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Electric marine craft will revolutionize coastal operations but not long-haul shipping

Pictured: an artist’s impression of a concept electric-powered and propelled tanker; Graphic: supplied by Mitsui OSK Line.

Clean-tech nerds around the world have been set aquiver by the news that a Japanese consortium is investigating the design of a wholly electric tanker. It is a tanker that would not even have a backup diesel generator. 

However, some commentators who have expressed hope this is the beginning of a conversion of the world’s merchant fleet to electricity will be disappointed. The current indications are that the long-distance commercial shipping fleet will swap first to liquefied natural gas (LNG), and then, later, to hydrogen

A few days ago, one of the world’s larger ocean shipping companies, Mutsui O. S. K. Lines, or “MOL,” set the nerd-o-sphere afire. It told the world that it, along with Asahi Tanker, Exeno Yamamizu Corp. and Mitsubishi Corp. would create a “strategic partnership” to focus on electrically powered vessels.

Their new company, e5 Lab, will work to “develop and promote” the greater use of “relatively clean modes of marine transport.”


The first objective for the joint venture is to build the world’s first “zero emissions” tanker, powered by electricity from batteries, by mid-2020 for coastal deployment in Tokyo Bay.

The key aim is to offer an “electric-vessel” platform to stakeholders, including shipbuilders, equipment manufacturers, ship owners, operators and cargo owners. Other objectives include: leveraging large-capacity, rechargeable batteries to provide emergency back-up power; control greenhouse gas emissions (GHG) to help combat the adverse impacts of climate change; and, finally, to “actively promote the electrification of both coastal and ocean-going vessels… to achieve the 50 percent GHG reduction target of the International Maritime Organization… the IMO wants to see annual emissions drop to half of their 2008 levels by the year 2050,” according to a statement from MOL.

So far, then, the Japanese electric tanker is just a concept ship – one that does not actually exist other than as a proposal.

Dreams of electric marine craft are over 180 years old

In many ways, the declaration of a desire for wholly electric watercraft is really, really, old news. The inventor of the first electric motor is thought to be British scientist William Sturgeon in 1832. The electric-powered watercraft came along not long after. Prussian inventor Moritz von Jacobi created a more powerful electric motor in 1834. He followed that up in 1838 with an electrically-powered boat deployed on the Neva River, in northern Russia. It could carry up to 14 people.

Jump forward in space and time to Germany, and by the early 1900s, the Bavarian Lakes Shipping Company was operating recreational electric-powered cruise boats on the Königssee lakes.

In history, there are a very great number of electrically powered boats around the world and there is not enough time and space here to review more than even the tiniest fraction of them. In regard to modern commercial electric vessels, there are many of these too; three sets of electricity-powered watercraft are featured below.

Modern commercial electric marine vessels: Scandinavian ferries

In Scandinavia there are at least two all-electric car ferries – the Tycho Brahe and the Aurora – both of which run the three-mile enclosed sea strait between Helsingor, on the Danish island of Zealand, and Helsingborg on the Swedish mainland. The two ferries carry more than 7.4 million passengers, 1.4 million cars and 390,000 trucks each year. Both ferries recharge at each terminal throughout the day as they discharge and load passengers and cargo. Unlike the Japanese oil tanker, these two ships actually exist and are in commercial operation.

New Zealand electric tug

More recently, the Ports of Auckland in New Zealand, has announced in the last few days that it has commissioned what it claims will be the world’s first fully electric tug, deliverable in 2021. Whether it is truly a “world-first” is debatable as there is also a small (18.7 meters) electric tug under construction in Turkey, which is designed with twin-screw propulsion.

It’s also not truly a “fully electric tug” because it carries two 1,000 kilowatt hour back-up generator sets. That back-up generation capacity gives the tug 40 tonnes of bollard pull in the event of an emergency, or if the vessel needs to operate for longer than the three to four hours that the batteries last. A re-charge will take about two hours.

That said, the New Zealand port company argues that the tug is not a hybrid system. “In normal circumstances, we will not use the generators,” it says.

The builder of Ports of Auckland’s tug is the Dutch company, Damen. The tug will have a bollard pull of 70 tonnes. A “bollard pull” is measured by modelling how much force a tug could apply by pulling at a bollard embedded in a dock in hypothetically perfect marine and weather conditions. Ports of Auckland says that the electric tug will have the same bollard pull as the port’s strongest diesel tug.

