The European HyPSTER Project is coordinated by Storengy and brings together seven partners from France, England and Germany. It aims to design and operate an industrial demonstrator for the production, underground storage, and use of green hydrogen. This project is located at the underground natural gas storage site at Etrez (Ain Department). This site is the ideal candidate for a project of this kind with, on one hand, operational salt cavities in the subsoil which can be converted in future to store hydrogen and, on the other hand, the river Rhône is nearby, being an industrial corridor with multiple potential users and uses.
The principle involves using electricity from renewable energy sources to produce hydrogen by electrolysis. This is then compressed and stored in an underground reservoir, in a salt cavity. The hydrogen is then tapped on demand. There are various potential uses for hydrogen, such as direct use by injection into the gas network, as a base substance in a wide range of industries, or after being converted into electricity to power vehicles.
Storing natural gas in salt cavities has been done for over 50 years, both in France and elsewhere in the world. So, from a technical and financial point of view, as well as in terms of safety, this technology is mature. Conversely, there is much less past experience of storing hydrogen in salt cavities, as there are only 4 such cavities in the world; in the United Kingdom and the United States.
Even though these cavities have been operated for decades without notable incident, hydrogen storage that aims to regulate variations in the production of renewable energies - which are by their very nature intermittent - will lead to far greater stress on the salt cavities, with more frequent cycles of injection and withdrawal, perhaps even on a daily basis. The safety aspect of using cavities in this way is still to be demonstrated.
The main risks associated with hydrogen storage in salt cavities are the same as those for the storage of natural gas. That is, a risk of leakage that could lead to ignition or an explosion. Even so, hydrogen’s physico-chemical nature, being a light, mobile, highly flammable substance which can react with the surrounding environment, needs to be considered when analysing and controlling risks. The cavity’s long-term mechanical stability, which is subject to strong, rapid demands, must also be carefully evaluated. These points are what Ineris will be studying in this project.
The HyPSTER Project has just entered it’s initial phase with the underground engineering and surface study. This stage will be carried out by constructing the facilities needed to produce hydrogen upstream (1 MW electrolyser attached to a compressor), and downstream, to treat and store it before it is supplied to users (dehumidifier, buffer storage). In terms of its production, what is called “green” hydrogen will be produced from electricity coming from renewable sources (solar panels, wind farms and hydraulic power). The 1 MW electrolyser will produce 400 kg of hydrogen per day. This represents the consumption of 16 hydrogen-fuelled buses. During the trial phase only a small section of the experimental cavity will be filled with hydrogen, so 2 to 3 tons of hydrogen. In a later commercial phase, this cavity could eventually reach a final capacity of 44 tonnes, equivalent to the consumption of 1,760 hydrogen-fuelled buses. The energy benefits are what make this project so strategic. However, it is important to make sure it is done in complete safety.
Launch of the engineering studies
Construction of the electrolyser unit and the storage facilities
Implementation and feedback on past experience from the experiment
Operational deployment and commercialisation of hydrogen for local users
A central aspect of the HyPSTER Project is the management of risks and environmental impact, from experience gained in the pilot project. Of course, this is a prerequisite for the experiment to be authorised by the French government, as well as being fundamental in demonstrating that mass storage of hydrogen in salt cavities can be deemed to be a safe and replicable solution. This is a major condition for the large-scale industrial development of this new subsidiary in Europe, and taking these risks on board early in the innovation process will play a part in the subsidiary’s success.
Ineris has been supporting the development of this hydrogen subsidiary for about ten years, and has thus accrued technical expertise and scientific skills in the area of chronic accident risk in the soil and subsoil. On the basis of the Institute’s own expertise, experimental platforms and digital modelling, this pilot’s aim is to assess its risk evaluation methods and tools, and to adapt them to the specifics of hydrogen. The Institute’s multidisciplinary skills are an asset in this kind of project, which requires knowledge in the field of underground risks, and equipment and facilities that contain flammable and explosive substances.
In this project, Ineris’ primary contributions, in collaboration with the project partner include:
- contributing to risk evaluation in order to ensure that the pilot experiment takes place under the right safety conditions;
- drawing lessons from the pilot project in terms of safety and environmental protection, so that future hydrogen storage in European salt cavities can benefit from it;
- reviewing the regulatory and normative frameworks for the safety of hydrogen storage in salt cavities at the European level, in order to define recommendations for promoting the safe development of this industry within Europe.
Thus, Ineris is actively participating in:
- developing a digital model representing the geomechanical properties of a storage cavity during injection/withdrawal cycles. The model developed will make a specific contribution to risk assessment;
- to the development and implementation of a system to monitor hydrogen leakage at the surface.
At the heart of Ineris’ strategy is support for energy and ecological transition and risk management; particularly emerging risks. In addition, safety in the hydrogen sector us one of the priority issues of the Ineris 2021-2025 Contract on Objectives and Performance.
This project benefits from financing by the Public-Private Partnership on Fuel Cells and Hydrogen (FCH 2 JU) under grant agreement no. 101006751. This Public-Private Partnership has received support from the European Union’s Horizon Programme H2020 for Research and Innovation, from Hydrogen Europe, and from Hydrogen Europe Research.
Project actors and their roles
- Storengy (FR): project coordinator for all partners. Manager and operator of the storage site and of the salt cavity used for the tests.
- Armines-École polytechnique (FR): this partner will participate in different studies as part of the HyPSTER project.
- INOVYN (UK): definition of the optimal cycle to be carried out for using the salt cavity (additions/removals of hydrogen to be consumed).
- ESK (DE): validation of compatibility of the existing infrastructure and cycling models (for natural gas) with hydrogen storage.
- Element Energy (UK): validation of the technical and financial aspect of the demonstrator in order for it to be replicated in other countries.
- Ineris (FR): risk management and environmental impact management for the demonstrator. Evaluation/definition of a regulatory framework for European development of this industry.
- Axelera (FR): monitoring of operating results in order to then share them with all partners and the scientific community. Communication, dissemination, strategic intelligence and networking with stakeholders in order to facilitate the use and reproduction of HyPSTER solutions outside of the project.