From The Guardian, 19 May 2017:
Nearly a century ago, British scientist JB Haldane saw an energy future in which wind power would be used to generate hydrogen; a fuel he described as, weight-for-weight, the most efficient known method of storing energy.
He thought this future was four hundred years away, but the so-called “hydrogen economy” may arrive a lot sooner thanks to a recent burst of innovations in hydrogen generation, storage, transport and use. And it could open a new energy export market for Australia.
Hydrogen itself isn’t actually a fuel – it’s an energy carrier.
The gas is produced by splitting water molecules into hydrogen and oxygen by the electricity-driven process electrolysis. That hydrogen is then condensed under pressure and at very low temperatures into a liquid, which can be used in much the same way as petrol and diesel, or it can be used in fuel cells to generate electricity.
The conversion of that solar, wind or water energy into liquid hydrogen also enables it to be transported to where it is needed, which in most countries in the world is a reasonable distance away from where the energy is generated in the first place. Read more.