Given that the sixteen largest ships are estimated to emit the same amount of CO2 as all the world’s cars combined, it is hardly surprising that some groups are beginning to push for the electrification of the shipping industry. While still very much in its infancy, the technology shows promise even in these early stages of adoption.
Battery-powered boats, in one form or another, are nothing new. Battery-powered canoes and barges were being used as early as the late 1890s, typically used for short trips as ferries, though the technology was expensive and not widespread. These, however, were quickly phased out – along with steam-powered boats – with the development of oil engines at the turn of the 20th century.
After this, though many electric boats were manufactured, none truly promised to make a mark on the transportation industry – the vessels functioned more as passion projects or one-off environmentally friendly alternatives.
Enter: Norway. In early 2021, Norway’s Turkish-built Bastø Electric ferry launched with a capacity of 600 passengers and 200 cars for trips across the Oslo Fjord. The ship represented a large leap forward for the technology, becoming the world’s largest commercial electric ferry.
The feasibility of such a vessel was greatly enhanced by the huge reduction in cost of lithium-ion batteries since 2010, with cells dropping in price as much as 89%. This price reduction, coupled with an ever-increasing awareness of the dangers of pollution, has lead many to speculate on the future of the technology.
Research carried out by the University of California, Berkley, and Lawrence Berkeley National Laboratory points towards electric ships becoming more feasible sooner than many might think.
Using current and near-future technology as the basis for their calculations, researchers modelled several common types of container ship across a variety of distances to assess the viability of battery-powered voyages. Ranging from small feeder-style vessels to ultra-large containers, the results varied considerably, trending towards shorter voyages becoming more efficient.
The graphs above outline the findings for both current technology (a) and near-future battery technology (b). The grey/white areas on the graphs represent shipping routes where the switch to battery power would immediately lower shipping costs; a trend that is only projected to grow as the technology develops.
With present technology, purely on a fuel/running-cost basis, most classes of ship become more efficient when battery powered when travelling under 2,000km, with some smaller vessels becoming economically viable as far as 3,000km. It is worth noting, however, that for long-distance travel current battery technology is not yet economically viable, especially for the larger classes of ships.
On the other hand, with near-future battery technology taken into consideration, the range at which the electrification of ships becomes economically viable increases dramatically, with nearly all classes of ship projected to save on shipping costs for journeys shorter than 4,000km.
The figure above illustrates some of the busiest bilateral shipping routes on earth, colour coded by their distance. Interestingly, many already sit in the range of 2,000km or less – the projected maximum cost-saving range of current battery-power shipping technology. Furthermore, the longer routes, illustrated in blue, sit at the upper end of the efficiency range for the researchers’ projected near-future battery technology.
This means – in the present, and particularly with regards to shorter trade routes such as those inside Europe or South East Asia – the electrification of many shipping routes would lead to a reduction in operating costs, as well as the emissions saved from the pollution caused by internal combustion engines.
Furthermore, one of the main technical considerations for the electrification of ships is the battery system’s size relative to the ship’s carrying capacity and existing engine system/fuel storage. For small neo-Panamax containerships, representing the average containership of the global fleet, the volume required for a battery system is actually less than that of an internal combustion engine, occupying c.32% of the ship’s carrying capacity.
While the researchers’ projections cast a positive image, it is important to consider the challenges of electrified containerships as well.
As previously mentioned, although at short range battery power might allow cost and space-saving opportunities, long distance voyages are still not suitable for electric ships, as the technology would take up too much space and cost more to run than a convention internal combustion engine.
Furthermore, the researchers are quick to point out that containerships, though the backbone of the global economy, represent only 23% of total maritime shipping emissions. To achieve larger reductions in said emissions, more nuanced work will need to be done to analyse the impact of electrification on other vessels such as bulk carriers and oil tankers, some of the worst maritime polluters.
While electrification remains firmly in the current sustainability zeitgeist as the silver bullet to the world’s climate change problems, the technology still has a way to go until it becomes truly viable in every industry.
The research citied in this article, however, puts forward a good case for the electrification of shorter-range vessels which not only curbs the emissions of said ships, but also their operating costs as well. It will be interesting to see how battery technology progresses and how this might impact the researchers’ future projections, as well as the real-life employment of the technology.
Modelling 5 to 10 GWh electrified containerships, researchers find that 40% of routes today could be electrified in an economically viable manner, before considering environmental costs.
