RINA approves Green Marine’s hydrogen CTV retrofit

Green Marine’s initiative looking to retrofit crew transfer vessels (CTV) with hydrogen, fuel cells and battery, with the aim to cut emissions while servicing offshore wind farms, has been granted Approval in Principle (AiP) by global classification society RINA.

The first phase of Project Verdant, involving a preliminary design and feasibility study, has now been completed and deemed viable, opening the door to subsequent project phases seeking to execute design, engineering and sea trials.

Led by Green Marine (UK), the Innovate UK funded project includes maritime consultancy Waves Group and the European Marine Energy Centre (EMEC).

Project Verdant’s conceptual design incorporates hydrogen fuel cells connected to electric motors, working in conjunction with existing diesel-fueled engines, which can be shut down to enable zero emission operation at slow speed while servicing offshore wind farms.

Hydrogen systems and marine fuel cell generator firm Energys helped design and provide engineering and modelling. Meanwhile, Engineered Marine Systems (EMS) supplied a design for the battery room, drawn from its extensive experience involving multiple hybrid CTVs.

Findings show the hybrid system could reduce the vessel’s CO2 emissions by up to 30% and NOx emissions by up to 40% – with CTVs commonly operating in loiter mode for long periods at a time.

The ultimate mission is to capture sufficient learning from the operation of a retro-fitted vessel to enable Green Marine UK to expand its fleet with new-build zero emissions CTVs and service operation vessels (SOVs).

Once the concept has been proven up, there is potential to rapidly replicate. This would enable economies of scale to be leveraged and remove barriers to adoption.