November 2022

AUTHORSDavid Sandalow
Chair, ICEF Innovation Roadmap Project
Columbia University
Roger Aines
Lawrence Livermore National Laboratory
Zhiyuan Fan
Columbia University
Julio Friedmann
Carbon Direct
Colin McCormick
Georgetown University
Ann-Kathrin Merz
Columbia University
Corinne Scown
Lawrence Berkeley National Laboratory

This roadmap was prepared to facilitate dialogue at the Ninth Innovation for Cool Earth Forum(October 2022), for final release at COP27 in November 2022.
We are deeply grateful to the Ministry of Economy, Trade and Industry (METI) and New Energy andIndustrial Technology Development Organization (NEDO), Japan for launching and supporting
the ICEF Innovation Roadmap Project of which this is a part.

CITATION
Cite report as: David Sandalow, Roger Aines, Zhiyuan Fan, Julio Friedmann, Colin McCormick,
Ann-Kathrin Merz and Corinne Scown, Low-Carbon Ammonia Roadmap (ICEF Innovation
Roadmap Project, November 2022)

CONTENTS

November 2022

Preface1

Executive Summary

2

CHAPTER 1 Introduction

6

CHAPTER 2 The Ammonia Industry: Past and Present

12

CHAPTER 3 Production of Low-Carbon Ammonia

19

CHAPTER 4 Ammonia Infrastructure

33

CHAPTER 5 Uses of Low-Carbon Ammonia

46

CHAPTER 6 Safety and Local Environmental Impacts of Ammonia

60

CHAPTER 7 Research and Development

69

CHAPTER 8 Policy

73

CHAPTER 9 Findings and Recommendations

79

iii

PREFACE
Modern society depends on ammonia (NH3). The chemical compoundplays a central role in modern agriculture, delivering nitrogen essential forsoil fertility. Ammonia is also a key feedstock in plastics, rubber and otherproducts.
Current methods of producing ammonia result in significant carbon dioxide(CO2) emissions—almost 2% of the global total. Low-carbon production
methods can dramatically reduce these emissions. Low-carbon productionof ammonia also creates a fuel with very low life-cycle greenhouseemissions and the potential to help decarbonize a range of sectors.
This roadmap explores a number of topics related to low-carbon ammonia.
The roadmap examines the global ammonia industry today, low-carbon
production options, infrastructure needs, potential uses for low-carbon
ammonia, safety and local environmental issues, R&D needs and policy
options. The roadmap finds that low-carbon ammonia could produce
significant greenhouse gas reductions in key sectors this decade and deep
reductions in some sectors by 2050.
This roadmap builds on the body of literature produced annually inconnection with the ICEF conference. Previous roadmaps have addressed:• Carbon Mineralization (2021)• Biomass Carbon Removal and Storage (BiCRS) (2020)• Industrial Heat Decarbonization (2019)• Direct Air Capture (2018)• Carbon Dioxide Utilization (2017 and 2016)• Energy Storage (2017)• Zero Energy Buildings (2016)• Solar and Storage (2015)

This roadmap is a team effort. We are deeply grateful for the support
provided by the ICEF Secretariat, ICEF Steering Committee (including
in particular its chair, Nobuo Tanaka), the New Energy and Industrial
Technology Development Organization (NEDO), experts at the Institute ofEnergy Economics-Japan, and our design and copy edit team (including inparticular Ms. Jeannette Yusko and Dr. Kathryn Lindl).
The ICEF Innovation Roadmap Project aims to contribute to the global
dialogue about solutions to the challenge of climate change. We welcome
your thoughts, reactions and suggestions.
David Sandalow
Chair, ICEF Innovation Roadmap Project
Inaugural Fellow, Center on Global Energy Policy, Columbia University

November 2022

PREFACEl1

EXECUTIVE SUMMARY
Chapter 1: Introduction
Ammonia (NH3) is one of the building blocks of modern society—a feedstock for fertilizers,
plastics, rubber, fibers, explosives and other products. Ammonia is a gas at room temperatureand liquid with modest pressure or refrigeration, which makes it easy to use and store.
Almost 2% of global carbon dioxide (CO2) emissions come from the production of ammonia. Mostof these emissions come from separating hydrogen from natural gas or coal. These emissions
could be reduced or eliminated with low-carbon production methods. The leading options are(1) capturing the CO2 emitted in these processes and storing it underground or in long-lived
products and (2) separating hydrogen from water using electricity made from zero-carbon
processes.
In this roadmap, we use the term “low-carbon ammonia” to refer to ammonia made with
low-carbon production methods. Low-carbon ammonia can contribute to decarbonization in two
ways. First, low-carbon production methods can reduce the CO2 emissions that currently comefrom ammonia production. Second, low-carbon ammonia can be used as a replacement for
carbon-intensive fuels in shipping, heavy industry, power generation and other sectors.
Many countries, including Chile, Saudi Arabia and Australia, are investing in low-carbon
production methods for ammonia. This has implications for agriculture, fuels, the naturalenvironment and geopolitics.

Chapter 2: The Ammonia Industry: Past and Present
The development of a method to synthesize ammonia by German chemists Fritz Haber andCarl Bosch was one of the most important technological advances of the 20th century. By one
estimate, half of the current global population could not be fed without synthetic ammonia.
Last year, almost 180 million tons (Mt) of ammonia were produced globally (72% from natural
gas and 26% from coal). The largest ammonia producer is China (approximately 30% of global
production), followed by Russia, the European Union, the United States, India and the Middle
East. Approximately 10% of global ammonia is traded internationally, with more than 100 ports
and nearly 200 ships currently capable of handling bulk ammonia. Ammonia is also transported
by pipeline (primarily in the United States and Russia/Ukraine), rail and truck.
The International Energy Agency’s Sustainable Development Scenario (SDS) envisions thatammonia demand in 2050 will total 230 Mt for fertilizer and 125 Mt for novel uses—primarily inmarine fuel and power generation.

Chapter 3: Production of Low-Carbon Ammonia
Today, almost all ammonia is made with hydrogen from fossil fuels (72% from natural gas and
26% from coal). Hydrogen production is responsible for roughly 90% of the CO2 emissions fromthe current ammonia synthesis industry.
Blue ammonia adds carbon capture to conventional hydrogen production from fossil fuels.
Adding carbon capture to steam methane reforming (SMR) is relatively inexpensive forapproximately two-thirds of the total CO2 emissions (which are already separated during
production) but is significantly more expensive for the remaining CO2 emissions. Modern SMR

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EXECUTIVE SUMMARYl2systems with a smaller primary reformer or oxygen-blown autothermal reformers (ATRs) may
bring these costs down substantially. Any upstream fugitive methane emissions increase total lifecycle emissions for these systems, and access to CO2 transportation and storage is a key barrier.
Green ammonia uses electrolysis—electric current flowing through water—to produce hydrogen.
The carbon intensity depends primarily on the electricity source. Zero-carbon electricity sources
can help produce very low-carbon ammonia, but high-carbon electricity sources can increase
total life-cycle CO2 emissions as compared to conventional SMR-based hydrogen production.
Limited global manufacturing capacity for electrolyzers is a key barrier.
Ammonia can also be produced from bio-hydrogen (hydrogen produced from biomass). Biomass
feedstocks include agricultural waste, forestry waste, black liquor from paper production,municipal solid waste, dedicated energy crops, and micro- and macro-algae.

Chapter 4: Ammonia Infrastructure
Ammonia requires special purpose infrastructure, including pipelines, tanks and facilities formaritime bunkering. At present, nearly 8000 kilometers of ammonia pipeline run worldwide,
along with 38 export and 88 receiving terminals. These facilities provide an excellent basis forunderstanding the likely costs and performance of additional ammonia infrastructure, which willbe critically needed as the ammonia industry grows. The need for innovation is limited; additionalammonia infrastructure principally depends on finance, economics and policy.
Pipeline transport of liquid ammonia is a safe, low risk and cost-effective mode of transporting
ammonia between locations. Almost all ammonia is stored in tanks. There are three main types—
pressurized, low-temperature and semi-refrigerated.
Port facilities will serve essential functions for the scale-up of low-carbon ammonia. For maritime
fuel application, bunkering is a key prerequisite for deployment. Liquified natural gas (LNG)
infrastructure—in particular LNG receiving terminals and storage facilities—can be converted touse for ammonia.
Human capital, permitting and environmental justice concerns are important in new ammonia
infrastructure. Without significant new infrastructure, ammonia cannot reach its full potential incontributing to deep decarbonization.

Chapter 5: Uses
Low carbon ammonia can be used in many sectors to reduce carbon emissions. The first, mostimportant use is as a drop-in replacement for conventional ammonia in existing applications,
including agricultural fertilizer and chemical feedstocks. Ammonia can also be used for marine
shipping, power generation, heavy industry, road transport, aviation fuel and refrigeration. The
potential market for low-carbon ammonia in 2050 is several times current global ammonia
production.
For ammonia to be more widely used in power engines and turbines, a better understanding ofammonia’s combustion characteristics is required. In the short-term, co-combustion of ammonia
mixed with other fuels (e.g., coal/natural gas) is the most technically mature with least risk. Moreadvances are required for high-blending ratios or pure ammonia combustion applications.
Low-carbon ammonia faces competition with other decarbonization strategies. The mostpromising new uses for low-carbon ammonia are in marine shipping fuel and power generation.
Developing novel uses for low-carbon ammonia will require investment in R&D.

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EXECUTIVE SUMMARYl3

Chapter 6: Local Environmental and Safety Risks
The widespread use of ammonia has led to a mature understanding of the safe handling ofammonia transportation and distribution and to appropriate risk management methods within
the existing application areas. Supplying low-carbon ammonia for existing applications will not
substantially alter the human health and environmental risks. If low-carbon ammonia is adopted
into new application areas, such as power generation and maritime fuels, new risks will require
careful attention and management.
The primary health and environmental concerns associated with ammonia are its flammability,
acute toxicity to humans at high concentrations, contribution to the formation of fine-particle
pollution in the atmosphere, and negative impacts on aquatic ecosystems.
Because ammonia has a low odor-detection threshold, a slow leak will easily be detected before
dangerous concentrations are reached. However, a large uncontrolled release poses serious
human health risks, and safety measures must be in place to minimize the likelihood of such
events.
Slow ammonia leaks and other limited releases are less of a concern for worker safety, but
released ammonia can react with other pollutants to form harmful particles in the atmosphere.
Ammonia can also deposit in water bodies and contribute to eutrophication, causing harmful
algal blooms that consume dissolved oxygen, leading to fish kills. The fate and transport ofammonia in the environment is complex and requires further research to develop an improved
understanding.

Chapter 7: Research and Development (R&D)
The research and development (R&D) needs for safely and sustainably scaling up low-carbon
ammonia are focused in four major areas:
1. Developing deep integration schemes with renewable energy, particularly solar, wind andbiomass, which tend to occur in areas far from ammonia markets.
2. Increasing life-cycle energy efficiency and reducing capital intensity.
3. Ensuring that we understand and can manage any safety and environmental risks.
4. Ensuring that energy and climate impacts of ammonia use are well understood.

Chapter 8: Policy
Policy support will be essential to substantially increase production and use of low-carbon
ammonia. Key policies for consideration include demand-side policies (such as carbon pricing,
low-carbon fuel standards and power plant emissions standards), supply-side policies (such as
investment in R&D and government loan guarantees), regulatory controls (such as health andsafety regulations) and enabling policies (such as accelerated permitting and public-private
partnerships).
One simple step governments could take is to highlight low-carbon ammonia more centrally
in their national hydrogen strategies. Guidelines on life-cycle assessments of greenhouse gas
emissions from ammonia fuels are also important. (The International Maritime Organization—
where work is already underway—is an important venue for developing such guidelines.) In many
governments, inter-ministerial coordination will help with policy development.
Governments should promote the optimal use of low-carbon ammonia within a broad portfolio
of decarbonization strategies—not simply strive for the maximum use of low-carbon ammonia
everywhere.
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EXECUTIVE SUMMARYl4

Chapter 9: Findings and Recommendations
FINDINGS
Finding 1: Low-carbon ammonia can produce significant greenhouse gas reductions in key
sectors this decade and deep reductions in some sectors by 2050.
Finding 2: There are no technical barriers to producing low-carbon ammonia in large volume
before 2030.
Finding 3: Cost is the chief barrier to deployment.
Finding 4: Safety and environmental risks from ammonia scale-up will require attention andmanagement.
Finding 5: Global low-carbon ammonia trade will require infrastructure investment and more
ships.
Finding 6: Before low-carbon ammonia can deliver substantial abatement of greenhouse gas
emissions, more work on applications is a priority.
Finding 7: Very few countries have policies that support low-carbon ammonia today.
Finding 8: Low-carbon ammonia trade could have geopolitical implications.

RECOMMENDATIONS
Recommendation 1: Governments should support investment in new low-carbon ammonia
supplies.
Recommendation 2: Governments should launch a set of public-private partnerships to plan,develop and finance key infrastructure for low-carbon ammonia production, transportation anduse.
Recommendation 3: Governments and industries should invest heavily in innovations for useof low-carbon ammonia.
Recommendation 4: Government regulators should take steps to prevent safety andenvironmental problems in the ammonia trade.
Recommendation 5: Key governments should institute supporting policies to drive wider useof ammonia as a fuel and feedstock.
Recommendation 6: Policy incentives for low-carbon ammonia should be based on carbon
intensity rather than ammonia “color” (such as green or blue).
Recommendation 7: Business and governments should support local, national andinternational data-gathering and data-sharing.
Recommendation 8: Business, governments and training institutions should focus on humancapital development.

November 2022

EXECUTIVE SUMMARYl5

Chapter 1

INTRODUCTION
Ammonia (NH3) is one of the building blocks of modern society—an essential feedstock for fertilizers on which
modern agriculture depends. (By one estimate, only half of the current global population could be fed withoutammonia.) Ammonia is also used in manufacturing plastics, rubber, fibers and explosives.
Almost 2% of global carbon dioxide (CO2) emissions come from the production of ammonia. Most of theseemissions come from separating hydrogen from natural gas or coal. These emissions could be reduced oreliminated with low-carbon production methods. The leading options are (1) capturing the CO2 emitted in theseprocesses and storing it underground or in long-lived products and (2) separating hydrogen from water using
electricity made from zero-carbon processes.
In this roadmap, we use the term “low-carbon ammonia” to refer to ammonia made with low-carbon production
methods. Low-carbon ammonia can contribute to decarbonization in two ways. First, low-carbon production
methods can reduce the CO2 emissions that currently come from ammonia production. Second, low-carbon
ammonia can be used as a replacement for carbon-intensive fuels in shipping, heavy industry, power generationand other sectors.
Much of the interest in ammonia as a clean-fuel solution is based on ammonia’s physical and chemical properties,
as well as the potential for manufacturing it with a low-carbon footprint.
• Ammonia is a gas at room temperature and a liquid with modest pressure or refrigeration. This makes it easy tostore and widely usable in many applications.
• Ammonia is one of the few synthetic fuels that does not contain carbon. Use of ammonia, either throughcombustion or conversion, releases no greenhouse gases.
• Ammonia has a higher energy density than liquid hydrogen. This makes it attractive as a carbon-free fuel fortransportation, heating, power generation and industrial applications.
• Ammonia made from low-carbon hydrogen—including blue hydrogen, green hydrogen and bio-hydrogen—canhave a near-zero carbon footprint and (if waste biomass and carbon capture technology is used) potentially netnegative life-cycle emissions.
• As a low-carbon fuel, ammonia can substitute for dirtier and more carbon-intensive fuels, including coal, oiland natural gas. This substitution can either be complete or as a blend with other fuels to reduce their total
environmental impacts, including in coal boilers, gas turbines, combined heat-power systems, steel mills andinternal combustion engines.
Ammonia is produced today at large scale—roughly 200 million tons per year (Mt/y) from roughly 35 Mt ofhydrogen—mostly for use in fertilizers. This means that some infrastructure already exists and that many
companies already make, ship and use ammonia. This also means that ammonia ships (and ports) already exist,
although more will be needed to achieve key national and international goals. Similarly, ammonia is already tradedand shipped around the world as a feedstock, making future global trade of ammonia as a fuel easy to understandand imagine in terms of cost, risk and logistics.
Three compelling issues drive decision making around the mix of low-carbon fuels, including ammonia: climatechange, geopolitics and human health impacts of dirty fuels.
Climate crisis needs are unambiguous—low-carbon clean fuels are essential to reduce the risk of climate change
and maintain economic activity and growth. The most recent Intergovernmental Panel on Climate Change (IPCC)
Working Group III Assessment Report1 delivers a strong scientific consensus, requiring deep, rapid and profoundNovember 2022

CHAPTER 1l6decarbonization in all sectors by 2060–2100. To reach these goals, estimates indicate that the use of low-carbon
fuels must increase by 50–100% before 2030 and 200–700% before 2050, depending on the scenarios.2
Geopolitical risk is a related concern and potential advantage for clean fuels. Heavy reliance on conventional fossil
fuel supplies has always posed geopolitical risks, but these risks have gained prominence and urgency following
the Russian invasion of Ukraine and the associated global political, economic and energy crisis. One consequenceof this invasion is that the European Union has placed immediate emphasis on domestic production of greenhydrogen3 and has accelerated imports of liquified natural gas (LNG) and other fuels (including low-carbon
ammonia) in some instances through new bilateral agreements (e.g., Renewables Now, 20224).
Although the human health and environmental consequences of fossil-fuel use have long been known, growthof fossil-fuel use in developing countries has made the costs more apparent.5 In addition, recent studies revealthat the health effects of even small exposure to soot, volatile organic compounds (VOC) and sulfur emissions are
more profound and long-lived than previously thought.6 As such, the economic benefit of reduced fossil-fuel use,
including through displacement by clean fuels, is equally profound—and indeed could yield net savings (negative
carbon prices) through health benefits.7,8Capturing the benefits of clean-fuel use, including ammonia, will require production, distribution and use at anenormous scale. Because of ammonia production’s dependence on hydrogen, their commercial growth is closely
connected. The International Energy Agency (IEA) estimates that more than 540 Mt/y of low-carbon hydrogen
will be needed by 2050 to limit warming to 2 °C (3.6 °F) over pre-industrial levels, and 730 Mt/y of low-carbonhydrogen will be needed by 2050 to limit warming to an increase of 1.5 °C (2.7 °F) over pre-industrial levels. This
represents a 6x increase compared to current production of conventional hydrogen (90 Mt/y) to achieve a 2 °C
(3.6 °F) stabilization by 2050 and an increase of over 400x in clean hydrogen production.9 In particular, this growthin demand will be necessary to decarbonize “harder to abate” sectors, such as heavy-duty transportation andheavy industry. Recent studies by the Energy Transition Commission10 and IEA11 point to the role of hydrogen inproviding low-carbon fuels or feedstocks for steel, cement, chemicals, sustainable aviation, long-haul trucking,maritime operations and shipping, as well as some applications in the power sector for nations with limited
renewable resources (e.g., Korea and Japan).
Markets have recognized the potential benefits of hydrogen in tackling climate change, and new projects,
companies and investments are appearing rapidly. The EU Green Deal (2021),12 EU FitFor55 plan (2022),13 US
Infrastructure Investment and Jobs Act (2021)14 and US Inflation Reduction Act (2022)15 feature policies toencourage growth in both production and use of low-carbon hydrogen. As of 2021, more than 520 new cleanhydrogen projects have been announced.16 According to the IEA,11 16–24 Mt/y of new hydrogen production
projects would come online by 2030—roughly 60% from electric water splitting and 40% from carbon captureand storage (CCS) of emissions from fossil fuels used in production. Nonetheless, the likely total costs could prove
substantial. The investments required to produce low-carbon clean fuels at that scale are likely to be enormous,
potentially exceeding $16 trillion over the next 28 years.2,17,18
Hydrogen also faces real challenges in deployment. The two most important challenges are hydrogen’s low energy
density and the difficulty in transporting it. Hydrogen’s low energy density is a function of its very low gravimetricdensity. Even when compressed to 300 atm pressure in tanks and pipelines, hydrogen has roughly 30% the energy
density of natural gas and 10% that of gasoline. As for transportability, hydrogen molecules are very small andprone to leaking, thus presenting challenges for conventional infrastructure.11 To move hydrogen by ship is much
more challenging than moving LNG: hydrogen only liquifies at extremely low temperatures (-253 °C) and very
high pressures (> 350 atmospheres), which both require very large energy inputs to achieve. As such, the costsof transporting and shipping hydrogen are commonly more than 30% of the total costs of delivering hydrogen tomarket19 and in some cases may exceed the costs of production.17,20
The physics and chemistry of ammonia overcome many of the challenges of hydrogen, especially ammonia’s
higher energy density, ease of storage and transport, and potential use directly as a fuel.21 Ammonia also appears
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to be the current and future lowest-cost synthetic fuel; the IEA predicts11 that ammonia costs will drop faster andto substantially lower levels than methanol or kerosene.
None of this suggests that ammonia is without environmental or health concerns—quite the contrary. Ammonia isa gas at ambient temperatures, leading to real concerns about vapor leakage (sometimes called “slip”). It can also
enter the environment through spills. Like other fuels, ammonia is toxic. If inhaled, it causes respiratory problems
and can have lingering health effects. Global growth and profound scale-up of ammonia production and use
would likely create some new environmental risks and could add environmental burdens. Since ammonia is often
produced in areas with heavy industrial footprints, these burdens could disproportionally affect disadvantaged andfrontline communities.
Since hydrogen can be produced in many geographies, the same is true of ammonia. Countries investing inammonia production include the following.
• Chile: Chile is positioned to become a major clean ammonia exporter given its domestic renewable energy

resources. Because Chile has extremely high-quality wind, solar and hydroelectric resources, its government hascreated a basket of policies to support production of hydrogen and ammonia. In its National Green Hydrogen
Strategy,22 Chile aims to be a major producer and exporter of liquid hydrogen, green ammonia and clean fuels to
global markets by 2030. From 2025 to 2050, Chile estimates that its exports of green ammonia could scale froma total market size of $0.4 billion per year in 2025 to $24 billion per year by 2050+. The country also plans to use
ammonia domestically for end-use applications, such as maritime shipping and oil refineries. A major project has
already been announced by Total Eren (a subsidiary of TotalEnergies) that is scheduled to produce 4.4 million
tonnes of renewable ammonia per year at full capacity.23• Saudi Arabia: Saudi Arabia hosts one of the world’s largest green ammonia projects, the Neom development.

