Ammonia is generally associated with a technological breakthrough of the past. As the key building block of nitrogen-based synthetic fertilizers, it played a critical role in feeding a rapidly growing global population over the twentieth century. Now, some see ammonia as having the potential to make a sizeable impact in the transition away from carbon-intensive fossil fuels.  

For that to happen, the current production process will have to change, as the overwhelming majority of ammonia is produced from natural gas.  The world currently produces about 175 million tons per year of fossil-fuel based ammonia mostly for use as fertilizer, and this releases vast quantities of greenhouse gases.

As the demand for low-carbon energy sources grows, clean ammonia – referred to by advocates as either green or blue ammonia, depending on how it is produced – is expected to dramatically increase in production. Developers in the U.S. have proposed the construction of 15 new ammonia plants, mostly in Texas and Louisiana, to produce ammonia for fuel, according to public records and data available in the Oil & Gas Watch database as of May 1, 2023.

“Green ammonia” is created from water, nitrogen from the air, and renewable energy like solar or wind to produce the ammonia molecule, NH₃, and is virtually carbon free. However, this process requires vast amounts of very pure water and large, albeit renewable, energy inputs.

So-called “blue ammonia” is ammonia produced with natural gas and nitrogen from the air, but with the carbon footprint allegedly reduced through the capture and storage of the carbon dioxide emissions. Because carbon capture and sequestration technology is largely untested and unproven on a large scale, “blue ammonia” produced with natural gas is less climate-friendly than “green ammonia” made entirely with solar or wind power. About two thirds of the proposed ammonia fuel projects are in this higher-polluting category that will rely on unproven carbon capture methods.

The focus for many clean ammonia advocates is to use the hydrogen in ammonia to help produce clean hydrogen fuel, which burns without releasing any greenhouse gases.  Ammonia is easier to ship in liquid form than hydrogen, which must be supercooled to form a liquid (an energy-intensive process). So the idea is to transport liquid ammonia on ships or via rail to manufacturing plants or other end users, and then convert ammonia to hydrogen fuel.

Clean ammonia advocates also argue that ammonia can also be used as a fuel itself.  Power companies in Asia are proposing to burn ammonia along with coal in power plants to reduce carbon dioxide emissions. The shipping industry is also interested in using it as a lower-carbon fuel to burn at sea.

No matter the color, ammonia production and use comes with environmental tradeoffs. “There’s no silver bullet here,” said Trevor Brown, Executive Director of the Ammonia Energy Association. “We’re looking at solutions for fuel molecules that don’t cause climate change.”

Ammonia fuel project announcements

An estimated 88 percent of the ammonia produced at 30 industrial facilities in the U.S. in 2021 was used as fertilizer or to make nitrogen-based fertilizer. And the fertilizer industry is growingly rapidly in the U.S., with companies planning to build nine new ammonia plants and expand three more to produce nitrogen fertilizer, according to a new EIP report, “The Fertilizer Boom.”  The growth of the US fertilizer industry can be attributed, in part, to the availability of inexpensive natural gas extracted through hydraulic fracturing. Additionally, the ongoing conflict in Ukraine has resulted in higher costs for nitrogen fertilizers produced in Europe and Russia, further driving demand for domestically-produced fertilizers in the U.S.

Incentives made available through the 2021 Bipartisan Infrastructure Law and the 2022 Inflation Reduction Act have spurred several companies to take steps to build “clean” ammonia plants that would make fuel, not fertilizer. To date, 15 new plants have been proposed. If just 8 of the 15 projects are built, ammonia energy production capacity could reach 27 million metric tons per year by 2030. Total ammonia production capacity in the US could reach 58.4 million metric tons per year—nearly tripling today’s production—if all the ammonia energy and fertilizer projects come to fruition.

The potential impact on the climate of all this is not yet clear, because the numbers are not yet available on half the proposed ammonia fuel projects. But the figures available so far suggest that the overall expansion of the ammonia industry could produce more than 54 million tons of greenhouse gases per year – as much as from 13 coal-fired power plants

The table below shows the locations and status of the proposed ammonia fuel projects:

Ammonia as a shipping fuel

Some of these proposed projects would use ammonia as a fuel to be burned directly in ships, as an alternative to petroleum-based “bunker fuel” to drive their engines. The term “bunker fuel” as ship fuel dates back to the days when steam-powered ships were powered by coal, which was stored inside coal “bunkers” onboard the ships.

“While I think ammonia will play a very significant role as a bunker fuel, we need to be careful with it,” said Brown of the Ammonia Energy Association. “What’s appealing are things like better energy efficiency and electrification. But those solutions can’t decarbonize shipping by themselves.”

Paul Wolfram with the Pacific Northwest National Laboratory, who's been researching ammonia as a fuel source, said ammonia has about one third of the energy density of diesel fuel, so ships fueled by ammonia will require larger fuel tanks and will sit lower in the water because of the heavier load of fuel they will need to carry. He also said there’s significant potential for pollutant releases including ammonia (itself an air pollutant) and nitrogen oxides. He also worries about the leakage of ammonia from production facilities and during distribution, storage, and handling.

