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The world’s most powerful electrical ferry

7. July 2017

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The Danish island Ærø plans to be self-sufficient in CO2 neutral energy in 2025. One of the steps on this journey is an electrically powered ferry to carry the island's inhabitants, tourists and businesses travellers back an forth to the island. The ferry will be the world’s most powerful electrical ferry. But a changeover doesn't come for free and the new ferry will bring a few challenges for the ferry owners who use Orbicon as their engineering consultants:

Limited charging time
Since an electrically powered ferry needs to be charged more often than a diesel ferry needs to be filled up, there has been a particular emphasis on time optimisation when the ferry docks in the port:

“The ferry can only be charged in Søby on Ærø – which means that it has to sail for one hour to Fynshav/Faaborg and one hour back, then it needs to charge again for 12 minutes before commencing a new two-hour trip. This has never been tried on this scale before”, explains Daniel Virgilsen from Orbicon.

This means that every minute counts, and this has put particular demands on the system:

“The ferry is docked at Søby for approximately 15 minutes, of which 12 minutes are required for charging. This means that as soon as it reaches the berth, the charger and the automatic moorings will be coupled within 30-60 seconds. Moreover, the charging unit needs approx. 60 seconds to get to full power, and after 12 minutes of charging, the charging unit needs to scale down and decouple before the ferry can set sail again”, continues Daniel Virgilsen.

Charging unit takes up space
The charging unit is the first in the world to be mounted directly onto the leaf of the bridge, and this has proved problematic in terms of space. Both vehicles and pedestrians need to use the bridge simultaneously, and there needs to be room for the charging unit. Safety concerns need to be taken into consideration, as the passengers will be walking close to a charging unit that delivers 4,000 V.

Half the energy consumption and shorter sailing times
In spite of these challenges, the ferry will be worth the trouble when it enters operation in 2018. Aside from being electrically powered, it reduces the energy consumption by half, and shorten the journey time from 70 to 55 minutes.