At $7 billion total estimated cost, the project will generate 5 GW of green electricity to make hydrogen, all ofwhich will become ammonia for global sale.24 In addition, Saudi Arabia is already producing “blue” ammonia
and shipping it to Japanese markets.25 They have already announced an 11 Mt/y blue ammonia project26 and are
expected to announce large additional ammonia projects later in 2022.

• Australia: The largest announced project is the Asian Renewable Energy Hub (AREH) in northwest Australia.

Although originally posed as a green electricity project for sale in Southeast Asia, it has since changed focus togreen ammonia production and export.27 The $40 billion project would yield 26 GW of electricity to produce 10
Mt/y of green ammonia.28 Also, like Saudi Arabia, Australia is home to large blue ammonia projects, including
the Latrobe Valley project—a joint venture with Kawasaki.

• Other geographies: New ammonia projects are emerging in geographies with high-quality renewable resources

or low-cost natural gas. These include, but are not limited to, Namibia, Iceland, Spain, Uruguay, Morocco,
Indonesia, the United Arab Emirates, Qatar, the United States and Canada.

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8The growth in both supply and demand for low-carbon ammonia reveals an avenue for global wealth creation.
It may also represent a geopolitical shift—with more fuel producers, the role of petrostates in determining
national policies may change profoundly. The growth in ammonia supply and use, especially in developing nations,
could present additional environmental concerns, ranging from local health effects of ammonia slip to global
consequences of hydrogen and ammonia leakage on climate. This last point is particularly noteworthy—recent
studies suggest that, by extending the life of non-CO2 greenhouse gases in the atmosphere and thus increasing
their effective radiative forcing, large-scale hydrogen production for ammonia and other uses could significantly
contribute to global warming if leakage rates are high.29,30
These issues prompt us to consider many features, aspects and points of concern in our roadmap for low-carbon
ammonia.
• Chapter 2 discusses the history and current state of the ammonia market globally.
• Chapter 3 discusses methods for producing low-carbon ammonia.
• Chapter 4 discusses ammonia infrastructure, including for pipeline transportation, shipping cargo, shipping fueland energy storage.

• Chapter 5 discusses how ammonia may be used in different sectors, including fertilizer manufacturing, heavy

industry, transportation and the power sector.

• Chapter 6 discusses the local environmental and safety risks related to ammonia production and use.
• Chapter 7 presents research and development priorities for low-carbon ammonia.
• Chapter 8 presents current and potential policy actions for scaling up of low-carbon ammonia production anduse.

• Chapter 9 presents findings and recommendations.

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25 Takeo Kumagai. Saudi Arabia ships maiden blue ammonia to Japan for zero-carbon emission power generation. S&P
Global Commodity Insights. https://www.spglobal.com/commodityinsights/en/market-insights/latest-news/

petrochemicals/092820-saudi-arabia-ships-maiden-blue-ammonia-to-japan-for-zero-carbon-emissionpower-generation (2020).
26 Brinda Darasha. Saudi Aramco aims to produce 11MMT blue ammonia; cut carbon emissions. ZAWYA. https://www.zawya.com/en/business/energy/saudi-aramco-aims-to-produce-11mmt-blue-ammonia-cut-carbonemissions-j4m04ocd (2022).
27 Ben Collins & Vanessa Mills. World’s largest renewable energy project proposed for north-west Australia ditches
electricity in favour of ammonia exports. ABC: Austrailian Broadcsting Corporation. https://www.abc.net.au/
news/2020-11-10/renewable-energy-hub-ditches-asian-cable-for-ammonia/12862916 (2020).

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10

28 Ruchira Singh. UK’s BP to acquire 40.5% stake in Australia’s 26 GW Asian Renewable Energy Hub. https://www.

spglobal.com/commodityinsights/en/market-insights/latest-news/energy-transition/061522-uks-bp-toacquire-405-stake-in-australias-26-gw-asian-renewable-energy-hub (2022).
29 I. B. Ocko & S. P. Hamburg. Climate consequences of hydrogen emissions. Atmos. Chem. Phys. 22, 9349-9368, https://doi.org/10.5194/acp-22-9349-2022 (2022).
30 Hadia Sheerazi Zhiyuan Fan, Amar Bhardwaj, Anne-Sophie Corbeau, Kathryn Longobardi, Dr. Caleb M. Woodall, Mahak
Agrawal, Dr. Julio Friedmann, Adalberto Castaneda, Ann-Kathrin Merz and Sebastian Orozco-Sanchez. Hydrogen
Leakage: A Potential Risk for the Hydrogen Economy. Columbia SIPA: Center on Global Energy Policy. https://www.

energypolicy.columbia.edu/research/commentary/hydrogen-leakage-potential-risk-hydrogen-economy(2022).

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11

Chapter 2

THE AMMONIA INDUSTRY: PAST AND

PRESENT

Ammonia is one of the four basic industrial chemicals that provide the foundation for all other chemicals andplastics production. Approximately 179 million tons (Mt) of ammonia were produced globally in 2020, a 40%
increase over 2001.1 The largest ammonia producer is China (approximately 30% of global production), followedby Russia, the European Union, the United States, India and the Middle East (see Figure 2-1). Existing global
ammonia production capacity has a utilization rate of roughly 80%, with the installed global annual production
capacity exceeding 230 Mt in 2020.2,3 The total global market size is estimated to be over $100 billion.4 As anenergy-intensive process, the production of synthetic (manufactured) ammonia consumes 8.6 EJ per year, orCanadaPakistan
Ukraine

China
PolandUnited States

Egypt
Qatar
Other

Germany
RussiaIndia
Saudi Arabia

Indonesia
Iran
Trinidad and Tobago

Figure 2-1. Global ammonia production by country and total (million metric tons/year). Data: USGS. Note that USGS data
are reported as tons of fixed nitrogen, which we adjust here to tons of ammonia.

approximately 2% of total final energy consumption globally.3,5 It is responsible for 450 Mt of direct CO2 emissions,as well as an additional 170 Mt of CO2e emissions due to the electricity consumed by the ammonia production
process and release of nitrous oxide that occurs when ammonia-derived fertilizers are applied to agricultural land.6
Unlike the other three basic industrial chemicals (methanol, ethylene and propylene), ammonia is primarily
used to produce nitrogen-based fertilizers, which include urea, ammonium nitrate and ammonium sulfate (seeFigure 2-2). Ammonia is also used directly as a fertilizer in North America. Ammonia-derived fertilizers are vitalfor supporting global food production; by one estimate, only half of the current global population could be
fed without synthetic ammonia (see Figure 2-3).7 The remainder of ammonia produced is used for a range ofapplications, including manufacturing plastics, rubber, fibers (via acrylonitrile) and explosives (via ammonium

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12

Figure 2-2. Ammonia is converted into multiple types of fertilizer using different chemical routes illustrated here.

nitrate), and directly as an air pollution control agent, refrigerant and cleaning agent. Development of a method tochemically synthesize ammonia was one of the most important scientific and technological advances of the 20th
century.7,8 The value of nitrogen-based fertilizers for agriculture has been understood for centuries, and the useof various forms of natural nitrogen fertilizers has a long history. Beginning in the 19th century, several nations
began to recognize the value of seabird guano as fertilizer, originating from island deposits in South America.
Following Peru’s independence from Spain in 1824, exports of guano from Peru grew rapidly, rising to hundredsof thousands of tons annually by the 1840s. This fueled the “Guano Boom” that dramatically increased crop yields
and enabled high population growth in many countries.9
Unfortunately, over-exploitation of the Peruvian guano resource led to a crash in supply by the late 19th century.
Exports shifted to nitrates from mined ore (caliche deposits), but the scientific community began to growconcerned that insufficient supplies of nitrogen fertilizer could lead to global starvation.10 Motivated by thisconcern and an interest in developing synthetic explosives to replace natural saltpeter deposits, chemists Fritz
Haber and Carl Bosch developed a high-pressure ammonia chemical synthesis method now known as the HaberBosch process.11
The Haber-Bosch process was the first industrial pressurized catalytic process and required several independent
technological innovations to become practical. One of the most important of these was to develop a reactor that
could withstand pressures of 200 bar, which was unprecedented. This required lining a pressure-bearing steel

Figure 2-3. The growth of global population has been partly enabled by a corresponding growth in the production ofsynthetic ammonia for fertilizers to support food production. From DOE, 2016.15

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exterior tube with soft iron and providing a means to release hydrogen that diffused through this liner so that it
would not embrittle and destroy the steel. A second key innovation was to find an economical alternative to theoriginal osmium and uranium catalyst used by Haber in early experiments. Bosch and his colleague Alwin Mittasch
tested thousands of alternatives, eventually identifying an iron-based catalyst with a small addition of aluminum,
which is still in broad use today.4,12,13
Bosch and Mittasch conducted their work as employees of German chemical company BASF, which built the firstindustrial Haber-Bosch plant in Oppau, Germany in 1913. The plant had a capacity of 10,000 tons of ammonia peryear; it used coal and air to produce nitrogen, and hot coke (derived from coal) and water to produce hydrogen.
The nitrogen and hydrogen were then reacted at high pressure and temperature over the iron catalyst to produce
ammonia.14 A key feature of the plant, and all subsequent Haber-Bosch plants, is the relatively low fraction ofreactants converted to ammonia in a single pass through the reactor. To address this, the unreacted components
are repeatedly recycled with the addition of fresh nitrogen and hydrogen, increasing the overall amount converted
to ammonia.15 Germany continued to be the only producer of synthetic ammonia using the Haber-Bosch process
through 1920, with BASF unwilling to offer licenses.16 However, many governments understood its importance andsought to develop or otherwise acquire it. The United States appropriated funds in 1916 to develop nitrogenfixation technology for both military and agricultural purposes, and the resulting military Fixed Nitrogen ResearchLaboratory (FNRL) was transitioned from the War Department to the Department of Agriculture in 1921.17 The
United Kingdom began developing a nitrogen-fixation plant during World War I, which was later converted tofertilizer production using the Haber-Bosch process and started producing ammonia in 1924.18 Several alternative
processes for synthetic ammonia production were developed throughout the 1920s and 1930s, in Italy (Casale,
Fauser processes), France (Claude, Mont Cenis processes), the United States (General Chemical/Allied, Nitrogen
Engineering processes) and Japan (Showa Fertilizer process).16,19 In general, these were variants of the HaberBosch process and were mostly available for licensing, leading to large-scale adoption in many countries by theend of the 1920s.
By 1934, the United States, Germany and Japan were the largest producers of synthetic ammonia. During the
1930s, coal remained the primary energy source for ammonia production, but up to 30% of ammonia produced
globally was made with hydrogen derived from hydro-powered electrolysis.16 While fossil-based ammonia
production gained market share after this, electrolysis-based ammonia plants continued to be constructed until atleast 1960.
An important development in the transition to the modern ammonia industry came during World War II, when
the United States constructed ten large-scale nitrogen fixation plants, seven of which used hydrogen derived fromthe steam reforming of methane (natural gas).20 This was a novel departure from the standard use of coal andcoke and provided several benefits, including much lower sulfur content, which reduced feedstock pre-treatment
requirements and allowed the use of advanced catalysts for carbon monoxide (CO) conversion. Reforming-basedammonia synthesis became increasingly standard during the 1960s due to its favorable economics. Other
important innovations introduced around this time included replacing reciprocating compressors with centrifugal
ones (allowing much greater unit capacities), introducing single stream reactors, and increasing the use of shaped
catalysts to improve activity while maintaining pressure drop.18
The tremendous importance of the Haber-Bosch process for fertilizer production continued to be recognized asthese innovations were introduced. The technology’s success may have played a role in China’s decision to open
to the West in 1972, as its agricultural production was under enormous strain from population growth. Following
President Nixon’s famous visit, US companies built at least eight large ammonia plants in China, helping tosignificantly increase synthetic fertilizer production there.21,22 China became the world’s largest ammonia producer
in 1991.

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14

Further innovations continued through the 1990s, leading to ever-larger plant capacities and corresponding
improvements to energy efficiency. Because of the need to provide high pressure and temperature, Haber-Boschplants display strong economies of scale, with a cost-scaling exponent of roughly 0.65.23 Average plant capacities
grew from 500 tons per day (tpd) in the 1960s to over 3000 tpd today (two orders of magnitude larger than theoriginal Oppau plant). At the same time, specific energy consumption has fallen from nearly 100 GJ/t ammonia forearly coal-based plants to 28 GJ/t today for new plants using natural gas as feedstock, approaching the theoreticalminimum specific energy of 18 GJ/t.24 Modern coal-based plants have specific energy consumption of 42 GJ/t.18
Modern Haber-Bosch plants are highly integrated and include additional innovations, such as lower-pressure
synthesis loops and radial and horizontal catalyst beds. Approximately three quarters of global production is basedon natural gas feedstock; most of the remainder, which is almost entirely in China, is based on coal. The front endof conventional natural gas–based plants consists of a methane desulfurization stage, followed by two reformers.
The first of these, called a steam methane reformer (SMR), is heated by external natural gas combustion (thedominant energy consumption of the entire process) and operates at 850–900 °C. (This first reformer is thereason these plants are often referred to as “SMR” ammonia plants.) The second, called an autothermal reformer(ATR), is heated to 900–1000 °C by injection of compressed air and partial oxidation of the reagents. This injectionof air also provides nitrogen for the Haber-Bosch reaction downstream. The resulting syngas and nitrogen are
passed through a water-gas shift (WGS) reactor to maximize the recovery of hydrogen, and heat from the ATR
and WGS reactors is used to raise steam for compression elsewhere in the plant. Following the WGS, CO2 isremoved (usually using the Rectisol, Selexol or Benfield process) and vented, and the remaining CO is converted
to methane to avoid poisoning the Haber-Bosch catalyst. The resulting feed—containing hydrogen, nitrogen,and residual argon and methane (which accumulate as inerts)—is fed to the Haber-Bosch reactor. Because of a
tradeoff between reaction speed and equilibrium, most reactors achieve a conversion to ammonia of only 10–15%
per pass (increasing to 20% for very recent plants). Following a cooling step in which ammonia is liquefied andremoved, the remaining hydrogen and nitrogen are recycled into the reactor to achieve overall conversion rates
that approach 100%. Today, a small number of vendors dominate the market for design and construction of newammonia plants and continue to pursue technology innovations for competitive advantage; as a result, bothaverage plant capacity and energy efficiency are likely to continue to increase.4,24,25 (See Chapter 3 – Production of
Low-Carbon Ammonia.)
Modern plants can produce ammonia at costs as low as $160/t due to economies of scale.23 However, this costis heavily dependent on the price of feedstock natural gas, which contributes more than half of the levelized
cost of ammonia production.26 As a result of sharp increases in natural gas prices, world ammonia prices haveincreased dramatically since 2021, from $200–300/t to over $1000/t in Europe, the Middle East and the UnitedStates.27 Idled capacity appears to be restarting in response to these price rises, but the market remains extremely
dynamic.28
Approximately 10% of global ammonia production is traded internationally, with more than 100 ports and nearly
200 ships currently capable of handling bulk ammonia.29 Ammonia is also transported by pipeline (primarily in
the United States and Russia/Ukraine), rail and truck. (See Chapter 4 – Ammonia Infrastructure.) Accidents haveoccurred with both production and transportation of ammonia and have been the subject of significant analysis,
which has led to improved safety, leak detection and accident mitigation procedures.30-33 (See Chapter 6 – Safety
and Local Environmental Impacts of Ammonia.)
Currently, the global ammonia market is undergoing significant changes. Concerns about climate change havesparked increasing interest in low-carbon ammonia as a replacement for carbon-intensive fuels, fertilizers andother products. A wide array of low-carbon ammonia production projects has been announced, including both“blue” ammonia, which adds carbon capture and storage (CCS) to conventional, natural gas- or coal-based
production, and “green” ammonia, which produces hydrogen through electrolysis powered by low-carbon

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CHAPTER 2l15

electricity. This includes many of the world’s largest fertilizer companies, such as Nutrien,34 Wesfarmers,35 CF
Industries36 and Yara International.37 Several shipments of blue ammonia have already been demonstrated,
including production by Saudi Aramco and Saudi Basic Industries Corporation (SABIC),38 as well as Abu Dhabi
National Oil Company (ADNOC) and Fertiglobe.39 (See Chapter 3 – Production of Low-Carbon Ammonia). Similarly,
many technology development and demonstration projects have been announced that focus on the use of lowcarbon ammonia in novel applications, particularly in power generation and marine fuels. (See Chapter 5 – Uses of
Low-Carbon Ammonia.)
The International Energy Agency’s Sustainable Development Scenario (SDS) envisions that ammonia demand
for fertilizer in 2050 will total 230 Mt, an increase over current demand that reflects population growth anddietary changes (increased consumption), as well as fertilizer application efficiency and a shift from urea toward
nitrate-based fertilizers (decreased consumption). The SDS also envisions 125 Mt of ammonia demand for novel
applications by 2050, primarily in marine fuel and power generation.5 While the latter category (energy carriers)
will be overwhelmingly low-carbon ammonia, the adoption rate of low-carbon ammonia into existing uses
(primarily fertilizers) is unclear. Other analysts have projected up to 150 Mt of ammonia demand for marine fuelalone40 and up to 200 Mt of ammonia demand for the power sector alone,41 both of which would presumably bedominated by low-carbon ammonia. As a result, forecasting the future demand for low-carbon ammonia depends
on a complex mix of factors but may be several times current global ammonia production.

REFERENCES
1

USGS: National Minerals Information Center. Nitrogen Statistics and Information. https://www.usgs.gov/centers/
national-minerals-information-center/nitrogen-statistics-and-information (Accessed September 2022).

2

Statista. Production capacity of ammonia worldwide from 2018 to 2021, with a forecast for 2026 and 2030. https://www.statista.com/statistics/1065865/ammonia-production-capacity-globally/ (Accessed September 2022).

3

International Fertilizer Association. Nitrogen Products: Ammonia. https://www.ifastat.org/supply/Nitrogen%20
Products/Ammonia (International Fertilizer Association).

4

Venkat Pattabathula & Jim Richardson. Introduction to Ammonia Production. American Institute of Chemical Engineers(AIChE), https://www.aiche.org/sites/default/files/cep/20160969.pdf (2016).

5International Energy Agency. Ammonia Technology Roadmap. (IEA, Paris, 2021 https://www.iea.org/reports/
ammonia-technology-roadmap).

6

International Energy Agency. “Executive Summary” in Ammonia Technology Roadmap
reports/ammonia-technology-roadmap/executive-summary)).

7

V. Smil. Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production. (MIT Press, 2004
(https://mitpress.mit.edu/9780262693134/)).

8

T. Hager. The Alchemy of Air: A Jewish Genius, a Doomed Tycoon, and the Scientific Discovery That Fed the World But
Fueled the Rise of Hitler. (Three Rivers Press, 2009 https://books.google.com/books?id=3AOMXyd2EGsC).

9

Ewald Schnug, Frank Jacobs & Kirsten Stöven. “Guano: The White Gold of the Seabirds” in Seabirds (ed Heimo Mikkola)(IntechOpen, 2018 https://doi.org/10.5772/intechopen.79501, 10.5772/intechopen.79501).

(2021 (https://www.iea.org/

10 R. Giffen. The Wheat Problem. Nature 61, 169-171, https://doi.org/10.1038/061169a0 (1899).
11 Jan Willem Erisman et al. How a century of ammonia synthesis changed the world. Nature Geoscience 1, 636-639,
https://doi.org/10.1038/ngeo325 (2008).
12 Claudia Flavell-While. Fritz Haber and Carl Bosch – Feed the World. The Chemical Engineer. https://www.
thechemicalengineer.com/features/cewctw-fritz-haber-and-carl-bosch-feed-the-world/ (2010).
13 Huazhang Liu. Ammonia synthesis catalyst 100 years: Practice, enlightenment and challenge. Chinese Journal of
Catalysis 35, 1619-1640, https://doi.org/10.1016/S1872-2067(14)60118-2 (2014).
14 Tor Erik Kristensen. A factual clarification and chemical-technical reassessment of the 1921 Oppau explosion
disaster - the unforeseen explosivity of porous ammonium sulfate nitrate fertilizer. Report No. 16/01508, (ISBN:
978-82-464-2793-5, 2016 https://www.ffi.no/en/publications-archive/a-factual-clarification-and-chemical-

technical-reassessment-of-the-1921-oppau-explosion-disaster-the-unforeseen-explosivity-of-porousammonium-sulfate-nitrate-fertilizer).

