• Storing electricity to accelerate the energy transition

    STOLECT is developing an innovative technology for large-scale electricity storage by thermal conversion, called Carnot battery

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  • Innovative and durable technology

    STOLECT is developing an innovative technology for large-scale electricity storage by thermal conversion, called Carnot battery

    Learn more
  • Promoting the integration of renewable energies

    STOLECT converts variable renewable electricity into dispatchable electricity and thus enables the development of 100% renewable grids at the scale of industrial sites, renewable production plants or entire electrical networks

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  • Company and team

    STOLECT has a team with proven experience in innovation, project construction in the energy sector, and a thorough knowledge of the electricity markets

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  • News

    Follow the latest news about STOLECT

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STOLECT is developing a large-scale electricity storage technology to build 100% renewable networks by turning variable renewable electricity into dispatchable electricity. This technology is an essential link in the effort to decarbonise the energy mix and support the energy transition of electricity networks and industrial companies.

STOLECT offers a breakthrough solution compared to existing technologies. The technology offers a system that is totally environmentally friendly, independent of critical metals, suitable for large-scale storage, safe, designed and manufactured in France and in Europe, and economically cost-effective.

The Technology

STOLECT is an electricity storage process based on the reversible conversion of electrical energy into thermal energy.

The conversion is done by using turbomachines to circulate air through the system.

  • In the charging phase, a compressor converts the electrical energy from the grid into heat by compressing air. This heat is then stored in natural rock (basalt) or recycled ceramics.
  • During the discharging phase, the materials give up their energy to the circulating air, which then drives a turbine, coupled to an alternator. The recovered energy is fed back into the electricity grid.

This design has many advantages:

Durable design
Cost-effective technology
Long operating life span
No location constraints
High efficiency
Modular and flexible design
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Storage, coupled with renewable generation, provides dispatchable and renewable electricity, which is essential to reduce our dependency on fossil fuels. Thus, storage is the key to assist the integration and development of renewable energies (mainly wind and solar) throughout the world and at different scales.

Large-scale storage allows to :

  • Provide dispatchable and decarbonised electricity,
  • Ensure grid stability and avoid congestion during production peaks,
  • Valorise production surpluses during periods of low consumption,
  • Take advantage of price variations on the electricity markets.

STOLECT applications can be grouped into three main categories:

Isolated areas and grid operators

STOLECT supports renewable production by storing excess production to ensure the autonomy of a non-interconnected zone, such as an island or an isolated area. STOLECT has a major impact in reducing pollution and costs generated by production means such as generators, and in improving the energy independence of these areas.

Renewable electricity producers

STOLECT allows renewable power plant operators to optimise their production profile to avoid excess production and low electricity market prices, and thus to shift or smooth out part of their production to sell it at the most interesting time.

STOLECT can also be used to optimise connection power, for example for wind repowering.

Electro-intensive industries

Industrial companies with high electricity consumption may be interested in optimising their consumption with respect to renewable energy production and market prices, in order to consume the least carbon-intensive and cheapest electricity possible. It may also be essential for some industries to secure their supply in the event of power cuts in areas where the electricity grid is weaker.

Would you like to know how cost-effective a storage system is for your application?

Please contact us to discuss the most suitable system for your needs.

Contact us

The team

Jean-François Le Romancer

PhD in energetics, IAE, IHEDN-CHEAr

José Da Silva

Sales Director
Industrial Maintenance Engineer (CNAM)

Gauthier Preux

Head of R&D
Centrale Paris Engineer, Research Master in Energy

Strategic committee




The company

STOLECT ambition is to create a new industrial value chain in the field of large-scale electricity storage, based on the know-how of French and European partners.

STOLECT relies on a team with proven experience in innovation and project construction in the energy sector and a thorough knowledge of the electricity market, as well as on a network of industrial partners with strong expertise in their respective fields.

In order to benefit from the know-how of its partners and to accelerate the implementation of the technology, STOLECT will rely on their existing production tools, before developing its own production means in a second phase.


Foundation stone laying ceremony - 13/04/2023

Published on 
13 April 2023
A few photos of the ceremony of the laying of the foundation stone of the STOLECT electricity storage system at the SNCF Maintenance Technicentre in Rennes. We would like to thank all the participants, and […]

Progress of the construction of the first demonstrator - 22/03/2023

Published on 
22 March 2023
Work is continuing on the SNCF Maintenance Technicentre site, the building is taking shape!

Visit of Mr Pierre Cazeneuve, Member of French Parliament, and Mr Pierre-Franck Chevet, President of IFPEN, at STOLECT offices

Published on 
20 March 2023
STOLECT would like to thank Pierre Cazeneuve, Member of Parliament for the Hauts de Seine and rapporteur for the Renewable Energy Acceleration Act, for honouring us with his visit on Monday 20 March 2023. STOLECT […]

Carbon permits prices exceed €100/t for the first time ever

Published on 
23 February 2023
Carbon permits prices in Europe have reached the symbolic 100 €/t bar for the first time in their history. Their value had risen significantly between 2020 and 2022, and had remained at very high levels […]

Progress of the construction of the first demonstrator - 23/02/2023

Published on 
23 February 2023
The foreman looks at the plan, it is reassuring. Work continues on the site of the Technicentre Maintenance SNCF Bretagne.
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