The hydrogen SOV is sailing out into the open waters

By Marek Grzybowski

Hydrogen-powered ships are still expensive, difficult to refuel, and hydrogen power is less efficient than traditional diesel propulsion. Yet shipowners operating wind farms introduce ships with such propulsion to operate offshore wind farms. This can be an important element of the competitive fight.
Recently, the shipowner Louis Dreyfus Armateurs (LDA) presented the SOV concept with a power plant using liquid hydrogen. According to the operator, the liquid hydrogen SOV is currently in the conceptual design phase. Its advantage is the fact that it will be able to operate for 95% of the operating time with zero carbon dioxide emissions. The result of combustion during standard operations will be water.
According to LDA, this solution will have a positive impact on emissions generated by service vessels used in connection with the operation of offshore wind farms. It has been calculated that the operation of hydrogen-powered units will prevent the emission of approximately 4,000. tons of CO2 per year.
LDA developed a conceptual design together with the Norwegian company Salt Ship Design, which designs units for MEW. An undisclosed leading European shipowner recently ordered two installation vessels (OCVs) with an option for two more. The ships will be built by Wuchang Shipbuilding Industry Group Co. Ltd from China. The ships are a continuation of the Salt 305 project previously built by the same shipyard for Sealion Shipping Ltd.
Sealion Shipping Ltd is a private operator based in Farnham, Surrey. Sealion is the shipowner and operator of Toisa Ltd. The main area of ​​activity is the oil and gas extraction industry. Sealion/Toisa also provide services to companies that install and maintain wind farm equipment, lay and repair cables. The company also provides support in the field of crew accommodation. It has ships capable of transporting and installing heavy loads.
The new OCV Salt 0494 engines will be adapted to run on alternative fuel and will be equipped with a large set of batteries. The project is implemented with the support of funds from the European Commission.
The French operator says the vessel will feature “best-in-class” CSOV operationality. There will be space for 90 technicians on board. The ship will be able to operate at sea for 14 days.
“We believe that hydrogen as a fuel is one of the key enablers to reduce the impact of the maritime industry in the coming years and helps achieve ambitious carbon emissions targets for the entire industry,” says LDA.
LDA in June 2023, together with joint venture partner Tidal Transit, was selected by Siemens Gamesa to provide transfer vessel (CTV) services for 24 technicians. The vessel will be used to operate and maintain the 497 MW Fécamp OWF.

Hydrogen cat to operate the OWF
In January this year The first hydrogen-powered CTV entered the open waters. It will operate German offshore wind farms.
The ship was put into operation by the operator FRS Windcat Offshore Logistics (FWOL). This is Germany’s first hydrogen-powered dual-fuel CTV ship. It will be used for the needs of the German transmission system operator (TSO) 50Hertz.
Hydrocat 55 is a CTV equipped with dual-fuel hydrogen technology from CMB.TECH, one of the shareholders of FWOL. Delivered in 2023, the vessel is built in the same way as Hydrocat 48, which was launched in 2022 as the first hydrogen-powered CTV. It was intended for operational activities in Belgium.
Hydrocat 55 is a 25-meter long vessel. But it can accommodate 24 passengers. Thanks to automation, it is operated by 2-3 crew members. The ship has tanks with a capacity of 207 kilograms of hydrogen. It was condensed in 27 cylinders.
– Using hydrogen, Hydrocat 55 can reduce diesel consumption and CO2 emissions – emphasizes the FWOL management. The engine was designed and manufactured by MAN Engines. The dual-fuel system involves direct injection of hydrogen into the engine. The hydrogen injection system for the dual-fuel engine was developed by CMB.TECH. The shipowner states that the ship consumes 34 kg of H2 at 20 knots.
In cooperation with Dutch joint venture partner Windcat, five more CTVs of this type are under construction. Work is ongoing to further optimize the ship’s technology and reduce CO2 emissions even further in the future, FWOL said. The trial operation period began in January 2024 and will last one year. During this time, the engines will use ecological hydrogen.
“Looking to the future, FWOL is committed to making a significant contribution to the decarbonization of offshore logistics and supporting the green production of renewable energy with the Hydrocat 55 and subsequent vessels of this type,” said Tim Kunstmann of FWOL when the vessel was put into service. FWOL and 50Hertz have been working together for over ten years. According to FWOL, two other ships in the fleet are currently serving the partner company.

Hydrogen innovation in Orkney
A CTV modernization project is also starting in Great Britain. The operator chose ships equipped with a set of hydrogen fuel cells.
Phase 1 of the project, financially supported by the UK’s national innovation agency Innovate UK, is currently underway, including initial design and a feasibility study. If the concept is deemed feasible, subsequent phases of the project will involve implementing the conceptual design and testing it in the field.
The conceptual design includes the development of a drive based on hydrogen fuel cells combined with electric motors. These will be able to work with ship engines powered by diesel oil. They will be able to be turned off to allow the electric motors to run at low ship speed. This is to ensure zero emissions of substances harmful to the environment when operating in the environment of offshore wind farms.
– The proposed hybrid system can reduce the ship’s CO2 emissions by up to 30% and NOx emissions by up to 40% – assume the principals of the new CTV project.
The project consortium is led by Orkney-based Green Marine and supported by project partners Waves Group and the European Marine Energy Center (EMEC).
– Several new-build hydrogen-powered vessels have been brought to market in recent years, but our current goal is to develop a system that can be easily fitted to a CTV and which would enable hydrogen fuel cells to be powered in low-activity mode [of the main engines – MG] for a significant part of the day – explains Jason Hayman, designer leading the Verdant project for Green Marine.
Hayman said that “Over the coming weeks and months, we will work with industry leaders and technical experts to develop the system design and specifications.” In the next stage, a feasibility assessment will be carried out to ensure that any risks identified during the project can be eliminated or mitigated.
During a recent conference devoted to the Polish flag, one of the Polish operators boasted that they had introduced a second-hand wind farm vessel into Polish waters. The withdrawal of older vessels by leading shipowners operating offshore installations means that the process of replacing the vessels with more modern and environmentally friendly ones has begun.
This is important market information, because it may turn out that installation companies will demand that they be serviced by ships with electric, hydrogen or at least hybrid propulsion. Then units from the secondary market will not be competitive. And again there will be complaints that the government did not provide local content.