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15 US Department of Energy. Sustainable Ammonia Synthesis: Exploring the scientific challenges associated withdiscovering alternative, sustainable processes for ammonia production. (DOE: Office of Science (DOE Roundtable
Report), Dulles, VA, 2016 (https://science.osti.gov/-/media/bes/pdf/reports/2016/SustainableAmmoniaReport.
pdf)).
16 Kevin H. R. Rouwenhorst, Anthony S. Travis & Leon Lefferts. 1921–2021: A Century of Renewable Ammonia Synthesis.
Sustainable Chemistry 3, 149-171, https://doi.org/10.3390/suschem3020011 (2022).
17 Timothy Johnson. Nitrogen Nation: The Legacy of World War I and the Politics of Chemical Agriculture in the UnitedStates, 1916–1933. Agricultural History 90, 209-229, https://doi.org/10.3098/ah.2016.090.2.209 (2016).
18 John Brightling. Ammonia and the Fertiliser Industry: The Development of Ammonia at Billingham. Johnson Matthey
Technology Review 62, 32-47, https://doi.org/10.1595/205651318X696341 (2018).
19 Anthony Stewart Travis. First Steps: Synthetic Ammonia in the United States. Substantia 5, 55 - 77, https://doi.
org/10.36253/Substantia-1181 (2021).
20 William H. Martin. Public Policy and Increased Competition in the Synthetic Ammonia Industry. The Quarterly Journal of
Economics 73, 373-392, https://doi.org/10.2307/1880610 (1959).
21 Michael Pollan. What’s Eating America. Smithsonian Magazine. https://www.smithsonianmag.com/history/whatseating-america-121229356/ (2006).
22 US Mission China. History of the U.S. and China. U.S. Embassy and Consulates in China. https://china.usembassychina.org.cn/history-of-the-u-s-and-china/ (2018).
23 Carlos A. Fernandez & Marta C. Hatzell. Editors’ Choice—Economic Considerations for Low-Temperature Electrochemical
Ammonia Production: Achieving Haber-Bosch Parity. Journal of The Electrochemical Society 167, 143504, https://iopscience.iop.org/article/10.1149/1945-7111/abc35b (2020).
24 Collin Smith, Alfred K. Hill & Laura Torrente-Murciano. Current and future role of Haber–Bosch ammonia in a carbonfree energy landscape. Energy & Environmental Science 13, 331-344, http://dx.doi.org/10.1039/C9EE02873K (2020).
25 Abdulkarem I. Amhamed et al. Ammonia Production Plants&mdash;A Review. Fuels 3, 408-435, https://doi.
org/10.3390/fuels3030026 (2022).
26 Katerina Kermeli et al. Energy Efficiency and Cost Saving Opportunities for Ammonia and Nitrogenous Fertilizer
Production: An ENERGY STAR® Guide for Energy & Plant Managers. (US EPA, 2017 https://www.energystar.gov/sites/
default/files/tools/Fertilizer_guide_170418_508.pdf).
27 US Energy Information Administration. U.S. ammonia prices rise in response to higher international natural gas prices.
https://www.eia.gov/todayinenergy/detail.php?id=52358 (2022).
28 Jeffrey McDonald. Higher ammonia prices prompting European restarts, but shortages remain: traders. S&P Global:
Commodity Insights. https://www.spglobal.com/commodityinsights/en/market-insights/latest-news/energy-transition/040122-higher-ammonia-prices-prompting-european-restarts-but-shortages-remain-traders(2022).

29 Lucy Hine. Ammonia swings into frame as a potential future marine fuel. TradeWinds: The Global Shipping News
Source. https://www.tradewindsnews.com/gas/ammonia-swings-into-frame-as-a-potential-future-marinefuel/2-1-523024 (2019).
30 TEAM2G, Palak Jain & Dhruv Patel. What has the Industry Experience Been with Ammonia Manufacturing Plants? Whatis their Track Record for Having Serious Process Safety Incidents? What Root Causes have Typically Led to Them? , (2019(https://engineering.purdue.edu/P2SAC/presentations/documents/Industry-Experience-With-AmmoniaManufacturing-Plants-Fall-2019.pdf)).
31 Fertilizers Europe. Guidance for Inspection of and Leak Detection in Liquid Ammonia Pipelines. (2018, https://www.

fertilizerseurope.com/wp-content/uploads/2019/08/Guidance_for_inspection_of_and_leak_detection_in_
liquid_ammonia_pipelines_FINAL_01.pdf).

32 US Department of Homeland Security. Feature Article: Securing Transportation of Ammonia—Agricultural Lifeline andFuture Affordable, Clean Energy Source. U.S. Department of Homeland Security: Science and Technology. https://www.
dhs.gov/science-and-technology/news/2021/06/17/feature-article-securing-transportation-ammonia (2021).
33 Mark Fecke, Stephen Garne & Brenton Cox. Hazards 26: Review of Global Regulations for Anhydrous Ammonia
Production, Use, and Storage. IChemE: Institution of Chemical Engineers. https://www.icheme.org/media/11771/

hazards-26-paper-34-review-of-global-regulations-for-anhydrous-ammonia-production-use-and-storage.pdf(2016).

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34 Nutrien. Nutrien Announces Intention to Build World’s Largest Clean Ammonia Production Facility. https://www.

nutrien.com/investors/news-releases/2022-nutrien-announces-intention-build-worlds-largest-cleanammonia (2022).

35 Julian Atchison. Australia’s first gas-to-hydrogen pipeline transition to feed ammonia production near Perth. Ammonia
Energy Association. https://www.ammoniaenergy.org/articles/australias-first-gas-to-hydrogen-pipelinetransition-to-feed-ammonia-production-near-perth/ (2022).
36 CF Industries. Mitsui & Co., Ltd. and CF Industries Announce Plans for New Blue Ammonia Capacity in the United States.
https://www.cfindustries.com/newsroom/2022/cf-mitsui-update (2022).
37 Robin Whitlock. Yara, ACME and Scatec sign term sheet for sale of green ammonia from Oman. Renewable Energy
Magazine. https://www.renewableenergymagazine.com/hydrogen/yara-acme-and-scatec-sign-termsheet-20220715 (2022).
38 Saudi Aramco, IEEJ & SABIC. (The Institute of Energy Economics, Japan (IEEJ), 2020, https://eneken.ieej.or.jp/
data/9135.pdf).
39 INPEX Corporation, IHI Corporation & Mitsui OSK Lines. INPEX, IHI, MOL Demonstrate Clean Ammonia Supply Chain
Linking UAE and Jap. https://www.inpex.co.jp/english/news/assets/pdf/20220630.pdf (2022).
40 Alfa Laval et al. Ammonfuel – an industrial view of ammonia as a marine fuel. https://hafniabw.com/wp-content/
uploads/2020/08/Ammonfuel-Report-an-industrial-view-of-ammonia-as-a-marine-fuel.pdf (2020).
41 Wood Mackenzie. Ammonia co-firing in thermal power plants could be worth US$100 billion in 2050. https://www.

woodmac.com/press-releases/ammonia-co-firing-in-thermal-power-plants-could-be-worth-us$100-billionin-2050/ (2022).

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Chapter 3

PRODUCTION OF LOW-CARBON
AMMONIA
Conventional ammonia production is an emissions-intensive, fossil fuel–based business. Of the 179 million tons(Mt) of ammonia produced in 2020, 72% relied on natural gas–based steam methane reforming (SMR), 26%
on coal gasification, 1% on oil products and finally a fraction of a percentage point on electrolysis.1,2 In terms ofgeographic concentration, China is the largest ammonia producer, at 30% of global production capacity, of which
85% relies on China’s coal reserves.2 The Middle East, United States, Russia, European Union and India eachaccount for 8–10%, with low-cost natural gas in the Middle East, United States and Russia fueling production
there.2
Ammonia production begins with the production of hydrogen, which is then combined with nitrogen in the HaberBosch process to produce ammonia.3 To achieve a sufficient reaction pace, modern Haber-Bosch plants operate
at high temperatures and pressures.4 These high capital costs result in significant economies of scale, leading toever-larger-scale ammonia production.5 The typical capacities for new-build plants have grown over time, reaching2000 t/day in the 2000s and increasing to 3300 t/day today.6,7High capital costs combined with plant lifetimes of 50 years builds inertia into the ammonia production system.2
The capital investment (including engineering, procurement and construction costs) for an SMR plant runs
around $1.675 billion.2 A carbon capture and storage (CCS) retrofit would require capital investments of around$335 million, or about 20% of the initial investment cost.2 Regional differences in plant age and local resource

Figure 3-1. BASF Ammonia Plant in Ludwigshafen, Germany. The first industrial scale ammonia synthesis plant was built by
BASF near Ludwigshafen (BASF).7

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availability mean that the most cost-effective path toward low-carbon ammonia will vary. CCS retrofits have an
outsized role to play in China, where an average plant age of 12 years means assets still have long remaining
lifetimes compared to Europe, where an average plant age of 40 years means assets are nearing the ends of their
lifetimes.2 As of October 2021, existing and announced low-carbon ammonia projects in the range of 8 Mt wereplanned to come online by 2030.2
The carbon footprint of ammonia production varies by plant age and fuel type. With the inefficiencies of today’s
aging fleet and the continued reliance on coal for some ammonia production, the average ton of ammonia
produced results in 2.4 tons of direct CO2. Thus, ammonia has a direct CO2 emissions profile that is twice as
intensive as crude steel and four times as intensive as cement on a mass basis.2 As newbuild ammonia plants
have achieved higher efficiencies with scale-up and technology optimization, a ton of ammonia produced withthe best available technology for SMR results in 1.8 tons of direct CO2 emissions, with the possibility of reducing
the emissions to 0.1 tons using CCS retrofits.2,6 Efforts to decarbonize ammonia concentrate on emissions fromhydrogen production because it is the most carbon-intensive part of the production process. Specifically, hydrogenproduction accounts for 90% of the carbon emissions in the synthesis of ammonia, assuming minimal emissions
from natural gas production and transport (see below).8
The major pathways to decarbonizing ammonia production are often described in terms of colors. Gray ammonia
refers to conventional, fossil fuel–based ammonia production methods. Blue ammonia is based on these same
conventional production methods, with the addition of carbon capture equipment to achieve a lower carbon
footprint. Green ammonia refers to ammonia produced using electrolysis powered by clean electricity. Despite
these qualitative descriptors, there is no widely accepted quantitative measure of how small the emissions
footprint of ammonia must be to qualify as “blue” or “green,” allowing for substantial variation in emissions withinthese categories. As a result, the label “blue” or “green” ammonia alone does not provide sufficient information todetermine whether a given batch of ammonia has low life-cycle emissions.
This chapter examines three pathways to low-carbon ammonia production:
1. Reducing CO2 emissions from existing ammonia production facilities with carbon capture or electrification.
2. Using electrolysis running on clean electricity.
3. Creating hydrogen from biomass with carbon capture (ammonia from bio-hydrogen).

Figure 3-2. Emissions intensity of hydrogen production methods vary widely. Sources: Minervini et al., 202123 and Fan et al.,202157
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Each of these pathways and the numerous design variations within them involve trade-offs between theachievable greenhouse gas emissions reductions, speed and scale of implementation, and the cost of production
and transportation. The most advantageous low-carbon ammonia pathway will vary by geography due to theimportance of local resources and infrastructure, as well as over time as some of the most promising pathways
under R&D have yet to reach the market.
Natural gas–based ammonia originally became widespread due to its low cost, with a levelized cost of ammonia
as low as $160/t due to economies of scale.9 However, the economic competitiveness of blue versus green
ammonia will depend partly on the relative differences in their primary production cost drivers—the price of
natural gas versus the price of clean electricity. The volatility of both natural gas and clean electricity prices creates
an uncertain future production landscape. For example, from 2000 to 2020, market prices for ammonia ranged
between $100/t to $600/t, but natural gas shortages starting in 2021 drove prices above $1000/t in all regions.10(See Chapter 2 – The Ammonia Industry: Past and Present.) As a result, green ammonia imports to Europe became
cheaper than fossil fuel–based gray ammonia in 2022.11 This variation in energy prices over time and geography,
in combination with the age and status of existing conventional ammonia production plants, leads to a complex
scenario in which both blue and green ammonia facilities are being developed in different locations globally. While
many analyses attempt to forecast the future balance between blue and green ammonia production, both need tobe scaled to meet projections for growing future demand for low-carbon ammonia.
Another important factor in price variation is the potential for different levels of centralization for blue and green
ammonia production. Given that gray ammonia production is centralized, blue ammonia will likely be similar,
resulting in additional costs for ammonia transportation and distribution of ammonia. This is estimated at $52/t
via pipeline, $100/t via truck or $140/t via railway for 1600 km.12 The modularity of green ammonia productionmeans there is less economic advantage from large-scale production facilities, creating greater opportunities for
distributed production with lower transportation costs to end users.
Each type of low-carbon ammonia production faces a number of barriers. The primary obstacle for blue
ammonia production is the enabling infrastructure to identify and then transport captured CO2 to storage sites.
Furthermore, while the concentrated process stream from reforming natural gas for blue ammonia is easily
captured, capturing the dilute CO2 from combustion is more difficult and expensive. For green ammonia, the likely
bottleneck for scale is the limited existing capacity to manufacture new electrolyzers, leading to a discrepancy
between announced projects and the likely ability to deliver on them. Green ammonia also struggles with theintermittency of renewable energy sources, potentially requiring the use of some higher-emissions grid-supplied
power. Finally, all forms of low-carbon ammonia face the barrier of a market reluctant to pay a green premium fora lower carbon footprint, meaning they depend on policy to drive an uptake in demand and for subsidies to closethe cost and corresponding price gap with gray ammonia (for further details, see Chapter 8: Policy).

Blue Ammonia
The existing fleet of coal- and natural gas–based ammonia production, as well as new builds using the same
technology, can become low carbon through the introduction of CCS technology. Without CCS, ammonia’s
carbon footprint is primarily determined by the emissions profile of the hydrogen production method. Ammonia
produced from coal has the largest carbon footprint, with a direct CO2 intensity of 3.2 tCO2/t, followed by natural
gas with SMR at 1.8 tCO2/t (see Table 3-1). This section will focus primarily on cutting emissions for natural gas–
based SMR, given its dominance at 72% of global ammonia production.2
The multistep SMR process is based on the reaction of desulfurized natural gas with steam at high pressure andtemperature, followed by further steps to purify the gas streams, including CO2 removal through absorption in anamine solution.2,13 (See Chapter 2 - The Ammonia Industry: Past and Present.) This produces a mixture of hydrogen

November 2022

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21

Table 3-1. Energy needs to produce one tonne of ammonia for each route using BAT.
Energy intensity (GJ/ton)

Production routeFeedstock

FuelElectricity

Steam

Gross

Net

Direct CO2 intensity(ton CO2/ton)Natural gas SMR

21.0

11.1

0.3

-4.8

32.4

27.6

1.8

Natural gas ATR

25.8

2.1

1.0

0.0

28.9

28.9

1.6

Coal gasification

18.6

15.1

3.7

-1.3

37.4

36.1

3.2

SMR with CCS

21.0

11.1

1.0

-3.1

33.1

30.0

0.1

ATR with CCS

25.8

2.1

1.5

0.0

29.4

29.4

0.1

Coal with CCS

18.6

15.1

4.9

2.6

38.6

41.2

0.2

Notes: SMR= steam methane reforming; ATR=auto-thermal reforming; CCS=carbon capture and storage. All energy intensities presented for the productionof 1 tonne of ammonia. The arrangements considered here include capture of both concentrated and dilute CO2 streams. Negative values represent net
steam generation, which is available for use by other process units or for export. Methane pyrolysis produces solid carbon as a by-product, the energy
content of which is not reflected in the values shown. Methane pyrolysis is at an early stage of technology development and the estimates provided direct
CO2 emissions from the energy system, following IEA emissions accounting conventions. Source: Data gathered and reviewed in collaboration with the IA
and its members.
IEA Ammonia Roadmap2. pg. 33

and nitrogen (which are subsequently reacted to
produce ammonia) and a separate stream of pure CO2(see Figure 3-4).
Natural gas–based SMR ammonia production iswell-suited for carbon capture because CO2 is alreadyseparated from the process gas and removed to
avoid poisoning the iron-based Haber-Bosch catalyst.
Conventionally, this pure stream of CO2 is simply
vented, but it can be dewatered and compressed forstorage or utilization at low cost, roughly $34/tCO2(NETL14; costs adjusted to 2022 using CPI). Transportand storage add approximately $25–50/tCO2 (seediscussion below) for a total of approximately $60–85/ Figure 3-3. CO2 pipeline infrastructure will be decisive for
tCO2. This reduces the overall process emissions byenabling carbon capture for blue ammonia production.
15
approximately two-thirds. Getting to 90% or greater
total emissions reductions is more difficult because it requires also capturing CO2 from the more dilute flue gas
stream that is emitted when natural gas is combusted to produce heat for the primary reformer.15 Capturing
these additional emissions in order to achieve this lower carbon footprint requires installing and operating
additional carbon capture equipment and incurring similar transport and storage costs and is thus significantly
more expensive, approximately $100–150/tCO2.10 Additionally, decarbonization of the full life-cycle of SMR-basedammonia is limited by the upstream greenhouse gas emissions resulting from the extraction, treatment andtransport of natural gas, which can be substantial in some cases.8
Some modern SMR plants have begun to adopt a design based on reducing the size and reforming capacity ofthe primary, externally heated reformer (the SMR) while increasing the reforming in the secondary, air-blownreformer called the autothermal reformer (ATR).16,17 When combined with a cryogenic nitrogen wash to adjust
the hydrogen:nitrogen ratio of process gas entering the synthesis loop, this configuration can potentially achieve
over 80% reduction of CO2 emissions just by dewatering and compressing the CO2 already separated from theprocess gas. Achieving higher capture rates involves either capturing CO2 from the dilute flue gas or designing theplant to produce excess syngas and combusting it (after CO2 has been removed). Notably, the former approach
may allow new build plants to achieve relatively high levels of CO2 reduction (potentially over 80%) while deferring

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CHAPTER 3l22

Figure 3-4. Steam Methane Reformation (SMR) Schematic (Royal Society 2020,8 pg. 13) shows that carbon dioxide (CO2)
removal is already embedded in the production of hydrogen from natural gas using SMR.

the additional expense of adding carbon capture equipment for even higher capture fractions—in response tochanging standards of required capture fraction— to a later date. (See Chapter 8 – Policy.)
Another approach for future blue ammonia production is a design that largely or entirely eliminates the primaryreformer (SMR) and instead relies on an oxygen-blown ATR in a (mostly) stand-alone configuration.18-20 The useof separate oxygen and corresponding nitrogen injections allows tuning of the hydrogen:nitrogen ratio andminimizes the need to combust feed gas to provide external heat, hence increasing the fraction of overall CO2that is separated from the process gas and allowing high capture rates (above 90%) without capture from dilute
flue gas. However, the electric load from the air separation unit (ASU) required to produce oxygen and nitrogencan be considerable and may lead to additional emissions (Scope 2) depending on the electric generation supply.
Estimated costs for capture of the pure CO2 stream are in the range of $40–80/tCO2, including similar transportand storage costs to the SMR case.2,10 While this approach is currently in use for methanol synthesis, it has not yet
been applied to ammonia production.
The relative advantages of these multiple approaches for blue ammonia optimization (including others notdescribed here and future innovations) remain to be seen, and a variety of market and other factors will
determine their rates of adoption.
It is important to note that transporting CO2 over long distances can also increase the total cost of CCS. For
example, Lee et al., 202221 found that increasing the CO2 transport distance from 100 miles to 1000 miles
increases costs by $60/tCO2.21 CCS projects are therefore enabled through appropriately sized geological storage
locations within a reasonable distance from the ammonia plant. Existing oil and gas fields are especially attractive
options, given the depth of the data already available on them.22 Governments can support the developmentof CCS by identifying suitable storage locations, which early analysis suggests can be identified in nearly every
industrialized region of the world.23 Given the sizeable impact of transport on the cost of CCS, the growth of CCS
will likely depend on clustering CCS hubs in industrial regions.22
While blue ammonia is often discussed in terms of carbon capture technology, electrifying conventional SMR
would also lower emissions. Using combustion of natural gas to heat the reforming reaction produces the fluegas stream, whose dilute carbon emissions are difficult and expensive to capture. One approach currently underdevelopment to eliminate these emissions involves electrically heating the reaction through an integrated catalytic
coating, which enables temperatures above those of conventional SMR reactors, thus producing higher methane
conversion rates and pushing start-up times down to minutes.24 With 17–41% of emissions in conventional SMR
produced from hydrocarbon combustion, electrification with renewables could produce substantial climate
benefits.24 In regions with abundant renewables, preliminary estimates suggest costs would be similar to
traditional SMR production.24

November 2022

CHAPTER 3l23

Figure 3-5. Green Ammonia
production depends upon thecontinued build-out of renewableenergy production capacity.
(credit: Ann-Kathrin Merz)

Green Ammonia
The green ammonia produced today only meets a fraction of a percent of the world’s ammonia demand, but toreach a net-zero world this share is expected to grow.2 Green ammonia differs from blue ammonia primarily in thehydrogen production method. Specifically, with green ammonia, hydrogen is produced via electrolysis, in which an
electric current flows through water to separate the hydrogen and oxygen atoms composing water molecules.25
Pure hydrogen is then combined with nitrogen separated from the air to run the Haber-Bosch process, creating
ammonia. Producing hydrogen via electrolysis as opposed to SMR results in minor differences in the Haber-Boschprocess. For instance, in an electrolysis-based Haber-Bosch plant, the ammonia synthesis loop has lower energy
losses because hydrogen can be produced at high pressure, there is no need to purge inert gases after synthesis,
and compressors powered by electric motors can achieve greater efficiencies.26

Figure 3-6. Green ammonia can be produced using water, air and clean electricity. The carbon footprint will depend
primarily on the carbon footprint of the electricity used. The Royal Society,8 pg. 15.
November 2022

CHAPTER 3l24

Source: Fasihi et al., 2021,31 pg. 6

Figure 3-7. The levelized cost of ammonia (LCOA) for ammonia production using alkaline electrolyzers powered by hybrid
PV-wind power plants and some balancing technologies is modeled. The Onsite Scenario (left graphs) represents thepotential for local consumption, while the Coastal Scenario (right graphs) represents the potential for export.

