Hydrogen has always been a fascinating possible substitute for fossil fuels. It burns cleanly, without emitting carbon dioxide; it is energy dense, so it is a good way to store energy from renewable sources intermittently; and you can make liquid synthetic fuels that directly replace gasoline or diesel. But so far, most of the hydrogen has been made from natural gas; the process is dirty and energy intensive.
The rapidly falling cost of solar and wind power green hydrogen is now cheap enough to be practical. You just have to zap the water with the electricity, and presto, you have hydrogen. Europe is showing the way and starting to build the necessary infrastructure. Peter Fairley argues that such projects are only a first step towards a planned global network of solar and wind-powered electrolysis plants, producing clean hydrogen.