So it’s got no shortage of grunt.

It will have Azimuth propulsion. These are propellers that are placed in pods that can be rotated in 360 degrees, which makes it very manoeuvrable. The propeller is connected to an electrical motor inside the pod.

The tug will have a life of about 25 years and it will be much cheaper to operate than a conventional tug because it will not burn through diesel fuel. The port reckons that, although the up-front cost of the tug is “roughly double” the cost of a conventional diesel tug, the operating cost of an electric tug is less than one-third of the cost of a diesel tug.

“While we pay more up front, over the life of the tug we’ll save around $12 million in operating costs, making our electric tug cheaper in the long-term,” said Tony Gibson, the CEO of Ports of Auckland.

That’s a clear business benefit. But that’s not the reason the port set out to get a wholly electric tug. The port wants to go zero carbon emission by 2040.

“We set this goal because we recognize that urgent action is needed on climate change, and we wanted to be part of the solution,” says Gibson.

A world first: Norway’s wholly-electric fully-autonomous boxship

Next year in Norway, the freight-hauling box-ship Yara Birkeland will be launched. It will have an overall length of 262 feet, a width of just under 50 feet, a draught (the underwater part of the hull) of 20 feet and an ocean shipping container cargo capacity of 120 twenty-foot equivalent units.

So, compared to the big 22,000 TEU monsters floating about the high seas, it is a bit of a tiddler.

But it is also, potentially, a massive game-changer.

It’s an all-electric ship with installed batteries with seven megawatt hours of power. It will not generate carbon emissions. Nor will it emit nitrous oxide emissions. It will also be fully autonomous. At launch, it will be manned and will stay crewed for the first two years of operation. After that, in 2022, it will be fully autonomous.

The owner, Yara, makes fertilizer. It needs to transport products from its Porsgrunn plant to ports at Brevik and Larvik. And from there, product is ocean-shipped to customers around the globe. The Yara Birkeland is basically a coastal box-feeder ship.

Putting the environmental angle to one side, and from a business perspective, the Yara Birkeland investment is attractive. The Porsgrunn-Brevik run in Norway is just over six miles as measured on a straight-line basis. The Porsgrunn-Larsvik run is just over 15 miles on a straight-line basis.

That’s 100 diesel truck journeys a day, the company says. And the Yara Birkeland will eliminate 40,000 trucking journeys a year.

That is a large amount of truck driver wages that won’t need to be paid in the future, not to mention all the avoided costs of owning/operating/leasing all those trucks.

Pictured: an artist’s impression of the fully autonomous, electrically powered and propelled container-feeder ship, the Yara Birkeland. Graphic: Yara.

What do tugs, ferries, tankers and boxships have in common?

All of these modern-day electrically propelled marine craft have something in common – whether it’s the Japanese conceptual tanker in Tokyo Bay, a short-run coastal container ship in Norway, a tug that will operate in largely sheltered waters at the Ports of Auckland or two car-ferries that run the three-mile enclosed sea strait between Denmark and Sweden.

They are all, or will be, operating in relatively sheltered waters (compared to the high seas) a short distance from land and over a short duration of time.

The basic problem for large scale, long-distance, international shipping, is that the available batteries can’t sustain the propulsion of very big, very heavy, commercial ships around the vast oceans. Or, at least, not for now.

FreightWaves spoke to Martin Byrne, the Federal President of the Australian Institute of Marine & Power Engineers. It’s the trade union for, well, marine and power engineers.

“There’s a ferry that does an hour-long run. You need a short operation if you rely on shore power and the vessel is not a diesel-electric hybrid. There’s too much risk otherwise.”

How long and how far an electric marine craft can operate depends on how much battery power a boat or ship operator is prepared to install in light of its commercial considerations, Byrne says.

But is electric propulsion suitable for long-haul shipping?

FreightWaves asks whether a wholly electric ship could be used for heavier-duty commercial operations, such as to propel a long-haul smaller handysize bulker filled with a cargo of, say, grain.

“I don’t see it for that application. It’s for niche applications. Our distances are great. Our coastal distances are great. Ports are separated by very large distances,” Byrne says.

In his view, the likely contender for maritime fuel of choice is likely, in the short-term, to be LNG. But it won’t keep its crown for long.

“LNG will take up an increasing amount of the market and then will likely be replaced by another gas. Probably hydrogen. Hydrogen is zero emissions,” he explained.