The Marram Energy Storage Hub (MESH) is an integrated offshore energy storage facility under development by EnergyPathways. It is designed to support the UK government’s energy strategy of transitioning to clean power by 2030.
MESH will provide long-duration energy storage solutions by combining natural gas, hydrogen, and compressed air technologies.
The project is expected to contribute to national energy security by offering up to 20 terawatt-hours (TWh) of storage capacity, which equates to approximately 7% of the UK’s current annual electricity demand.
Project Location
MESH is situated approximately 11 miles offshore from Blackpool, in Block 110/4a of the East Irish Sea. The onshore component will be based in Barrow-in-Furness, using repurposed industrial land. This location enables integration with nearby offshore wind resources and access to regional hydrogen and gas infrastructure.
Capacity and Infrastructure
The project will have a total storage capacity of up to 20TWh. This includes underground gas storage in a depleted gas field (Marram A) with a planned capacity of up to 17TWh and additional hydrogen and compressed air storage in up to 20 offshore salt caverns with a combined capacity of up to 2.8TWh. The facility will have the capability to supply up to 2.4GW of dispatchable energy.
The initial phase will consist of low-emission indigenous gas production, followed by transition to hydrogen and compressed air energy storage (H-CAES). The project will include a 400MW compressed air energy storage unit, operating at a projected efficiency of up to 70%.
Development and Timeline
The project is progressing through the necessary licence and planning stages. EnergyPathways has submitted applications for relevant licences and expects the initial phase of the gas storage project to be operational by 2028. Hydrogen and compressed air storage operations are planned to follow between 2028 and 2029. A final investment decision is anticipated in 2025.
Financing and Ownership
MESH is fully owned by EnergyPathways. The project is expected to be financed through private capital focused on supporting the UK’s energy transition. EnergyPathways has already invested in early concept development and planning.
Technological Details
MESH will incorporate integrated storage and dispatch capabilities across three technologies: natural gas, hydrogen, and compressed air. The storage infrastructure will utilise repurposed gas production assets and new salt cavern wells. Onshore and offshore facilities will be electrified and powered by renewable electricity.
The project will include Artificial Intelligence-based energy management systems to optimise operation and balance variable supply and demand. The H-CAES unit will provide multi-day power supply capacity and aims to operate at lower capital expenditure than conventional battery energy storage systems.
MESH will initially connect to around 1GW of the existing 8GW of offshore wind capacity in the Irish Sea. These connections will be established behind the transmission grid, bypassing national grid constraints.
Power Purchase Agreements
The project’s output will be integrated with the UK’s National Grid through existing offshore wind transmission lines. As the hydrogen and low-carbon power generation components mature, MESH may secure agreements with industrial users and grid operators. No power purchase agreements have been formally disclosed.
Contractors and Suppliers
EnergyPathways has engaged multiple Tier-1 UK-based offshore contractors for early-stage technical development. These include engineering partners supporting geoscience modelling and front-end engineering design. Specific contractor names for later stages have not yet been disclosed.
Energy Security and Future Integration
The UK plans to maintain approximately 35GW of gas reserve capacity by 2030. MESH’s storage is positioned to support this requirement by reducing exposure to import dependency and global gas price volatility. When fully developed, MESH could become the UK’s largest gas storage facility.
MESH is compatible with future integration into the HyNet North West hydrogen network and Morecambe Net Zero carbon capture projects. A repurposed trunkline to Barrow and potential new pipeline infrastructure are planned to enable this connectivity.
The facility’s low-carbon flexible power generation capacity will begin with natural gas and transition to hydrogen over time. MESH is expected to provide up to 1.5GW of flexible power using stored energy.
