O.S. Energy and Ecomar Propulsion secures Lloyd’s Register approval for the Prince Madog’s hydrogen storage, fuel cell and battery integration design.
The UK-flagged research vessel Prince Madog has received certification for a hydrogen fuel cell retrofit, following approval by Lloyd’s Register (LR) under its ShipRight Risk Based Certification (RBC) framework.
The certification was formally presented during Seawork 2026 in Southampton, highlighting progress in the adoption of hydrogen-based propulsion and power systems within the maritime sector.
The project, delivered by vessel owner O.S. Energy’s Naval Architecture and R&D office in collaboration with hydrogen and clean energy systems specialist Ecomar Propulsion, included the development of the vessel’s gaseous hydrogen storage system and the detailed integration design of the associated fuel cell, battery and ancillary systems.
Lloyd’s Register’s ShipRight RBC framework provides an assurance route for technologies that fall outside traditional regulatory frameworks. The approach allows innovative projects to move forward, while maintaining robust safety and risk management standards.
The certification follows LR’s recent Approval in Principle (AiP) for the design, recognising the safe integration of the hydrogen system and its alignment with class requirements. The project was supported through the UK Government’s Clean Maritime Demonstration Competition (CMDC).
Mark Nijhoff, Lead Specialist Piping & Decarbonisation Systems, Lloyd’s Register, said: “Through our ShipRight Risk Based Certification framework, we are helping innovators bring new technologies to market while maintaining the highest standards of safety and assurance.
“Projects such as the Prince Madog ‘TransShip II’ project are important because they demonstrate that hydrogen technologies can be implemented safely and pragmatically across the maritime sector.”
Oliver Cornforth, Head of Projects at O.S. Energy, said: “As Project Lead for O.S. Energy throughout the TransShip II project, I am extremely proud to have achieved this recognition from Lloyd’s Register.
“This significant milestone reflects the hard work and dedication of the entire project team over the last 3 years. We now look forward to completing the Hydrogen-Battery retrofit and demonstrating the zero-emission operation of the Prince Madog.”
“The Prince Madog will be the first sea-going, manned hydrogen retrofit of its kind, and the project is helping to establish a pathway for the adoption of hydrogen propulsion on workboats and larger commercial vessels, supporting the maritime industry’s transition towards Net Zero 2050.”
Nik Lekkas, CTO at Ecomar Propulsion, said: “This certification is an important milestone for the Prince Madog, for Ecomar Propulsion and for me personally, having helped drive Ecomar’s scope from system development through to integration and certification from the ground up.
“The recognition this brings to the wider project team reflects the effort required to take hydrogen technology from concept towards safe, certified vessel operation. It also demonstrates the growing maturity of hydrogen-powered solutions and gives the industry greater confidence in adopting zero-emission clean energy and propulsion systems.
“Ecomar Propulsion is now even better positioned to support ports, shipowners, vessel operators and new-build programmes with hydrogen storage, fuel cell integration and clean propulsion system development, from port infrastructure through to vessel propulsion.”
Lloyd’s Register has published a report in its award-winning Fuel for thought series, providing a comprehensive assessment of hydrogen’s potential role in maritime decarbonisation.
Fuel for thought: Hydrogen examines hydrogen from production and supply through to onboard use, highlighting the fuel’s advantages alongside the safety, infrastructure and cost challenges that currently restrict its adoption.
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