In July, two companies announced a collaboration aimed at helping to decarbonize maritime fuel technology. The companies, Brooklyn-based Amogy and Osaka-based Yanmar, say they plan to combine their respective areas of expertise to develop power plants for ships that use Amogy’s advanced technology for cracking ammonia to produce hydrogen fuel for Yanmar’s hydrogen internal combustion engines.

This partnership responds directly to the maritime industry’s ambitious goals to significantly reduce greenhouse gas emissions. The International Maritime Organization (IMO) has set stringent targets. It is calling for a 40 percent reduction in shipping’s carbon emissions from 2008 levels by 2030. But will the companies have a commercially available reformer-engine unit available in time for shipping fleet owners to launch vessels featuring this technology by the IMO’s deadline? The urgency is there, but so are the technical hurdles that come with new technologies.

Shipping accounts for less than 3 percent of global human-caused CO₂ emissions, but decarbonizing the industry would still have a profound impact on global efforts to combat climate change. According to the IMO’s 2020 Fourth Greenhouse Gas Study, shipping produced 1,056 million tonnes of carbon dioxide in 2018.

Amogy and Yanmar did not respond to IEEE Spectrum‘s requests for comment about the specifics of how they plan to synergize their areas of focus. But John Prousalidis, a professor at the National Technical University of Athens’s School of Naval Architecture and Marine Engineering, spoke with Spectrum to help put the announcement in context.

“We have a long way to go. I don’t mean to sound like a pessimist, but we have to be very cautious.” —John Prousalidis, National Technical University of Athens

Prousalidis is among a group of researchers pushing for electrification of seaport activities as a means of cutting greenhouse gas emissions and reducing the amount of pollutants such as nitrogen oxides and sulfur oxides being spewed into the air by ships at berth and by the cranes, forklifts, and trucks that handle shipping containers in ports. He acknowledged that he hasn’t seen any information specific to Amogy and Yanmar’s technical ideas for using ammonia as ships’ primary fuel source for propulsion, but he has studied maritime sector trends long enough—and helped create standards for the IEEE, the International Electrotechnical Commission (IEC), and the International Organization for Standardization (ISO)—in order to have a strong sense of how things will likely play out.

“We have a long way to go,” Prousalidis says. “I don’t mean to sound like a pessimist, but we have to be very cautious.” He points to NASA’s Artemis project, which is using hydrogen as its primary fuel for its rockets.

“The planned missile launch for a flight to the moon was repeatedly postponed because of a hydrogen leak that could not be well traced,” Prousalidis says. “If such a problem took place with one spaceship that is the singular focus of dozens of people who are paying attention to the most minor detail, imagine what could happen on any of the 100,000 ships sailing across the world?”

What’s more, he says, bold but ultimately unsubstantiated announcements from companies are fairly common. Amogy and Yanmar aren’t the first companies to suggest tapping into ammonia for cargo ships—the industry is no stranger to plans to adopt the fuel to move massive ships across the world’s oceans.

“A couple of big pioneering companies have announced that they’re going to have ammonia-fueled ship propulsion pretty soon,” Prousalidis says. “Originally, they announced that it would be available at the end of 2022. Then they said the end of 2023. Now they’re saying something about 2025.”

Shipping produced 1,056 million tonnes of carbon dioxide in 2018.

Prousalidis adds, “Everybody keeps claiming that ‘in a couple of years’ we’ll have [these alternatives to diesel for marine propulsion] ready. We periodically get these announcements about engines that will be hydrogen-ready or ammonia-ready. But I’m not sure what will happen during real operation. I’m sure that they performed several running tests in their industrial units. But in most cases, according to Murphy’s Law, failures will take place at the worst moment that we can imagine.”

All that notwithstanding, Prousalidis says he believes these technical hurdles will someday be solved, and engines running on alternative fuels will replace their diesel-fueled counterparts eventually. But he says he sees the rollout likely mirroring the introduction of natural gas. At the point when a few machines capable of running on that type of fuel were ready, the rest of the logistics chain was not. “We need to have all these brand-new pieces of equipment, including piping, that must be able to withstand the toxicity and combustibility of these new fuels. This is a big challenge, but it means that all engineers have work to do.”

Spectrum also reached out to researchers at the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy with several questions about what Amogy and Yanmar say they are looking to pull off. The DOE’s e-mail response: “Theoretically possible, but we don’t have enough technical details (temperature of coupling engine to cracker, difficulty of manifolding, startup dynamics, controls, etc.) to say for certain and if it is a good idea or not.”

This article was updated on 5 August 2024 to correct global shipping emission data.