EnergyPathways plc (AIM: EPP) said development of its Marram Energy Storage Hub in the East Irish Sea is progressing across long-duration electricity storage, strategic gas and hydrogen storage, and hydrogen, ammonia and graphite production. The UK government designated the project as of National Significance in September 2025.
The centrepiece is a proposed 300MW / 55GWh compressed-air energy storage facility, designed to provide more than 100 hours of storage using offshore salt caverns around 11 miles off the Lancashire coast. EnergyPathways says the facility could become the UK’s largest long-duration energy-storage project.
Pre-FEED work on the LDES project has been completed and Jacobs has been appointed to support the Development Consent Order process and the company’s planned participation in Ofgem’s next Cap & Floor round, expected in the fourth quarter of 2026. EnergyPathways is also discussing financing and capacity offtake with banks, institutional investors and strategic industry participants.
The company estimates LDES capital expenditure at £450 million-£500 million, with a targeted final investment decision in 2028 and commercial operations from 2031-32. Company-developed scoping economics indicate potential annual revenue of £100 million-£200 million, EBITDA of £40 million-£120 million and an NPV8 of £300 million-£500 million. These figures remain subject to FEED, approvals, financing and definitive offtake agreements.
EnergyPathways is also advancing a strategic gas and hydrogen storage project after receiving a Gas Storage Licence from the North Sea Transition Authority in July 2026. The proposed facility is designed for around 1.3 billion cubic metres of working gas capacity, which the company says could roughly double UK domestic gas storage from six to 12 days.
That project carries a further estimated £450 million-£500 million of CAPEX, with a targeted FID in 2027-28 and commercial operations from 2030-31. Company scoping estimates point to annual revenue of £100 million-£150 million, EBITDA of £50 million-£70 million and an NPV8 of £250 million-£500 million, again subject to further engineering, approvals, financing and offtake.
The third element is a proposed hydrogen, ammonia and graphite production facility using methane-pyrolysis technology. EnergyPathways is studying a plant capable of producing around 110,000 tonnes of ammonia, 20,000 tonnes of hydrogen and 60,000 tonnes of graphite annually.
Estimated CAPEX for that project is £120 million-£200 million, with a targeted FID in 2027-28 and operations from 2029-30. Company scoping economics indicate potential annual revenue of £100 million-£200 million, EBITDA of £40 million-£60 million and NPV8 of £200 million-£300 million.
The scale of the programme means financing is now the central issue. EnergyPathways estimates combined development and construction expenditure across the three projects at £1.02 billion-£1.20 billion and is seeking DEVEX funding in the near term while trying to progress longer-term CAPEX discussions into definitive term sheets.
The company currently has a £5 million three-year convertible loan note and £10 million at-the-market facility. It has drawn £2 million under the loan note, of which £500,000 has been converted into shares, while shares issued under the ATM programme have already been sold into the market.
Ben Clube, EnergyPathways’ CEO, commented: “We are now entering a critical phase in the lifecycle of all three projects. Engineering, regulatory and financing workstreams are being progressed at pace with the team, along with the Company’s external advisors engaging deeply and constructively with multiple stakeholders. I believe that we are on the cusp of significant development milestones for each project coming to fruition and look forward to making these announcements when they have been achieved.”
For investors, the next material milestones are therefore less about headline project size and more about execution: entry into the Ofgem Cap & Floor process, grid-connection arrangements, FEED progression, DEVEX funding and binding financing or offtake agreements. Until those are secured, the company’s revenue, EBITDA and NPV figures remain scoping estimates rather than financed project economics.
