Ammonia sail-powered tugboat shows path to emissions reduction for first time

KINGSTON, N.Y. — On a tributary of the Hudson River, an ammonia-powered tugboat pulled away from a shipyard on Sunday and headed out to sea for the first time to show how the maritime industry can cut planet-warming carbon dioxide emissions.

The tug was powered by diesel. New York startup Amogy bought the 67-year-old vessel to switch to clean ammonia, a new zero-emission fuel.

The tug’s maiden voyage Sunday evening is a milestone in the race to develop zero-emission propulsion using renewable fuel. Emissions from shipping have soared over the past decade — to about 3% of the world’s total, according to the United Nations — as ships have become much larger, carrying more cargo per voyage and using vast amounts of fuel oil.

CEO Seonghoon Woo said he founded Amogy with three friends to help the world solve a huge, urgent problem: a pillar of the global economy has not yet begun the transition to clean energy.

“Without solving the problem, it will not be possible to make the planet sustainable,” Woo said. “I don’t think this is a problem for the next generation. It’s a really big problem for our generation.”

The friends met while studying at the Massachusetts Institute of Technology. In their spare time during the COVID-19 pandemic, they brainstormed ideas for clean power for heavy industry. In November 2020, they launched their startup in a small space in the Brooklyn Navy Yard. The name Amogy comes from a combination of the words ammonia and energy.

They searched for boats and found a tugboat in the Feeney shipyard in Kingston, New York, languishing without a mission. It could break ice, but in recent years, almost no ice had formed on that part of the Hudson, so it was available for sale.

“This shows how serious the problem is when it comes to climate change,” Woo said. The project, he said, “not only demonstrates our technology, but it really tells the story to the world that we need to solve this problem sooner rather than later.”

They named the tug NH3 Kraken, after the chemical formula for ammonia and the method of “splitting” it into hydrogen and nitrogen. The Amogy system uses ammonia to generate hydrogen for a fuel cell, turning the tug into an electrically powered vessel. The International Maritime Organization has set a goal for international shipping to achieve net-zero greenhouse gas emissions by 2050 or thereabouts.

Shipping needs to cut emissions quickly, and there are currently no widely available solutions to completely decarbonize deep-sea shipping, according to the Global Maritime Forum, a nonprofit that works closely with the industry. There is a lot of interest in ammonia as an alternative fuel because the molecule is carbon-free, said Jesse Fahnestock, who leads the forum’s decarbonization efforts.

Ammonia is widely used as a fertilizer, so the infrastructure already exists to handle and transport it. Ton for ton, it can hold more energy than hydrogen and can be stored and distributed more easily.

“It certainly has the potential to become a mainstream, even a mainstream fuel,” Fahnestock said. “It has the potential to have a very friendly greenhouse gas footprint.”

Ammonia has its drawbacks. It is toxic. Currently, almost all of it is made from natural gas in a climate-damaging process. And its combustion must be carefully designed, otherwise it, too, contains traces of the potent greenhouse gas.

Amogy’s technology is different.

The tug ran on green ammonia produced from renewable electricity. A 2,000-gallon tank is housed in the old fuel tank location, allowing for 10-12 hour days at sea.

It separates liquid ammonia into its components, hydrogen and nitrogen, and then feeds the hydrogen into a fuel cell that generates electricity for the ship without emitting carbon dioxide. The process doesn’t burn ammonia like an internal combustion engine would, so it produces mostly elemental nitrogen and water as emissions. The company says there are trace amounts of nitrogen oxides, which it aims to eliminate entirely.

Amogy first used ammonia to power a drone in 2021, then a tractor in 2022, a truck in 2023, and now a tugboat to prove the technology. Woo said their system is designed for use on vessels as small as a tugboat and as large as container ships, and could also generate electricity on land to replace diesel generators in data centers, mining and construction, or other heavy industries.

The company has raised about $220 million; Amazon, a company with huge transportation needs, is among the investors. Nick Ellis, director of Amazon’s $2 billion Climate Pledge Fund, said the company is excited and impressed by what Amogy is doing. By investing, Amazon can show shipowners and shipbuilders that it wants its goods to be delivered without emissions, he added.

“A lot of people will now have the opportunity to see and understand how real and promising this technology is, and that within a few years it could be used in container ships or tugboats,” he said. “If you had asked five years ago, I think a lot of people would have given up. … And suddenly we have not only a compelling example, but a commercially viable one. This kind of thing doesn’t happen every day.”

Other companies are developing ammonia-powered ships that still use some diesel fuel.

In March, Fortescue’s Green Pioneer showed in Singapore how ammonia can be used in combination with diesel as a marine fuel. An ammonia-powered container ship, the Yara Eyde, will be afloat in 2026 with an engine powered by green ammonia, according to Yara Clean Ammonia. In Japan, NYK Group has converted the tug Sakigake to run on ammonia instead of liquefied natural gas.

In the next step, Amogy is working with major shipyards to introduce ammonia energy into the marine sector. South Korean shipbuilder Hanwha Ocean is buying its technology. HD Hyundai and Samsung Heavy Industries are working with Amogy on ship projects.

Sangmin Park said that because Amogy has made significant progress in proving ammonia’s potential as a clean fuel, “we expect the industry to move more quickly toward adoption.” Park is a senior vice president at HD Hyundai subsidiary HD Korea Shipbuilding & Offshore Engineering.

“For the past few years, the industry has recognized the potential of ammonia as a zero-carbon fuel,” Park wrote in an email, “but having the first ship built and sailing is a real breakthrough.”

McDermott reported from Providence, RI.

Copy link to story