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8GW of battery storage pre-qualifies for UK’s T-4 Capacity Market auction

By Alice Grundy
A UK battery storage project. Image: Zenobe.

Prequalification results for the UK’s T-4 and T-1 Capacity Market auctions have been released, with battery storage rising significantly in both.

The T-4 auction for delivery year 2025/26 saw 8.3GW of battery storage registered – although after derating this drops to around 2.3GW – according to data released by EnAppSys.

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Aurora Energy Research’s research associate Asgeir Fridrik Heimisson wrote on social media site LinkedIn that the 8.3GW figure is “significantly up from last year’s auction when almost 2GW pre-qualified”, adding that the increase was driven by one hour duration batteries.

In total, 50,850MW (~42,240MW derated) of capacity pre-qualified for the T-4 auction, EnAppSys said, with ~16,500MW (10,800MW derated) conditionally prequalifying. The auction has a target of 42,100MW of de-rated capacity. 

This is compared to a target of 40.1GW last year, with 63,334MW pre-qualifying and 139MW conditionally pre-qualifying. This auction – for delivery year 2024/25 – cleared at £18//kW/year, a small jump from the previous year’s T-4 auction, which cleared at £15.97/kW/year.

The 2024/25 T-4 auction also saw a rise in battery storage capacity, which doubled from the 117.0237MW awarded contracts in the 2023/24 auction to 251.98MW.

For 2025/26, gas-fired capacity makes up the greatest component of likely capacity in the auction at 36GW of de-rated capacity, EnAppSys said, with this followed by interconnectors (7GW).

To read the full version of this story visit Current±.

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