Because green ammonia production is powered by electricity, its carbon footprint depends on the emissions
intensity of the electricity source used. For example, hydrogen from electrolysis powered by approximately
one-third zero-carbon power and two-thirds power from natural-gas combined-cycle generation will have a higher
carbon intensity than conventional hydrogen from natural gas via SMR.27 The capacity of a green ammonia plant toproduce carbon-free ammonia will therefore be determined by a location’s energy profile, including how long andat what times low-carbon electricity sources are available. With capacity factors of 25% for solar, 35% for wind, 50%
for hydropower (albeit ranging widely between 25% and 80%), 70% for geothermal and 90% for nuclear, the hourly
availability of clean electricity will vary dramatically with resource availability in each geography.28,29 Early adoptionof green ammonia will therefore likely begin in geographies with exceptionally generous renewable energy profiles,
such as a cost-effective location in Tasmania’s grid in Australia, which runs 80% on hydropower.30 Locations withmultiple complementary clean energy sources will also be attractive.
The primary obstacle for the deployment of green ammonia is its high cost. When assuming an electricity price of
7 cents per kWh, the baseline levelized cost for green ammonia is roughly $1000/t using renewable energy and$900/t using nuclear energy.21 The primary cost driver of green ammonia is the cost of green hydrogen, which isdependent on the price of electricity. In places where optimal renewable conditions produce low electricity prices,
green ammonia may already be cost competitive, such as at prices of 4.5, 3.2 and 2.3 cents/kWh for utility solar in
Morocco, Chile and Saudi Arabia.8 Furthermore, massive investments by government and industry are expected todrive down capital costs. In fact, the cumulative capacity for projects under development is already projected toreduce capital expenses by almost 60% by 2030.15
Government investment to cut the cost of green hydrogen will further improve green ammonia economics.
Figure 3-8 shows the cost of avoided CO2, calculated as the increase in the levelized cost of ammonia production(compared to conventional production) divided by the decrease in greenhouse gas emissions (also compared toconventional production).21 At green hydrogen costs of $4/kg, the cost per ton of avoided CO2 for green ammonia
production is above $250/tCO2.21 Yet if the cost of clean hydrogen were to fall to $1/kg in line with the target set

November 2022

CHAPTER 3l25

Figure 3-8. The US Department of Energy’s target to bring costs of hydrogen down to $1/kg dramatically cuts the cost of
avoided CO2 (Lee et al., 202221, pg. 12)by the US Department of Energy in June 2021, this would bring the cost of avoided CO2 down to $16/tCO2.21,32
This low cost of avoided CO2 would be well below the average global CO2 price of around $30/tCO2 at the start of2022.33
Given the novelty of electrolyzer technology and the changing dynamics of the energy system, there is no current
consensus on the most effective electrolyzer type and configuration for ammonia production in the long-term.
In the short-term, limited electrolyzer manufacturing capacity is one of the likely obstacles for the rapid growthof green hydrogen or ammonia production. Unfortunately, industry analysis estimates that the worldwide
electrolyzer supply by 2030 will likely fall in the 30–40 GW range, compared to 54 GW of announced projects
and 94 GW of “pledged” projects.34 This suggests that existing electrolyzer capacity, as well as the capacity to
manufacture additional electrolyzers, will be essential.
A potential bottleneck in electrolyzer supply gives the incumbent—the alkaline electrolyzer—increased
importance. Alkaline electrolyzers made up 61% of installed capacity in 2020 and currently have the lowest capital
cost among all electrolyzer technologies.15,35,36 Given the technology’s long commercial history—400 alkaline
electrolyzers were already running by 1902, many for ammonia production37—some industry voices have doubted
the possibility of further cost reductions or substantial innovations, such as increasing their ability to rapidly ramp
capacity in response to fluctuating renewable electricity. However, recent efforts have shown progress in achieving
ramping times on the order of seconds, and other innovations, such as zero-gap technology to reduce specificenergy consumption and cost-efficient coatings to drive down costs while enhancing cell efficiencies, are being
pursued.38,39
Proton exchange membrane (PEM) electrolyzers represent 31% of current installed capacity, and have theadvantage of delivering hydrogen at high pressure, reducing compression costs.12,15,26 Furthermore, their wide
operating range (0–160% of design capacity) and extremely fast ramping rate give them a flexibility well-suited for
integration with renewables.36,40 First commercially introduced in the late 1980s, PEM electrolyzer technology is
still improving.41 Efficiencies for PEM electrolyzers are reported between 60% and 75% lower heating value, withsome commercially available PEM electrolyzers self-reporting efficiencies as high as 84%.42,43 Industry experts
likewise expect substantial future cost reductions.44
Finally, solid oxide electrolyzers (SOEC) may be well-suited for green ammonia production due to their hightemperature, high-efficiency operation. First, the typical SOEC operates at 600–850 °C.45 Because the typical
Haber-Bosch process runs at lower temperatures of 425–450 °C, this enables additional efficiencies from heat
integration. Furthermore, SOECs outperform alkaline and PEM electrolyzers on efficiency. The IEA estimates
November 2022

CHAPTER 3l

26

Table 3-2. Techno-economic characteristics of different electrolyzer technologies.

Source: IEA 2019,“The Future of
Hydrogen”36

Alkaline electrolyzer

PEM electrolyzer

SOEC electrolyzer

67-74

Today
74-81

2030
77-84

Long
term
77-90

650 –
1500

200 –
900

2800 –
5600

800 –
2800

500 –
100

60000 –
90000

100000 –15000010000 –
30000

40000 –
60000

75000 –
100000

Today

2030

Long
term

Today

2030

Long
term

Electrical efficiency(%, LHV)

63-70

65-71

70-80

56-60

63-68

CAPEEX (USD/kWe)

500
–1400

400 –
850

200 –
700

1100 –
1800

Stack lifetime(operating hours)

60000 –
90000

90000 –
10000

10000 –
15000030000 –
90000

Load range(%,relative tonominal load)

10-1100-160

20-100Operatingtemperature (0C)

60-80

50-80

6501000

Operating pressure
(bar)

1-30

30-80

1

Notes: LHV = lower heating value; m2/kWe = square metre per kilowatt electrical. No projections made for future operating pressure and temperature orload range characteristics. For SOEC, electrical efficiency does not include the energy for steam generation. CAPEX represents system costs, including powerelectronics, gas conditioning and balance of plant; CAPEX ranges reflect different system sizes and uncertainties in future estimates.
Sources: Buttler and Spliethoff (2018), “Current status of water electrolysis for energy storage, grid balancing and sector coupling via power-to-gas andpower-to-liquids: a review”; Agora Verkehrswende, Agora Energiewende and Frontier Economics (2018), The Future Cost of Electricity-Based Synthetic
Fuels; NOW (2018), Studie IndWEDe Industrialisierung der Wasserelektrolyse in Deutschland: Chancen und Herausforderungen für nachhaltigen Wasserstoff
für Verkehr,Strom und Warme; Schmidt et al. (2017), “Future cost and performance of water electrolysis: An expert elicitation study”; FCH JU (2014),
Development of Water Electrolysis in the European Union, Final Report; Element Energy (2018), “Hydrogen supply chain evidence base”.

efficiencies of 74–81%, while commercially available SOECs self-report efficiencies as high as 84%.36,46 In the longterm, if electricity costs continue to constitute the majority of green ammonia production costs (estimated at 85%
today),8 then efficiency levels will be an important factor in choosing an electrolyzer technology, likely favoring
SOEC. While much remains unknown at the pre-commercial stage, some industry experts expect substantial cost
reductions will make the SOEC technology disruptive to the industry.44
Gray ammonia production was optimized through large-scale production and centralization, and these features
will likely apply to blue ammonia as well. However, the geographical spread and diversity of clean energy sources
for green ammonia production may give rise to small-scale, distributed production. Interest in improving the
economics of small-scale, distributed green ammonia motivates research into redesigning the Haber-Boschprocess for operation at milder conditions. This research explores both catalyst development and alternative
methods to separate out produced ammonia. A typical ammonia synthesis reactor uses a fused-iron catalyst
combined with other promoter materials, which is heated to 400 °C at around 150 bar.26 This produces a singlepass conversion rate below 20%, requiring produced ammonia to be separated out with condensation, meaning
it is cooled to -25 to -33 °C at 140 bar before being compressed back to reaction conditions to repeat the cycle.26
Studies on catalyst development explore strategies for achieving higher catalytic activity at milder conditions,such as by employing alternative metals, using cocatalysts, increasing tolerance to poisons and improving catalyst
regeneration.4,5,47 Likewise, separating newly generated ammonia with absorption technology enables conversion
rates of around 80% at pressures as low as 25 bar.48 Using absorption as opposed to condensation may also
provide cost savings, as it reduced manufacturing costs 10% in a 55t/day renewable ammonia pilot plant.49

November 2022

CHAPTER 3l27

Bio-Hydrogen
Ammonia can also be produced from bio-hydrogen, which refers to hydrogen produced from biomass. Biomass
feedstocks include agricultural waste, forestry waste, black liquor from paper production, municipal solid waste,
dedicated energy crops, and micro- and macro-algae.50 Many biomass feedstocks have a high hydrogen-tocarbon ratio, meaning they serve as hydrogen-rich fuel sources.51 Hydrogen is produced through the thermal
decomposition of biomass or through biological processing by living organisms like bacteria.50

Figure 3-9. Energy consumption in (a) RXN-CON (150 bar) and (b) RXN-ABS (20 bar). The bigger pie represents energy
consumption of the whole plant consisting of hydrogen/nitrogen production and the ammonia synthesis loop. The smaller
pie illustrates the energy consumption of unit operations in the ammonia synthesis loop. (Lin et al. 2020,49 pg. 15525).

The use of biomass to produce hydrogen can sometimes lead to land-use change (LUC), particularly if economic
incentives for producing particular types of biomass are large. This can significantly increase the carbon footprint
from bio-hydrogen, such as in the case of converting forest to farmland, which releases stored CO2 from the soil
and vegetation. By contrast, growing perennial grass on depleted land increases the soil’s ability to hold CO2,
avoiding major LUC-based emissions.52 In general, creating carbon sinks on degraded or abandoned land throughcrops such as switchgrass is preferable and also avoids a competition with land for food or fiber production.50
The use of agricultural, forestry or municipal residues and wastes as feedstocks also has a low emissions footprint
and eliminates harmful methane emissions released by waste during decomposition, as well as the air pollution
released from burning.50 For instance, roughly 80% of forest residue is burned to prevent forest fires, resulting
in additional emissions.53 Therefore, harvesting wastes and residuals for bio-hydrogen production is typicallyconsidered carbon neutral feedstock. Furthermore, ammonia from waste biomass can achieve a negativeemissions balance under some circumstances, meaning more greenhouse gases are absorbed throughout the
production process than are released to the atmosphere. When biomass feedstocks are (close to) carbon neutral
and CCS is used to capture and store this biogenic CO2 during production,54 bio-hydrogen is CO2 net-negative. In
a life-cycle analysis of ammonia produced using wood as the biomass feedstock, which is carbon positive due toNovember 2022

CHAPTER 3l28

Figure 3-10. The benefits of hydrogen from biomass depend on implementation. Using waste feedstocks is one avenue tomaximize benefits.

LUC and emission during production, employing CCS resulted in negative emissions of -1.7 kgCO2/kgNH3, meaning
the production of ammonia from wood biomass with CCS sequestered more emissions than it released on alife-cycle basis. Although the production pathways and feedstocks for bio-hydrogen vary dramatically, net negativeemissions can be achieved in almost all scenarios when CCS is deployed. Conversely, directly using biomass as fueldoes result in re-release of carbon stored within the biomass, but in some cases—notably manufacturing ethanol
and ammonia—carbon is released as a high purity CO2 stream thatis relatively easy to capture and store.50
Biomass has additional features that make it particularly amenable
to being used with carbon capture to achieve a negative carbon
footprint. Biomass resources are often co-located with places ideal
for geological storage of carbon emissions, reducing transportation
costs for biomass and/or CO2.50 With biomass’ low bulk density,transport over large distances could consume more fuel thanis stored in the biomass; a 100-km limit is recommended fortransport distance.55
Depending on the balance between feedstock and electricity
prices, ammonia from bio-hydrogen may have a cost advantage
over other low-carbon ammonia production methods. In a casestudy of low-carbon ammonia production routes in the UnitedStates, using hardwood as a fuel was 8% more profitable thannatural gas in Texas and 32% more profitable than natural gas
in California.56 Wind and solar were not competitive with either,
given that the low efficiency of water electrolysis resulted in highelectricity consumption and costs.56 The case study speaks to theimportance of local prices, conditions and feedstock availability indetermining bio-hydrogen’s cost effectiveness.

November 2022

Figure 3-11. Environmental performance:
IPCC07 method GWP 100 years. (Source: Tock etal, 2015,54 pg. 360).
CHAPTER 3l

29

Just as biomass has the potential to do tremendous good through effective implementation, it can also cause
tremendous harm when done poorly. Biomass cultivation for carbon removal could damage diverse ecosystems(such as through destructive monocultures), have an adverse impact on food security by competing with arable
farmland, result in net increases in CO2 from a poor understanding of emissions in the biomass life-cycle, and risk
eco-colonialism should wealthy countries negatively exploit resources in developing countries to mitigate climatechange.50 Responsible sourcing and implementation are central to ensuring biomass is employed to produce
ammonia using methods that maximize societal benefit.

REFERENCES
1

Lori E. Apodaca. Nitrogen (Fixed)—Ammonia. U.S. Geological Survey, Mineral Commodity Summaries. https://pubs.
usgs.gov/periodicals/mcs2022/mcs2022-nitrogen.pdf (2022).

2

International Energy Agency. Ammonia Technology Roadmap. (IEA, Paris, 2021 https://www.iea.org/reports/
ammonia-technology-roadmap).

3

Caneon Kurien & Mayank Mittal. Review on the production and utilization of green ammonia as an alternate fuel indual-fuel compression ignition engines. Energy Conversion and Management 251, 114990, https://doi.org/10.1016/j.
enconman.2021.114990 (2022).

4

John Humphreys, Rong Lan & Shanwen Tao. Development and Recent Progress on Ammonia Synthesis Catalysts
for Haber–Bosch Process. Advanced Energy and Sustainability Research 2, 2000043, https://doi.org/10.1002/
aesr.202000043 (2021).

5

Manoj Ravi & Joshua W. Makepeace. Facilitating green ammonia manufacture under milder conditions: what doheterogeneous catalyst formulations have to offer? Chemical Science 13, 890-908, http://dx.doi.org/10.1039/
D1SC04734E (2022).

6

K. H. R. Rouwenhorst et al. “Chapter 4 - Ammonia Production Technologies” in Techno-Economic Challenges of Green
Ammonia as an Energy Vector (eds Agustin Valera-Medina & Rene Banares-Alcantara) p. 41-83 (Academic Press, 2021,

7

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9https://doi.org/10.1016/B978-0-12-820560-0.00004-7 https://doi.org/10.1016/B978-0-12-820560-0.000047).
BASF. Ammonia plant at Ludwigshafen site. https://www.basf.com/global/en/media/events/2019/half-yearfinancial-report/photos-pk.fragment.html/overview_copy_copy$/global/press-photos/en/photos/2019/07/
hy-pc/5114_Ammonia_plant_at_Ludwigshafen_site.jpg.html (Accessed September 2022).
The Royal Society. Ammonia: zero-carbon fertiliser, fuel and energy store (Policy Briefing). https://royalsociety.org/-/
media/policy/projects/green-ammonia/green-ammonia-policy-briefing.pdf (2020).

Carlos A. Fernandez & Marta C. Hatzell. Editors’ Choice—Economic Considerations for Low-Temperature Electrochemical
Ammonia Production: Achieving Haber-Bosch Parity. Journal of The Electrochemical Society 167, 143504, https://iopscience.iop.org/article/10.1149/1945-7111/abc35b (2020).

10 IRENA/AEA. Innovation Outlook: Renewable Ammonia. International Renewable Energy Agency (Abu Dhabi) andAmmonia Energy Association (Brooklyn). https://irena.org/-/media/Files/IRENA/Agency/Publication/2022/May/
IRENA_Innovation_Outlook_Ammonia_2022.pdf (2022).
11 RMI. Green Hydrogen and Ammonia Imports Are Cost-Competitive Solution to Europe’s Dependence on Fossil Fuels in
Heavy Industry. https://rmi.org/press-release/hydrogen-and-ammonia-imports-are-cost-competitive-solution/(2022).
12 Miao Wang et al. Can sustainable ammonia synthesis pathways compete with fossil-fuel based Haber–Bosch processes?
Energy & Environmental Science 14, 2535-2548, http://dx.doi.org/10.1039/D0EE03808C (2021).
13 Hafiz Hamza Faheem et al. Comparative study of conventional steam-methane-reforming (SMR) and auto-thermalreforming (ATR) with their hybrid sorption enhanced (SE-SMR & SE-ATR) and environmentally benign process models forthe hydrogen production. Fuel 297, 120769, https://doi.org/10.1016/j.fuel.2021.120769 (2021).
14 W. Morgan Summers, Steve E. Herron & Alexander Zoelle. Cost of Capturing CO2 from Industrial Sources. Energy Sector
Planning and Analysis (ESPA) for the United States Department of Energy (DOE), National Energy Technology Laboratory(NETL). https://www.netl.doe.gov/projects/files/CostofCapturingCO2fromIndustrialSources_011014.pdf(2014).
15 International Energy Agency. Global Hydrogen Review 2021. https://www.iea.org/reports/global-hydrogenreview-2021 (2021).
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16 KBR. KBR’s First PurifierPlus™ Ammonia Process Based Plant Commissioned at PAU in Indonesia (Press Release). https://www.kbr.com/en/insights-news/press-release/kbrs-first-purifierplustm-ammonia-process-based-plantcommissioned-pau (2018).
17 KBR. KBR Purifier™/PurifierPlus™ Process: A Superior Technology for Blue Ammonia production https://www.kbr.com/
en/insights-news/thought-leadership/kbr-purifiertmpurifierplustm-process-superior-technology-blue (2022).
18 Klaus Noelker & Joachim Johanning (Uhde). Autothermal reforming: a flexible syngas route with future potential.
NITROGEN & SYNGAS 2010 International Conference. (Bahrain, 2010, https://ucpcdn.thyssenkrupp.com/_legacy/

UCPthyssenkruppBAIS/assets.files/download_1/ammonia_2/autothermal_reforming_syngas_2010_paper.
pdf ).
19 TOPSOE. SynCOR™ - Autothermal Reformer (ATR). https://www.topsoe.com/our-resources/knowledge/ourproducts/equipment/syncortm-autothermal-reformer-atr (Accessed September 2022).

20 NETL et al. Comparison of Commercial, State-of-the-Art, Fossil-Based Hydrogen Production Technologies. US DOE Officeof Fossil Energy (FE) NETL (DOE/NETL-2022/3241). https://doi.org/10.2172/1862910 (2022).
21 Kyuha Lee et al. Techno-economic performances and life cycle greenhouse gas emissions of various ammonia
production pathways including conventional, carbon-capturing, nuclear-powered, and renewable production. Green
Chemistry 24, 4830-4844, http://dx.doi.org/10.1039/D2GC00843B (2022).
22 Patricia Loria & Matthew B. H. Bright. Lessons captured from 50 years of CCS projects. The Electricity Journal 34,
106998, https://doi.org/10.1016/j.tej.2021.106998 (2021).
23 Oey Minervini, Chris Consoli & David Kearns. CCS Networks in the Circular Carbon Economy: Linking Emissions Sources toGeologic Storage Sinks. Global CCS Institute. https://www.globalccsinstitute.com/wp-content/uploads/2021/10/
CCE-CCS-Networks-Report-2.pdf (2021).
24 Sebastian T. Wismann et al. Electrified methane reforming: A compact approach to greener industrial hydrogenproduction. Science 364, 756-759, https://www.science.org/doi/abs/10.1126/science.aaw8775 (2019).
25 Giovanni Cinti et al. Coupling Solid Oxide Electrolyser (SOE) and ammonia production plant. Applied Energy 192, 466476, https://doi.org/10.1016/j.apenergy.2016.09.026 (2017).
26 Collin Smith, Alfred K. Hill & Laura Torrente-Murciano. Current and future role of Haber–Bosch ammonia in a carbonfree energy landscape. Energy & Environmental Science 13, 331-344, http://dx.doi.org/10.1039/C9EE02873K (2020).
27 Alex Zapantis. Blue Hydrogen. Global CCS Institute. https://www.globalccsinstitute.com/resources/publicationsreports-research/blue-hydrogen/ (2021).
28 US Department of Energy. What is Generation Capacity? DOE Office of Nuclear Energy. https://www.energy.gov/ne/
articles/what-generation-capacity (2020).
29 IRENA. 7: Hydropower (in Renewable Power Generation Costs in 2014). International Renewable
Energy Agency. https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/

IRENA_RE_Power_Costs/IRENA_RE_Power_Costs_2014_report_chapter7.
pdf?la=en&hash=C3567A03B3C4A37BD8AB71E81C8B40A527C318B0#:~:text=CAPACITY%20FACTORS%20
FOR%20HYDROPOWER,range%20is%20to%20be%20expected. (2014).

