We are at a pivotal point in the race to net-zero, with various incredible developments being made across industries to decarbonise. Many are presented with challenges, but a particular area problematic to decarbonise is maritime.
The use of hybrid electric vessels is increasing – in fact all new vessels in the UK are required to have zero-propulsion capabilities from 2025. But the range of these vessels are constrained by their battery capabilities. Restricting charging to within ports and harbours limits the duration and distance electrified vessels can travel. The ability to re-charge offshore will not only see a substantial reduction of CO2 emissions and fuel costs, it fundamentally makes electric and hybrid vessels fully viable. Developing offshore charging is imperative to ensure the benefits of hybrid vessels are maximised to their full capabilities.
Potentially the first to provide offshore charging is the wind industry. Offshore wind is increasing globally, with the UK at the forefront of progressing this renewable energy source with 40 wind farms operational or under development, totalling over 2,500 individual turbines. This is an encouraging step towards decarbonisation, although efforts must be taken to decarbonise the wind industry itself.
Research by ClimateXChange found that most of the carbon emissions that arise during the operation of wind farms are attributed to maintenance activities and that shipping is responsible for 70% of these emissions. A study by Offshore Renewable Energy Catapult found Crew Transfer Vessels (CTVs) are the primary vessel involved in the operation and maintenance of wind farms, accounting for 76% of annual onsite activity.
Currently the majority of the 140 CTVs in the UK are solely powered by diesel, producing unacceptably high CO2 emissions. CTVs consume 320 litres of fuel per hour while transiting to wind farms at an average speed, equating to 999.1 kg CO2e per hour. In total, CTVs produce 514.9 tonnes CO2e annually travelling to one small wind farm (ORE Catapult).
Both wind farm operators and vessel owners are urging the transition to electric vessels. In addition to decarbonisation, electric vessels bring cost savings due to the reduction in fuel consumption. With many wind farms out of range that can be provided by battery power, re-charging offshore is vital for full advantages to be met.
We have developed the first offshore charging station, the Oasis Power Buoy (OPB). Our design optimises CO2e reduction by charging vessels from a zero-emission power source fed directly from the wind farm. Hybrid and electric vessels are fitted with a bespoke mooring system, including a winch that pulls the lines from the buoy into position and locks in the electrical cables.
For near-shore windfarms, the OPB could facilitate a complete elimination of diesel use by allowing hybrid and electric vessels to continually operate on green electrical power. Wind farms further afield would still see significant reductions as batteries can be fully charged for the return to shore. By providing in-field charging, the OPB will significantly reduce operational emissions by 70%.
In addition to transiting to wind farms, 88% of a CTV’s usage is spent loitering in-field, manually maintaining constant position. This requires significant fuel – 130 litres per hour, producing 406kg CO2e every hour. For one small wind farm this means 1,534 tonnes CO2e is produced every year by CTVs waiting in-field. (ORE Catapult). As the OPB also doubles as a mooring point, the vessel’s engine can be turned off whilst connected in-field, thereby eradicating the use of fuel and its astronomical emissions.
The offshore wind industry may be the first to enable offshore charging, but once demonstrated, the technology can be applied further afield. This is essential as offshore charging will be crucial for the decarbonisation of the maritime industry and reaching overall Net Zero targets by 2050.
Sources:
Setting a benchmark for decarbonising O&M vessels of offshore wind farms – ORE (catapult.org.uk)
Life Cycle Costs and Carbon Emissions of Offshore Wind Power (climatexchange.org.uk)
