Green ambitions: charterer opts for first hybrid SES CTV

A global energy transformation is underway, underpinned by governmental policies promoting the transition to greener power and the reduction of CO₂ emissions. Among international energy companies, Scandinavian windfarm operator Ørsted is in the vanguard of this movement, leveraging emerging technologies and partnering with suppliers to decarbonise its operations and supply chain.

One recent example of this is Ørsted’s long-term charter agreement with UK-headquartered CWind, announced in October, for the world’s first hybrid-powered surface effect ship (SES). Under the three-year charter agreement, which contains options for two more years, CWind’s hybrid SES crew transfer vessel (CTV) will operate out of the Dutch port of Vlissingen serving the offshore windfarms Borssele 1 and 2 in the North Sea, starting in mid-2020.

CWind says the CTV will utilise electric and diesel propulsion in combination with its surface effect and heave compensation technology to operate in sea states of up to 2.0-m significant wave height, whilst decreasing fuel burn and CO₂. CWind expects the hybrid SES to deliver technicians faster and more comfortably to windfarm sites, resulting in increased operational days.

“Our development of the vessel has been driven by listening to the market and our customers who want a greener, safer and more efficient CTV to support their commercial and green objectives,” says CWind managing director, group business operations Ian Bryan.

Part of the Global Marine Group, CWind has a fleet of 17 CTVs, two of which are small waterplane area twin hull (SWATH) vessels. This new vessel would be the company’s first SES.

The hybrid SES CTV was developed in partnership with Norwegian naval architectural firm ESNA, which specialises in surface effect vessel development for commercial applications.

ESNA co-founder Trygve H. Espeland says: “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.”

CWind says fuel savings will result from optimising engine loads, reducing inefficient low engine power running hours by using battery drive modes, including windfarm standby and low speed/harbour operations. This leads to a 50% reduction in engine operating hours during windfarm battery standby operation, it says.

Propulsion for the catamaran-hulled vessel will be supplied by two Scania diesel engines, each generating 809 kW, that drive two Rolls-Royce Kamewa S50-3/CA waterjets, via marine gearboxes. Rounding out the vessel’s propulsion equipment are two 130-kW electric generator motors, one 75-kW electric power bank, and one 200-kW centrifugal lift fan used for SES operation.

The vessel will have a service speed of 27 knots and maximum speed of 33 knots, which can be increased to 38 knots for a limited period using battery power. It will have an estimated fuel consumption of approximately 330 l/hr at full speed and 180 l/hr at service speed.

For strength and to reduce weight, the CTV’s deckhouse will be built of composite material and its hull from aluminium. The vessel will have an overall length of 22 m, beam of 8.9 m and draught of 0.5 m when in cushion operation and 1.6 m hull borne.

For crew and passenger comfort, the CTV will have active motion damping. This will be accomplished through active pressure/airflow control of the air cushion for heave damping and the use of active transom interceptors for rolling damping and trim control.

The UK’s Wight Shipyard has been contracted to build the hybrid SES CTV at its facility on the Isle of Wight. The boatbuilder constructs workboats, high-speed ferries and, in June, unveiled a new line of windfarm catamaran-hulled vessels in co-operation with Australian design firm Incat Crowther.