30 Nicholas Salmon & René Bañares-Alcántara. Impact of grid connectivity on cost and location of green ammonia
production: Australia as a case study. Energy & Environmental Science 14, 6655-6671, http://dx.doi.org/10.1039/
D1EE02582A (2021).
31 Mahdi Fasihi et al. Global potential of green ammonia based on hybrid PV-wind power plants. Applied Energy 294,
116170, https://doi.org/10.1016/j.apenergy.2020.116170 (2021).
32 US Department of Energy. Energy Earthshots Initiative. DOE Office of Policy. https://www.energy.gov/policy/energyearthshots-initiative (Accessed September 2022).
33 The World Bank. Carbon Pricing Dashboard. https://carbonpricingdashboard.worldbank.org/map_data (Accessed
September 2022).
34 Leigh Collins. Jeffries: ‘There won’t be enough electrolysers to meet green hydrogen demand in 2030’: US investmentbank. Recharge. https://www.rechargenews.com/energy-transition/there-wont-be-enough-electrolysers-tomeet-green-hydrogen-demand-in-2030-us-investment-bank/2-1-1096617 (2021).
35 George Bristowe & Andrew Smallbone. The Key Techno-Economic and Manufacturing Drivers for Reducing the Cost ofPower-to-Gas and a Hydrogen-Enabled Energy System. Hydrogen 2, 273-300 (2021, https://www.mdpi.com/26734141/2/3/15 ).
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36 International Energy Agency. The Future of Hydrogen. https://www.iea.org/reports/the-future-of-hydrogen (2019).
37 Marcelo Carmo. Introduction to Liquid Alkaline Electrolysis. NEL Hydrogen. https://www.energy.gov/sites/default/
files/2022-02/2-Intro-Liquid%20Alkaline%20Workshop.pdf (2022).
38 Christopher Varela, Mahmoud Mostafa & Edwin Zondervan. Modeling alkaline water electrolysis for power-to-x
applications: A scheduling approach. International Journal of Hydrogen Energy 46, 9303-9313, https://doi.
org/10.1016/j.ijhydene.2020.12.111 (2021).
39 Ed Revers. Cell-Level Challenges in Alkaline Water Electrolysers (Advanced Liquid Alkaline Water Electrolysis Workshop).
De Nora. https://www.energy.gov/sites/default/files/2022-02/3-Interfaces-Liquid%20Alkaline%20Workshop.
pdf (2022).
40 K. Nikiforow et al. Power ramp rate capabilities of a 5 kW proton exchange membrane fuel cell system with discrete
ejector control. Journal of Power Sources 381, 30-37, https://doi.org/10.1016/j.jpowsour.2018.01.090 (2018).
41 M. Paidar, V. Fateev & K. Bouzek. Membrane electrolysis—History, current status and perspective. Electrochimica Acta
209, 737-756, https://doi.org/10.1016/j.electacta.2016.05.209 (2016).
42 Zoe Clarke et al. Carbonomics: The Clean Hydrogen Revolution. Goldman Sachs Research. https://www.
goldmansachs.com/insights/pages/carbonomics-the-clean-hydrogen-revolution.html (2022).
43 PlugPower. The 5MW Electrolyzer: Best-in-class life expectancy of 80,000 hours. (Accessed September 2022).
44 Tom Smolinka et al. Studie IndWEDe - Industrialisierung der Wasserelektrolyse in Deutschland: Chancen undHerausforderungen für nachhaltigen Wasserstoff für Verkehr, Strom und Wärme. Fraunhofer IPA. https://www.ipa.
fraunhofer.de/de/Publikationen/studien/studie-indWEDe.html (2018).
45 A. Hauch et al. Recent advances in solid oxide cell technology for electrolysis. Science 370, eaba6118, https://www.
science.org/doi/abs/10.1126/science.aba6118 (2020).
46 Sunfire. Hydrogen: The renewable feedstock and energy carrier. https://www.sunfire.de/en/hydrogen (Accessed
September 2022).
47 Tian-Nan Ye et al. Efficient Ammonia Synthesis over Phase-Separated Nickel-Based Intermetallic Catalysts. The Journal of
Physical Chemistry C 124, 28589-28595, 10.1021/acs.jpcc.0c09590 (2020).
48 Edward Cussler et al. Ammonia Synthesis at Low Pressure. JoVE, e55691, doi:10.3791/55691 (2017, https://www.jove.
com/t/55691 ).
49 Bosong Lin, Theodore Wiesner & Mahdi Malmali. Performance of a Small-Scale Haber Process: A TechnoEconomic Analysis. ACS Sustainable Chemistry & Engineering 8, 15517-15531, https://doi.org/10.1021/
acssuschemeng.0c04313 (2020).
50 David Sandalow et al. Biomass Carbon Removal and Storage (BiRCS) Roadmap. U.S. Department of Energy: Office of
Scientific and Technical Information. https://www.osti.gov/biblio/1763937 (2021).
51 Paul Gilbert et al. Assessing economically viable carbon reductions for the production of ammonia from biomass
gasification. Journal of Cleaner Production 64, 581-589, https://doi.org/10.1016/j.jclepro.2013.09.011 (2014).
52 Martin Drews, Morten Andreas Dahl Larsen & Jenny Gabriela Peña Balderrama. Projected water usage and landuse-change emissions from biomass production (2015–2050). Energy Strategy Reviews 29, 100487, https://doi.
org/10.1016/j.esr.2020.100487 (2020).
53 Susanjib Sarkar, Amit Kumar & Arifa Sultana. Biofuels and biochemicals production from forest biomass in Western
Canada. Energy 36, 6251-6262, https://doi.org/10.1016/j.energy.2011.07.024 (2011).
54 Laurence Tock, François Maréchal & Matthieu Perrenoud. Thermo-environomic evaluation of the ammonia production.
The Canadian Journal of Chemical Engineering 93, 356-362, https://doi.org/10.1002/cjce.22126 (2015).
55 Pratham Arora et al. Remote, small-scale, ‘greener’ routes of ammonia production. Journal of Cleaner Production 199,
177-192, https://doi.org/10.1016/j.jclepro.2018.06.130 (2018).
56 C. Doga Demirhan et al. Sustainable ammonia production through process synthesis and global optimization. AIChE
Journal 65, e16498, https://doi.org/10.1002/aic.16498 (2019).
57 Zhiyuan Fan et al. Green Hydrogen in a Circular Carbon Economy: Opportunities and Limits. Columbia University Schoolof International and Public Affairs (SIPA) Center on Global Energy Policy. https://www.energypolicy.columbia.edu/
research/report/green-hydrogen-circular-carbon-economy-opportunities-and-limits?https://cvn.columbia.

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Chapter 4

AMMONIA INFRASTRUCTURE
Using ammonia as a fuel, feedstock or commodity requires special purpose infrastructure dedicated to trade,transportation and fueling. This infrastructure is independent of infrastructure for ammonia production (such astransmission power lines for green hydrogen production) or use (such as local fueling infrastructure). The special
purpose infrastructure includes pipelines for transportation, tanks for storage and facilities for maritime bunkering.
The type of infrastructure needed is in general a function of the distance ammonia is being transported, with rail
and maritime shipping commonly used for transporting ammonia long distances (Figure 4-1).1

Figure 4-1. Average distance per shipment by pipelines, motor vehicles, rail and marine vessels in 2017. Source: Elishav etal., 2021.1

At present, the limited extent of this infrastructure constrains the production, trade, shipment, monetization
and use of ammonia. Inevitable chokepoints will slow ammonia deployment without substantial investment inpermitting, siting and building. The high capital costs and immature markets of today would benefit from new
approaches to building and financing dedicated ammonia infrastructure.

Existing Infrastructure and Associated Standards
Ammonia infrastructure, although limited compared to projected demand, exists today with specifications
described in standards and executed by regulatory bodies. For example, nearly 8000 kilometers of ammonia
pipeline run worldwide today, along with 38 export and 88 receiving terminals (Figure 4-2).2,3 The US alone has
5000 kilometers of ammonia pipeline and more than 10,000 ammonia storage tanks (Figure 4-3).3, These facilities
provide an excellent basis for understanding likely costs, performance and scale of ammonia as a future fueland feedstock. As such, the need for innovation is limited, and the roadmap for deployment is essentially about
finance, economics and policy.
These assets and infrastructure elements are built and operated according to standards and regulations in hostnations. They generally reflect the core physics and chemistry of ammonia and are well-aligned world-wide. For
example, the US Occupational Safety and Hazard Authority (OSHA) publishes their anhydrous ammonia storagetank standard 1910.111,5 which is similar to the Minnesota pipeline requirements6 (and built upon the American
Society of Mechanical Engineers (ASME) standard B31.47). The standards include requirements for operatingpressure, metallurgy, corrosion resistance and labeling.

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Figure 4-2. Map of global ammonia facilities, including a heat map of liquid ammonia carriers and existing ammonia port
facilities. Source: Royal Society, 2020.3

Figure 4-3. Map of central US storage facilities and pipelines. Orange line is the Kaneb Pipeline; red is the Magellan
pipeline. Circles are storage facilities, with largest circle representing 100,000-ton storage capacity. Source: Royal Society,2020.3 Data, EPA, 2017.4
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Ports and Bunkering Facilities
Port facilities will serve essential functions for low-carbon ammonia scale up. Chiefly, they will serve as hubs oftrade, where large volumes of ammonia are stored and shipped as cargo. They will necessarily serve as bunkering(fueling) facilities for maritime fuel use. In addition, they will host some production facilities and ammonia
conversion and use facilities. To accommodate these roles, existing facilities will be upgraded, existing ports will be
expanded, and new ports and facilities will be added to the global portfolio.

PORTS
The majority of ammonia ports today (120 ports out of 195 total) are receiving terminals linked to fertilizer
production. A smaller number (35) are cargo export terminals.8 Projected increases from announced projects
would grow 50% by 2030 and 100% by 2040.8 Many of these will serve southeast Asia, for maritime fueling andlogistics support as well as local consumption and use.
Table 4-1. Liquid hydrogen terminals and ammonia terminals – a comparison.

Export terminal parameters

Unit

LH2 carrier

HN3

Tank capacity

m3

192,000

104,000

CAPEX

M$

1161

209

Electricity consumption

kWh/kg0.2

0.001

Duration one loading

days

1.5

1.5

Time between loadings

days

15

15

Import terminal parameters

Unit

LH2 carrier

HN3

Tank capacity

m3

192,000

104,000

CAPEX

M$

1161

209

kWh/kg0.2

0.001

Boil-off rate

%

0.1

0.1

Duration one loading

days

1.5

1.5

Time between loadings

days

15

15

Electricity consumption

Cost assumption based on data from the Institute of Applied Energy (Japan) report: “Economical Evaluation and Characteristic Analyses for Energy Carrier
Systems (FY 2014–FY 2015) Final Report”. Link: www.nedo.go.jp/library/selka/shosai_201610/20160000000760.html
˄˄(IEA, 2021,9 pg. 109)

Port of Rotterdam Facility
The Port of Rotterdam is Europe’s largest port and industrial hub, including serving current fuel and feedstock
imports (i.e., liquefied petroleum gas (LPG) and liquefied natural gas (LNG)) that supply refineries, chemical
manufacturers, and steel and cement production. To meet EU climate obligations (specifically the “FitFor55”
plan”), national obligations (e.g., the Netherlands Paris commitments), and the proposed carbon borderadjustment mechanism, as well as reducing reliance on important natural gas, the Port has set a target of
supplying northern Europe with 4.6 Mt/y of clean hydrogen by 2030,10 largely supplied by green and blue
ammonia.
Three projects have been announced to date—all in 2022:• OCI will expand its current ammonia facility from 400,000 t/y to 1.2 Mt/y—a 3x expansion. This project has
already received final investment decision and should be operational by 2023. This first phase of the projectwill cost less than $20 million.11 In the second phase, a new ammonia tank will be built to allow throughput toincrease beyond 3 million t/y.11
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Figure 4-4. Gasunie’s planned hydrogen distribution infrastructure for northern Europe.
• Gasunie, HES International and Vopak will develop a new import terminal (the ACE terminal) for ammonia

adjacent to Gasunie’s existing ammonia storage complex. The project will expand existing tank storage, add
a new deep-sea quay and include a cracking facility that ties to existing hydrogen pipelines and repurposed
natural-gas pipelines. The project should be operational in 2026. While data on the cost of the ACE terminal are
not publicly available, it will likely fall in the range of the GATE LNG terminal nearby, with costs of $1.1 billion in
2011.12
Air Products and Gunvor Petroleum are modifying an existing refinery to serve as a green-ammonia receiving
terminal. The new facility should be operational in 2026.
Ports for loading and unloading ammonia cargo require docks, quays, berths and storage tanks. The tanks arepressurized isothermal tanks connected to special pipe and valve systems that discharge and receive ammonia
cargo and are placed on special pressurized, refrigerated ships (similar to LPG tankers). For a substantial facility,
costs can exceed $1 billion for this infrastructure, as shown by a detailed US Army Corps of Engineers analysis of anew port in Galveston, TX.13,14

BUNKERING
For maritime fuel application, bunkering is a key prerequisite for deployment and requires separate considerationfrom fuel supply or cargo storage infrastructure. In many ports, physical space for these new elements (fuelingstorage and bunkering facilities) is a limiting constraint. In others, fuel supply is the limiting constraint. For
example, the storage tanks at bunkering facilities are commonly 25–50% greater capacity than the ships they
serve.1
Investment is urgently needed to assess the challenges of bunkering and develop potential solutions. Many groups
have begun work to develop alternatives and solutions:• Analysis: Japan, Singapore, France and other nations have created a joint study framework15 that will include

assessments of challenges and solutions for both bunkering and maritime architecture for ammonia fueling.

• Investment: Several governments, including Japan,16 have dedicated funds to building ammonia bunkering

infrastructure, in partnership with domestic17 and international companies. Similarly, the Singapore-based Global

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Centre for Maritime Decarbonisation has approved funding for pilots18 of both truck-to-ship and ship-to-ship
bunkering with an eye toward knowledge-building for regulation and safety practice.
• Floating bunkering: To avoid space constraints, bunkering facilities can be added offshore. One company,

Azane Fuels, has developed floating, movable bunker19 equipment, specifically to help facilitate the transition
to ammonia as a maritime fuel. Yara, a Norwegian fertilizer producer, has pre-ordered20 the first 15 21 of thesefacilities for Scandinavian green ammonia supplies. Singapore has commissioned a ship-to-ship bunkering
assessment22 with the goal of creating the first green ammonia bunkering hub.

As part of a transition roadmap to low-carbon ammonia use, analysis on the costs and trade-offs of bunkering
infrastructure would greatly reduce risk and cost while speeding deployment. Importantly, companies and nations
should share information from such analysis to avoid waste or delay in deployment. Such information sharing
could begin easily under existing bilateral agreements and be further facilitated by the International Maritime
Organization (IMO) or groups like the Ammonia Energy Association or the Clean Fuel Ammonia Association.

Ammonia Storage
Ammonia must be stored before transport and shipping. Although there is a rich set of ideas and potential novel
approaches to ammonia storage (a search revealed over 270 US patents for ammonia storage technology), almost
all ammonia is stored in tanks. There are three main types of storage system: pressurized, low-temperature andsemi-refrigerated.1 The majority of tanks are the low-temperature variety (Figure 4-5), of which there are five main
designs (Figure 4-61,23) that can hold large volumes of ammonia (up to 50,000 tons). Tanks are built and operated
to commercial standards (e.g., the API 620 R or EN 14620 standards), and tank construction and operation are
straightforward, with many companies providing these services.
Costs are relatively well known and can represent a substantial cost to project developers. For a proposed Mt/yfacility in Galveston, TX, the two storage tanks required have a combined estimated cost of $500 million.
Salt caverns could provide a storage option for large ammonia volumes at low cost. Salt domes occur on every
continent, and some are used today to store other fuels and feedstock (e.g., crude oil, natural gas and hydrogen).
Salt caverns are made through dissolution mining and can store large amounts of energy indefinitely at low cost(~$1/kwH up-front cost). Room and pillar mining is also an option in the right geologies. Salt-cavern storage can bedifficult to permit depending on local circumstances.
Despite being an old idea (patents stretch back to 195424 ), there appear to be no subsurface ammonia facilities
operating today (although at least one US facility stored ammonia underground in salt, unexpectedly, in New
Jersey25). It is believed that conventional salt domes can serve as large, localized storage hubs, like those used tostore crude oil and hydrogen today. It is unclear what is needed to convert a salt storage facility to ammonia withrespect to metallurgy, other special materials and permitting.

Ammonia Pipelines
Large volumes of ammonia move across continents by pipeline. Most pipelines are short; for example, although
Europe has 25 pipelines, most are less than 10 km in length and only two are 25 km or greater.1 However, theUS does have several major trunk lines totaling nearly 5000 km, and Russia has built a 2400 km pipeline. The US
pipelines move over 2 million tons of ammonia per year (Mt/y) and were built with an estimated cost of ~$250
million in 2019 dollars.26,27
Pipeline transport of liquid ammonia is a safe, low risk and, once installed, cost-effective mode of transporting
ammonia between locations.28 Overall, ammonia pipelines appear to have an excellent safety record—roughly 2
times better than other pipelines and 7–8 times better than other forms of bulk transportation (NuStar, 202129
based on 2019 Bureau of Labor Statistics studies).

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Figure 4-5. Refrigerated ammonia storage tanks.

Figure 4-6. Low-temperature ammonia storage tank types: (A) steel tank enclosed by a concrete wall, (B) tank with outerand inner steel walls, (C) tank with distant partial height concrete bund, (D) tank with earth dike, and (E) single wall tank.
Source: Elishav et al., 2021.1 Original image courtesy of Fertilizers Europe; 201423.

NEW PIPELINES
New pipeline costs vary as a function of flow-rate, length, diameter, geography and temperature. Long-distancecosts do not require compressors but do require pumps (usually centrifugal pumps). Costs are reasonably wellunderstood—CAPEX costs are roughly $500/km/year and OPEX per booster station is ~$400,000/y.28
Such costs are ultimately low. Salmon et al., 202128 estimates that, for 1000-km pipelines that are 1 Mt/y or larger,
the costs are $2–4/t of ammonia, or less than 1% of the market delivery price. Al-Breiki & Bicer, 202030 foundsimilar estimates at ~$1/GJ.
In general, ammonia moves through pipelines as a liquid, not a gas. As such, the footprint is reasonably small—commonly 6–10-inch (20–26-cm) diameter and as large as 16 inches (~50 cm). Carbon steel is sufficient totransport ammonia, so no special alloys are required, although low water content is also required. Because of therelatively low pressures involved, most refrigeration operating costs are similar to those of LPG pipelines—roughly
50% less than pressurized natural gas distribution lines and 75% less than dedicated new hydrogen pipelines.30
Many different pipeline materials (and storage materials) are compatible with ammonia (Table 4-2.31). In particular,
plastic compounds (nylon, neoprene, PVC) appear effective. The most commonly used material for ammonia tanks
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38

Table 4-2. Material Compatibilities of Ammonia. A = excellent; B = good (minor effect, slight corrosion); C = fair (moderate
effect, not recommended for continuous use); D = severe (not recommended). Source: Crolius et al., 2021,31 data fromCole-Parmer.

is carbon steel, which has proven effective overall. However, steel and some steel alloys, suffer stress corrosion
cracking, which present a valid risk to operations.1,31 Although corrosion can be prevented or limited by simple
low-cost approaches (e.g., adding small amounts of water or hydrazine), care must be taken in building andoperating pipelines, and regular surveys and checks are recommended. In addition, on a performance and exergy
basis, circulating loops can help reduce corrosion from volumetric differences in transfer points.32
An innovation agenda focused on novel, low-cost solutions to ammonia-related stress corrosion cracking (bothprevention and mitigation) would likely serve companies and the communities involved. To quote Elishav et al.,2021,1 “additional research on suitable corrosion-resistant steels is vital to reduce construction metal capital costs
in ammonia combustion services.”

RETROFIT/REPURPOSED PIPELINESIn anticipation of ammonia infrastructure build out, recent research has focused on repurposing existing natural
gas lines for ammonia transport. At ambient conditions (i.e., in gaseous form), the physical properties of ammonia
and methane (such as density, specific heat, compressibility, viscosity) are quite similar. In addition, ammonia lines
have benefited historically from joint construction of LPG and refined product pipelines in terms of materials,
rights of way and construction costs.26
Based on limited study,1 it appears that no special metallurgy or retrofit is required. However, to avoid substantial
pressure changes, it appears that pipelines of diameter >0.75 m show the most promise for repurposing.
Also, since many natural-gas pipeline networks have multiple diameters and compositions along any given
length, detailed survey and testing is required. Finally, the different chemistry of natural gas requires purging,decommissioning and recommissioning prior to use for ammonia transport. Permitting bottlenecks and lackof human capital may limit the speed and scale to which natural gas systems could be converted for ammonia
transport.

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39

Generally speaking, repurposing of existing infrastructure (natural gas, LPG, etc.) for ammonia transport is underinvestigated. This area represents another potential focus for R&D and analysis as part of a low-carbon ammonia
transition roadmap.

Hybrid LNG-Ammonia Infrastructure
It appears straightforward to convert LNG infrastructure—in particular LNG receiving terminals and storage
facilities—to ammonia.33 This has important implications, specifically around avoiding or mitigating fossil fuelinfrastructure lock in.
Two key infrastructure elements for both import and bunkering are the regasification and storage systems (Figure4-7). Some important components of the systems, such as the compressor systems, pumps, and sensors orcontrol systems, would require substantial modification or replacement.33 However, the full capital cost of thesemodifications represents a small fraction (11–20%) of the total capital cost of the original system. For a facility
that cost roughly $1 billion to build, repurposing costs would range from roughly $100–200 million per facility—asubstantial cost but within the realm of both public and private financing.
For storage systems, the materials and metallurgy for LNG and ammonia storage are compatible.33 Stress corrosion
cracking (described above) would remain an issue for those tank systems built of carbon steel and nickel steel.
Owners and operators must adhere to the design codes for storage tanks to avoid additional safety and cost risks.
Since the storage temperatures for ammonia are much higher than for LNG, repurposed tanks would alreadyreach the boil-of-gas thresholds for operation.
Conversion from LNG to ammonia would require decommissioning and recommissioning. Again, this could present
both time and cost for adoption based on the ability of permitting agencies to grant permits—which itself is afunction of local laws and regulations—and human capital.

Figure 4-7. Schematic diagram of an LNG import and storage facility that has been converted to ammonia. The blue
shading indicates equipment and material that require substantial modification or replacement for ammonia import andstorage. Ghasemi, 2020.33
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CHAPTER 4l40

Table 4-3. Estimated capital expense required to convert an existing LNG export terminal into an ammonia terminal.
Ghasemi, 202033
Impacted SysLNG Import
Modification
Total CAPEX
tems
CAPEX (%)
cost impact (%)
impact (%)
Remarks

Storage Tank

40-50

3

1.0-1.5

Full containment, 63% capacity

Boil-off gas (BOG)
system10-15

5-8

5.0-8.0

A new compressor package is required (total
CAPEX impact), based on 2x50% compressors.

LP/HP pump

3-5

1-3

1.0-3.0

New pumps as old pumps are replaced

Piping5-10

40

2.0-4.0

Includes flare support & new flare-stack piping

Instrument &Control System

3-5

70

2.0-3.5

Includes control valves, fire & gas sensors,
inline devices, etc.

Total

11.0-20.0

In considering LNG-ammonia hybrid-design or retrofit, forward analysis would help investors and policy makers
understand the range of potential opportunities, costs and barriers. Such analysis could provide insights toroadmaps and better frame policy options for public financing, incentives and public-private partnerships
associated with both new facilities (fixed or floating) and retrofits for existing facilities. Such policies would affecttimelines for deployment and, potentially, affect national commitments to clean energy transition.

Additional concerns
Overall, design and construction of ammonia infrastructure for transportation, bunkering and storage is wellunderstood and relatively straightforward. However, rapid deployment as part of the energy transition is likely toface challenges from limits that lie outside technical or financial concerns. The most critical limits include limits inhuman capital, rate of permitting and concerns around equity and justice.

