How we save the planet is clear: we need to prevent global temperatures from rising more than 1.5 degrees in order to avoid doing irreversible damage.

But exactly what should we do to reduce damaging greenhouse gas emissions? In recent years, hydrogen has emerged as a promising source of clean energy. It has been called ‘freedom fuel’, the ‘Swiss army knife’ of the energy transition, and a ‘silver bullet’ for decarbonisation. That’s because it can be used in heavy-duty industries such as shipping and aviation, and because it can be stored for a long time.

Hydrogen, however, is only as green as the energy source used to produce it. Truly carbon-free hydrogen can only be made with renewable electricity, and right now genuinely green hydrogen makes up only a small fraction of overall hydrogen production. Skeptics point out that it would require huge investment to ensure the hydrogen we use is green. And they warn that a focus on hydrogen could divert attention away from other important elements of the energy transition, including further electrifying our homes, transportation and industry. Is hydrogen really the solution to our environmental problems?

We separated fact from fiction in this discussion with energy experts Barry Carruthers, hydrogen director of ScottishPower; Fiona Harvey, The Guardian’s environment correspondent; and Professor Nigel Brandon, Chair in Sustainable Development in Energy at Imperial College London.