U.K.’s first hybrid crew transfer vessels feature Volvo Penta technology

Written by Nick Blenkey
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The 35-meter (112-foot) CTVs have been designed by MHO&Co in cooperation with Incat Crowther.

Two hybrid crew transfer vessels on order for operator MHO-Co A/S, Ejsberg, Denmark, to serve Ørsted’s Hornsea Two offshore wind farm off the U.K. coast will be powered by innovative technology developed by Volvo Penta in close collaboration with Danfoss Editron.

Set to be launched in summer 2021 from Afai Southern Shipyard in China, the 35-meter (112-foot) CTVs have been designed by MHO&Co in cooperation with Incat Crowther.

Volvo Penta marine gensets will help power these vessels—the electric propulsion power for the driveline will come from five variable speed Volvo D8 gensets. The use of variable speed gensets combined with the selectable multi-genset option has major environmental advantages and will ensure high availability resulting in extremely low downtime. Additionally, the use of the smaller D8 units allow for the use future technologies by replacing one (or more) of the generators with fuel-cells or similar solutions when the technology allows.


Volvo Penta’s Inboard Performance System (IPS) technology is moving forward into a new chapter with these vessels: electric IPS. Volvo Penta has worked closely with Danfoss Editron to create a breakthrough serial hybrid system consisting of a Volvo Penta IPS Quad set-up in which two of the four legs are powered by Volvo Penta D13 diesel propulsion engines and two legs are powered by Danfoss Editron’s electric motors, which are in turn powered by five Volvo Penta D8 variable speed gensets.

Two of the four Volvo IPS in each vessel will be powered by a Danfoss Editron electric motor.

Additionally, a battery pack will be installed to support peak-shaving and to allow the vessels to operate in fully electric mode at low speed, and during long stationary periods.

Erno Tenhunen, Marine Director, Danfoss Editron said: “This project will open the market for more hybrid CTVs. Previously, the size of electric motors and components were too big for CTVs. Our compact and lightweight technology has overcome this issue and solved the challenges faced by vessel designers, shipyards, and end customers. Our system, in combination with Volvo Penta’s compact drivelines and gensets, makes installation easy, even in a limited space. Plus it allows flexibility on system concepts and machinery room design.”

Both CTVs will be capable of operating in either fully electric or hybrid mode. When cruising to windfarms all four Volvo Penta IPS can be powered, two mechanically and two electrically. In harbor or at the wind farm there is the option to run the vessels with either battery to the electrical Volvo Penta IPS legs or any combination of 1-5 gensets, depending on weather conditions. It is estimated that this choice of operation is set to save about 127-metric tons of CO2 compared to traditional diesel-powered vessels.


From the bridge, these vessels act as a Volvo Penta IPS Quad with hybrid options, assisted by the Danfoss Editron Control System (ECS). The vessels are commanded by Volvo Penta controls and the EVC system (Electronic Vessel Control), which communicates to the D8 gensets as well as the Danfoss Editron ECS. The ECS calls off genset power and/or battery power automatically, or when ordered from the captain’s HMI-display.

“Our many years of working in the offshore wind industry, coupled with Incat Crowther’s expertise, have brought the design of these vessels to life,” says Mik Henriksen, founder of MHO&Co. “However, the technological developments behind these vessels have been a learning process for all involved. As a company we have been a longtime user of Volvo Penta IPS – and have always been fans of the superior propulsion, thrust, and maneuverability of the system. To be able to take this trusted technology to the next level and go electric is a big win for us in terms of future opportunities.”

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