Insights

UK T‑4 Capacity Market 2029/30 results: Battery Energy Storage dominates new build capacity

03/19/202603/19/2026 Insights

BESS secures 95% of new build capacity, reinforcing its central role in the UK’s energy transition

The results are in from the UK’s T-4 Capacity Market auction for delivery year 2029/30, and they signal a decisive shift toward energy storage in Great Britain’s power infrastructure.

Key takeaways

Total capacity secured: 40 GW at a clearing price of £27/kW/year
New build capacity: 1,250 MW of new generation secured across 97 projects
Battery storage dominance: 1,184 MW of new build Battery Energy Storage Systems (BESS) capacity awarded, 95% of all new build capacity in this auction. The installed capacity of these projects will be closer to 3.8 GW before derating is applied.

What this means

The success of BESS in this auction underscores the critical role that flexible storage will play in the UK’s energy transition. With storage durations ranging from 30 minutes to 8 hours, these projects will provide essential grid stability and flexibility as the UK moves toward its net-zero targets.

The diversity of BESS configurations awarded highlights the market’s recognition that different storage durations serve different grid needs – from frequency response (shorter duration) to peak shifting and renewable integration (longer duration).

What’s next for developers, investors, and lenders

These provisional results (expected on 20^th March, 2026) represent significant opportunities, but also technical and commercial complexities to be resolved to transition these awards into on the ground developments.

At Enertis Applus+, our UK‑based team works on the ground with developers, investors and lenders, providing independent BESS consultin g, engineering, and QAQC services throughout the full project lifecycle, from early‑stage development and financing through to construction oversight, on‑site testing and commissioning.

With local presence and deep market knowledge, we help ensure that awarded BESS projects are technically robust, bankable, and ready to perform in real operating conditions.