Supporting renewable energy

Each year, the amount of renewable energy (such as wind power, biomass and solar power) used globally grows. While weather-based energy sources are clean and sustainable, we have no control over when they provide power – they only work when the wind blows or the sun shines. Sometimes the amount of renewable energy available does not match demand, so other energy sources such as natural gas are required to make up the difference. Along with batteries or hydroelectric dams, hydrogen could change this by storing up surplus energy for when it is needed. The gas can be stored in pressurised containers, or underground given suitable geology such as salt caverns.
One example of storing energy as hydrogen is a process called power-to-gas.

Just like with any energy conversion, there will be some losses involved in the power-to-gas process. Nevertheless, hydrogen has the potential to be a cheaper energy store than batteries. Examples of power-to-gas include GRHYD, a project in the Dunkirk region run by energy company ENGIE and supported by the French Government; and German project Energiepark Mainz.

Using hydrogen safely

Hydrogen is flammable and ignites easily, which carries safety risks. Hydrogen gas has unique physical and chemical properties; understanding the way it behaves in different situations is vital so it can be used safely. Organisations such as the UK Health and Safety Executive and Hydrogen Europe, as well as private companies, are conducting research into the operational risks of using hydrogen for new applications like heat and transport. When using a new energy source, it is important to learn as much as possible about any potential risks and how to manage them – our use of natural gas has progressed in the same way.

Hydrogen is a non-toxic gas with no colour, taste or smell. It burns with a very pale blue flame and does not produce hot ash or smoke, so it is difficult to detect when it is burning or leaking. One option is to add a suitable strong-smelling chemical called an odorant to the gas mix so that it is easy to detect – an odorant is what gives natural gas its distinctive smell. However, odorants can contaminate technologies, such as fuel cells , which require pure hydrogen gas.

Hydrogen gas has a lower density than air, which means that if it leaks, it will quickly float away. However, as with other flammable gases, if the leak is indoors the gas could build up and cause a fire or explosion. Buildings using hydrogen should include suitable ventilation for pipes and boiler systems – rooms can also include one-way, mechanical ventilation which will allow any gas that builds up to escape. Infra-red sensors can be installed to detect leaks at the meter.