Cleve Hill Solar Park (formerly Project Fortress) is a photovoltaic power station on the Graveney marshes between Faversham and Whitstable, Kent in the UK. It began commercial operation in July 2025 and forms part of one of the country’s largest co-located solar and battery energy projects.

It is the largest solar farm in the UK, generating 373 MW of electricity from around 900 acres (360 ha) of solar panels, and also includes a 150 MW Battery Energy Storage System (BESS). The battery facility stores renewable electricity and releases it when demand is higher, helping increase grid flexibility and reduce renewable curtailment.

Electricity from the site is exported via the 400 kV National Grid substation at Cleve Hill, originally built for the London Array offshore wind farm in the Thames Estuary. The battery installation, located alongside this infrastructure, charges during periods of strong solar generation and discharges energy when required by the electricity network.