Silent Sailing

With the world’s fleet of electric vessels set to grow, Selwyn Parker explores the quiet revolution taking place at sea

The Bastø Electric ferry from Horten to Moss in Norway. Photo credit: Bastø Fosen AS

When a ferry named Bastø Electric began sailing the main Oslo fjord in March 2021, it was a landmark in a crossing that started nearly 440 years ago.

Ferries have plied between two towns – Moss and Horten –  on opposite sides of fjord since 1582, according to local historians. It’s just a 30-minute crossing, but it’s a vital link for locals. In an average year, these ferries, run by a company called Basto Fosen, transport about 1.8 million vehicles and almost four million passengers anxious to avoid the city’s heavy traffic.

It is Norway’s busiest ferry connection. As DNV GL – the classification society – puts it: “The ferries are a constant: a symbol of reliability, stability and trust.”

But reliable and trustworthy as they are, these crossings were diesel-driven. The Basto Electric, however, heralds a new era. At 144 metres long, she is the world’s largest all-electric ferry and can transport up to 200 cars, 24 big trucks and 600 passengers, all borne along by a 7 200 kW battery system.

By 2022 when the company converts two more diesel-powered vessels to all-electric propulsion, the fjord will be quieter and the air will be cleaner. According to DNV GL, the three ferries will slash diesel consumption by six million litres a year in what can only be seen as a portent of things to come in global shipping as the power of batteries continues to grow in ways that few believed possible even a decade ago.

Bastø Electric is a paradigm shift for the route, the shipowner and arguably the wider passenger ship segment in Norway and beyond,” foresees the classification society.

And having written many articles about the electrification of shipping and talked recently with dozens of people within the industry, I can only agree. This is, literally, a quiet revolution. Because the world is much more interested in electric vehicles, the rapid advances in battery-powered shipping have received relatively little attention.

Shipping is a notoriously conservative industry, but it is becoming excited by the potential of electrification, with good reason. As experts point out, it offers huge advantages over diesel-powered propulsion because it is more responsive, more robust, easier to maintain, more reliable because batteries offer more backup, quieter, and of course, cleaner.

So what’s not to like? Well, batteries can catch fire but then so do engine rooms.

Even sceptics can see that the advantages of batteries over fossil fuels become more compelling as they continue to pack more punch for their weight. The latest Blue Whale system developed by Norwegian manufacturer Corvus Energy delivers three and a half times more energy – up from 545 kwh to 1 892 kwh – than its predecessor. It will be installed shortly on a Canadian roll-on, roll-off ferry plying the Salish Sea off British Columbia. Although the system won’t be powerful enough to drive the entire ship in normal operations, it will be able to do so for short periods.

AIDAperla leaves the Port of Hamburg, Germany

Giant cruise ships will soon switch to battery-powered propulsion in ecologically sensitive waters as well as to run some shore operations. One vessel, the 300 metre-long AIDAperla, will this summer go into “silent sailing” mode by virtue of a 10 megawatt battery pack, the most powerful in a passenger ship anywhere. Although these floating hotels can only ghost along under pure battery power – at least for the present, silent sailing is a winner with passengers who, after all, aren’t in a hurry.

Other sectors of shipping have seen the light. Until now, confined mainly to passenger ships, battery power will soon revolutionise that snub-nosed workhorse of the ports, the tugboat. Canada-headquartered naval architect Robert Allan Ltd has unveiled all-electric designs with the power of diesel-fuelled ones – but with none of the pollution. Small though it is, the typical harbour tug pumps out a lot of CO₂ – about 1 700 tonnes a year – which is equivalent to the emissions of more than 300 cars. Thus, as Robert Allan predicts, electric tugs have the potential to clean up some of the world’s busiest marine hubs.

Tugs at work in port

And in Japan, a consortium of companies has thrown its weight behind the development of the world’s first all-electric tanker, a 62 metre-long vessel to be launched in early 2022. Demonstrably good for the environment, the ship will also be congenial for the crew because the vibration is much reduced.

The global fleet of all-electric or hybrid-powered vessels of all kinds currently numbers around 250, if vessels in operation and on order are included. And it’s growing almost by the month. As the vast global fleet of inner-city ferries, for instance, falls due for replacement, all-electric power has become the default option. Rotterdam is converting its water taxis to battery power and Kiel is doing the same with the ferries that work the local fjord as part of the authorities’ pledge to become a CO2-free city by 2050.

The hybrid electric Gaarden ferry on the Kiel Fjord, Germany

Historically speaking, battery-powered ferries aren’t new. Since 1909, in a remarkable technological feat of the time, all-electric passenger boats have sailed the pristine waters of the Konigsee in Germany. But it was the Nordic countries that took zero-emission propulsion into the 21st century under a 45-year-old cooperative initiative that is now led by Oslo-based Nordic Energy Research. As a study by the International Transport Forum called Navigating Towards Cleaner Maritime Shipping noted in late 2020: “It is an approach that holds many lessons for shipping nations seeking to decarbonise their fleet as quickly as possible.”

It’s a fair assumption though that not even the founders of this initiative expected to see an all-electric, 144 metre-long ferry on the Oslo fjord as soon as 2021.


Selwyn Parker is an independent author and journalist who writes for a wide range of publications on transport and related technology in all its forms.

See more ITF work on maritime transport

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