Op-Ed: Ammonia power in maritime

By Anastasija Kuprijanova, director of maritimebusiness development, Amogy

As pressure grows for the shipping industry to decarbonize, ammonia is emerging as a viable fuel alternative.

Ammonia is a powerhouse of versatility, already integral to agriculture, refrigeration, and household cleaning products. As one of the most widely produced chemicals, it’s now gaining attention as a highly viable, energy-dense fuel source, with the potential to transform heavy industries globally—including the shipping sector.

Maritime shipping emits close to a billion tons of greenhouse gasses each year, on par with G7 nations like Germany and Japan. Amid growing regulatory pressure to adopt alternative fuel sources, driven by the increasing consequences of climate change, land and air transportation sectors are steadily shifting toward green energy solutions, which means the shipping industry’s share of global carbon emissions is expected to rise. Shipping currently accounts for 3.1% of these emissions; if nothing is done, that could grow to 17% by 2050.

To keep pace with the clean energy transition across industries and countries, the shipping industry must embrace ammonia as a crucial component of the alternative energy mix.

Regulatory pressure mounts to go green

The United Nations and nations worldwide have set 2050 as the target date for achieving net-zero emissions, driving the adoption of robust national policies to support the clean energy economy. In alignment with these efforts, the International Maritime Organization (IMO) has adopted a Greenhouse Gas (GHG) Strategy that calls for the use of alternative zero and near-zero GHG fuels by 2030. This initiative is a key step in the broader goal of achieving net-zero emissions in international shipping by around 2050. The draft strategy also includes a proposal to charge shippers a fee for every ton of carbon they emit. With the stage set for alternative energy, shippers and business leaders must now invest in the technology—paving the way for both environmental sustainability and long-term success.

Why ammonia power is the right fit

Ammonia has long been utilized as a fuel source, with its history dating back decades. During World War II, the U.S. military mixed ammonia with coal gas to fuel transport aircraft. In the 1960s, NASA used liquid ammonia and liquid oxygen to power the X-15 manned rocket, which set new records for hypersonic flight.

Historically, ammonia has been used as a fuel through combustion. However, recent advances in ammonia “cracking” technology are transforming it into a true source of carbon-free energy. As the maritime industry shifts towards decarbonization, ammonia—with the help of these recent technological innovations—emerges as an ideal fuel for a sustainable future.

By splitting or “cracking” liquid ammonia into its base elements, hydrogen can be fed into a hydrogen-to-power system, such as a fuel cell or a hydrogen engine, to generate carbon-free electricity. This method allows ammonia to be used as a hydrogen carrier, leveraging ammonia’s high density and hydrogen’s usability.

A number of other factors also serve to make ammonia a good fuel source for shipping. In liquid form, it has a high volumetric energy density, 2.7 times greater than hydrogen. And although it must be pressurized in liquid form, it’s easier to store, transport, and distribute than hydrogen.

Because of ammonia’s widespread use, it’s already frequently shipped as cargo. Thus, the industry benefits from well-established infrastructure for its production and distribution, including pipelines, tankers, and availability at about 200 ports globally, with more opening each year. Additionally, a century of safe ammonia use in the fertilizer industry has led to established safety protocols for its handling and transportation. While the maritime sector will need to adapt these practices to its unique needs, progress is already underway. For example, the Maritime Energy Training Facility (METF) in Singapore is preparing maritime personnel to safely handle alternative fuels, including ammonia.

Offering flexibility for the shipping industry, ammonia-powered systems can be retrofitted onto existing vessels and are highly scalable. Initially, ammonia could serve as auxiliary power, complementing traditional combustion engines, and gradually take on a larger role in the ship’s propulsion system. This phased approach allows shippers to minimize the costs associated with transitioning to alternative fuels while meeting the need for cleaner energy sources. Ammonia-to-hydrogen technology presents a promising solution, positioning ammonia as a key component of future-proofed fuels for the shipping industry.

The next steps toward net-zero

As the 2030 regulatory deadline approaches, shippers must act swiftly to begin decarbonizing their fleets. Fortunately, they can leverage ongoing initiatives and efforts aimed at accelerating the adoption of ammonia-to-hydrogen power and other alternative fuels. Equally important is prioritizing specialized training for their workforce to ensure the safe handling and effective implementation of these advanced technologies.

Successfully navigating this transition will require a unified, collective effort. Support must come from all regions and stakeholders, including academia, the offshore and nearshore markets, and both the private and public sectors. Through collaboration and innovation, the shipping industry has a unique opportunity to lead the charge toward a cleaner, more sustainable future.