World’s largest electric ferry completes maiden voyage

E-Ferry Ellen, with an electric propulsion system powered by a 4.3 MWh battery – the largest ever in a boat – has completed its maiden voyage connecting the ports of Søby and Fynshav, on the islands of Ærø and Als in southern Denmark.

To give you an idea of that kind of power capacity, it could meet all the electricity needs of the average US home for 5 months straight. (US Energy Information Administration, 2017).

a huge room sized battery on the deck of a ship

The groundbreaking  battery system was developed and supplied by Swiss firm Leclanché and uses high-energy G-NMC lithium-ion technology (Graphite-Lithium Nickel Manganese Cobalt oxide). The company holds over 100 patents in lithium-ion battery cell technology and production.


Ellen sets multiple world records

Largest battery on a ship is only one of the world records set by the Ellen, along with:

  • Longest travel distance of any electric ferry
  • First ferry with no emergency diesel generator on board
  • Most powerful all-electric ferry

The electric motors for the ship – two 750 kW drives and two 250 kW motors for manoeuvring – are from Danfoss Editron. Danfoss also supplied the energy management system and the coastal charging station. Danfoss is no stranger to world records, having contributed to the world’s first electric boat built for fish farming.

an artists painting of how a large electric motor system works for ships

The Ellen is the completion of a project started in 20-15 as part of Denmark’s Natura project and was partly funded by the European Union’s Horizon 2020 Innovation Program. The project is broadly known simply as the ‘E-Ferry’.


The maiden voyage is great news, as there have been a few hurdles along the E-Ferry way – inevitable in any project of this size and imagination. It was originally scheduled to go into operation in late 2018, then the first quarter of this year. It has undergone extensive testing and tweaking over the past year, and the crews also had to be trained in operating all of the new technology.

Longest electric ferry route in the world

The 57m / 190ft Ellen can carry about 200 passengers and 30 vehicles and will replace a diesel ferry which previously served the 40 km / 22 nm route from Ærø to Als. While there are a number of electric ferries in operation, that trip is 7 times longer than any other e-ferry route.

“Over one year, the E-Ferry will prevent the release into the atmosphere of 2,000 tons of CO2, 42 tons of NOX, 2.5 tons of particulates and 1.4 tons of SO2” said Anil Srivastava, CEO of Leclanché. “This project demonstrates that we can replace fossil fuel thermal drives with clean energy today, and contribute to the fight against global warming and pollution for the well-being of our communities.”

Skipper Søren Svendsen, who is accustomed to sailing diesel vessels, describes change to electricity “like going from a Trabant to a Tesla.” The Ellen is expected to be in full service in the next couple of weeks.

Take a look at some of the other World’s Firsts in electric boats and ships covered by Plugboats over the past few months.

Photos: E-Ferry, Riviera Maritime Media

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