Amazon invests in ammonia fuel tech to curb cargo ship emissions

Major U.S. retailers have pledged to curb their supply-chain emissions by powering warehouses with renewable energy and replacing diesel vans and trucks with electric vehicles. But when it comes to using greener ships to import toys, T-shirts and tablets, companies are in a bind: No zero-emissions fuels are available at scale for oceangoing freighters.

So big cargo importers like Amazon are investing in early-stage solutions that have long-term potential to clean up cargo shipping.

The e-commerce giant recently revealed that it is backing Brooklyn-based Amogy, a startup developing an ammonia-driven power system for ships and heavy-duty road transportation. The technology takes liquid ammonia — a carbon-free, globally abundant chemical — and converts it into hydrogen gas, which then runs through a fuel cell. The one-year-old company says it aims to launch a small demonstration vessel by early 2023, along with large road vehicles.

Amazon announced the investment on December 14 but declined to disclose the amount. The Seattle mega-retailer is backing Amogy through its $2 billion Climate Pledge Fund, which has so far supported 13 climatetech startups working on everything from low-carbon concrete and smart greenhouses to hydrogen-electric aircraft and battery recycling. The fund steers venture capital toward companies that Amazon believes will help meet its corporate goal of achieving ​“net-zero” carbon emissions by 2040.

“As we look at our own supply chain and the carbon footprint that is counted against us for cargo shipping, we really want to invest in the future of that industry,” Matt Peterson, the head of Amazon’s Climate Pledge Fund, told Canary Media. The idea, he said, is to push shipping ​“in a direction that is more sustainable and also, by definition, helps us meet our carbon-reduction goals.”

Hauling goods by sea contributes nearly 3 percent of the world’s annual greenhouse gas emissions, a number that’s projected to soar in coming decades if ships keep burning fossil fuels. Cargo ships are also significant sources of smog-forming nitrogen oxides and particulate matter, which threatens the health of waterfront communities.

Environmental groups and consumers are increasingly pushing Amazon, Ikea, Walmart and other retailers to take more responsibility for the environmental toll of importing billions of dollars’ worth of goods to U.S. ports every year. Last week in Minneapolis, where Target is headquartered, city council members urged the company to transition to using zero-emissions cargo ships by 2030. Activists with the Ship It Zero coalition handed Target executives a 20,000-signature petition making the same request.

Shipping companies do have ways to immediately lower emissions and pollution to some extent, though most are not yet common practice. Ships can operate at slower speeds, switch to running on low-sulfur petroleum distillates instead of sludgy heavy fuel oil, and plug into electricity supplies when docked instead of continuing to run their diesel engines. Over a dozen vessels are currently sailing with ​“wind-assisted propulsion” devices such as spinning rotor sails to reduce the use of diesel fuel, with more expected to follow suit next year.

But completely replacing the oil and engines that drive tens of thousands of cargo ships will be a trillion-dollar, multidecade enterprise, according to University Maritime Advisory Services, a leading research consultancy in London. That work is only just getting started.

Shipping industry eyes ammonia as the fuel of the future 

Amogy’s waterfront office sits in the Brooklyn Navy Yard, a former shipbuilding facility that serves as a hub for tech startups and manufacturers. Seonghoon Woo, Amogy’s CEO, founded the company in late 2020 with three fellow doctoral graduates from the Massachusetts Institute of Technology. Since then, the startup has grown to a 30-person team and raised $22.3 million in funding from five investors, including Amazon.

Amogy aims to enable widespread use of ammonia in cargo ships, Woo said. The toxic chemical is gaining favor within the global shipping industry as a potential fuel for large, ocean-crossing freighters in particular — which can sail for weeks between refueling stops and weigh hundreds of thousands of tons.

Ammonia (NH₃) contains one nitrogen atom and three hydrogen atoms, so it doesn’t create carbon-dioxide emissions when used as fuel. The infrastructure needed to produce, move and store ammonia already exists worldwide, since the chemical is widely used to make fertilizer, plastics and refrigeration systems. Ammonia is relatively energy-dense, meaning it requires far less room to store on board than an equivalent amount of hydrogen or battery power.

And, though nearly all NH₃ today is made using fossil fuels, a handful of facilities are under development to produce ​“green ammonia” from renewable energy.

“We know ammonia has to be a solution [for shipping] in the future, given ammonia’s energy density,” Woo said. ​“However, you don’t see any ammonia-powered ships yet.”

That’s because, for all its promise, many barriers still stand in the way of ammonia’s maritime takeover. It can be burned in an internal combustion engine, but that yields air pollutants and small amounts of nitrous oxide, a potent greenhouse gas. Ammonia can also be used in fuel cells, which convert chemical energy into electrical energy without creating emissions. But experts say ammonia isn’t compatible with the most common type of fuel cell: polymer electrolyte membrane, or PEM. Amogy’s approach bypasses that last hurdle by converting ammonia into hydrogen, which can be used with PEM fuel cells.

Breaking ammonia’s bonds

To make that fuel switch, Amogy is developing a chemical reactor that splits ammonia back into its constituent parts of hydrogen and nitrogen. Liquid ammonia flows over a ​“bed” of catalysts, which spurs a reaction that breaks the bonds between atoms and produces hydrogen gas. The hydrogen then runs through a fuel cell that will, eventually, drive a ship’s motors and turn its propellers.

Other startups and research institutes are working to split ammonia, primarily for road transportation. Long-haul trucks, delivery vans and passenger cars can run on hydrogen fuel cells, but today drivers have very few places where they can stop and refuel. Rather than build new hydrogen pipelines and fuel networks, researchers say a better move might be to use existing ammonia infrastructure.

“Delivery of hydrogen has become a bottleneck for using fuel cells, so the idea has emerged to use ammonia as a way to ship hydrogen, and then decompose that ammonia on-site,” said Sossina Haile, a professor of materials science and engineering at Northwestern University. Haile’s lab is developing a technique to convert ammonia gas into pure hydrogen gas using an electrochemical reaction.

For Amogy, the challenge is not only to produce hydrogen but also to build a system that easily fits on cargo ships, where space comes at a premium. The process of decomposing ammonia requires extremely high temperatures, which in turn requires extra components to create and manage that heat. Woo said Amogy has ​“miniaturized” both the reactor and the heat-related parts.

This summer, Amogy demonstrated its ammonia-to-hydrogen technology in a personal drone, which hovered above the grass using a 5-kilowatt power system. The startup has since built a 50-kilowatt device and, with its latest funding round, is developing a system of several hundred kilowatts that it plans to retrofit onto an existing cargo ship. (For context, that’s roughly the size of three new Toyota Mirai hydrogen passenger cars.) From there, Amogy aims to develop multi-megawatt systems that can drive ammonia-powered container ships.

“We are the most interested in the shipping industry, simply because the shipping industry is kind of waiting for the ammonia solution,” Woo said. ​“They really have to decarbonize as soon as possible.”