HOW GREEN IS HYDROGEN?

Hydrogen is plentiful, but it exists mostly in the form of water. Water can be split into its constituent hydrogen and oxygen when an electrical current is passed through it, called electrolysis. But the most common way of making hydrogen is to react natural gas or coal gas with steam, creating carbon monoxide and CO2 in the process. More than 19 out of every 20kg of hydrogen produced are made in this way, generating 830 million tonnes of CO2 every year. This is so-called grey or black hydrogen.

Electrolysis is energy intensive, requiring 52kwh to produce a single kilo of hydrogen. But industry estimates suggest that a whopping 1.5 trillion Watts of wind power were shut down in 2016 to balance the UK’S electricity grid – all of it renewable power which could have been used. That’s enough to make nearly 29,000 tonnes of hydrogen.

Pilot projects are running all over the world, so production of green hydrogen is expected to pick up very quickly.