Electricity storage: the challenges of tomorrow

Against a backdrop of decarbonisation of energy use, electrification of mobility and growth in intermittent renewable energies, stationary electricity storage using batteries has become an essential link in the European electricity system. To support this dynamic, De Gaulle Fleurance, in partnership with Clean Horizon, Harmony Energy France, Liedekerke (Belgium), WKB (Poland) and Shakespeare Martineau (UK), is presenting the ^6thedition of its Observatory of Energy Transitions on electricity storage.

This report provides a snapshot of the legal, regulatory, fiscal and operational framework for battery storage in 4 major European countries. It highlights the persistent obstacles to its deployment and the concrete opportunities for investment and acceleration. This edition combines legal and technical expertise to provide a realistic, shared perspective on the development needs of European markets.

Key figures

France

According to RTE’s 2023 Generation Adequacy Report, the share of renewable energies is set to rise from 120 TWh in 2023 to 270 or even 320 TWh in 2035, increasing the need for electricity storage.

Hydraulic storage represents the largest share of storage capacity, amounting to 5 GW in turbines and 4.3 GW in pumped storage in 2024. Additional capacity should not exceed 1.5 GW by 2035, according to RTE.

The installed base of batteries will reach 1.07 GW by the end of 2024, compared with less than 50 MW 5 years ago.

More than 7 GW of projects have already reserved their grid access rights, reflecting strong development momentum, according to an RTE study published in February 2025.

Belgium:

Installed BESS capacity: 200 MW / 800 MWh by the end of the first quarter of 2025, compared with 0 at the start of 2021.

Poland:

Installed capacity: 165 MW in 2022, 2.5 GW in 2024 (a 10-fold increase in the space of 2 years).

United Kingdom

2,469 energy storage projects (active and inactive)

Installed capacity: 4.7 GW

In February 2025 revenues from the battery balancing mechanism reached a record £27k/MW/year.

The £27.8 billion National Wealth Fund is designed to stimulate the ecological transition.

The development of electricity storage is accompanying the boom in renewable energies in Europe. Storage batteries can bring flexibility to the grid and create new revenue opportunities. By storing electricity produced when it is abundant (and cheap) and feeding it back into the grid when demand is high (and therefore at higher prices), storage is becoming a strategic source of revenue. Several countries are actively supporting this dynamic through targeted measures. The UK, for example, has abolished VAT on domestic batteries in 2024 to encourage their installation. Poland has eased administrative constraints for small-scale projects. Belgium has transmission tariff exemptions applicable to storage. Finally, the UK has also introduced a “ceiling/floor” mechanism to guarantee a certain level of income for producers. These measures are helping to create a favourable framework for investment in storage, which is now seen as an essential pillar of the energy transition.

Corentin Baschet, Partner, Clean Horizon

Electricity storage plays a key role in balancing power grids, providing flexibility to grid operators. In France, the current storage capacity includes nearly 5 GW of pumped hydro storage and 1 GW in battery systems. As flexibility needs grow in line with the energy transition, Clean Horizon estimates that battery capacity in the country will reach 6 GW by 2030.

Clément Girard, COO and Managing Director, Harmony Energy France

The storage business model in France is currently based largely on system services, in particular aFRR. But in the medium term, arbitrage on the wholesale markets will take over. The increased volatility of electricity prices, linked to the rise of renewables and the limited flexibility of nuclear power, will make storage a key player in balancing the grid.

Damien Verhoeven, Partner, Thomas Vanthournout, Partner, Vincent Verbelen, Lawyer, Liedekerke (Belgium

In Belgium too, BESS projects expand remarkably. The installed capacity already evolved from zero to 200 MW in the last five years. The projects under development are however where the boom takes place, both in size (e.g. with a single project of 700MW/2800 MWh) and in numbers (with a lot of reserved capacity for a 3,27GW/11.776MWh at the end of 2034).  This reflects the need of the market and the trust of investors for such projects, helped by a rather light regulatory landscape.

Sylvie Perrin, Partner, and Béatrice Boisnier, Lawyer, De Gaulle Fleurance (France)

With limited development margins for hydraulic storage, battery storage is emerging as a key flexibility vector in a context of significant growth in renewable energies. However, unlike other countries (United Kingdom, Italy, Germany), which have sometimes launched dedicated calls for tenders for storage, France does not yet have a direct national support scheme reserved for batteries.

Maciej Szambelańczyk, Partner Co-managing the energy practice, Agata Fabiańczuk, Attorney-at-law specialising in energy law, Katarzyna Paździorko, Lawyer, WKB (Poland)

Poland has seen spectacular growth in the energy storage market, with contracted capacity increasing from 165 MW in 2022 to more than 2.5 GW in 2024. This dynamic reflects the growing importance of battery storage in managing renewable energies and stabilising the electricity grid, particularly in the context of the energy transition

Peter Dilks, Renewable Energy Partner, Isaac Murdy, Energy Lawyer, David Houston, Head of Knowledge Management, Shakespeare Martineau

The UK is showing that the development of battery storage is an essential prerequisite for a successful energy transition. With a backlog of projects equivalent to more than four times the needs of the grid by 2035, and fast-growing revenues, batteries are emerging as a strategic pillar of power system flexibility.