Solar power depends on the solar cell. Wind power, the wind turbine.

The key to the green hydrogen economy is a little-known machine with a name out of 1950s science fiction — the electrolyzer. And after a century of obscurity, the electrolyzer’s moment has come.

The device uses electricity to split water into hydrogen and oxygen. If that electricity comes from wind turbines, solar panels or a nuclear reactor, the whole process gives off no greenhouse gases. Factories, power plants, even jet aircraft can then burn that hydrogen without warming the earth.