UK's largest compressed air energy storage project moves toward 2028 funding decision

Marram Energy Storage Hub (MESH) advances grid-scale renewable integration through Ofgem's second round of cap-and-floor support, targeting final investment by 2028.

The UK's largest compressed air energy storage project, Marram Energy Storage Hub (MESH), has secured invitation to Ofgem's second round of cap-and-floor scheme support. This follows a six-month delay to its original 2026 launch timeline, with the project now targeting a final investment decision by 2028 and first operations by late 2031. MESH—a 300 MW/55.2 GWh facility in the Irish Sea—uses salt formations 500-600 meters thick for cavern construction, with each cavern measuring 700,000 cubic meters. The project aims to address UK gas supply security challenges, as current storage capacity holds less than six days of national supply.

MESH’s design enables scalability through potential deployment of up to 60 caverns, integrating compressed air with gas and hydrogen storage. This approach targets grid stability during peak renewable generation cycles, directly responding to the UK’s gas storage shortfall that currently lasts less than six days of national supply.

For energy security, MESH could reduce reliance on volatile gas markets by storing excess renewable energy for extended periods. However, its operational timeline remains contingent on regulatory consents and Ofgem’s cap-and-floor support. The project’s national significance designation is company-stated, not independently verified, and its impact on gas supply security depends on achieving FID by 2028. What follows will determine whether this storage capacity translates into reliable, affordable energy for households and industry.

Source: pv magazine