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

By Alice Grundy
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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.

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. 

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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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