French storage operator adjusts to new demands: interview

Since mid-April, French Engie’s storage division Storengy has had a new head: Camille Bonenfant-Jeanneney. She was previously the head of another Engie subsidiary, Compagnie Parisienne de Chauffage Urbain and so she is aware of the need for reliable energy for heating. 

Storengy operates storage facilities with a combined capacity of 136 TWh, spread across 21 sites in France, Germany and the UK. NGW interviewed Bonenfant-Jeanneney by email mid-May.

What challenges are regulated entities facing in Europe?
Preparing the world of tomorrow by adapting their assets to the low-carbon market while ensuring daily security of supply and the energy system's resilience.

Does the company consider putting any of its assets in the UK or the EU on standby, or increasing their capacity?
This question raises the importance of storage for the energy transition and beyond, embedded into the development of the hydrogen sector. As we are entering a transitional phase, gas storage continues to play a key role by ensuring security of supply on the European energy market.

Owing to its major storage capacities, Europe can rely on a flexible offering which is adapted to the market conditions. As the market is currently under the influence of fluctuating LNG availability, storage can be used to balance international variations by absorbing surpluses during the summer. With high filling level and quick withdrawal capacities, storage sites can react to periods of elevated stress by directly supplying the European market, as we have seen this winter, when cargos return to Asia.

For instance, during the first week of January in France, two thirds of the national gas consumption were covered by withdrawal from storage facilities. We will need to further adapt our storage sites to respond to long-term challenges and be able to offer security and flexibility to the entire energy system (by storing hydrogen from renewable energy sources). The investments required will largely depend on the development of the hydrogen economy and the penetration rate of renewable electricity sources in the mix, which is going to require more flexibility.

Is Storengy aiming at zero net carbon through solutions such as biomethane mixed with natural gas?

Biomethane clearly shows Storengy's commitment to the energy transition. As a response to the current market needs, biomethane is already being injected into the grid and also stresses our environmental commitment. Henceforth, in addition to developing this sector, it is crucial to invest in green hydrogen. Storengy is engaged in the development of hydrogen storage and hopes to be able to convert its salt cavern sites to hydrogen in the near future.  

Does Storengy prefer long-term storage system (depleted gas reservoirs), or salt caverns for quick recycling? Could this change in the future?

Storengy is present in Europe with three subsidiaries – Storengy France, Storengy UK and Storengy Deutschland – and is able to offer different flexibility sources due to the various storage types available on these markets. As they offer increased flexibility, salt cavern storage sites will have a larger role to play in the future. 

Does Storengy aim to develop its activity? Or is the current capacity sufficient?

Regarding natural gas storage, Storengy is following the guidelines of national energy policies to adapt its storage facilities to the needs of the respective energy systems. In France, for instance, the 2020 multi-annual energy programme PPE specifies the storage facilities required to ensure the country's security of supply. Today, these needs are covered by Storengy's existing storage sites.

We don't have the intention to develop more natural gas storage sites in the three countries where Storengy operates as the needs for storage to ensure security of supply are already covered. Today, Storengy's development is aimed at renewable gas storage, such as biomethane, hydrogen and synthetic methane (e-methane). Technical modifications are required to be able to store these new gases in the existing facilities.

Studies and investments are currently being made by Storengy in this respect. In late 2020, Storengy launched the HyPSTER project aiming to convert the first salt cavern to hydrogen storage at its site in Etrez. Partly financed by the European Commission, this project is aimed at bringing the first cavern into operation in 2023. During the first phase, 2 metric tons (mt) of hydrogen will be stored, followed by 44 mt in phase two.

Other projects are in place to develop flexibility solutions supporting the future European hydrogen system (European H2 Backbone), such as Hygreen Provence at our site in Manosque, and Stor'hy in Cerville.

In Germany, we have three salt cavern storage sites which could be converted to hydrogen storage to support the development of this market and its infrastructure. Likewise, the UK's largest salt cavern storage site in Stublach, which is operated by Storengy, is undergoing studies which are part of the hydrogen initiatives launched at national level, especially in the northwest of England.

In addition to converting existing storage assets, the developing European hydrogen market will require new storage capacities, especially in salt caverns. Thanks to almost 70 years of experience in this field, Storengy is resolutely striding down this path of dynamic development and ambitions to become a major player of the European hydrogen flexibility market.