Hydrogen energy

Hydrogen energy for the uninitiated

The ramifications of the Russian invasion of Ukraine has prompted many countries to raise their ambition to use hydrogen energy. The European Union is backing green hydrogen and it published new rules in February 2023 to clarify which hydrogen energy would be counted as renewable. The UK Government is also focusing on hydrogen as a way forward. A hydrogen village trial is proposed, where 1,000-2,000 properties will be to converted hydrogen or alternative heating solutions instead of natural gas. Wales has its own Hydrogen Centre, where experimental development of renewable hydrogen production and novel hydrogen energy storage is carried out.

It is important to note that, unlike wind or solar, hydrogen is not a renewable source of energy. Hydrogen has to be extracted from the air or water by industrial processes not all of which are environmentally friendly or could not be labelled renewable. The process used defines the hydrogen “colour”. Brown hydrogen is produced from the gasification of coal, while grey hydrogen is produced by mixing fossil gas (natural gas) with steam. Both processes emit harmful by-products into the atmosphere, including large quantities of carbon dioxide and have a significant environmental footprint. Grey hydrogen processes currently account for over 95% of the significant majority of all hydrogen production. A cheaper option is blue hydrogen, which is produced when natural gas undergoes a process called steam-methane reforming. In this case the carbon dioxide is supposedly captured and stored underground. It is energy intensive, leaves a mark on the planet and projects to date have not managed to capture enough of the carbon dioxide produced.

To address the environmental concerns associated with hydrogen production, governments and industries around the world have been exploring green hydrogen.Green hydrogen is produced when water is electrolysed, powered by renewable electricity sources like solar and wind. Hydrogen and oxygen molecules are split and the process produces pure hydrogen, with no harmful by-products. This method offers the potential to divert any excess electricity, which is hard to store, to the electrolysis process. For example, surplus solar and wind power could create hydrogen gas that can be stored for future energy needs.If the electricity comes from a nuclear power plant, it becomes pink hydrogen.

The Institute of Mechanical engineers have suggested that offshore wind farms are well placed for green energy production. The excess renewable energy could be used where it is generated and there is a ready supply of seawater, which can be used for the electrolysis however the seawater first needs to be converted to freshwater, which is costly.

Challenges

There are many challenges to overcome if green hydrogen is to be economically viable and used successfully. It still needs significant amounts of electricity to produce and ‘it makes no sense to use hydrogen whenever direct electrification is possible.

Critics say that hydrogen is inefficient and more expensive than existing renewable technologies like electric heat pumps for our homes.

The technology is relatively new, unproven at scale and the current infrastructure would need adapting. Thus, it is suggested that it should only be used in sectors that need it.

Is hydrogen used already?

There are already cars that run on hydrogen fuel cells which can be topped up at a hydrogen fuel station, in a similar way to filling a petrol car. The hydrogen is then used to create electricity ‘on the go’ to power the electric motor. Leading the way are China and Japan, with only a handful of stations in the UK. The international delivery company DHL already has a fleet of ‘H2 panel vans’, capable of travelling 500km without refuelling. River Simple, a local company in Llandrindod Wells is also building hydrogen fuel cell cars.

There is a lot to learn about green hydrogen and perhaps those who have more specialist knowledge could tell us more about its advantages and disadvantages.

Notes and further information

1 The EU rules say green hydrogen can only utilise ‘additional’ amounts of renewable electricity that would otherwise not be used.

2 https://www.imeche.org/news/news-article/5-major-challenges-in-the-hydrogen-economy-and-5-potential-engineering-solutions

3 https://www.energymonitor.ai/tech/hydrogen/eu-sets-out-rules-for-green-hydrogen-inviting-promise-andperil/