The two-hour Clay Tye BESS will be located in Essex. Image: FRV.

The 99MW/198MWh Clay Tye battery energy storage system (BESS), a joint project between Harmony Energy and Fotowatio Renewable Ventures (FRV), has been set live.

Clay Tye operates 52 Tesla Megapack lithium-ion batteries, each with a capacity of 198MWh, connected to the UK Power Networks’ distribution network. The project also uses Tesla Autobidder AI software for energy capacity sharing.

Both Felipe Hernández, chief innovation officer of FRV and Peter Kavanagh, CEO of Harmony Energy, called the project “an important milestone”. David Menéndez, managing director UK and BESS CoE at FRV added that the project was “one of the UK’s largest battery storage in operation per MWh”.

The project builds on the joint portfolio shared by the renewable energy development company and the renewable energy operator, which includes the 34MW/68MWh Contego BESS in West Sussex and the 7.5MW/15MWh Holes Bay.

The Hole Bay project began operation in June 2020, just as construction began on the Clan Tye site. FRV closed financing for a non-contracted revenue model for the project with NatWest in October 2021.

Earlier this year, Harmony Energy Income Trust, advised by Harmony Energy Advisors Limited, a wholly-owned subsidiary of Harmony Energy, successfully bid six BESS projects in the latest T-1 Capacity Market auction for delivery years 2024/25, which the company says will increase its revenue for this period to £3.2 million.