Ærø, Denmark
Commissioned by the Municipality of Ærø in Denmark and dubbed “Ellen,” Danish naval architect Jens Kristensen designed this 100 percent electric-powered ferry to sail back and forth between Søby and Fynshav in the Funen archipelago in southern Denmark.
Ellen´s 4.3 MWh battery pack enables the vessel to sail two times 10.7 nautical miles, with spare capacity in the battery pack, e.g. for a search and rescue or a man overboard situation, making the electric ferry have the longest reach in the world.
This reach should also be seen in light of the 100 percent electric operation, as opposed to hybrid operation. This means that Ellen has no combustion-based propulsion onboard – nor a diesel emergency generator.
The E-ferry is a project supported by the European initiative Horizon 2020 involving the design, building and demonstration of a fully electric-powered ‘green’ ferry that can sail without polluting and CO2 emissions.
It promotes energy efficiency, zero GHG emission and air pollution, free waterborne transportation for island communities, coastal zones and inland waterways in Europe and beyond.
Τhe overall objective of E-ferry is to apply an extremely energy-efficient design concept and demonstrate a 100 per cent electric, emission-free, medium-sized ferry for passengers and cars, trucks and cargo in full-scale operation on longer distances than previously seen (> 5 nautical miles (Nm)) for electric drive train ferries, i.e. the medium-range connections Søby-Fynshav (10.7 Nm) and Søby-Faaborg (9.6 Nm) in the Danish part of the Baltic Sea connecting the island of Ærø to the mainland.
Ellen´s design was primarily due to a number of rational decisions.
Subsequently, efforts were made to make the ferry look good.
While the focus below the waterline was to have a very slim and efficient hull, the ferry design above the waterline was also characterized by a focus on energy efficiency, which contributes to Ellen being a record-setting electric-powered ferry.
The idea of designing Ellen as a double-ended ferry, meaning a design with an identic bow and stern and a wheelhouse to be used for sailing in both directions, was quickly abandoned.
That design is an ideal solution for port calls since it saves time and energy on maneuvers, but it is also a solution with many hydrodynamic compromises in relation to hull efficiency while sailing.
Designer Kristensen did not just design a typical modern single-ended hull, instead, he chose to turn back the clock.
This seems almost paradoxical, as Ellen was also built as a world record in the rapid development race in the field of electric-powered ferries.
He was thus inspired by specific hull lines on former Ærø ferries all the way back in the 1950s and 1960s.
As he put it, they were simply better at building small, slim ferries back then, which easily sailed 13-14 knots with limited machinery.
According to him, one reason for this is the important role played by the extremely slim hulls of the great ocean liners of the 1950s and 1960s in the minds of contemporary naval architects.
This was later replaced by a focus on capacity.
They are therefore typical examples of ferries that were built at a time when energy efficiency was not yet highly prioritized in the design of new ferries.
However, the wind shifted later with the shipping industry´s focus on reducing its carbon footprint – the same wind that is also driving the electrification of ferries.
Ellen´s design was primarily due to a number of rational decisions. Subsequently, efforts were made to make the ferry look good.
While the focus below the waterline was to have a very slim and efficient hull, the ferry design above the waterline was also characterized by a focus on energy efficiency, which contributes to Ellen being a record-setting electric-powered ferry.
Ellen´s lightweight was originally projected at 706.5 tonnes.
However, the weight was exceeded by more than 40 tons during the construction of the ferry.
Project: Ellen e-Ferry
Designers: Jens Kristensen Consulting Naval Architects
Owner: The Municipality of Ærø
Manufacturer: Søby Værft, Søby
Design Team: Jens Kristensen, Claus Bendix Nielsen, Michael Hansen, and Anders Vester