Powered by ammonia, an old tug learns a new trick

A 57-year-old tugboat retrofitted with fuel-cell technology became the world’s first carbon-free, ammonia-powered vessel, following a demonstration voyage north of New York City on 23 September.

Five-year-old, Brooklyn-headquartered start-up Amogy was behind the ground-breaking project, which it calls “a significant step towards reducing global carbon emissions and moving the maritime industry closer to IMO’s target of net-zero emissions by 2050.”

Company chief executive and co-founder, Seonghoon Woo, knows weaning the maritime industry off carbon-intensive fuels won’t be easy. “Governments across the globe and industry organisations like the IMO have set aggressive goals to reduce global carbon emissions. These goals seem daunting, but they’re necessary – and our successful demonstration of the world’s first carbon-free, ammonia-powered vessel proves that they’re achievable.”

“Organisations have set aggressive goals to reduce global carbon emissions”

Amogy will use learnings from the demonstration project to move quickly to commercialisation and real-world applications. “The opportunity to decarbonise the maritime industry is within reach, and for Amogy, it’s just the beginning,” he says.

Amogy will apply knowledge gained from this demonstration to real-world applications of its technology, including both retrofit projects and newbuilds. In April, Amogy signed a memorandum of understanding with class society KR and South Korean companies Hanwha Ocean and Hanwha Aerospace to collaborate on the design, development, testing and certification of ammonia reformers and fuel-cell systems for ships. 

Cracking technology

Powering the 32-m harbour tug, cleverly named NH3 Kraken, is Amogy’s patented ammonia-to-electrical system which ‘cracks’ liquid ammonia into its base elements of hydrogen and nitrogen. The hydrogen is then funneled into a fuel cell which generates high-performance power with zero-carbon emissions.

The vessel is powered by Ballard’s FCwave 200-kW fuel cell, which facilitates scalable power output and flexible integration onto the vessel. The FCwave was the first hydrogen-powered fuel cell module to achieve marine Type Approval, and is now certified by DNV, Lloyd’s Register and ABS.

“We should not have to deal with carbon”

During this demonstration, NH3 Kraken was fueled with green ammonia, produced with renewable energy, and supplied by Yara Clean Ammonia from its Skrei plant.

Fuel-cell supplier Ballard says the demonstration project proves the viability of decarbonised technology in transportation sectors that depend on fossil fuels.

Amogy has received approval in principle (AiP) from Lloyd’s Register on its ammonia-to-electricity powerpack and is aiming to gain Type Approval for the technology from other classification societies. Additionally, it is working with the US Coast Guard to confirm the powerpack’s regulatory compliance.

Why ammonia?

Speaking at Riviera’s Maritime Decarbonization Conference, Americas 2023 in Houston, Mr Woo explained why Amogy choose to use ammonia as fuel.

“Ammonia truly has the potential to become the dominant fuel in global shipping in the long term,” he said, adding “Because fundamentally, we should not have to deal with carbon.”

The ammonia molecule (NH3) does not contain carbon. Already a widely traded and transported global commodity used mostly in fertiliser production, ammonia is intriguing for several reasons, said Dr Woo. “Ammonia has high energy density, even higher than liquid hydrogen on a volumetric basis,” he observed, adding it is liquid at room temperature, making it easy to transport and store, and [it has] the lowest price point on a dollar-per-megajoule basis than other future fuels. He sees ammonia as “the lowest carbon, highest energy density, and most affordable fuel we could possibly have to transition this industry.”

And while he is “excited” by developments in ammonia dual-fuel marine engines, he notes all these solutions require pilot fuels that potentially generate GHG emissions.

Unlike traditional marine fuels that are combusted in two- and four-stroke engines, Amogy’s solution combines a conventional proton exchange membrane (PEM) fuel cell with its reforming technology to convert ammonia to hydrogen, which is used in the fuel cell to produce electricity. Amogy’s power pack incorporates the reactor modules, the NH3 adsorber and the hydrogen fuel cell.

Over the last few years, Amogy has been focused on scaling up the technology, first applying it to fuel a 5-kW drone in July 2021, then a 100-kW John Deere tractor in May 2022 and a 300-kW Freightliner Cascadia semi-truck in January 2023.

“Ammonia-to-power fuel-cell technology has notable advantages, even over battery technology for road transport,” he observed.

“This truck was designed to have the equivalent electric energy of a Tesla semi, with 500 miles of capability. But now you can fill this tank within seven minutes,” he said.