Now, researchers are homing in on an artificial photosynthesis device that could let us do the same trick, turning sunlight and water into clean-burning hydrogen fuel for our cars, homes, and more.

Solar cells already let us convert sunlight into electricity. Artificial photosynthesis devices, however, use sunlight to turn water or carbon dioxide into liquid fuels, such as hydrogen or ethanol.

These can be stored more easily than electricity and used in different ways, allowing them to substitute for fossil fuels like oil and gas.