KEY BENEFITS

■■ Green energy storage: Zero CO2 emission fuel

■■ Storage capacity from 10 GWh to several hundred GWh

■■ Combined uses (mobility, industry and electricity)

■■ Solution to integrate intermittent renewable energies into the power grid

WHAT ARE THE STAKES?Ambitious targets for the penetration of renewables into the electricity production mix come with new challenges, such as the integration of intermittent electricity into the transmission and distribution grid. When renewable electrical power exceeds demand, massive water electrolysis, hydrogen production and storage in salt-leached caverns becomes an attractive and mature technology. When needed, stored hydrogen can then be used as a zero-emission fuel for:

■■ Mobility: it is especially interesting for vehicles used intensively (e.g. taxis and bus fleets) and over long distances (e.g. trains, trucks, ships)

■■ Industry: replacing fossil fuels for heat production in various processes

■■ Electricity production: electricity can be produced by fuel cells when demand requires it. In this case, the round-trip efficiency is currently approximately 30%, but is likely to drastically improve thanks to new technologies being developed for electrolysis and fuel cells.

HYDROGENSTORAGE IN SALT CAVERNSHydrogen production by water electrolysis is one answer to the challenge raised by the incorporation of renewable, intermittent power sources into the electricity mix.

Stored in salt caverns, Hydrogen becomes a zero CO2-emission fuel available for mobility and industry applications, as well as electricity production when needed.

HOW IS GEOSTOCK INVOLVED?Gestock’s expertise in the design, construction and operation of salt cavern storage facilities has led to its participation in the following public-funded (by the French national research agency ANR and/or Géodénergies) collaborative R&D projects:

■■ Rostock-H, in partnership with Air Liquide, Mines ParisTech, Université de Lorraine and Ineris. This project aims at improving knowledge about specific phenomena involved in storing H2 in salt caverns.

■■ FluidStory, in partnership with BRGM, Mines ParisTech, Ecole Polytechnique, Brouard Consulting and Areva H2Gen. The project aims to study the storage of electricity in salt caverns through the “Electrolysis-Methanation-Oxycombustion” process, in which the electrolysis of H2O into H2 and O2 is only the first step.

■■ Stopil-H2, in partnership with Storengy, Air Liquide, Mines ParisTech, Ineris, BRGM and Brouard Consulting. The project involves a Feasibility study of a pilot H2 storage facility in a brine cavern at the Etrez site.

In France, the HyGreen Provence project considers developing a large PV electricity production facility, converting part of it into H2 that could be stored in salt caverns and then used to fuel a fleet of public buses. Geostock’s technical know-how has been solicited, together with Storengy, by the natural gas storage company Géométhane in order to study the implementation of the H2 storage facility in the salt caverns they own.

Geostock is also involved in R&D studies into Hydrogen Power-to-Power solutions with its shareholders, Entrepose and Vinci Construction.

OUR SERVICES■■ Site selection, investigation work and underground storage design.■■ Drilling engineering services and construction of the underground storage cavern.■■ Definition and optimisation of operational cycles, including thermodynamic simulation of the hydrogen cavern’s behaviour using GUSTv2.■■ Specific Hydrogen completion. ■■ Entire Hydrogen Storage Project Management, from design to construction to commissioning.

2, rue des Martinets - CS 70030 • 92569 Rueil-Malmaison Cedex • FranceTel.: +33 1 47 08 73 00 • Fax: +33 1 47 08 73 73 www.geostockgroup.com

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