Eight years ago, when I was working for an electric car charging company, we did a calculation aiming to prove the benefits of battery storage. We compared two hypothetical electric vehicles powered with the same initial amount of renewable electricity: one using hydrogen for storage and the other using batteries. Our conclusion was that the battery electric vehicle could easily drive further. I became a hydrogen sceptic.

A hydrogen-powered bus in the French city of Pau. Credit:

Years later, I learnt about the advantages that clean hydrogen offers in a range of scenarios: for long-haul heavy-duty trucks, trains and ships, for making green steel, for seasonal storage of solar and wind electricity in remote communities, and its unrivalled suitability for “shipping sunshine” – clean energy from Australia to the rest of the world. In short, I realised that hydrogen has the potential to fulfil a rich and complex set of low-emission roles. I became a hydrogen convert.

However, my scepticism returned when I first heard of the suggestion to produce clean hydrogen from coal and natural gas using carbon capture and storage (CCS).

There is nowhere on Earth that you can drill a well and find hydrogen gas. To produce it, you must first extract it from water using either renewable electricity or fossil fuels such as natural gas or coal. The production process determines the amount of carbon dioxide created. When hydrogen is produced via the renewable electricity pathway (solar, wind or hydro) there are no carbon dioxide emissions. But, when hydrogen is produced via the fossil fuel pathway, carbon dioxide is emitted as a by-product. It is therefore necessary to capture and store the carbon dioxide, deep underground, so that it does not escape into the atmosphere. If hydrogen is produced today using electricity from a common household wall socket, the amount of carbon dioxide generated is very high (41 kilograms of carbon dioxide emitted per kilogram of hydrogen produced).