the when, but not the if, of the eventual depletion of fossil fuels -- are predicting that within decades the world will switch to a utopian hydrogen economy, where energy will be abundant, inexpensive and nonpolluting.
Hydrogen is used by fuel cells to generate electricity without generating those nasty greenhouse gases.
Hydrogen can be extracted from fossil fuels, but currently it's more expensive than directly using oil or natural gas, so this method is only a temporary fix. Water can be split into hydrogen and oxygen through electrolysis, but that requires electricity generated from fossil fuels, or from renewable sources such as wind or solar that are even more costly.
The potential of algae to be used as microscopic power plants was first discovered by Hans Gaffron, a German researcher who fled the Nazi party and came to the University of Chicago in the 1930s. Gaffron observed in 1939 that the algae would for a then-unknown reason sometimes switch from producing oxygen to instead creating hydrogen, but only for a short period of time.
For 60 years, researchers tried to harness the power potential of algae, without success.
A breakthrough came in 1999 when University of California at Berkeley professor Tasios Melis, along with researchers from the National Renewable Energy Lab, discovered that depriving the algae of sulfur and oxygen would enable it to produce hydrogen for sustained periods of time."