Since 1997, four double-ended and double-decked ferries, all with hanging deck, have been the guarantee (along with the dangerous goods ferry M/V Holger Danske) for an efficient and reliable transport service over Fehmarn Belt for both passengers and freight customers.

Together, these four diesel electric ferries offer close to 34,000 departures per year. Every ship sails approx. 6,200 hours and is at port for 2,560 hours per year. The ships’ engines (two to four) are operating 17,000-30,000 hours per year. With this much operating time, any kind of efficiency improvement will lead to great results, which is why Scandlines is continually on the lookout for new ways to optimise the operation.

Scandlines introduced the hybrid propulsion system in 2013 and implemented the system on the three remaining ships on the route Puttgarden-Rødby during 2014. Scandlines’ hybrid ferry is a significant milestone because it represents the world’s largest ever hybrid propulsion marine battery pack – the system equals approximately 182 hybrid cars and can propel the 8,800 ton ship for about 30 minutes without diesel fuel.

The hybrid propulsion system combines traditional diesel power with electric battery power. Especially during port times, excess energy produced can now be stored in batteries on board the ferry. When more energy is needed than the diesel generator can provide, the necessary energy will be tapped from the system. When less energy is needed the system is filled up with surplus energy. This ensures that the diesel engine always operates at an optimal load.

Siemens Drive Technologies, one of the world’s leading suppliers of propulsion systems and energy optimising systems, has provided ESS, while Corvus Energy, a global producer of lithium polymer batteries for hybrid and electrical commercial applications, has provided the battery packs.

The hybrid propulsion system marks the start of a series of large investments in environmental technologies. 2013-2019, Scandlines invested more than 38 million EUR in sustainable technologies on the route Puttgarden–Rødby. In addition, Scandlines investe 280 million EUR  in two new hybrid ferries for the route Rostock-Gedser.

Scandlines investeda total of 15 million EUR in the hybrid systems with financial aid from EU via the TEN-T programme, which aims to strengthen the internal market by promoting more efficient, cross-border transport corridors.

The hybrid system optimises the output of the ships’ engines, but also has the purpose of reducing the number of operating diesel generators to one. This way it is only necessary to install a scrubber on one of the ferry’s four engines in order to meet the IMO requirements (MARPOL) of max. 0.1 per cent sulphur in emissions after 1 January 2015. The three remaining engines will run on gas oil, which (unlike the heavy fuel used on the engine with the scrubber) contains only 0.1 per cent sulphur and consequently does not require cleaning in order to meet MARPOL requirements.