Dutch windfarms are to begin using a hybrid vessel with a surface effect catamaran hull form to minimise CO2 emissions.

The new CWind Hybrid SES supports Ørsted’s ambition of a world that runs entirely on green energy

The new CWind Hybrid SES supports Ørsted’s ambition of a world that runs entirely on green energy

CWind has announced a long-term charter contract agreement with Ørsted, delivering by mid 2020, the world’s first hybrid powered Surface Effect Ship (SES) to Borssele 1 and 2 offshore wind farms.

The agreement between the world’s leading windfarm operator Ørsted and CWind, part of the Global Marine Group, covers an initial three-year firm charter with options available for a further two years. The Hybrid SES crew transfer vessel will be operating from the Dutch port of Vlissingen, to Borssele 1 and 2, located 23km from the Dutch coast in the North Sea.

The development of the Hybrid SES for use as a crew transfer vessel is in response to an industrywide push to develop and deploy innovative technologies that reduce CO2 emissions, whilst cost effectively servicing windfarms located further offshore. CWind’s Hybrid SES crew transfer vessel achieves this through a combination of electric and diesel propulsion which, when combined with the surface effect hull form and heave compensation technology, is able to operate in sea states of up to 2.0m Hs, whilst decreasing fuel burn and CO2. The Hybrid SES is, therefore, able to deliver crew faster to these sites and with improved comfort, resulting in increased operation days offshore for the client’s O&M and construction activities.

Ian Bryan, Managing Director, Group Business Operations said: “We are delighted to announce the agreement with Ørsted, and look forward to delivering the world’s first Hybrid SES for them in 2020. Our development of the vessel has been driven by listening to the market and our customers who want a greener, safer and more efficient Crew Transfer Vessel to support their commercial and green objectives.”

The new CWind Hybrid SES will enable Ørsted to not only deliver and service windfarms efficiently through reduced transit times, but it also supports Ørsted’s ambition of a world that runs entirely on green energy. The Hybrid SES crew transfer vessel was developed in partnership with ESNA, a ship design company based in Kristiansand, Norway. ESNA specialises in surface effect vessel development to deliver commercially competitive vessels with significant carbon reductions by design.

Naval architect and co-founder of ESNA, Trygve H. Espeland, also explains: “The vessel design will accommodate further developments in hybrid propulsion and battery technology, ensuring it has the capability of being developed into a totally carbon-free solution in the future”. The vessel will be built by Wight Shipyard Company, a leading UK boat builder.

The Hybrid SES propulsion engine will deliver sprint speed and extreme bollard push, from its 1,300 kW installed diesel engines, which can be battery boosted up to 1,500kW. Significant fuel savings are produced through balancing engine and inefficient low engine power running hours, with battery drive modes including wind farm standby and low speed/harbour operations. This leads to engine operating hours being reduced by 50% during wind farm battery standby.

SES vessels use lift fans to create an increase in air pressure in a void beneath the hull (in the case of a catamaran, the void is already conveniently present in the area under the bridgedeck between the hulls which is why the majority of SES vessels are catamarans). This air pressure lifts the hulls higher in the water than they would be without the lift fans so reducing the hulls’ skin and wavemaking drag, thus increasing overall system efficiency. Less hull in the water and riding partially on air is also claimed by proponents to be beneficial to the ride of the vessel. Catamaran SESs normally require flaps down to water level between the hulls at the transom and bow to maintain the pressurised air, but flexible and so capable of supporting a range of different ride heights and capable of deforming when hit by waves in a similar way to a hovercraft skirt.

By Jake Frith