There is currently a potential to utilize salt domes in order to store excess energy during times of excess production, and withdrawn again when energy demand exceeds production, enabling us to better utilize energy from temporally inconsistent sources (for example, wind). The excess energy is used to produce H₂ and O₂ by hydrolysis of water and stored in underground caverns in the salt domes. When then needed, the stored gases are used in gas turbines or SOFC fuel cells. At the same time clean CO₂ can economically be produced for Enhanced Oil Recovery (EOR). This paper will present the technical and economical potential in such a system.

We have in Denmark good experience using salt caverns for storage of natural gas. Utilising domes close to areas with district heating networks, such as salt domes between Holstebro and Struer or south of Ålborg, it will be possible to also use of the heat from the converting energy loss.

Storage should not only include H₂ but also the O₂ , which then can be used in oxy fuel burning of bio fuels or natural gas, resulting  in clean CO₂. The clean CO₂ can be shipped to the North Sea oilfields for EOR. Canadian results show that extra 10% of the original oil in place can be extracted with use of CO₂. Based on resource estimates from The Danish Energy Agency, this would yield an extra income of more than 725,000 million DDK. In this way pay for the development cost of this new technology, and help to fund the transition to an economy based upon renewable energy.