Project Verdant
Green Marine’s Green Storm vessel (Credit Green Marine)
Timescale:
2023 – 2024
Funders:
Innovate UK
Project Overview:
The first phase of Project Verdant was a preliminary design and feasibility study that investigated the viability of integrating a hydrogen fuel cell system onto an existing offshore wind crew transfer vessel (CTV) to reduce greenhouse gas (GHG) emissions and increase efficiency.
The study focused on the conversion of the Green Storm, an existing 25m CTV vessel operated by Green Marine that is equipped to carry out personnel transfers on offshore wind farms, to be able to operate in zero emission mode when operating at slow speeds within offshore wind farms. The project looked to produce a detailed design specification for the CTV conversion as well as obtain approval in principle from the MCA and the vessel classification society. This design would then be used to conduct a detailed economic modelling exercise.
Partners:
- Green Marine (vessel owner and lead partner)
- Waves Group
- EMEC
EMEC’s role:
EMEC advised on the refuelling, logistics, training and safety aspects of the project as well as conducting the economic modelling for the retrofitted hydrogen CTV, looking at the capital and operating expenditure costs and other variables such as sea trials and training required for the conversion of the CTV.
Results:
The conceptual design developed by Waves Group incorporated hydrogen fuel cells connected to electric motors, working in conjunction with existing diesel-fuelled engines, which can be shut down to enable zero emission operation at slow speed while servicing offshore wind farms.
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.
Within the project, the conceptual design and associated documentation was developed and submitted for review. As a result Approval in Principle (AiP) has been granted by global classification society RINA. This enables the project to move towards a detailed design phase.
The economic modelling for a hybrid hydrogen-electric CTV vessel resulted in a more favourable outlook in the mid-longer term, despite initial high costs. In the short term, the current cost of green hydrogen as a fuel is high when compared with MGO and other factors, such as maintenance and additional operators for refuelling, would need to be factored in. Consideration would also need to be given to shoreside hydrogen bunkering infrastructure requirements and safety considerations. That said, in the mid to long term, the economic case for the use of hybrid electric hydrogen vessels becomes more viable if the wider maritime industry makes steps to decarbonise using hydrogen as a fuel, allowing infrastructure and operator costs to be shared. In addition, the cost of green hydrogen will decrease as more offshore wind projects come online and additional green hydrogen production facilities are commissioned.
Overall, while the short-term costs are high, the long-term economic case for hybrid hydrogen-electric CTVs is more feasible, aligning with wider maritime industry trends and policy supporting the path towards decarbonisation.
