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Smaller, better, faster, shorter

Battery powered ships might work, actually

Last month UMAS, a partnership between UMAS International Ltd and the University College London (UCL) Energy Institute, released a report suggesting that nearly 20% of the US fleet could be replaced with battery-powered vessels. Crucially, it said, this could be achieved without needing to scrap vessels before they reached the end of their service lives.

In the last decade, shipping’s answer to many problems with emissions has been to simply buy a new ‘eco-ship’ (though the term has recently fallen out of favour.) But the imbued carbon cost of doing this is not so often considered. A major shipyard consumes about 200GWh per year, Lloyd’s List recently calculated – enough to keep every wind turbine in Europe busy for a week.

One option, however, has been laughed out of the room until now: batteries. Assumptions surrounding economies-of-scale dictate that every new ship be a 15,000teu giant, and it would not be remotely possible to power one these using batteries – the range requirements, as well as the size, mean that such a vessel, if battery-powered, would essentially need to tow a second ship, full of batteries, behind it.

But as Engineering at Sea has previously discussed, deploying a megaship on every trade is neither necessary nor desirable, and there is considerable appetite for smaller ships. Indeed, only a few months following this discussion, vessels of 5,000teu, began securing rates of $135,000 per day, well beyond the wildest expectations of charterers. From a green perspective, smaller ships make far more sense in many respects: they can be more flexible, and call at smaller ports, making them a great bet for getting trucks off the road in coastal countries. One of the best strategies for decarbonizing could be reviving the feeder models of yore, and as UMAS points out, electrification would be a great way to further incentivise this.




There is only one existing example of a containership running on batteries: the Yara Birkeland. It has a tiny container capacity of 120teu, but for Yara International’s niche use-case – offloading containers along the Norwegian shore, charging its 6.7 MWh batteries with shore power each time it calls at port – the economics stack up.

But what about trying out the principle on a slightly larger scale? FleetZero, an American company, is developing a containerised ship battery, which would be lifted onto the deck by a normal container crane along with the rest of its cargo, and plug in there. The advantage of this approach is that ports will only have to charge individual battery containers. This is a much less imposing proposition than demanding they all fit shore power, which, the evidence suggests, they will not.

In a recent article, FleetZero said that ships already in the water can easily be retrofitted to use the containerised batteries in conjunction with an electric motor. A portion of the deck cargo would be lost to the batteries, and FleetZero acknowledges this. But, it counters that savings on fuel costs will compensate for this, an effect that will only become more pronounced as shipping switches to costly e-fuels like ammonia and methanol. If a new ship is purpose-built to operate in this way, the company says, the far smaller footprint of the electric powertrain would create enough space to entirely mitigate the loss of cargo.




Further, FleetZero said, the ability to get into smaller ports and get cargoes closer to the end user would open up a modal shift toward shipping, and therefore, new types of trade. Far from suffering, then, shortsea shipping would benefit from new opportunities opening up – particularly, the company insisted, in the American Jones Act market.

FleetZero cites a possible route between Long Beach and Portland, Oregon, which would “effectively take thousands of trucks off the road,” adding that road freight is more expensive. It is not difficult to imagine this working in Northern Europe, as well. After all, a sea voyage between LA and Portland is over 1500km; Hamburg-Gothenburg, for example, or Antwerp-Newcastle, are less than half that. Presumably, there would be ample opportunity for battery feeders to recharge — or perhaps more accurately ‘reload’ — on such routes.

It has been a challenge to find an application for batteries in shipping thus far, as their power density is trifling compared with e-fuels. But FleetZero certainly seems to believe there is a way in. It is worth bearing in mind that batteries’ relative impracticality has not prevented the trucking industry from considering them. It stands to reason therefore that in this arena, shipping ought to be able to leverage scale – even if it is only four-figures, this time – to its advantage.