The biggest conversion project of conventional Ro/Ro ferries into plug-in hybrid ferries will get underway in the second half of 2025. Denmark’s Scandlines working with Wärtsilä will convert two 27-year-old vessels to hybrid operations with the capability to conduct 80 percent of their voyages by battery.
The Deutschland and Schleswig-Holstein were each built in 1997 and operate a 45-minute run between Puttgarden in Germany and Rødby in Denmark. The vessels, which are 466 feet (142 meters) in length have a capacity to carry up to 1,200 passengers and 364 cars. The vessels operate at a speed of 18.5 knots.
After a competitive tender process that was launched in 2023 with several suppliers, Scandlines chose Wärtsilä to supply the electrical system for the ferries. The vessels currently operate with MAK engines and were previously fitted in 2013/2014 with an energy storage system, one with a capacity of 1,600 kWh and the other vessel with 2,600 kWh.
The new project involves replacing an engine and diesel generator with a new shore-charged electrical system, including a large energy storage system with a 5 MWh capacity. Wärtsilä will engineer and deliver the hybrid converters, the energy storage system (ESS), and the energy management system (EMS), as well as the switchgears, transformers, the onboard port charger, and replacement components in the existing switchboard equipment. In addition, Wärtsilä will supervise the installations, carry out the commissioning, and provide preventive maintenance support services.
The company highlights that ship electrification is one of the solutions for marine decarbonization. This project demonstrates the advancements in the technology and energy storage to expand the range of the vessels. The company highlights that it undertook the first conversions a decade ago and today four of its six hybrid ferries operate on this route. They also built a hybrid ferry in 2016 and two of its ferries are fitted with wind rotors.
A key part of the project is the shore charging capabilities. Last year, Scandlines selected Norwegian maritime system integrator NES to supply the land-based charging system for the ferry berth in Puttgarden and connect the equipment to the power grid operated by the regional grid operator, Schleswig-Holstein Netz. The required onshore components include a 30 MVA grid transformer, medium and low voltage transformers, and switchgear, as well as a control and data acquisition system. According to the company, this will make it possible for the vessels to recharge in 12 minutes while the loading operations are proceeding in port.
It will be the latest in a long-step of projects for Wärtsilä. The company did its first hybrid retrofit in 2012 and today attests to having done the most on ships worldwide.
Electric hybrid propulsion continues to draw strong interest among ferry companies. DFDS recently announced plans to invest €1 billion in battery electric ships to operate crossing the English Channel. The company plans six ferries operating between Dover, England and Calais and Dunkirk in France. The first two ferries are due to enter service in 2030 with the others to follow before 2035.