HUMAN CAPITAL
Three kinds of human capital are required to deploy ammonia bunkering and storage infrastructure. The firstis experts in ammonia-specific construction, including specialty welders, builders, electricians and maritime(surface and subsea) workers. The second is designers and architects, both maritime and onshore, familiar withthe construction of ammonia pipelines, tanks and port facilities. The third is experts in regulation and approval,
including inspectors, regulators and safety authorities.
All three are in short supply. In general, skilled workers are in short supply and demand competitive wages (e.g.,
Boreham, 202234), which can increase labor and project costs. Similarly, the number of years of experience inammonia handling (e.g., refrigeration) has decreased due to labor shortage; quoting Evapco, 2017,35 which states“the number of available ammonia… jobs dwarfs the number of qualified operator/technicians available. Utilizing…
ammonia systems does not eliminate the need for operator training.” In addition, training and regulatory bodies(e.g., the US OSHA) have rigorous training requirements and educational standards.36 The same is true fordesigners, architects, inspectors and regulators—there is a global shortfall of trained experts with experience.
This problem could be resolved through focused and committed training programs. Programs could be expanded
within existing industrial and commercial companies and supported through a combination of public-private
partnerships. Trade schools and community colleges could play outsized roles (e.g., apprenticeship programs), andminority-serving institutions could receive additional support to expand programs and, with them, opportunities.
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Governments could expand certification training programs and pay for short courses, both online and in the field,
to expand the worker pool. Absent such measures, it is likely that projects and roadmaps will experience delays in
implementation due to worker shortages and face increased risk due to lack of training and expertise in the field.

PERMITTING
Timely approval of permits for ammonia infrastructure faces challenges beyond human capital shortages. Becauseof the popularity of anhydrous ammonia as a fertilizer and the risks associated with transportation and storage,
many nations have specific regulations for ammonia handling and infrastructure.37 Approval for permits to buildand operate ammonia infrastructure can be time consuming, specifically because the health and environmental
risks are substantial.
The tendency of many government officials and regulators in such circumstances will be to take additionaltime or add requirements to projects, especially large projects of regional or national importance. This is not
limited to ammonia. Hydrogen pipelines have already suffered these delays (e.g., in the EU), which will directly
limit ammonia opportunities. The approval process has also languished for natural gas pipelines,38 offshore
wind projects39 and power transmission lines.40-42 Regional regulators with limited or no experience permitting
analogous systems will reasonably wish to take extra care in approval. In addition, permitting guidelines arechanging, often to reflect new desires for both better local environmental outcomes and environmental justice.43
Absent direct focus on accelerating approval processes without compromising safety, it is reasonable to expect thepermitting and approval process to be a chokepoint. Legislators and regulators should work with experts in safety,
environment and health to understand what the most salient concerns and risks are and how to respect thoserisks while approving projects.

ENVIRONMENTAL JUSTICE AND EQUITY CONCERNS
Ammonia storage, bunkering and pipeline facilities raise concerns about equitable application of existing laws.
Some portion of these facilities—potentially a large portion—will seek permits to build and operate in areas with
underserved and disadvantaged populations. Although the substantive health, safety and environmental hazards
can be managed effectively and well, communities near proposed facilities may have reasonable concerns about
potential risks, ranging from property values to disease and childhood mortality.
Recent focus on questions of equity and justice around energy development, notably in the US, have prompted
questions about how best to balance the needs of disadvantaged communities with the needed rapid response
to climate change. At present, there are few clear pathways to both respect and resolve concerns. The Biden
Administration has created special offices, in both the White House44 and the Department of Energy,45,46 tobetter serve community needs while also supporting valid projects of import. As ammonia projects grow in local
and national importance, these offices will generate new findings and processes that hopefully can serve all
stakeholders well.

REFERENCES
1

O. Elishav et al. “Chapter 5 - Storage and Distribution of Ammonia” in Techno-Economic Challenges of Green Ammonia
as an Energy Vector (eds Agustin Valera-Medina & Rene Banares-Alcantara) p. 85-103 (Academic Press, 2021, https://doi.org/10.1016/B978-0-12-820560-0.00005-9 https://doi.org/10.1016/B978-0-12-820560-0.00005-9).

2

Alfa Laval et al. Ammonfuel – an industrial view of ammonia as a marine fuel. https://hafniabw.com/wp-content/
uploads/2020/08/Ammonfuel-Report-an-industrial-view-of-ammonia-as-a-marine-fuel.pdf (2020).

3

The Royal Society. Ammonia: zero-carbon fertiliser, fuel and energy store (Policy Briefing). https://royalsociety.org/-/
media/policy/projects/green-ammonia/green-ammonia-policy-briefing.pdf (2020).

November 2022

CHAPTER 4

l

42

4

US Environmental Protection Agency. Facility Registry Service (FRS). https://www.epa.gov/frs (Accessed 2017).

5

US Department of Labor Occupational Safety and Health Administration (OSHA). 1910.111 - Storage and handling ofanhydrous ammonia. https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.111 (Accessed
September 2022).

6

Minnesota Department of Agriculture. Anhydrous Ammonia System Piping Requirements. Minnesota Department ofAgriculture: Pesticide & Fertilizer Management Division. https://www.mda.state.mn.us/sites/default/files/inlinefiles/Anhydrous%20Ammonia%20System%20Piping%20Requirements.pdf (Accessed September 2022).

7

The American Society of Mechanical Engineers (ASME). Pipeline Transportation Systems for Liquids and Slurries. (TheAmerican Society of Mechanical Engineers, 2019 (https://www.asme.org/codes-standards/find-codes-standards/
b31-4-pipeline-transportation-systems-liquids-slurries)).

8

International Energy Agency. Ammonia Technology Roadmap. (IEA, Paris, 2021 https://www.iea.org/reports/
ammonia-technology-roadmap).

9International Energy Agency. The Role of Low-Carbon Fuels in the Clean Energy Transitions of the Power Sector. IEA.

https://www.iea.org/reports/the-role-of-low-carbon-fuels-in-the-clean-energy-transitions-of-the-powersector (2021).
10 Port of Rotterdam. Rotterdam can supply Europe with 4.6 megatonnes of hydrogen by 2030. https://www.
portofrotterdam.com/en/news-and-press-releases/rotterdam-can-supply-europe-with-46-megatonnes-ofhydrogen-by-2030 (2022).
11 Port of Rotterdam. OCI expands import terminal for (green) ammonia. https://www.portofrotterdam.com/en/
news-and-press-releases/oci-expands-import-terminal-for-green-ammonia (2022).
12 Reuters. GasUnie, HES, Vopak plan ammonia, hydrogen terminal at Rotterdam. https://www.reuters.com/article/
netherlands-hydrogen/gasunie-hes-vopak-plan-ammonia-hydrogen-terminal-at-rotterdam-idUKL2N2W918W(2022).

13 Business & Industry Connection (BIC) Magazine. Major ammonia plant project to start construction in the Gulf
Coast. https://www.bicmagazine.com/expansions/downstream/major-ammonia-plant-project-to-startconstruction-in-the-gul/ (2020).
14 Gulf Coast Ammonia LLC. Permit Drawings Gulf Coast Ammonia Terminal Dock. https://www.swg.usace.army.mil/
Portals/26/docs/regulatory/PN%20Dec/PN%20upload/ Plans_201700096.pdf?ver=2018-12-27-151431-183(2018).
15 Ajsa Habibic. Singapore: Industry partners to study ammonia bunkering safety, promote fuel supply base. https://www.

offshore-energy.biz/singapore-industry-partners-to-study-ammonia-bunkering-safety-promote-fuel-supplybase/ (2022).
16 Rieko Suda. Japan to back ammonia bunkering infrastructure building. Argus. https://www.argusmedia.com/en/
news/2217849-japan-to-back-ammonia-bunkering-infrastructure-building (2021).

17 Max Tingyao Lin. Itochu to develop ammonia bunkering infrastructure in Japan. TradeWinds: The Global Shipping News
Source. https://www.tradewindsnews.com/regulation/itochu-to-develop-ammonia-bunkering-infrastructurein-japan/2-1-979501 (2021).
18 Julian Atchison. Building a “regulatory sandbox” for ammonia bunkering trials in Singapore. Ammonia Energy
Association. https://www.ammoniaenergy.org/articles/building-a-regulatory-sandbox-for-ammoniabunkering-trials-in-singapore/ (2022).
19 Azane. Azane: Fuel Solutions. https://www.azanefs.com/ (Accessed September 2022).
20 Naida Hakirevic Prevljak. Yara pre-orders world’s 1st green ammonia floating bunkering terminals. Offshore Energy.

https://www.offshore-energy.biz/yara-pre-orders-worlds-1st-green-ammonia-floating-bunkering-terminals/(2022).

21 Lloyd’s List. Yara to bunker green ammonia. https://lloydslist.maritimeintelligence.informa.com/LL1140378/Yarato-bunker-green-ammonia (2022).
22 Damon Evans. Singapore eyes world’s first green ammonia bunkering. Energy Voice. https://www.energyvoice.com/
oilandgas/305872/singapore-eyes-worlds-first-green-ammonia-bunkering/ (2021).

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43

23 Fertilizers Europe. Guidance for Inspection of Atmospheric, Refrigerated Ammonia Storage Tanks. (2014, https://www.fertilizerseurope.com/wp-content/uploads/2019/08/Guidance_for_inspection_of_atmospheric__
refrigerated_ammonia_storage_tanksVJ_website.pdf).
24 Loyd W Adams & John E Cottle. Underground storage of ammonia and its recovery (1954, https://patents.google.
com/patent/US2901403A/en ).
25 Ted Pallis. Underground Storage Caverns. New Jersey Geological and Water Survey. https://www.nj.gov/dep/njgs/
enviroed/infocirc/StorCavsIC.pdf (2019).
26 Travis P. Hignett. “Production of Ammonia” in Fertilizer Manual Vol. 15 (ed Travis P. Hignett) (Springer Netherlands,
1985, https://doi.org/10.1007/978-94-017-1538-6_6).
27 George Thomas & George Parks. Potential Roles of Ammonia in a Hydrogen Economy. (2006, https://www.

researchgate.net/publication/331595915_Potential_Roles_of_Ammonia_in_a_Hydrogen_Economy ).

28 Nicholas Salmon, René Bañares-Alcántara & Richard Nayak-Luke. Optimization of green ammonia distribution systems
for intercontinental energy transport. iScience 24, 10.1016/j.isci.2021.102903 (2021).
29 NuStar. Pipeline Transportation of Ammonia: Helping to Bridge the Gap to a Carbon Free Future. https://www.

ammoniaenergy.org/wp-content/uploads/2021/11/AEA-Ammonia-Pipeline-Transportation-MEA-11-4-2021.
pdf (2021).

30 Mohammed Al-Breiki & Yusuf Bicer. Comparative life cycle assessment of sustainable energy carriers including
production, storage, overseas transport and utilization. Journal of Cleaner Production 279, 123481, https://doi.
org/10.1016/j.jclepro.2020.123481 (2021).
31 S. Crolius et al. “Chapter 10 - Safety Aspects” in Techno-Economic Challenges of Green Ammonia as an Energy Vector(eds Agustin Valera-Medina & Rene Banares-Alcantara) p. 221-257 (Academic Press, 2021, https://doi.org/10.1016/
B978-0-12-820560-0.00010-2).
32 A. O. Gezerman. Industrial Scale Ammonia Pipeline Transfer System and Exergy Analysis. Kem. Ind. 20, 711–716,
https://doi.org/10.15255/KUI.2020.080 (2021).
33 Mehran Ghasemi. Converting LNG Import Terminals to Ammonia Import Terminals. Black and Veatch. https://bv.com/
perspectives/converting-lng-import-terminals-ammonia-import-terminals (2020).
34 Tim Boreham. Long list of high-paying in-demand jobs in energy sector. Financial Review. https://www.afr.com/workand-careers/workplace/long-list-of-high-paying-in-demand-jobs-in-energy-sector-20220620-p5av8k (2022).
35 Kurt Liebendorfer (Evapco) & Mike Chapman (Stellar). Advantages of Low Charge Ammonia Systems for Operator
Training & Regulatory Compliance (White Paper). RETA 2017 Conference. (Evapco, Hershey, PA, US, 2017, https://www.evapco.com/sites/evapco.com/files/2019-06/RETA-Tech-Paper-LowCharge-Ammoia-Systems-Evapcold.
pdf ).

36 US Department of Labor Occupational Safety and Health Administration (OSHA). Training Requirements in OSHA
Standards. https://www.osha.gov/sites/default/files/publications/osha2254.pdf (2015).
37 Mark Fecke, Stephen Garne & Brenton Cox. Hazards 26: Review of Global Regulations for Anhydrous Ammonia
Production, Use, and Storage. IChemE: Institution of Chemical Engineers. https://www.icheme.org/media/11771/

hazards-26-paper-34-review-of-global-regulations-for-anhydrous-ammonia-production-use-and-storage.pdf(2016).

38 Gerson Freitas Jr. Key U.S. Natural Gas Pipeline Delayed as Costs Grow to $6.6 Billion. Bloomberg News; Financial Post.

https://financialpost.com/pmn/business-pmn/key-u-s-natural-gas-pipeline-delayed-as-costs-grow-to-6-6billion (2022).
39 S&P Global: Commodity Insights. Ideas Connected. Commodities Enlightened. https://www.spglobal.com/
commodityinsights/en/campaigns/energy-transition-service (Accessed September 2022).
40 Joe Romero (Woods Rogers Vandeventer Black). Legal Alert – U.S. Army Corps Pauses Permit Decisions. JD Supra.
https://www.jdsupra.com/legalnews/legal-alert-u-s-army-corps-pauses-9026601/ (2021).
41 Daniel Moore. States Balk at Permitting Plan’s ‘National Interest’ Power Lines. Bloomberg Law. https://news.

bloomberglaw.com/environment-and-energy/states-balk-at-permitting-plans-national-interest-power-lines(2022).

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42 Catherine Clifford. Fierce local battles over power lines are a bottleneck for clean energy. CNBC. https://www.cnbc.
com/2022/06/26/why-the-us-has-a-massive-power-line-problem.html (2022).
43 Samuel L. Brown. California Takes Steps to Incorporate Environmental Justice into Permitting Decisions. The National
Law Review. https://www.natlawreview.com/article/california-takes-steps-to-incorporate-environmentaljustice-permitting-decisions (2021).
44 The White House. Environmental Justice. https://www.whitehouse.gov/environmentaljustice/ (2022).
45 US Department of Energy. Environmental Justice. U.S. Department of Energy (DOE) Office of Legacy Management.
https://www.energy.gov/lm/environmental-justice (Accessed September 2022).
46 US Department of Energy. Community Engagement Initiatives. Department of Energy (DOE) Office of Legacy
Management. https://www.energy.gov/lm/community-engagement-initiatives (Accessed September 2022).

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Chapter 5

USES OF LOW-CARBON
AMMONIA
Low-carbon ammonia could help cut greenhouse gas emissions across many sectors. This chapter explores that
potential, examining possible uses of low-carbon ammonia, their technical feasibility and the extent to which using
low-carbon ammonia could contribute to net-zero emissions.
Ammonia is already in widespread use globally, as a fertilizer and for other purposes. (See Chapter 2 – The
Ammonia Industry: Past and Present.) The most straightforward way for low-carbon ammonia to contribute toachieving net-zero emissions is by replacing conventional ammonia in existing applications. This could cut global
CO2 emissions by roughly 1.3% (the percent of global emissions currently attributable to ammonia production).1
Beyond that, low-carbon ammonia could substitute for fossil fuels in transportation, the power sector and heavy
industry. This appears to be a promising decarbonization strategy in some sectors and sub-sectors, thoughless promising in others. In all cases, low-carbon ammonia will need to compete against other decarbonization
strategies as the world transitions to net-zero emissions.

Low-carbon fertilizer
Ammonia is most widely used today as nitrogen fertilizer for agriculture. Around 70% of ammonia production
globally is used to make fertilizers, with the rest used as a feedstock in making explosives, plastics and otherproducts.1
Emissions of ammonia for fertilizer production amount to 434 million tons of CO2 per year (MtCO2/y). This
includes 315 MtCO2/y from direct emissions from the ammonia production process (Scope 1), as well as 119
MtCO2/y emissions from external power and steam consumption (Scope 2) and fertilizer synthesis, such as urea orammonium nitrate (Scope 3), combined.1 The International Energy Agency (IEA) projects that ammonia demand
for agriculture will grow roughly 40% by 2050 as a result of population growth and economic development,
if governments’ current policies remain roughly the same. Emissions from ammonia production will growproportionally unless changes are made to current production processes.
The climate impact of low-carbon ammonia for fertilizer is a function of the replacement ratio (i.e., how muchconventional ammonia is replaced by low-carbon ammonia) and the carbon footprint of the low-carbon ammonia
itself. Because the use of ammonia-based fertilizer is a technically mature application, no innovation is required
to transition to low-carbon ammonia in agriculture from an application perspective; it is effectively a “drop-in”
replacement for conventional ammonia. The agriculture sector can therefore immediately adopt low-carbon
ammonia within the existing infrastructure for ammonia transport and distribution and directly apply it (orderivatives, such as urea and ammonium nitrate) to crops. However, this is likely to increase costs compared toconventional ammonia.
Substituting low-carbon ammonia for conventional ammonia will not change the greenhouse gas emissions
caused by applying ammonia fertilizer to fields. This process releases the greenhouse gas nitrous oxide (N2O) tothe atmosphere no matter how the ammonia is made, although different ammonia-derived fertilizers have very
different N2O emissions levels after application (see Figure 5-1).2 Sosulski et al., 20203 analyzed the relationshipof soil N2O emission level with the fertilizer application, showing that excessive surface-soil fertilizer application
will lead to unnecessary high-level N2O emission, which can be greatly abated by precise deep-soil application.
Low-carbon ammonia substitution, however, only contributes to climate-change mitigation by eliminatingproduction-phase N2O emissions, which are already insignificant. Strategies for reducing N2O emissions from

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Figure 5-1. Nitrogen fertilizer application by region and product. (Source: IFA4)

agricultural application of ammonia fertilizer is a separate research topic. It is worth noting that any ammonia thatleaks during production and transport may lead to additional N2O emissions, depending on its fate. (See Chapter 6– Safety and Local Environmental Impacts of Ammonia.)

Hydrogen carrier
While ammonia is used as a fertilizer because of its nitrogen carrier capability, it is now widely investigated for
its hydrogen carrier capability. This is because ammonia is much easier to store and transport at large scalethan hydrogen due to its much stabler and more moderate physical and chemical properties. The International
Renewable Energy Agency (IRENA) estimates that 127 Mt/y of ammonia (18% of total global production and ~37%of globally transported ammonia) will be converted back to hydrogen before being used in 2050.5
Ammonia conversion to nitrogen and hydrogen (also known as ammonia decomposition, cracking or
dehydrogenation) is a thermo-catalytic process under relatively high temperature, roughly 200–400 °C dependingon the types of catalysts.6 Typically, after ammonia decomposition, the hydrogen stream will be harvested andused for further applications, and the nitrogen stream will be directly vented to the atmosphere. This process
requires energy input and results in inevitable energy loss, typically 0.28–0.30 MWh/ton-ammonia.7 For highpurity hydrogen applications, 15% hydrogen loss is considered the current best practice scenario because only
85% of the input hydrogen can be recovered due to the purification process. The combination of energy andhydrogen loss leads to a total ammonia cracking efficiency of 76%.7 Additional losses will occur if there is a needfor additional compression and transportation/delivery of the resulting hydrogen.
The decomposition reactions can also be applied as part of a two-step indirect ammonia fuel-cell system: (1)ammonia decomposition to N2 and H2 and (2) using hydrogen for power generation in a standard hydrogen fuelcell. The indirect ammonia fuel-cell system can maximize the technology benefit from the hydrogen fuel-cellsystem, which leads to potential cost saving and technical maturity, representing an opportunity available in the
short-term. (Direct ammonia fuel cells that avoid decomposition to hydrogen have a much lower technology
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Ammonia combustion
Many of the proposed novel applications of low-carbon ammonia are based on combustion. Compared to carboncontaining synthetic fuels (e.g., methanol, bio-diesel, synthetic methane), ammonia combustion is carbon-freewith no direct greenhouse gas effect from CO2. Ammonia is also relatively easy to store and transport, providing
an option for international trading and long-term storage to balance seasonal demand. However, these novel
ammonia combustion applications all face similar challenges because of the drawbacks of combusting ammonia
compared to well-established carbon-based fuels.8-10 Similarly, due to its nitrogen element, ammonia combustion
also has drawbacks compared to pure hydrogen combustion, which is also a strong candidate currently underdevelopment.
First, ammonia is harder to ignite than hydrogen and hydrocarbon fuels because of its relatively high auto-ignition
temperature (650 °C compared to methane at 630 °C and hydrogen at 520 °C) and lower flame temperature,
meaning it is hard to ignite while the heat release rate is generally lower. Additionally, ammonia oxidation during
flame combustion is very different from the ignition phase: the ignition phase lacks O/H radicals but is dominatedby N2Hi radicals, which are far less important during flame combustion. In many cases, this can be addressedby initiating combustion with a more easily ignited fuel and then transitioning to pure ammonia fuel.11 Anotherapproach is to use an ammonia blend with hydrogen or similar fuel for spark ignition engines, or an ammoniadiesel or -dimethyl ether (DME) blend for compression ignition engines. Ammonia combustion in furnaces iscurrently being tested with coal co-firing in Japan. Industrial processes with furnaces typically use enrichedoxygen (O2) or multi-stage air injection to address the ignition and combustion challenges. In all cases, this adds
complexity to the engine/furnace design and potentially to fuel management.
Second, once ammonia or an ammonia-blend fuel has been ignited, maintaining flame stability is difficult becauseof the narrow flammability range in air. The very slow laminar flame speed of ammonia also makes it challenging
to enable good flame propagation and stability. As noted above, the heat release rate and flame temperatureof ammonia/air combustion are also lower than methane/air combustion, which creates additional challenges
for maintaining a stable flame. These characteristics lead to a narrow stable operation range of ammonia
combustion compared to carbon-based fuels. As with ignition, blending ammonia with hydrogen or other fuels
can partially compensate for these drawbacks at the cost of some increased complexity in engine design and fuelmanagement.12 An alternative approach is to enrich the oxygen content of combustion air, which can improveflame stability, although it introduces additional costs for oxygen production. The logical extrapolation of thisapproach is pure ammonia-oxygen combustion, which has also received significant research attention but implies
even higher costs for oxygen supply.
Third, exhaust management of ammonia combustion is problematic because of the increased potential forammonia slip and the formation of N2O and NOx.13 Ammonia slip results from the difficulty of maintaining stablecombustion, which can result in uncombusted ammonia being directly emitted with exhaust gas. The formationof N2O and NOx results from complex combustion chemistry. Unfortunately, these two engine design challenges
are in tension with each other because a higher combustion temperature usually leads to a more complete
combustion that consumes all fuels to avoid slip, but it can also lead to more NOx formation and emission forammonia combustion. The understanding of foundational combustion chemistry and applied engine design ofammonia fuel (either pure or blended) remains incomplete and is an important area for further research.
Generally, ammonia-fueled engines have lower power output compared to hydrogen engines or carbon-based fuelengines due to drawbacks listed above, which can be partially mitigated by fuel blending. While the understandingof both pure and blended ammonia combustion has improved, important gaps remain in the ability to fully modelits physical and chemical properties in technologically relevant engines, turbines and other systems. Further
progress is needed on fundamental science and high-fidelity simulations to help guide the engineering design ofthese devices.

