Hydrogen

The most common and the lightest chemical element, Hydrogen, makes up around 75% of the mass of the universe. Yet hydrogen doesn’t usually exist by itself in nature (as just H2), but rather within compounds that contain it (e.g. H2O). Hydrogen can be produced by separating these compounds.

Today, hydrogen is mostly produced from fossil fuels (‘grey hydrogen’), in particular from natural gas and coal [1]. A by-product of this is carbon dioxide which when released into the atmosphere contributes to climate change [2]. Hydrogen can also be produced by splitting water with electricity. Using renewable energy (e.g. solar) in production of that electricity, makes so-called ‘green hydrogen’.

Why are people talking about hydrogen?

Hydrogen is not a source of energy, it is a carrier meaning it has properties which allow it to deliver or store energy. Significantly, hydrogen can store renewable energy (which is otherwise variable), offering an alternative to battery storage and an avenue to get more renewable energy into the energy system.

Currently, hydrogen is not that widely used as a fuel. But alongside global commitments to take action against climate change, policymakers are looking to green hydrogen as a clean energy alternative.

Use of hydrogen is usually considered in place of fossil fuels such as diesel in a car or as a substitute for natural gas in homes. It is also lauded for its potential to reduce greenhouse gas emissions in sectors in which it would be otherwise hard to do so, such as heavy-duty transport (e.g. aviation) and energy-intensive industries (e.g. steel-making).

However, today very little hydrogen is actually produced from low-carbon sources [3] and it is argued that championing hydrogen does little to disrupt the status quo and plays to the incumbent fossil fuel corporations.

Hydrogen certainly has its proponents and opponents but it’s potential as a clean energy alternative is gaining momentum as governments (e.g. the UK) and businesses (such as those in the Hydrogen Council) back hydrogen as part of the solution for decarbonsied economies.

A lot is still to be determined but with climate targets looming, will the hydrogen hype amount to much more than hot air?

[1] IEA (2020). Hydrogen Tracking Progress https://www.iea.org/reports/hydrogen

[2] Grey hydrogen paired with carbon capture and storage or utilisation, is called ‘blue hydrogen’.

[3] IRENA (2019). Hydrogen: a renewable energy perspective https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Sep/IRENA_Hydrogen_2019.pdf