Making offshore wind completely carbon free

Last month MPI Adventure, a jack-up vessel deployed for planned maintenance at the Ormonde offshore wind farm, spectacularly dropped a huge rotor hub and blades into the Irish Sea.

Luckily no-one was hurt, but the widely shared footage highlights the crucial role that support vessels (OSVs) provide for offshore wind farms. 

It is a fast-growing business. MarineTraffic data shows that there are currently 3,420 active OSVs. This figure includes platform supply vessels (PSV) for oil rigs, anchor handling tugs, offshore construction vessels (OCV), and remote operated support vessels (ROV), amongst others. Of this figure, there are 686 active service vessels, 429 offshore vessels and 134 tug and supply vessels, a proportion of which will be interacting with offshore wind farms, as they transfer personnel, spare parts, and provisions.

Supply and service vessels

In Europe, the offshore wind sector has now reached a scale and size where the operational and contractual complexities are comparable to its oil and gas projects. The market primed for take-off in the Asia Pacific region and significant projects off the US coasts are coming onstream. The offshore renewable industry requires support from vessels from initial surveying and installation through to operations and maintenance.

wind farms
European countries made an early start in wind farm development. Source: MarineTraffic

wind farms

Wind farms off the coast of China. Source: MarineTraffic

But offshore wind farm companies don’t just expect their operations to be safe and efficient. They need to demonstrate to an environmentally aware public that the entire life-cycle of their wind farms is sustainable. Everything from the manufacture, transport and installation of wind turbines, underwater electricity cables running to the shore, and the movement of personnel to maintain the installations carry a carbon footprint. The pressure is now on the owners and operators of support vessels who play a critical role in this supply chain to reduce emissions and ensure vessel reliability for the environmentally sensitive wind farm operators.

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Examples of low-carbon initiatives for offshore support vessels are already emerging. 

Maersk Supply Service has introduced measures to start decarbonising its vessels, such as battery optimisation, use of biofuels and hydrogenated vegetable oil (HVO), behavioural and operational optimisation and use of shore power, amongst others. Biodiesel enables vessel operators to reduce their carbon footprint by 20-30% without the need for engine modifications. However, the veg-oil derived fuel needs to be stored carefully, is easily contaminated and throws up challenges of lubricity and its flow properties need monitoring.

Recently (30 September), the UK-based Alicat boat yard was awarded a contract to build two hybrid-powered vessels designed by naval architects Charwell Marine. The vessels will be used to transfer technicians from their accommodation on OSVs to work on the Dogger Bank turbines.

Seacat Services, which operates a fleet multi-purpose offshore energy support vessels, became the first company in June this year to adopt the Carbon Management Plan – an emissions reduction strategy introduced by new maritime sustainability consultancy, Cedar Marine. The plan will require the fleet operator to introduce operational changes and invest in research and development to bring down its emissions. Seacat has already started on its journey with introduction of alternative fuels, and it recently powered its crew transfer vessel, Seacat Enterprise, with HVO30 (fuel made with 30% hydrogenated vegetable oil and marine gas oil blend) for operations at Triton Knoll Offshore Wind Farm off the UK coast.

Like every part of the shipping industry, the offshore support sector faces challenges to power its vessels without creating emissions in the process. Methanol, hydrogen fuel cells and batteries all have the potential to play their part in the powering of marine engines, but delivering this at scale is still to happen. However, it is likely that many of the breakthroughs required will be first seen in this sector. 

These are exciting but challenging times for the offshore industry and the marine sector continues to play a crucial supporting role.

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