KINGSTON, N.Y. (AP) - On a tributary of the Hudson River, an ammonia-fueled tugboat pulled away from a shipyard dock and set sail for the first time to demonstrate how the maritime industry can dramatically reduce carbon dioxide emissions that are driving global warming.
The tugboat was powered by diesel. New York-based startup Amogy bought the 67-year-old vessel to convert it to clean ammonia, a new, carbon-free fuel.
The tug's maiden voyage on Sunday night is a milestone in a race to develop zero-emission propulsion using renewable fuel. Emissions from shipping have risen in the past decade - to about 3% of the global total, according to the United Nations - as ships have grown much larger, carried more cargo per voyage and burned vast amounts of fuel oil.
CEO Seonghoon Woo said he and three friends founded Amogy to help the world solve a major and pressing problem: the backbone of the global economy has not yet begun to transition to clean energy.
"Without solving the problem, it will not be possible to make the planet sustainable," he said. "I don't think this is the problem of the next generation. This is a very 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 about how to power heavy industries in a clean way. They launched their startup in November 2020 in a small space at the Brooklyn Navy Yard. The name Amogy comes from the combination of the words ammonia and energy.
They searched for a boat and found the tugboat languishing without a mission at the Feeney Shipyard in Kingston, New York. It could break ice, but there has been little to no ice formation on that stretch of the Hudson River in recent years, so it was for sale.
"It shows how serious the problem is when it comes to climate change," Woo said. The project, he said, "not only demonstrates our technology, it's really going to tell the world that we need to solve this problem as quickly as possible."
They named the tug NH3 Kraken, after the chemical formula for ammonia and their method of "cracking" it into hydrogen and nitrogen. Amogy uses its ammonia in a fuel cell, making the tug an electrically powered vessel. The International Maritime Organization has set a goal for international shipping to achieve net zero greenhouse gas emissions by or near 2050.
Shipping needs to cut emissions quickly and there are currently no solutions available to fully decarbonize deep-sea shipping, according to the Global Maritime Forum, a nonprofit that works closely with the industry. Ammonia has attracted a lot of interest as an alternative fuel because the molecule is carbon-free, said Jesse Fahnestock, who leads the forum's decarbonization work.
Ammonia is widely used in fertilizers, so there is already infrastructure in place to process and transport it. Ton for ton, it can hold more energy than hydrogen, and it can be more easily stored and distributed.
"It certainly has the potential to become a main fuel or even the main fuel," Fahnestock said. "It has a potentially very friendly greenhouse gas footprint."
Ammonia has drawbacks. It's toxic. Almost everything is made from natural gas in a process that's harmful to the climate. And its combustion has to be carefully designed, or it also produces traces of a potent greenhouse gas.
Amogy's technology is different.
The tug runs on green ammonia produced by renewable electricity. A 2,000-gallon tank fits in the old fuel tank room, for a 10- to 12-hour day at sea.
It splits liquid ammonia into its components, hydrogen and nitrogen, and then feeds the hydrogen to a fuel cell that generates electricity for the ship without carbon emissions. 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 traces of nitrogen oxides that it is trying to eliminate entirely.
Amogy first used ammonia to power a drone in 2021, then a tractor in 2022, a truck in 2023 and now the tugboat to prove out the technology. Woo said their system is designed to be used on vessels as small as the tug and as large as container ships, and could also generate electricity onshore to replace diesel generators for data centers, mining and construction, or other heavy industries.
The company has raised about $220 million. Amazon, a company with immense shipping needs, is among the investors. Nick Ellis, managing director of Amazon's $2 billion Climate Pledge Fund, said the company is excited and impressed with what Amogy is doing. By investing, Amazon can show ship owners and shipbuilders that it wants its goods to be delivered with zero emissions, he added.
"A lot of people are now getting the chance to see and understand how real and promising this technology is, and that it could actually be applied to container ships or tugboats within a few years," he said. "If you had asked five years ago, I think a lot of people would have thrown their hands up ... And suddenly we have not only a compelling example, but a commercially viable example. These kinds of things don't come along every day."
Other companies are developing ships that run on ammonia, but still use some diesel.
In Singapore, Fortescue's Green Pioneer vessel demonstrated in March how ammonia can be used with diesel as a marine fuel. An ammonia-powered container ship, the Yara Eyde, is set to launch in 2026 with an engine that runs on green ammonia, according to Yara Clean Ammonia. In Japan, the NYK Group converted the tug Sakigake to run on ammonia instead of liquefied natural gas.
As a next step, Amogy is working with major shipbuilders to bring ammonia power to the maritime sector. South Korean shipbuilder Hanwha Ocean is buying its technology. HD Hyundai and Samsung Heavy Industries are working with Amogy on ship designs.
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 acceptance." Park is senior vice president at HD Hyundai subsidiary HD Korea Shipbuilding & Offshore Engineering.
"In recent years, the industry has recognized the potential of ammonia as a carbon-free fuel," Park wrote in an email, "but actually building and sailing the first ship is a true milestone."
___
McDermott reported from Providence, R.I.
___
Associated Press climate and environmental reporting receives funding from multiple private foundations. AP is solely responsible for all content. Find AP's standards for working with philanthropies, a list of supporters and funded reporting areas at AP.org.