Transition to renewable energy sources requires storing energy to buffer the fluctuating production. One way to achieve that is by stash hydrogen in depleted underground gas storages. However, several microorganisms that are sometimes found in these underground gas reservoirs can feed on hydrogen and CO₂, thereby producing methane. This is extremely advantageous as methane rather than hydrogen can be easily transported and used with existing infrastructure. Thus combining energy storage with renewable energy production has a tremendous potential for climate neutral energy production.