2025 in Review: Battery storage – a breakout year for a maturing asset class

Battery energy storage systems (BESS) have travelled a long road in a very short period of time. Little more than a decade ago, they were still treated as an experimental adjunct to the renewable sector. By 2025, however, storage is firmly embedded in Europe’s energy transition architecture, and arguably became the fastest growing asset class in the energy transition sector. In the UK and EU alike, investors, lenders, developers and policymakers now see BESS as a critical enabler of renewable penetration and system stability. This year marked a decisive shift, in terms of project finance, technology and policy: 2025 was, by most measures, the year in which grid-scale BESS achieved commercial and political maturity across Europe. As the year comes to an end, inspiratia unpacks the defining trends, landmark transactions and evolving policy frameworks which shaped BESS in the UK and EU in 2025.