Statera Energy has begun operating the biggest BESS project in the UK, connected to a National Grid substation that formerly supported two coal power plants.
The developer announced earlier this week (18 August) that its 300MW/600MWh Thurrock Storage battery energy storage system (BESS) project in Essex, Southeast England, is delivering energy to the grid.
Originally planned as a 1-hour duration project, the 2-hour BESS asset is part of Thurrock Flexible Generation, a complex that will also feature a co-located 450MW flexible generation gas-fired thermal power plant.
National Grid connected Thurrock Storage to its Tilbury substation just south of the project site, noting that the transmission infrastructure formerly served to connect the now-retired Tilbury A and Tilbury B coal-fired power plants to the grid.
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National Grid said work is underway to connect the site’s gas-fired generation to the grid.
Statera claimed the combination of batteries and gas generation at one site enables Thurrock Flexible Generation to respond to fluctuations in supply and demand created by the addition of solar PV and wind for extended periods of shortfall.
Statera specialises in flexible energy resources that can play a role in the low-carbon grid alongside renewables, claiming to have more than 2.1GW of projects in the UK already delivered or in construction, plus a further 16GW in development or consented, comprising batteries, pumped hydro energy storage (PHES), hydrogen and flexible generation technologies.
UK’s largest project: fact or fiction?
Statera’s claim that Thurrock Storage is the UK’s largest operational BESS facility rings true. However, several projects are in construction or development, which will likely take over the unofficial title soon.
These include a number by Statera itself. In fact, according to Solar Media Market Research analyst Josh Cornes, whose team publishes the Battery Storage: UK Pipeline & Completed Assets Database, with Thurrock Storage now online, three out of the six largest grid-scale battery storage projects in the UK have been built by the developer.
Before Thurrock Storage, the largest to date in the country was developer-investor Zenobe Energy’s Blackhillock 200MW/400MWh grid-forming BESS, between Inverness and Aberdeen in Scotland, announced as operational in February, Cornes said.
Looking further ahead, four 1GW or larger UK projects with planning approval in place are awaiting construction, including the 1.4GW Thorpe Marsh project by Onpath Energy, approved in January 2025, Innova’s 1,025MW Almhome Energy Hub, and others.
Cornes also confirmed that with no other significant renewable or flexibility resources connected at the Tilbury substation, but with 800MW of solar PV operational near the Essex site with 1.7GW under construction or at the ready-to-build stage, Statera’s claim of picking a strategically significant location also rings true.
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