EnergyPathways PLC's (AIM:EPP) proposed Marram Energy Storage Hub, known as MESH, has taken on fresh significance after new figures showed Britain wasted a record amount of wind energy in 2025.
The Montel report revealed that 10 terawatt hours of wind power were curtailed last year, enough to supply every home in London for a year. Without large-scale storage, such as MESH, this waste is set to grow.
Located off the Lancashire coast, MESH would store up to 20 terawatt hours of energy.
That is equal to 7% of UK annual electricity demand. The system combines natural gas, compressed air and hydrogen to deliver long-duration, dispatchable power.
The first phase would repurpose depleted gas fields to hold 17 terawatt hours. Later phases would use salt caverns to store hydrogen and compressed air.
The Montel report blames grid bottlenecks for the waste. Northern Scotland saw the most curtailment, with 8.8 terawatt hours of wind power switched off.
When this happens, wind farms are paid to shut down, and gas plants are paid to fill the gap. These curtailment charges cost UK billpayers £1.4 billion last year.
MESH aims to solve this by storing excess renewable energy and releasing it when needed. The site would connect directly to Irish Sea wind farms and feed power into the national grid using existing infrastructure.
The compressed air system would offer multi-day energy supply. Hydrogen will cut emissions to zero over time.
EnergyPathways is working with Siemens Energy, Wood Group, Costain and KBR. A final investment decision is expected once permits and financing are in place. Construction of the first phase could begin in 2028.
The MESH project arrives as curtailment costs continue to rise. Ofgem has approved £90 billion of grid upgrades, but these will take at least five years to complete.
Without more storage, curtailment charges could reach £10 billion annually by 2030, according to Octopus Energy.
EnergyPathways expects the first phase of MESH to cost £200 million. That is roughly a tenth of the estimated cost of upgrading Centrica’s Rough gas storage site.
The Montel report highlights what EnergyPathways sees as a clear gap in the UK energy system.
Without storage, renewable power will continue to be wasted. MESH is one of the few projects in development with the scale to change that.