Ocean carriers, international organizations, marine engineering firms and shipyards are quietly working toward a future where diesel-powered vessels are as relevant to the maritime industry as steamships, all in a concerted effort to meet the ambitious decarbonized shipping goals set by the International Maritime Organization (IMO).
According to the U.S. Department of State, if the collective worldwide maritime industry were a single country, it would be in the top 10 emitters of global greenhouse gases.
Last November, the department partnered with the Norwegian government to launch the Green Shipping Challenge at COP27, an annual United Nations conference on climate issues. More than 40 maritime companies, ports, government agencies and nongovernmental organizations announced moves toward cleaner energy technologies at the conference.
A key element of the Green Shipping Challenge is the development of so-called green shipping corridors dedicated to showcasing low- or zero-emission vessels that emit no carbon gases during transit. The Ports of Long Beach/Los Angeles and Singapore, for example, used the conference to pledge the development of a green corridor in the transpacific trade between their respective points.
There’s no consensus on which net-zero vessel technologies will dominate so far, but efforts generally fall into one of two categories:
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alternative fuel-powered vessels, with methanol, biomethanol and ammonia among the most popular proposals; and,
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advanced wind propulsion technologies, which include hard-sail rigging systems or giant vessel-pulling kites to harness the age-old power of the wind.
Biofuel test
A test voyage of the 610-foot tanker Cajun Sun departed Geismar, La., on Jan. 17 and arrived in Antwerp on Feb. 4, fueled by a blend of conventional methanol — a natural gas-derived fuel in use for some years — and biomethanol derived from methane gas captured from cow manure.
Cajun Sun is owned by the Japanese maritime carrier Mitsui OSK Lines (MOL) and chartered to Canada-based Waterfront Shipping, a joint venture of MOL and Methanex Corp., a pioneering producer of methanol.
The vessel is equipped with a dual-fuel engine that can accommodate conventional methanol, biomethanol and diesel fuel as needed. MOL currently owns five dual-fuel methanol ships chartered to Waterfront, but the recent Cajun Sun voyage was the first employing the biomethanol blend. In 2016, MOL, Methanex and Waterfront Shipping, along with other key partners, built Taranaki Sun, the world’s first oceangoing methanol dual-fuel tanker.
“By blending ISCC-certified biomethanol that has negative carbon intensity with natural gas-based methanol [approximately 80% biomethanol and 20% conventional methanol], Methanex was able to achieve net-zero greenhouse gas emissions for the voyage using this innovative fuel,” said Paul Hexter, president of Waterfront Shipping, Methanex’s tanker operating subsidiary.
Emissions are considered “net zero” when the amount of greenhouse gases emitted into the atmosphere is equal to the amount that is removed. With a net-zero approach, emissions are essentially cancelled out, whereas a zero-emissions approach means no greenhouse gases are emitted at all.
According to Fumie Matsumoto, a spokesperson for MOL, Cajun Sun’s net-zero emissions were verified by a third party, and the voyage’s length was no different from that of a diesel-powered vessel. The company has considered the one-off voyage a success and is studying the technology as part of its strategy to achieve net-zero vessel operations by 2050, in line with the IMO’s target goals.
Hexter believes that methanol/biomethanol will be the easiest alternative fuel for carriers to adopt going forward. “Methanol dual-fuel engines are available today and proven, with adoption requiring minimal investment and training for shipowners and crew when compared to other alternative fuels, such as hydrogen and ammonia.”
That said, MOL has recently commissioned the design of two ammonia-fueled vessels, one a tanker and one a bulk cargo vessel. The company also has had a hard-sail vessel, the coal-carrier Shofu Maru, in operation since October of last year.
With a goal of achieving net-zero operational status in 2040, Maersk is another carrier moving aggressively into methanol-powered vessels in addition to dipping its toes into the ammonia debate.
Currently, Maersk has a virtual armada of 14 dual-fuel, “green” methanol containerships on order from Hyundai Heavy Industries, all in the massive 16,000- to 17, 000-TEU range. Those vessels are scheduled for delivery in 2024 and 2025 and are part of a plan to replace 150,000 TEU of retiring Maersk tonnage in the near future. These green Maersk ships will use biomethanol made from plant waste or e-methanol made from hydrogen and captured carbon dioxide, the company reported.
In line with this huge order of new dual-fuel ships, Maersk has concluded agreements worldwide with eight producers that will provide the methanol to operate them. The company has also announced that it is developing a ship engine that can run on “green” ammonia with Copenhagen-based engine builder MAN Energy Solutions.
Green ammonia is produced from renewably sourced hydrogen in a process called electrolysis and is a zero-carbon fuel, according to the Norwegian maritime classification organization and marine advisor DNV. Ammonia, however, remains controversial because of the potential for highly toxic fuel leaks.
Engine designers are well aware of the risks and are tapping into the experience of shipping operators who already handle ammonia as cargo for the design of safety measures. DNV anticipates that the first ammonia-powered engines will be installed on ammonia-carrying tankers, which already have trained crews and leak safeguards in place for handling the chemical.
Back to the future: Wind power
In January of this year, the France-based Neoline Armateur announced the construction at Turkey’s RMK Marine shipyard of a 136-meter-long, 265-TEU roll-on/roll-off (ro-ro) vessel that harnesses advanced wind power technology for propulsion.
The project is supported by a number of environmental and shipping interests, including the CMA CGM shipping group, which is aiming to decarbonize its operations by the 2050 IMO target date.
The new Neoliner vessel will use a rigging technology called Solid Sail, which was developed by another French company, Chantiers de l’Atlantique. It employs foldable, hard sails made of a carbon-fiber composite material. Neoline said that the vessel will be primarily propelled by its 3,000-square-meter sail area, but it will have a backup engine for in-port positioning and scheduled maintenance.
While a 265-TEU ro-ro ship would seem a modest start for a hard-sail shipping pilot project, other companies have more ambitious plans.
Cargill Ocean Transport, for instance, is developing a hard-sail technology called WindWings with U.K.-based engineering firm BAR Technologies. Depending on pilot results, the company may add the technology to many of its existing bulk carriers. Like the Solid Sail, WindWings are large, solid, foldable sails that are equipped with a system to collect data to facilitate maximum operational performance.
Meanwhile, the Japanese carrier K Line is betting big on gigantic automated “wind kites” designed by Airseas, a company spun off by Airbus aerospace engineers. The huge kites, called Seawings, can assist with propulsion on conventional ships, cutting carbon emissions by up to 20%, with K-Line looking to install as many as 50 Seawing systems in the future. To start, the shipping line announced on March 23 that it was installing a Seawing on Corona Citrus, an 88,000 dwt special coal carrier.