Against a backdrop of decarbonisation, the electrification of mobility, and the rapid expansion of intermittent renewable energies, stationary electricity storage using batteries has become a cornerstone of the European electricity system.
To support this evolving sector, De Gaulle Fleurance, in partnership with Clean Horizon, Harmony Energy France, Liedekerke (Belgium), WKB (Poland), and Shakespeare Martineau (UK), has released the sixth edition of its Observatory of Energy Transitions, focusing on electricity storage.
This latest report offers a comprehensive snapshot of the legal, regulatory, fiscal, and operational frameworks for battery storage across France, Belgium, Poland, and the United Kingdom.
It highlights persistent barriers to deployment while identifying tangible opportunities for investment and acceleration.
By combining legal and technical expertise, the report presents a realistic, unified perspective on the development needs of European markets.
In France, the growth in renewable energy is driving an unprecedented need for electricity storage.
According to RTE’s 2023 Generation Adequacy Report, renewables are projected to increase from 120 TWh in 2023 to between 270 and 320 TWh by 2035, amplifying storage requirements.
Hydraulic storage remains dominant, with 5 GW in turbines and 4.3 GW in pumped storage as of 2024, but additional capacity is expected to be limited to 1.5 GW by 2035.
Battery installations have surged, reaching 1.07 GW by the end of 2024, up from less than 50 MW five years ago.
More than 7 GW of projects have already secured grid access rights, signalling robust development momentum.
Belgium has witnessed a dramatic rise in battery energy storage system (BESS) capacity, growing from zero at the start of 2021 to 200 MW/800 MWh by the end of the first quarter of 2025.
In Poland, installed capacity soared from 165 MW in 2022 to 2.5 GW in 2024, a tenfold increase in just two years.
The United Kingdom now boasts 2,469 energy storage projects — both active and inactive — with an installed capacity of 4.7 GW.
In February 2025, revenues from the battery balancing mechanism reached a record £27,000 per MW per year.
The UK’s £27.8 billion National Wealth Fund is designed to stimulate the ecological transition.
The development of electricity storage is closely linked to the boom in renewables, offering grid flexibility and new revenue streams.
By storing electricity when it is abundant and inexpensive, and releasing it during periods of high demand and prices, storage is becoming a strategic revenue source.
Several countries are actively fostering this growth through targeted measures: the UK abolished VAT on domestic batteries in 2024, Poland eased administrative constraints for small-scale projects, and Belgium introduced transmission tariff exemptions for storage.
The UK has also implemented a “ceiling/floor” mechanism to guarantee a minimum income for producers.
These policies are creating a favourable investment climate, positioning storage as a critical pillar of the energy transition.
Corentin Baschet, Partner at Clean Horizon, emphasised the importance of storage: “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 of Harmony Energy France, noted the evolving business model, stating: “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.”
From Belgium, Damien Verhoeven, Thomas Vanthournout, and Vincent Verbelen of Liedekerke highlighted the sector’s momentum, stating: “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 and Béatrice Boisnier of De Gaulle Fleurance observed that “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.”
From Poland, Maciej Szambelańczyk, Agata Fabiańczuk, and Katarzyna Paździorko of WKB described rapid progress, stating: “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, Isaac Murdy, and David Houston of Shakespeare Martineau underscored the UK’s leadership, stating: “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.”
As the European Union continues to refine its regulatory landscape — including the introduction of the new EU Batteries Regulation, which enforces sustainability, recycling, and safety requirements — battery storage is set to play an ever more vital role in achieving the continent’s energy transition goals.
