The startup Stolect is testing a prototype of massive green electricity storage with the SNCF

For Stolect, an Ile-de-France startup founded in 2019, the SNCF is a key partner. It is moreover at the Technicentre Maintenance Bretagne in Cesson-Sévigné, near Rennes, that this specialist in massive electricity storage will build, between the end of 2022 and June 2023, its first demonstrator, based on the principle of thermal conversion. . Called Carnot battery, it is a type of storage of electricity in the form of heat. During the destocking phase, the heat extracted from the storage is reconverted into electricity, reinjected into a site or into the network.

Consisting of two enclosures five meters in diameter and six meters high, in which only air circulates, the future system with a capacity of 1MW / 5MWh, and whose design is patented, contains 100 tonnes of materials refractories (basalts, ceramics). The tests, which will be carried out using electricity drawn from the network, will take place in 2023.

Solution adapted to solar or wind power

For this test phase, we have chosen a representative site. The SNCF is the leading consumer of electricity in France. She consumes a lot but not at the right time, rather in the morning and evening, times that correspond to expensive tariff schedules. In the current context, the bill flies away explains Jean-François Le Romancer, founder and president of Stolect.

The idea of ​​the project is to promote the integration of renewable energies into the networks. Our solution is suitable for storing electricity from both photovoltaic and wind power,” adds the leader.

This stationary storage technology is even a driver, according to him, because it has the advantage of offering storage capacities that can range from several hours to several days.

The overall efficiency of the cycle is targeted at 70%, which is possible thanks to the operation in a closed circuit continues Jean-François Le Romancer.

The Eren Group in the funding round

To accelerate the technical development of its solution by recruiting and installing this first demonstrator, the entrepreneur has just announced a fundraising of 4 million euros.

Gathered in part in the form of equity, European subsidies (Brittany Feder) and loans (Bpifrance, Banque Populaire Grand Ouest, Caisse d’Épargne Bretagne Pays de la Loire), this financing comes mainly from entrepreneurs and industrialists from energy, digital and carbon finance sectors. The Eren group, via its production subsidiary Total Eren, but also Jean-François Vaury, administrator of Johes, which finances projects related to renewable energies, are part of the round table.

A second fundraising is already planned for the end of the year in order to prepare for the marketing stage scheduled for 2024, in France and internationally. And for the installation of storage units of identical and higher capacity, between 2 and 5 MW (10/20 MWh).

Meet the needs of isolated areas or industrialists

Stolect opens up the possibility of operating networks using 100% renewable energy (ENR) by converting variable production into controllable electricity. The stationary electric storage market is estimated at 50 billion dollars per year until 2030, excluding electric mobility, it is global calculates Jean-François Le Romancer.

The leader is exploring three growth markets in particular: isolated areas still supplied with fossil energy, in North Africa, Asia or Indonesia for example, electricity network managers and players in the energy mix such as those in Drom-Com who are encouraged to make production and consumption coincide, and finally electro-intensive industrialists (SMEs, agri-food sector, etc.) concerned with lowering their energy bills. Market developments over the past few months have also prompted Stolect to look at areas of activity and local authorities in France.

Limit the carbon impact of technology

Currently based in Rueil-Malmaison, Stolect aims to install around twenty units by 2026 for a turnover of between 40 and 50 million euros. The cruising speed envisaged by the company is around fifteen installations per year after 2026.

While its project has been supported from the start by the SMILE project dedicated to the development of smart grids (intelligent energy systems) in Brittany and Pays-de-la-Loire, Stolect also plans to move its offices and future technical workshops for manufacturing and maintenance in Rennes within two years, as close as possible to the first demonstrator.

In addition to the fact that it could become a customer, the SNCF will perhaps also be, tomorrow, an important support for the SME in the conveyance on train of the elements of its storage system and to limit the carbon impact of its technology.