“Powering all ships with ammonia, all else equal, would entail a quintupling of global ammonia production, and if even a small portion of this nitrogen escapes from the fuel production and use cycle, it could more than offset the global impacts of any agricultural nitrogen mitigation efforts,” Wolfram said. “Understanding the future for ammonia-energy will need dialogue between the various research communities to examine the relative importance of nitrogen vs. carbon mitigation, actual observed nitrogen releases in ammonia demonstrations and deployments, and other real-world data on costs and risks that will reduce some of the uncertainties we have today.”

The shipping industry currently accounts for around three percent of global greenhouse gas emissions. The U.N.’s International Maritime Organization has called for curbing annual shipping-related emissions by at least 50 percent compared to 2008 levels by 2050. Ammonia advocates see ammonia bunker fuel as critical in lowering the industry’s carbon footprint because it is relatively energy-dense, does not require cryogenic temperatures to freeze (like hydrogen), and the global infrastructure already exists to produce, store, and transport ammonia.  

In the U.S., a Brooklyn-based startup company called Amogy is working to launch an ammonia-powered ship in New York that would be the first of its kind. The company recently secured $139 million in private venture capital funds to help work towards the commercialization of the company's ammonia-to-power technology, which cracks ammonia into hydrogen and nitrogen and puts the hydrogen through a fuel cell where the chemical energy is converted into electricity. Amogy has used this technology to power a 300-kilowatt semitruck and is in the process of designing a 1-megawatt version to power a retrofitted tugboat that formerly ran on diesel.  

Seonghoon Woo, CEO and cofounder of Amogy, said the maritime industry has shown great interest in ammonia. But he said a lot still needs to be done to educate policymakers and the general public about how the safe and efficient use of ammonia can support energy security and decarbonization efforts. He said with the shipping sector emitting about 1,000 million tons of carbon dioxide annually, or 13 percent of the greenhouse gas emissions from global transport, it is important to utilize solutions such as green ammonia.

“While there are always risks in any industry, there are over 100 years of experience in the making, transporting, and storing of ammonia,” said Woo. “Plus, as one of the most widely used commodities on the planet, regulations are in place to ensure it’s used safely. For us, safety is our number one priority.”

Safety is very important when it comes to ammonia. Ammonia is highly flammable and corrosive, making it potentially risky as a source of bunker fuel for ships.

Ammonia, itself a toxic form of nitrogen pollution that can be harmful to aquatic life if released into waterways. An Environmental Integrity Project analysis recently found that in 2021, 22 U.S. ammonia plants that manufacture nitrogen fertilizer discharged an estimated 3.9 million pounds of ammonia from their wastewater outfalls. Eighty-six percent of this ammonia was discharged into waterways that are near communities where more than 30 percent of people are considered low income or more than 40 percent are people of color.

Planned ammonia manufacturing plants could add a considerable amount of this pollution to waterways, especially if EPA fails to update and strengthen outdated pollution control standards for the industry.

Ammonia also contributes to nitrogen-fed algae blooms and low-oxygen dead zones, like the one that has persisted in the Gulf of Mexico. Spills of ammonia at sea or at port could also harm aquatic ecosystems.

“Ammonia is toxic and there are still many gaps in knowledge that need to be filled in order to enable its safe use as a shipping fuel,” said Marie Cabbia Hubatova, Director of Global Shipping for the Environmental Defense Fund Europe. “Much more research needs to be done to better understand the implications ammonia can have on the environment as well as human health. Moreover, ammonia engines are likely to produce NOx and nitrous oxide. A better understanding of the extent and technological options for its mitigation are imperative for its safe use.”

She continued: “I think ammonia will play an important role in decarbonizing the shipping sector, but we need to fill the current gaps in knowledge in order to use it in a safe way.”

As this research plays out, new clean ammonia projects continue to pop up regularly. In early April, a blue ammonia project was announced for development on a reclaimed coal mining site in Mingo County, West Virginia. The proposed Adams Fork clean ammonia project will serve as the anchor for an Appalachian Regional Clean Hydrogen Hub, and could produce up to 2.16 million metric tons per year of ammonia while controlling its carbon dioxide emissions with carbon capture and storage.  

West Virginia Senator Joe Manchin praised the announcement, saying it will ensure the “Mountain State continues to be a leader in American energy innovation and support good paying, West Virginia energy jobs.”

Manchin thanked the Inflation Reduction Act and Bipartisan Infrastructure Law, both passed during the previous session of Congress under Democratic leadership, for making the ammonia project possible. The Inflation Reduction Act combines an array of clean energy tax incentives, totaling an estimated $369 billion, meant to address energy security and climate change over the next decade, including generous tax credits for carbon capture and storage projects.  

Lead photo courtesy of Amogy.