Shipping is a huge industry with a huge carbon footprint, in part because the fuel that it uses – bunker fuel – is the dirtiest type of oil-based fuel there is. If it was a country, maritime transport would be the world's sixth largest greenhouse gas emitter, according to UBS.
The sector’ s governing body, the International Maritime Organisation, has been accused of dragging its feet on tackling the sector’s emissions. But as other parts of the economy decarbonise, it is coming into the spotlight more – and the IMO now requires new ship designs to progressively improve, cutting CO2 emissions 50% by 2025 and 70% by 2050.
In response, a number of solutions are emerging.
One of the most exciting sights in sailing is the giant America’s Cup yachts flying across the water on hydrofoils at speeds of up to 60 miles an hour. The America’s Cup is the Formula One of sailing, and acts as a similar hotbed for innovations that can eventually be transferred into more everyday forms of transport.
These racing yachts achieve the speeds they do because the hydrofoils lift them out of the water, reducing the drag enormously. While hydrofoil technology for passenger vessels is nothing new of course, researchers from Sweden’s Chalmers University of Technology have developed a unique method for further developing a new generation of hydrofoils that can significantly increase the range of electric vessels and reduce the fuel consumption of fossil-powered ships by 80%.
Laura Marimon Giovannetti, lead author of the study setting out the research, is a former elite sailor and an advisor to the Swedish national team. She specifically mentions the impact of the America’s Cup on ship design. “We've seen a huge increase in sailing boats with hydrofoils. With this new method and knowledge, we are able to bring together a range of different branches of engineering – naval architecture, advanced materials and aeronautics as well as renewable energy.”
Air freight alternative
Now a number of companies are working on translating this principle into a reality for commercial shipping and leisure craft.
Boundary Layer Technologies, a start-up based in California, has unveiled a zero-emissions hydrofoiling containership concept design called ARGO. The ship is much smaller than most containerships at 200 tonnes, but the company says it will have a range of up to 1,500 nautical miles and be able to cruise at 40 knots, twice the speed of conventional freight carriers.
Boundary Layer envisages the vessels being powered by fuel cells using green hydrogen and plying major intra-Asia trade routes and offering a zero-emission shipping alternative to air freight.
This performance would enable door-to-door transit times only 15 to 24 hours slower than air freight, but at 50% of the price, according to the company. It will also have a “dwell time” (ie time spent unloading and loading) of just two hours instead of three days for bigger vessels and will be able to dock virtually anywhere.
Meanwhile, the first electric ferries are carrying passengers in Scandinavia. The Ellen, a 60m vessel operating in Denmark, can carry 200 passengers and 30 cars and it saves 2,000 tonnes of CO2 a year. Norway also has a number of electric ferries operating on routes including the Oslo fjord, the country’s busiest route. New Zealand launched the southern hemisphere’s first such vessel in early 2022.
There is a reason that batteries are mainly being used on ferries rather than larger containerships – they generally run on short routes and so will not run out of power before they can be recharged. But if batteries can be combined with hydrofoils, the range of battery-powered can be extended significantly, greatly expanding their potential applications and even more replacement of fossil fuel shipping. Boundary Layer Technologies is also working on a fully electric hydrofoiling ferry with a range of up to 100 nautical miles.
Deep sea solutions
However, electrification is not feasible for the very largest ships and the longest routes, so to decarbonise global shipping fleets we need an alternative fuel that meets the needs of large, deep-sea vessels such as bulk carriers, oil tankers and container ships.
The choices for alternative fuels include green methanol, liquid hydrogen and ammonia. According to S&P Global Platts Analytics, methanol appears to be a front-runner. The costs for modifying existing engines to methanol is significantly lower compared to installing or modifying engines for other alternative fuels.
At the same time, the oldest form of propulsion of all is making a comeback, as a number of companies, such as Windship Technology and MOL Drybulk, reimagine wind power with “hardsail” technology to be used in conjunction with traditional engines.
Windship says that its “whole-ship solution” that harnesses wind, carbon capture, solar energy, renewable power, weather routing, hull design and highly innovative engine design, can cut emissions by 49%.
Others, such as AirSeas, an Airbus spin-off, envisage an instant 20% reduction in fuel use and emissions using giant, 1,000 sqm kites to pull ships along.
With oil prices at record highs, the business case for developing these technologies as quickly as possible grows ever stronger.