Wind turbines and solar panels (China). © chungking - Fotolia

FluidSTORY: investigating the feasibility of a solution for future below-ground energy storage

07.18.2016
FluidSTORY, launched in 2016, is a 4-year project co-funded by the French National Research Agency (ANR). The aim is to investigate the feasibility of the EMO technique (Electrolysis-Methanation-Oxycombustion) as a solution for future energy storage. The EU has set a target of 20% renewables in the European energy mix by 2020. Most of these energy sources, such as wind and solar power, are "intermittent". In order to match energy supply and demand and to guarantee grid stability, solutions are needed to store and release energy as and when required. Mass energy storage is therefore a major challenge to ensure a successful energy transition.

Most sources of renewable energy are "intermittent", so that solutions are needed to store and release the energy produced as and when required. © Chungking - Fotolia

An innovative solution for the energy transition

The BRGM is coordinating the FluidSTORY project, launched in 2016 with co-funding from the French National Research Agency (ANR). This 4-year, 2.1 million € project is investigating the feasibility, for operational implementation in France in 2030-2050, of a solution for future below-ground energy storage.

The EMO concept (Electrolysis-Methanation-Oxycombustion) is based on a closed loop system capable of absorbing surplus electricity and releasing it at a later stage, again as electrical power, via temporary storage in the form of oxygen, CO2 and methane in fluid form.

The technique involves transforming surplus electricity into methane. This takes place in two stages: first, electrolysis to produce hydrogen and oxygen from water, followed by the reaction of the hydrogen with CO2 to produce methane. The methane is then used to drive a turbine that again generates electricity. The process implies temporary and reversible storage of large quantities of fluids (oxygen, CO2 and methane).

The FluidSTORY project is focusing in particular on coupling this technique with underground storage in saline cavities. The idea is to store the fluids in cavities in deep brine layers, such as those already used for strategic and seasonal storage of hydrocarbons.

A multidisciplinary approach

The main aim of FluidSTORY is to investigate the feasibility, safety and reservoir integrity of storing the oxygen and CO2 required to apply the EMO concept in saline cavities.

The project also includes an economic component: the operational conditions required to apply the concept are being investigated with the aim of achieving cost-effective energy and economic yields by 2030-2050. An inventory of suitable geological formations and saline cavities will also be produced to complete the analysis of the concept's development potential.

The regulatory context, risk factors and conditions of operational performance are being investigated in detail.

An operational synthesis of these studies will be produced in the form of recommendations to guide the subsequent development of technical solutions.

Opportunities for research and industry

The FluidSTORY project is aiming to develop the EMO storage concept for transfer to industry in the medium term. It involves 3 public and 4 private partners providing specialised expertise on markets, technological solutions and development needs:

  • BRGM (Bureau de recherches géologiques et minières, the French Geological Survey): coordination, geological inventories, safety and risks
  • ARMINES: thermodynamics and geochemistry, surface processes
  • X-LMS Ecole Polytechnique: thermomechanics, simulations and experimentation
  • Brouard Consulting: thermomechanics
  • Geostock: geotechniques, expertise on cavities
  • Geogreen: strategy and economics
  • AREVA H2-GEN: electrolysis

Work under the project is monitored by an external committee of energy industry representatives, including Air Liquide and Engie. The committee acts in an advisory capacity to guarantee the technical and energy market relevance of the options investigated.

The project is supported by the AVENIA and S2E2 competitiveness clusters.

It also holds out opportunities for the dissemination of research results:

  • two theses are to be developed under the project, one on the geochemical behaviour of the fluids stored and the other on the geomechanical responses of saline cavities.
  • The research work is to be presented through specialised symposia and publications. An international workshop will be organised when the project closes to present the main advances made and opportunities for development.
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