Large-scale underground energy storage

Fossil fuels can be converted into energy when there is a demand. Many renewable energy sources, including solar and wind energy, are a lot less flexible: they produce when nature provides. In order to meet demand in the future, as the role of these energy sources increases, it is necessary to create flexibility. Therefore it is necessary to store large stocks of energy during peak production times, in order to be able to use them on a cold, windless, cloudy day.

Storage in the form of hydrogen and compressed air

How and where can we store energy? How much storage capacity is required to meet demand in the future? TNO investigated these questions, addressing major technical, economic, legal and social challenges affecting the market implementation of large-scale underground energy storage. In any case, the Dutch subsurface  offers sufficient opportunity for the development of large-scale energy storage in the form of hydrogen and compressed air. The risks associated with the use of subsoil for the storage of energy in the form of hydrogen or compressed air were also identified.

Techniques and development of energy demand

The report extensively covers the (im)possibilities of the various techniques. This involves looking at various ways in which the energy market will develop up to 2050. This was based on four in-depth studies into the role of large-scale energy storage in the Dutch energy system (links and short description can be found below).

Challenges underground energy storage

The challenges for the development of underground hydrogen storage in the Netherlands mainly comply the risks of interaction of hydrogen with rocks, liquids and microorganisms in reservoirs and the long-term effects of cyclical loading and exposure to hydrogen on well materials.

For compressed air storage, there are economic challenges in relation to the accumulation of revenues from services to different markets. Furthermore, for both forms of storage, barriers in terms of legislation and regulations must be removed.

Finally, for the social acceptance of these forms of energy storage underground, it is of great importance that stakeholders (especially the local community) are involved well before, during and after the decision-making process regarding new initiatives. They should not only suffer, but also benefit from the new development.



The main findings of the study are summarized in the report  “Large Scale Energy Storage in salt caverns and depleted fields”. The extensive research results are described and can be found in the reports below.