UK bus operator First Bus has unveiled its largest battery energy storage system (BESS) to date, installing a 1 MW/2 MWh unit at its Hoeford depot in Hampshire. The system, which comes with a two-hour duration, is set to begin operations next month.
The launch marks a major step in First Bus’s efforts to support the charging of its 1,200-strong electric bus fleet while strengthening grid stability. The system will store surplus electricity and release it back during peak demand, helping to maintain energy supplies and reduce strain on the grid.
Later this year, First Bus will commission a larger facility—a 2MW/4MWh battery unit—at its Aberdeen depot, with additional sites under consideration across the UK.
The company also plans to repurpose end-of-life bus batteries for energy storage, giving them a “second life” beyond vehicle use. At Hoeford, the depot will host space for nearly three bus batteries with a combined potential to store 1 MW of power.
In parallel, FirstGroup Energy, the energy arm of First Bus’s parent company, announced an investment in Palmer Energy Technology (PETL), a battery storage manufacturer founded by former Aston Martin CEO and Nissan COO Andy Palmer. The investment joins backing from Barclays and Oxford University to accelerate development of next-generation control systems for BESS.
“With buses at the forefront of the transition to electric vehicles and net-zero transportation, I’m delighted to welcome investment from FirstGroup Energy,” said Andy Palmer. “This will accelerate our business and give the UK a leading position in battery energy storage system technology.”
The initiative underscores First Bus’s strategy of combining large-scale electrification with sustainable energy solutions, reinforcing its role in the UK’s shift toward cleaner public transport and grid resilience.
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