If you want hydrogen to power an engine or a fuel cell, it’s far cheaper to get it from natural gas than to make it by splitting water. Solar power, however, could compete with natural gas as a way to make hydrogen if the solar process were somewhere between 15 and 25 percent efficient, says the U.S. Department of Energy. While that’s more than twice as efficient as current approaches, researchers at Stanford University have recently developed materials that could make it possible to hit that goal. The work is described in the journal Science.

via Artificial Photosynthesis Made Practical | MIT Technology Review.