Electricity can be stored in a variety of ways, including in batteries, by compressing air, by making hydrogen using electrolysers, or as heat. Storing hydrogen in solution-mined salt caverns will be the best way to meet the long-term storage need as it has the lowest cost per unit of energy storage capacity.
What electricity storage will be needed, and what are the alternatives? Electricity can be stored in a variety of ways, including in batteries, by compressing air, by making hydrogen using electrolysers, or as heat.
The Commission adopted in March 2023 a list of recommendations to ensure greater deployment of energy storage, accompanied by a staff working document, providing an outlook of the EU’s current regulatory, market, and financing framework for storage and identifies barriers, opportunities and best practices for its development and deployment.
Today, an estimated 4.67 TWh of electricity storage exists. This number remains highly uncertain, however, given the lack of comprehensive statistics for renewable energy storage capacity in energy rather than power terms.
Electricity storage is currently an economic solution of-grid in solar home systems and mini-grids where it can also increase the fraction of renewable energy in the system to as high as 100% (IRENA, 2016c). The same applies in the case of islands or other isolated grids that are reliant on diesel-fired electricity (IRENA, 2016a; IRENA, 2016d).
With growing demand for electricity storage from stationary and mobile applications, the total stock of electricity storage capacity in energy terms will need to grow from an estimated 4.67 terawatt-hours (TWh) in 2017 to 11.89-15.72 TWh (155-227% higher than in 2017) if the share of renewable energy in the energy system is to be doubled by 2030.