By making a solar photovoltaic material more resilient, researchers may have found a way to make artificial photosynthesis—that is, using sunlight to make fuel—cheap enough to compete with fossil fuels.

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.