Renewable electricity can be effectively stored by converting it into renewable hydrogen or ammonia through the process of electrolysis. These fuels can be utilized directly in various end-use sectors or stored for later conversion back into electricity. When produced using renewable or low-carbon energy sources, hydrogen offers a unique opportunity for decarbonizing energy-intensive and hard-to-abate industrial sectors where thermal heat is essential. Additionally, hydrogen proves valuable for long-term storage and addressing seasonal demand fluctuations.
However, it’s important to acknowledge a key drawback: the process of converting electricity into hydrogen and back again is notably inefficient, retaining only around 30% of the initial electricity’s energy content. To provide flexibility benefits to the power grid, developing a cost-efficient method for hydrogen storage is crucial. For large volumes and extended time periods, such as inter-seasonal storage underground, hydrogen storage becomes more viable than traditional tank storage methods.
There are four major underground storage types: depleted gas reservoirs, aquifers, salt caverns, and hard rock caverns (with a smaller share). Among these, salt caverns stand out as the most suitable option for hydrogen storage, both technically and economically, despite posing environmental constraints. In EU member countries, 83% of salt cavern capacity is concentrated in Germany, with significant capacity also found in France, the Netherlands, and Poland.
While there are operational hydrogen storage projects in the UK and the US, Europe is also actively developing demonstration projects. These efforts underscore the growing recognition of renewable hydrogen’s potential in enabling renewable energy integration, supporting grid stability, and advancing the transition towards a low-carbon future.