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Marine fuelThe global shipping industry is responsible for emissions of slightly more than 1 Gt CO2 per year, withapproximately three-quarters of that due to international shipping.14 Recent International Maritime Organization(IMO) regulations have significantly limited the amount of sulfur that is allowable in marine fuel,15 and theindustry has committed to a 50% reduction in greenhouse gas emissions by 2050 compared to a 2008 baseline.16
These changes have prompted a re-examination of the options for marine fuel, which today is primarily heavy
fuel oil (HFO) and marine gas oil (MGO). Low-carbon ammonia is one of the leading candidates for adoption as adecarbonized fuel for shipping and is receiving considerable attention.
The global shipping industry already has extensive experience handling ammonia as a cargo. (See Chapter 4 –Ammonia Infrastructure.) Ammonia is a globally traded commodity—in 2019, international trading approached
20 Mt/y, about 10% of total global production.1 There are 120 terminals that import/export ammonia globally,
covering all major economic zones, some of which are close to existing ammonia plants and equipped withstorage/handling facilities.17 (See Chapter 4 – Ammonia Infrastructure).
Low-carbon ammonia is appealing as a marine fuel for several reasons. First, as a carbon-free molecule, all CO2
emissions will occur upstream during production, not during use (see Figure 5-218). This eliminates the needto consider on-board carbon capture and storage (CCS) systems for ships, which face considerable economic,
logistical and technological hurdles,19 and are thus a problematic consideration for carbon-based fuel, such as
liquified natural gas (LNG).
Second, despite the different characteristics of ammonia combustion, dual-fuel (ammonia/diesel) two-stroke
marine engines for large vessels are under rapid development and are expected to be commercially available
starting in 2024, with retrofits available shortly thereafter.20-26 “Ammonia-ready” ships that can be easily converted
from other fuels (such as LPG) to ammonia in the future are also under rapid development.27,28 Although early
development is focusing on two-stroke combustion engines, four-stroke engines and ammonia fuel cells are also
under active development.29
Future advancement of ammonia-hydrogen co-combustion and ammonia fuel-cell systems can further improvethe carbon footprint without worrying about ammonia-diesel co-combustion lock-in. In fact, Imhoff et al., 202130

Figure 5-2. Shipping fuel carbon intensity (g-CO2/MJ) by fuel types. (Sources: DNV18)

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found that a mixture of 28% hydrogen and 72% ammonia by volume yields combustion characteristics that arecomparable to methane combustion in air. Furthermore, fuel-cell systems could potentially serve as the long-term
permanent solution for using ammonia fuel due to the higher maximum efficiency potential.29,31
By 2050, ammonia might contribute to more than one-third of total shipping fuel consumptions, much larger thanany other alternatives.32 According to the long-term business as usual (BAU) scenario by IEA and IMO,33,34 1.5 Gt/ytotal emissions will come from the shipping sector by 2050. Ammonia as an alternative shipping fuel therefore has
the potential to reduce greenhouse gas emissions by 500 Mt/y assuming one-third fuel replacement with carbonneutral ammonia (see Figure 5-332). For ammonia dual-fuel engines, the blending ratio (typically 40–60%) limits
the maximum decarbonization potential using ammonia, assuming that the low-carbon ammonia is carbon neutral
itself.35 Further increasing the total decarbonization potential would require either a higher blending ratio (which
necessitates more technical advancement) or a pure ammonia-powered system.

Figure 5-3. Ammonia as alternative shipping fuel will gradually increase its market share in the following decades. (Source:
ABS, 201932)

Economic feasibility remains a major challenge for ammonia used as shipping fuel. Fuel is the largest cost
component of shipping operations, making up more than 30% of the total cost for bulk cargo ships and morethan 50% for container ships.36,37 To illustrate this, if green hydrogen were to fall in cost to $2/kg-H2 by 2030,
resulting in green ammonia costs of $600–700/t, the per-unit energy cost of this low-carbon ammonia would beapproximately 2–5 times that of current HFO.38
Another major challenge comes from the high capital cost of ships and shipping engine systems. International
shipping fleets have very long lifetimes (about 30 years) and turn-over rate (about every 10 years), meaning
the existing fleet will serve for a long time and lock in the fuel consumption for the duration of service.39 One
approach to resolving the uncertainty of low-carbon fuel is to develop dual-fuel engines to minimize the fuelingcost and supply risk of a single low-carbon fuel.40 In an attempt to future-proof new builds beginning construction
today, a growing number of ships are designed to be “Ammonia-Ready,” meaning that the main engine, fuel tank,generator and boiler are designed to allow a retrofit to ammonia fuel.41 Whether the high cost of conversion
will be economical remains to be seen. Nonetheless, strategies to accommodate multiple fuel types in ships
November 2022

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are becoming increasingly valuable, as this approach protects ship owners against potential issues with futureavailability of low-carbon fuels, which they view as one of the top risks for investment in low-carbon ships today.40
Ammonia used for marine fuel for dual-fuel engines is one of the most technically mature applications of novel
uses for ammonia with great emissions-abatement potential. Future use of higher ammonia blending ratios, pureammonia combustion, and ammonia fuel-cell systems remain to be explored and developed.

Power generation
The global power sector currently relies primarily on fossil fuels (coal, natural gas and oil) to generate electricity—roughly 63%. Electricity and heat production are responsible for ~14 Gt-CO2/y, the largest of all sectors, making it
imperative to find methods for reducing its emissions.42 Power generation using low-carbon ammonia (or generally
low-carbon alternative fuels) is of special interest when other decarbonization pathways are not available or are
limited due to a shortage of renewable resources and CO2 storage.
One strategy for decarbonizing power generation is to substitute low-carbon fuels for fossil fuels in the existing
power systems, such as gas-fired turbines and coal-fired boilers. This includes adoption of ammonia as a fuel,either in a co-firing configuration (i.e., blended with fossil fuels) or as a complete fuel replacement. Ammonia
could also be converted (cracked) to hydrogen and used through co-firing or in fuel cells for power generation.
Such low-carbon fuel power generation strategies are of special interest for some nations (e.g., Japan, South
Korea) with limited renewable resources (wind, solar, hydro) that are projected to continue importing energy but
intend to transition from fossil fuels to chemicals such as hydrogen and ammonia.
While ammonia has appropriate energy density and combustion physical properties to be used for power
generation, it is not a direct drop-in replacement, meaning that significant modifications to current coal/natural
gas power generation equipment are required.35 These modifications are due to the typical challenges of ammonia
combustion discussed above and apply to all ammonia power generation.
Some of these limitations can be overcome with co-firing. An initial approach for adopting ammonia in power
generation is co-firing it with coal. The Japanese Chugoku Electric Power Corporation successfully tested a 1%
share of ammonia co-firing system for a commercial coal power station (120 MW) in 2017. Higher blending—up to 20% ammonia (percentage of energy)—is theoretically feasible with minor reconfiguration and has

Figure 5-4. Direct ammonia fuel cell (left) and indirect ammonia fuel cell with ammonia decomposition (right).

November 2022

CHAPTER 5l51been successfully tested with smaller prototypes.43 Such technology can be achieved without sacrificing thedesigned maximum power output and can still meet the NOx emission limits without ammonia slipping into
exhaust gas, through the use of a more advanced combustion system and exhaust post-treatment similar toautomobiles.44,45Ammonia can also be used in gas-fired power plants, both boiler and turbine configurations,with similar combustion to natural gas. The life-cycle assessment (LCA) shows that ammonia replacing natural
gas in the gas turbine can reduce its greenhouse gas emission level by 60% based on the current demonstrated
blending limit of ammonia with methane, but it can be as high as 100% if blended with hydrogen.8,46 From the LCA
perspective, the main greenhouse gas emissions of ammonia firing for power generation remain the production
emissions of ammonia itself. The remaining greenhouse gas emission contributions come from residual fossil
fuel combustion and potential excessive non-CO2 greenhouse gas emission, such as N2O.47,48 Research anddevelopment (R&D) is currently underway to establish fundamental understanding of ammonia-combustion
physics for ammonia power generation, including controlling N2O and NOx formation, preventing ammonia slip,
and achieving a stable flame.49,50
Direct ammonia fuel-cell power generation represents a long-term opportunity with higher power-generation
efficiency. These direct ammonia fuel-cell technologies have various subtypes according to the electrolytematerials and are mostly still at the R&D level.51 Direct ammonia solid-oxide fuel cells (SOFCs), whose operation
temperature ranges from 500-1000 °C, are typically regarded as the most efficient method for power generation
with ammonia and are also the most widely studied so far. One potential concern is the formation of NOx,although some subtypes of SOFCs appear to be able to significantly reduce this. Compared to SOFCs, alkaline-,
molten alkaline– and alkaline membrane–based ammonia fuel-cells are far more developed for practical systems,
operating at temperatures ranging from 200–450 °C. Unlike SOFCs, alkaline-based fuel cells can decompose
ammonia at the very initial stage without forming NO and produce electricity directly. They are conceptuallyeasier to operate but have lower potential than SOFCs for achieving maximum overall efficiency by combining
waste-heat recycling management. Microbial-based direct ammonia fuel cells may be able to combine wastewater
treatment capability with power generation. All of the above pure-ammonia fuel-cell systems are not yet mature
for commercial applications and are still limited to lab-scale development.51

Heavy industry – feedstocks and energy source
Ammonia has a long history of being used for industrial feedstocks to form other chemicals: nitric acid, fibers
and plastics, explosives, cyanides, etc. Similar to fertilizers, low-carbon ammonia can be used directly as a drop-in
replacement for conventional (fossil-derived) industrial feedstock for these applications, making it an immediate
opportunity for decarbonization. This portion of non-agricultural ammonia demand represents about 30% of
global total demand (54 Mt/y ammonia) and an emissions reduction potential of 136 MtCO2/y.1
Another important and potentially far-reaching application of ammonia within heavy industry is providing primaryenergy, most importantly for high-temperature, high-quality heat. Most industrial heat is provided throughcombustion of fossil fuel, making it the biggest source of industrial emissions—contributing about 10% of global
greenhouse gas emissions.52 High-quality heat is particularly important in blast furnace operation (steel making),
kiln operation (cement making) and reactor operation (e.g., methanol, ethylene and even ammonia production).
Combusting ammonia could potentially replace this usage of fossil fuels, leading to deep decarbonization.
However, similar to the power case (above), it would not be a drop-in replacement, requiring substantial
modification of operating systems or brand-new system design.
Studies on ammonia used for industrial heat applications remain at an initial stage. Lots of recent studies address
the details of ammonia combustion characteristics, which differ significantly from conventional hydrocarbon fossil
fuels. Honzawa et al., 202053 uses numerical simulations to study the ammonia/city gas (hydrogen and methane)
mixture used for industrial heating fuels and the effectiveness of moderate or intense low-oxygen dilution (MILD)

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CHAPTER 5l52

combustion to reduce the potential NO emissions. MILD combustion is also called flameless combustion for the
diluted fuel and slow reaction rate (long reaction time to consume unstable NO formation), which is suitable forsome stable high-temperature industrial furnace reactions. Such studies aim to resolve the barriers to ammonia
combustion for high-temperature industrial applications, such as very low burning velocity, low flammability,
higher ignition temperature and lower burning temperature. Efforts are also being made to resolve the generalapplication of ammonia furnace development. Murai et al., 201954 investigated the fundamentals of directammonia combustion in industrial furnaces. Typical drawbacks of ammonia combustion can be mitigated bystandard strategies, such as adjustment of oxygen concentration, air-fuel ratio, etc.
Compared with ammonia’s application for power generation, ammonia uses for industrial energy purposes
are much less well understood. Since more complicated chemical reactions are typically involved for industrial
production, introducing ammonia fuel combustion internally (such as in blast furnaces, cement kilns andautothermal reforming units) creates different oxidation kinetics in the overall reaction and introduces more
uncertainties for product quality control, a topic that has received only minimal investigation so far.8 Using
ammonia combustion to provide heat externally will be technically more straightforward as it can be done
without altering existing chemical reactions. The application of ammonia for industrial energy use, especiallyhigh-temperature heat, therefore, needs significant research before it can be adopted at scale. In particular, R&D
studies are needed that focus on fundamental characteristics to fully investigate the feasibility of ammonia forindustrial energy.

Heavy-duty road/surface transport
The fundamental technical details of ammonia used for heavy-duty road transport are very similar to those
discussed in previous sections. For example, ammonia used for diesel internal combustion engines sharescharacteristics with ammonia used for 2-stroke diesel engines for shipping. Ammonia fuel-cell systems used to
power road transport vehicles share the same design as ammonia fuel-cell systems used for stationary electric
power generation.
Despite concern regarding health and safety risks of handling ammonia as a fuel, as well as potential NOx
emissions, ammonia fuel for city transport is overall more environmentally friendly than diesel and gasoline,
based on a combined emission metric that includes particulate matter, soot, NOx, SOx and other pollutants.11
From the global warming potential (GWP) perspective, ammonia fuel can reduce 40–60% of total greenhouse gas
emissions through dual-fuel blending, provided that the ammonia itself is carbon neutral. Similar to shipping andother applications that use ammonia as an energy source, the vast majority of greenhouse gas emissions fromammonia come from upstream production rather than onsite combustion. Ammonia fuel combustion has overalllower pollutant emissions than high-sulfur diesel and bunker fuel combustion, therefore potentially abating rain
acidification and ozone depletion, especially in jurisdictions where trucks and trains use high-sulfur diesel without
NOx controls. Low-carbon ammonia was found to greatly reduce the overall environmental impact of city transportof human health.55
Successful testing has already been performed for ammonia-fueled road transport. Gitlin (2022)56 reported thatthe world’s first ammonia-powered tractor started testing in June 2022. China’s first ammonia diesel engine
for heavy vehicles was ignited for testing in April 2022, jointly developed by Dongfeng Commercial Vehicle andTsinghua University.57 Recent studies have also investigated ammonia-hydrogen dual-fuel combustion for heavyduty engines.58 These very recent developments demonstrate that ammonia is a potential fuel option for someroad-transport applications.
Compared to other alternative fuels (e.g., methanol, alcohol, bio-diesel) used for internal-combustion engines,
ammonia is not ideal for compact road/surface transportation. Experimental results suggest that ammonia slipping(unburnt ammonia directly emitted to the atmosphere) is problematic for small internal-combustion engines.59
Due to space and operation limitations, high-temperature ammonia fuel cells such as SOFCs are not suitable
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CHAPTER 5l53for road transport. Some fuel-cell systems like proton-exchange membrane (PEM), direct ammonia-alkaline
membrane fuel cells, and on-board ammonia cracking hydrogen fuel cells60 can operate at room temperature but
are not technically mature today.
Compared to ammonia used for stationary electric power generation and shipping fuels, ammonia faces stronger
economic, infrastructure and performance competition from other fuels in the road transport sector and may
prove a minor player. As battery and hydrogen fuel-cell vehicles are more technically mature and likely to becheaper, major adoption of ammonia-powered vehicles is likely to be limited to heavy-duty diesel vehicles, such as
long-haul trucks and trains.

Refrigerant/coolant
Ammonia is currently widely used as a refrigerant in some industrial systems, such as food refrigeration,
distribution warehousing and process cooling. There has also been discussion about ammonia use for residential/commercial air conditioning, but this has not yet been widely adopted because of safety concerns.
Ammonia can be considered a potential refrigeration alternative to conventional hydrofluorocarbons (HFCs). The
advantages of ammonia used for refrigeration are well understood and are chiefly functions of its chemical andphysical properties:
1. High latent heat, providing more refrigeration effect per unit mass flow compared to any other commercial
refrigerant with vapor compression systems.
2. Low gas density, providing increased compressor swept volume.
3. High critical temperature, suitable for air-cooled equipment in high ambient temperatures.
4. High acoustic velocity, resulting in small liquid pipe size and a more compact system.
Combining these advantages, ammonia refrigeration has a very high coefficient of performance (CoP, a ratio of
useful thermal energy transferred per unit of electrical energy consumed by heat pumps), making it a strong andefficient choice.
However, before ammonia can replace traditional refrigerants, it must be proven safe (from both a humanhealth and an environmental perspective), simple, cheap and, most importantly, technically mature. The safety
considerations are the biggest barrier for ammonia refrigeration. The toxic effect of ammonia depends on
concentration (see Chapter 6 – Safety and Local Environmental Impacts of Ammonia), making ammonia unsuitablefor use in residential refrigerators or airconditioners because it is not compatible
with the materials commonly used inthese systems, particularly copper.61 The
biggest potential for ammonia refrigerants
is for industrial applications, such as airto-air industrial-sized heat pumps, water
chilling equipment62 and marine vessels.63
The size of the market and the impact ongreenhouse gas emission reduction are
unclear and remain prominent research
and analysis topics. Adopting low-carbon
ammonia to replace conventional fossil
ammonia for refrigeration/cooling systems
does not provide additional benefit andadvantages other than the production
emission itself. The potential for further
Figure 5-5. Industrial ammonia refrigeration system65

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CHAPTER 5l54adoption of ammonia refrigeration/cooling is estimated to be low, as there is already effort toward developing
new refrigerants with low GWP that are both safe and cost competitive.64

Aviation fuelAmmonia can potentially be used as a low-carbon aviation fuel.59,66,67 Compared to other potential aviation-fuelalternatives, such as hydrogen, ammonia has advantages due to its moderate physical and chemical properties: itis very stable, which is safer for aviation applications, and it can be easily transported and stored under moderatepressure and temperature. The fundamental principles of aviation engines are similar to the gas turbines
discussed in the power generation section, so there is no theoretical application barrier in using ammonia foraviation. Recent progress has been made toward the first ammonia-powered jet flight, which is expected to occur
in 2023 with a small nine-seat passenger jet68 with at least one of the jet engines powered by ammonia. Active
research for ammonia jet-engine development by multiple research groups is underway.69 Research has foundthat blending ammonia in jet engines can greatly reduce greenhouse gas emissions by at least 60% with 70% mass
blending ratio,70 but may significantly increase NOx emissions.71
From energy density (energy per volume) and specific energy (energy per mass) perspectives, ammonia is not
an ideal aviation fuel alternative. For economic considerations, the aviation industry has very high requirements
for fuels’ energy density and specific energy, especially on long-haul flights, due to limited space and strict masscontrol. Additionally, commercial jets have very strict safety regulations that limit development of new aviation
fuels that are yet unproven. All non-drop-in fuels for aviation, such as methanol and hydrogen, are facing adoption
challenges similar to ammonia and, as a result, drop-in fuels (e.g., bio-fuels, e-fuels derived from hydrogen andCO2) or even fossil fuel offsets72 are widely considered to be preferable.

Summary discussion
Ammonia, as a hydrogen-based fuel, is of high interest and potential for various energy applications. Both the
IEA and IRENA forecast that there will be hundreds of millions of tons of ammonia used for energy purposes by
2050, mostly in the transportation and power-generation sectors.1,5 IEA’s projection1 under the 2050 net-zerotarget shows about 266 Mt/y ammonia (57 Mt/y hydrogen feedstock conversion) for power generation andtransportation, satisfying 45% of global shipping energy demand and a small portion of power generation. IRENA’s
projection5 shows that, in 2050 under the 1.5 °C scenario, 354 Mt/y of ammonia (about half of total annual
demand) will be for energy applications; specifically, 127 Mt/y of ammonia will be produced as a hydrogen carrier(and then converted back to hydrogen for final energy application) and the rest will be used for shipping andpower generation (Japan only). The future potential demand for ammonia for energy applications is larger than
the total demand for ammonia today, marking a significant market opportunity.
A few common characteristics are observed across different ammonia applications:
1. Low-carbon ammonia’s high production cost (see Chapter 3 – Low-Carbon Production of Ammonia) is
a major barrier for low-carbon ammonia’s adoption. High cost of low-carbon ammonia compared toconventional ammonia and baseline fossil fuels makes it financially unattractive, greatly limiting potential
technological advancement and low-carbon ammonia adoption. Production cost reduction and market
strategy aiming to close the cost gap is critical to low-carbon ammonia’s widespread deployment, andgovernment support will be essential to accomplish this (see Chapter 8 – Policy).
2. Current technologies are not commercially mature enough to support large-scale ammonia energy
applications, and the technical barriers are similar across different types of ammonia applications. Evenfor the most technologically mature sectors, such as ammonia shipping fuel and ammonia-fueled power
generation, system-level integration is not yet mature enough to support a high blending ratio. Other
potential ammonia applications, such as industrial energy uses and ammonia fuel-cells, are still at very earlystages of development. R&D and demonstration projects are critical for achieving technological maturity
November 2022

CHAPTER 5l55and expanding the application potential for ammonia applications that share typical barriers and thus havepotentially similar solutions. Common research topics include ammonia combustion physics (pure ammonia
combustion or co-firing with other fuels), NOx emission control and system optimization.
3. Despite the widely available ammonia infrastructure existing today, a new global ammonia infrastructure
suitable for non-agricultural applications using hundreds of Mt/y is required (see Chapter 4 – Ammonia
Infrastructure). Both IEA and IRENA project that around half of global ammonia production by 2050 will be
globally traded, demanding a significant increase in ammonia transportation and storage. Each of ammonia’s
specific energy applications will also demand specific infrastructure for ammonia delivery and storage. Key
infrastructure support is essential for global ammonia trading and applications in countries that cannot
produce ammonia locally (e.g., Japan).
Overall, there are significant challenges in extending the use of ammonia to new sectors. The most promising newuses are concentrated in shipping fuels and power generation. In both these sectors, significant growth in the useof ammonia is possible by 2030. In other sectors, new uses of ammonia are limited by technical challenges andcompetition from other low-carbon pathways, including electrification.

