Gas storage in rock cavities (LRC)

Underground storage and its strategic role in securing Switzerland's energy supply.

The natural gas storage project in Switzerland's Upper Valais region aims to strengthen the country's energy security by developing an underground storage infrastructure at Oberwald, in the Grimsel region. The project is being carried out by Gaznat SA, in collaboration with partners such as Gazoduc SA, Holdigaz SA and Services Industriels de Genève (SIG).

This project is of strategic importance for Switzerland, which currently has no natural gas storage capacity on its territory. The Confederation's energy storage strategy is due to be published in 2025. As the role of energy storage is a major issue in the context of the Swiss government's 2050 energy strategy, this rock-cavity gas storage project in the Upper Valais will enable us to respond fully to the challenges posed, particularly in terms of seasonal storage and security of supply.

Rock cavity storage in the Upper Valais

The technology used is Lined Rock Cavern (LRC). It involves excavating cavities in the rock, then lining them with a steel casing to ensure watertightness. The gas is then compressed in these cavities at high pressure (around 300 bar). This method can be used to store natural gas, and potentially in the future, renewable gases such as hydrogen or synthetic methane.

The project calls for the construction of four caverns capable of storing up to 1.48 TWh of energy, or around 4% of Switzerland's annual gas consumption. This capacity is comparable to the energy stored in the Grande Dixence storage lake. The estimated cost of the project is around 400 million Swiss francs.

Initial geological studies carried out between 2020 and 2021 have yielded positive results, indicating that the quality of the rock is adequate to withstand the pressure required for storage. However, several stages remain to be completed before commissioning: Detailed geological studies; Design of cavities and ancillary facilities; Construction authorization procedures; Construction work. Construction is not scheduled to start before 2027, with commissioning planned for 2030 at the earliest.

Study by the Paul Scherrer Institute

As part of the SWEET/SURE program, the Paul Scherrer Institute (PSI) carried out a study on the technical and commercial aspects of gas storage. The aim of this study was to show how large-scale gas storage (seasonal volume) could be integrated into the Swiss energy system, taking into account energy strategy and climate objectives, as well as security of supply constraints.

This study clearly demonstrated the benefits of implementing gas storage in Switzerland, not only from an economic point of view (with considerable added value in financial terms), but also from a technical point of view, to ensure the stability of gas networks in the event of disruptive elements. Certain framework conditions now need to be discussed with the federal authorities before a building permit application can be submitted, and if the project obtains the expected political support, it could be operational in 2030 at the earliest. In addition to the geopolitical importance of gas, the development of renewable gases and hydrogen, carbon dioxide capture and storage of excess energy produced in summer, will become a major challenge if we are to contribute to the climate objective of zero net greenhouse gas emissions by 2050.