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10th International Energy Conversion Engineering Conference. (Atlanta, Georgia, US, 2012, https://doi.
org/10.2514/6.2012-4055 ).
71 Norihiko Iki et al. Micro Gas Turbine Firing Kerosene and Ammonia. ASME Turbo Expo 2015: Turbine TechnicalConference and Exposition.
72 Julio Friedmann et al. Levelized Cost of Carbon Abatement: An Improved Cost-Assessment Methodology for a Net-Zero
Emissions World. Columbia School of International and Public Affairs (SIPA) Center on Global Energy Policy at Columbia.

https://www.energypolicy.columbia.edu/research/report/levelized-cost-carbon-abatement-improved-costassessment-methodology-net-zero-emissions-world (2020).

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Chapter 6

SAFETY AND LOCAL ENVIRONMENTAL
IMPACTS OF AMMONIA
Ammonia is widely used today in a variety of applications, primarily as a fertilizer and chemical feedstock but
also as a refrigerant, cleaning agent and air pollution control agent (see Chapter 2 – The Ammonia Industry).
This widespread use has led to a mature understanding of the safe handling of ammonia transportation anddistribution and to appropriate risk management methods within these application areas. It has also led to anunderstanding of the environmental impacts of ammonia in these use cases. To the extent that low-carbon
ammonia will displace conventional ammonia in existing applications, there will be no qualitative changes tothe associated human health and environmental risks, and no substantially new or modified risk management
strategies will need to be adopted.
However, if low-carbon ammonia is adopted into new application areas, such as power generation and maritime
fuels, new potential risks to human health and the environment may arise. These risks will require carefulattention and management. Additionally, if the total quantity of ammonia that is transported and handled globally
increases significantly, existing impacts may increase correspondingly. This chapter outlines the state of knowledge
regarding ammonia’s impact on human health and safety and on air and water quality and the ways in which thoserisks may change with new applications. Ammonia does not contribute directly to ozone depletion or climate
forcing; instead, ammonia’s human health and environmental risks are primarily due to (1) flammability, (2) acutetoxicity to humans at high concentrations, (3) chronic toxicity to humans at low concentrations (due to ammonia’srole in the formation of fine particles in the atmosphere) and (4) negative impacts on aquatic ecosystems.

Flammability and Acute Toxicity
FLAMMABILITY
Like other fuels, ammonia can burn in air. This poses risks when ammonia is transported and/or stored in enclosed
environments, such as industrial buildings. Pure anhydrous ammonia must reach concentrations of at least 15% in
air (lower flammability limit, see Table 6-1) for combustion to occur, which is much higher than methane (4.4%).
As a result, the risk of unintended fires or explosions associated with ammonia leaks is lower than with methaneand most other hydrocarbon fuels (e.g., propane) because building up this higher concentration from leaks or
accidental releases is less likely. However, at ammonia concentrations of 16–25% there is a risk of fire or explosion,and the US Environmental Protection Agency (EPA) cautions that this range may be expanded when ammonia iscontaminated with lubricating oil.1 In fact, a prior study indicated that lubricating oil contamination can reduce thelower flammability limit to 8%, depending on the composition and quantity of oil present.2 Particularly in cases
where contamination or intentional blending of ammonia with other substances will take place, safety standards
should be updated accordingly based on the behavior of these mixtures.
In terms of managing releases, diluting leaks quickly is the key approach for preventing unintended combustion.
In situations where ammonia could build up in enclosed environments, venting to the atmosphere via pressure
relief valves is generally effective at avoiding dangerously high concentrations and thus mitigating flammability
risk.3 Although ammonia has several advantages over natural gas in terms of its flammability risks, concerns
remain regarding its use as a refrigerant in non-industrial settings (e.g., residential heat pumps) because of bothits flammability and human toxicity (see below).3 However, as none of the proposed large-scale novel applicationsof low-carbon ammonia would be in non-industrial settings, it is reasonable to assume that appropriate safetymeasures (such as venting) will be in place at any location where large quantities of ammonia are stored or used.

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Table 6-1. Ammonia concentrations in parts per million (volume) and corresponding impacts on air quality and human health.

Concentration (volume-based)

Impacts

0.0011–0.010 ppm

Typical outdoor concentrations, no noticeable effects

0.008–0.061 ppm

Typical indoor concentrations, no noticeable effects

1–5 ppm

Odor detection threshold

25 ppm8-hour exposure limit13

30–35 ppm

Short-term exposure limit13

100–200 ppm

Immediate eye irritation occurs

400 ppm

Immediate throat irritation occurs

700 ppm

Coughing and severe eye irritation occur, possible loss of sight141700 ppm

Can cause serious lung damage, death if not treated142400 ppm

Life threatening after 30 minutes of exposure

5000 ppm

Life threatening after several minutes of exposure13

150,000 ppm

Lower flammability limit

ACUTE HUMAN HEALTH EFFECTS FROM AMMONIA EXPOSURE
The most common health effect from ammonia inhalation is chemesthesis (irritation of the skin and mucous
membranes).4 As shown in Table 6-1, relatively low concentrations (100–200 parts per million (ppm)) will cause
eye irritation, concentrations of 400 ppm will cause throat irritation, 700 ppm will cause coughing and severe
eye irritation with possible loss of sight, 1700 ppm causes serious lung damage, and 2400 ppm results in death
after 30 minutes of exposure. A key advantage of ammonia is that humans can smell it at concentrations evenlower than the threshold for irritation; odor detection thresholds are around 1.5 to 5 ppm.5,6 Further, the intensityof ammonia’s odor increases with its concentration, which is not the case with all airborne compounds (e.g.,hydrogen sulfide). These odor properties mean that ammonia is “self-alarming,” and any leaks occurring nearhumans are likely to be detected and repaired quickly.3
In the presence of a slow leak, people will easily detect increased concentrations of ammonia in air long before
they rise to levels that pose major health hazards, allowing them to take action to leave the area, dilute withfresh air and/or address the source of the leak. Similarly, the threshold for combustion (15% or 150,000 ppm)
far surpasses the level detectable by people, so concentrations would be unlikely to reach this level in areas
where people are nearby unless there is a rapid and catastrophic release. Ammonia’s narrow flammability range
has been cited as evidence that it can be stored safely on board ships.7 A recent quantitative risk assessment for
ship-to-ship bunkering of ammonia noted that the risks associated with toxicity exceeded those associated with its
flammability, highlighting the need to avoid uncontrolled releases near people.8
In rare industrial accidents, ammonia has been released at sufficiently high rates that it cannot be diluted before
workers or other populations are exposed to unsafe concentrations. The US Chemical Safety Board reviewed a2010 incident in which approximately 15 metric tons of anhydrous ammonia were released at Millard Refrigerated
Services Inc. in Alabama (United States) as a result of a catastrophic pipe failure, ultimately exposing 150 nearby
workers and resulting in hospitalization of approximately 30 people.9,10 Proper training for workers, adequate
safety protocols and periodic hazard analysis at industrial facilities are necessary to prevent future unintended
releases.10,11 Storing ammonia at atmospheric pressure, for example, and avoiding large swings in temperature andpressure wherever possible can reduce the risk and severity of unintended releases. Ammonia is also corrosive,
so selecting appropriate materials for storage and operation is critical to avoiding uncontrolled releases. While
there are valid concerns about the potential for catastrophic releases in freight transport applications, particularly
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with regard to worker safety, the transport of large volumes of ammonia is not entirely new. Ammonia is alreadytransported in maritime shipping as a refrigerant and as liquefied cargo.12

Role of Ammonia in Particle Formation andChronic Human Health Impacts
At concentrations far below the odor detection threshold, ammonia emissions contribute to the formation of fineparticles that remain in the atmosphere for days. At ground level, these particles can be inhaled by humans. At
higher altitudes, they can impact cloud formation (with highly uncertain impacts on climate forcing). Commonlyused integrated assessment models (e.g., APEEP, EASIUR) predict that increasing ammonia emissions will cause
substantial human health damages, particularly when the emissions occur near sources of other common air
pollutants (sulfur oxides (SOx) and nitrogen oxides (NOx)). This raises potential concern about how a dramaticincrease in ammonia production and use may impact air quality and human health.
At concentrations commonly found both indoors and outdoors, ammonia participates in reactions that form
PM2.5 (particulate matter with a diameter < 2.5 μm) in the atmosphere.15 PM2.5 is the primary driver of air quality–
related human health damages, including cardiovascular disease, intracellular oxidative stress, mutagenicity/
genotoxicity and inflammatory responses.16 As summarized in the review by Nazaroff & Weschler,17 ambientindoor ammonia concentrations can range from 8 to 61 parts per billion (ppb), with human skin and breath
serving as the main source of emissions (ammonia is emitted naturally when microbes break down proteins).18
Ambient outdoor ammonia concentrations in those same locations tend to be an order of magnitude lower thanindoor concentrations (1.1 to 10 ppb). However, even at these low concentrations, the reactions that form PM2.5
will occur. In the outdoor environment, ammonia drives the formation of PM2.5 by reacting with sulfuric acid
(H2SO4) and nitric acid (HNO3) to form sulfate and nitrate salts: ammonium sulfate ((NH4)2SO4) and ammonium
nitrate (NH4NO3) (see Figure 6-1). H2SO4 and HNO3 are produced in the atmosphere when SOx and NOx emissions
react with water and oxygen (this is also what causes acid rain). NOx and SOx are products of combustion, withsources ranging from cars and trucks to power plants and iron and steel mills. Thus, ammonia is likely to have thegreatest impact on formation of PM when it is released near large sources of NOx and SOx.
Predicting the marginal impact of ammonia emissions on PM2.5 formation is difficult because it varies widely on
a location and even hour-by-hour basis. For example, a study in Pittsburgh, Pennsylvania (United States) tracked
a nucleation event in which ammonium as a fraction of total mass of aerosols in the atmosphere increased fromnear-zero to approximately 20% in a matter of hours.19 In particular, temperature plays a role in governing theformation and residence time of sulfate and nitrate salts in the atmosphere. Furthermore, the degree to whichammonia forms these salts can also be impacted by the presence of other pollutants; ammonia has been shown

Figure 6-1. Primary mechanisms for secondary particle formation involving ammonia (adapted from Ehrnsperger andKlemm, 202121)

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to react with other organic particles in the atmosphere, thus reducing its availability to form ammonium sulfate
and ammonium nitrate salts.20 21
There are efforts to improve basic scientific knowledge of particle formation, although some of the most highprofile studies have focused on particle formation at higher altitudes and the resulting impacts on cloud formation(and possible climate forcing effects), rather than on ground-level concentrations that affect human health. Since
it began in 2009, the Cosmics Leaving Outdoor Droplets (CLOUD) experiment at CERN (the European Organization
for Nuclear Research) has yielded new insights into how ammonia reacts with ammonium sulfate and ammonium
nitrate to form particles that act as cloud condensation nuclei—seeding clouds in the lower atmosphere. Kirby
et al., 201122 used the CLOUD experiment to explore the dependence of nucleation rates (PM2.5 formation) on
ammonia concentration when it reacts with H2SO4. They found that ammonia concentrations of 100 parts pertrillion (ppt) increased the nucleation rate of particles (e.g., NH4HSO4) by more than 100–1000-fold.
More recent research has highlighted how much is still not known about the fate and transport of ammonia
and revealed higher-than-anticipated ammonia concentrations in the upper troposphere where particles
can act as cloud-condensation nuclei. For example, ammonia was previously believed to be short-lived in theatmosphere because of its solubility in water and reactivity with acids. Then a 2022 study using the CERN CLOUD
chamber found concentrations of 30 ppt averaged over 3 months and up to 1.4 ppb in hotspots within theupper troposphere over the Asian monsoon region.23 Notably, in the upper troposphere, nitric acid producedby lightning is more readily available to react with ammonia.24 While these particles are too far above groundlevel to directly impact human health, their effect on cloud formation can substantially impact global radiative
forcing (whether the impact is positive or negative is highly uncertain and dependent on optical properties of theresulting clouds).23 In short, ammonia emissions in the Asian monsoon region may impact climate forcing, but themagnitude and direction of those impacts remains uncertain.
Even at ground level, there is still much to be learned about how local meteorology, background concentrations ofother pollutants and net changes in ammonia emissions will impact PM2.5 concentrations. However, there is broadconsensus that the marginal impact of increasing (or decreasing) ammonia emissions depends on (1) backgroundemission rates of NOx and SOx and (2) how much ammonia is already present in the air (from other sources). Thissecond point addresses whether the local atmospheric chemistry is and will continue to be ammonia-limited.
An ammonia-limited environment refers to local atmospheric conditions in which ammonia is the limiting
reactant, meaning that if more ammonia is added to the atmosphere, other pollutants are available at sufficientconcentrations to form more PM2.5. An agricultural area with high concentrations of ammonia and relatively low
NOx and SOx emissions is unlikely to be ammonia-limited. Conversely, an urban or heavy industrial area, including
ports, with very little agricultural activity is far more likely to be ammonia-limited. Some studies have attempted toquantify these ammonia concentration thresholds, but large gaps in scientific knowledge remain.
In an effort to capture the cost-benefit tradeoffs of mitigating nitrogen emissions (both NOx and ammonia), Gu
et al., 202125 estimated the global average relationship between ammonia emissions and PM2.5 formation using a
combination of atmospheric chemistry transport models (EMEP-WRF, TM5-FASST and GEOS-Chem). The authors
converted the resulting changes in PM2.5 concentration to monetized human health damages based on mortality.
They calculated a marginal global average health damage cost of 5.7 (range of 3.1 to 9.0) $/kg ammonia. Wu etal. (2016)26 similarly indicated that in China many regions are not ammonia-limited and PM2.5 concentrations are
more strongly related to changes in ammonia emissions than to shifts in NOx and SOx emissions. Results in the
United States have been more mixed. Baker and Scheff (2007)27 studied one urban and nine rural locations acrossthe central and eastern United States and found that these locations were nitric acid–limited (not ammonialimited). A study comparing different organic waste–management strategies in California (United States) used two
different US-specific integrated assessment models (EASIUR and APEEP) and found that human health damages
from ammonia dominated their total social cost results, with damage factors varying widely by specific location
within the study area and model type ($44/kg ammonia to more than $300/kg).28
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Air Emissions from Ammonia Combustion
As noted in Chapter 5, NOx is an air pollutant that contributes to the formation of smog—namely ozone andsecondary PM2.5—in the atmosphere. Ammonia, if unintentionally released during production, storage, transport
and/or use, can react with nitric acid in the atmosphere (a product of reactions between emitted NOx, water andair). The combustion of ammonia can itself serve as a source of NOx, raising the question of whether simultaneous
increases in ammonia leakage and NOx emissions could have a synergistic effect, driving the formation of
additional PM2.5 in the atmosphere.
Ammonia is used as a reducing agent in selective catalytic reduction (SCR) to convert NOx emissions from power
plants and vehicles to N2. However, ammonia can also be oxidized to NOx during combustion. The degree towhich this occurs and the net impacts on NOx emissions relative to alternative fuels depend on the engine type,combustion conditions, and whether ammonia is combusted as a neat fuel (which has disadvantages as discussed
in Chapter 5) or co-fired with methane, hydrogen or other fuels.13 Because of the nonlinear effects that co-firingammonia with a variety of fuels has on NOx emissions, it is difficult to say with certainty whether the possibilityof elevated NOx emissions can be easily addressed. However, given the potential for synergistic effects between
ammonia and NOx emissions in terms of secondary particle formation, the net effects of ammonia combustion on
NOx emissions must be further studied and regulated.

Ammonia Impacts on Aquatic Ecosystems
Direct releases of ammonia into bodies of water, such as a spill of liquid ammonia, can kill aquatic life, including
fish. Many existing emissions sources contribute to acute aquatic toxicity from ammonia, including release of
untreated municipal wastewater, agricultural and urban runoff, manure management, and the release of leachatefrom landfills. In water, ammonia takes both its un-ionized form (NH3) and ionized form (NH4+), the balance of
which depends on the local water body’s pH and temperature. Un-ionized ammonia is very toxic to fish and otheraquatic animals, while ionized ammonia is less toxic.29,30
If ammonia is released into the atmosphere, it may react with other molecules or it may be directly depositedon surfaces or in water bodies (known as dry and wet deposition, respectively). Salts formed when ammonia
reacts with acids in the atmosphere can also be deposited in water bodies. Excess nitrogen present in water
bodies, known as eutrophication, causes harmful algae blooms, which consume dissolved oxygen and lead to fishkills.31,32 The impacts will vary depending on which nutrient is limiting (nitrogen or phosphorus). Current life-cycle
assessment models used to characterize eutrophication impacts make the simplifying assumption that freshwater
ecosystems are phosphorus-limited while marine ecosystems are nitrogen-limited.33 Following this logic, ammonia
releases will cause more eutrophication impacts if they occur along the coast or from offshore sources. Ammonia
emissions would then have less of an impact on freshwater ecosystems (e.g., lakes and rivers). However, Morelli
et al., 201833 point out that this simplified assumption does not always hold true, and the conditions of local water
bodies should be taken into account.
Historically, fertilizer use and the resulting runoff from agricultural activities has been the primary driverof eutrophication impacts.31,34 The degree to which an expanded ammonia industry may drive additional
eutrophication will depend on the magnitude of releases and the ultimate fate of those emissions, as discussed
further below. Monitoring nutrient levels in water bodies near key ammonia production and storage operations
will be critical, and further research is required to better understand the fate of ammonia releases from industrial
activities.

Leak Detection and Mitigation Measures
Avoiding undue burdens on workers, nearby communities and ecosystems requires leak detection and mitigation
measures. The appropriate mitigation measures for ammonia leaks depend on the specific conditions in which
the release is occurring. Enclosed spaces where ammonia is stored or pumped should be continuously vented
November 2022

CHAPTER 6l64and monitored with ammonia detectors because workers, who would otherwise detect leaks based on odor, may
not be present in all of these spaces. This monitor-and-vent strategy prevents accumulation to hazardous levels.
When ammonia is released (intentionally or unintentionally) in open spaces, water may be sprayed to dissolve
released ammonia until concentrations are below hazardous levels. Finally, in cases of over-pressurization oftanks, rapid release using pressure-release valves and flaring may be necessary.35 Regular monitoring of ammonia
concentrations downwind of storage sites and other large infrastructure can also be an effective strategy to ensurethat emissions do not exceed allowable levels. Multiple technologies are available for measuring the concentrationof ammonia in air,36 and these measurements can be used to estimate emission rates from individual sources.

Current and Potential Future Sources of Ammonia Emissions
Ammonia is emitted from a wide variety of anthropogenic and natural sources. Livestock, fertilizer application,
forest fires and biomass burning, soils, concrete treated with urea-based antifreeze, selective catalytic reduction
systems in vehicles, industrial processes, domestic activities such as cooking and cleaning, and even humans
themselves are all sources of ammonia.17 According to US EPA reports, flux measurements from natural vegetation
and agricultural lands have suggested that soil and vegetation can be a source or sink for ammonia.37 However,the combined impact of agricultural activities, including livestock, fertilizer volatilization, emissions from soils andbiomass burning, are estimated to contribute more than 80–90% of global ammonia emissions currently.38-40
Global ammonia emissions in 2012 were estimated to be 58,671 Gg (58.671 million tonnes).41 This includes
emissions from the microbial decomposition of nitrogen-rich material and the application of nitrogenous fertilizer(neither of which are considered leakage). Of that total ammonia emissions value, only 6.346 million tonnes were
estimated to come from non-agricultural sources,41 which includes ammonia slip from SCR systems on motor
vehicles, biomass burning, industrial processes, refrigerant leakage, human waste and natural emissions fromsoils.42 This raises the question: how significant of an impact would novel ammonia applications have on global
ammonia emissions and how might this impact the global nitrogen cycle?
If ammonia emissions from novel uses are driven by leakage, one potentially useful point of reference is methaneleakage in the oil and gas industry. Alvarez et al., 201843 estimated a US-wide methane leakage rate of 2.3% asa fraction of total production. It is reasonable to expect that novel uses of ammonia would result in leakage
at or below this level given that ammonia is more easily detected and mitigated due to the “self-alarming”
characteristic described above, namely its distinctive odor and low detection threshold. Also, while methaneis transported into homes for use in cooking, heating, etc., ammonia storage and use is expected to be more
centralized. Based on an International Energy Agency (IEA) scenario in which 125 million tonnes of ammonia are
introduced for novel uses (power and marine fuels),44 a hypothetical 2.3% ammonia leakage/release rate would
translate to 2.9 million tonnes of additional ammonia released to the atmosphere. Compared to the 58.671
million tonnes emitted in 2012, the result would be a 5% increase in emissions.
Based on these ammonia emissions calculations, the potential increase in ammonia emissions through leakage
is likely to be small relative to existing (and future) agricultural ammonia emissions. However, the magnitudeof global ammonia releases from novel uses ultimately depends on both the leakage rate and total annual
consumption. If either or both of those values greatly exceeds the figures discussed here, ammonia leakage could
become a more significant environmental concern.45
Another issue raised by Wolfram et al., 202245 is the potential for ammonia emissions to drive an increase in
N2O emissions (a potent greenhouse gas) from the microbial process known as denitrification. Based on the
2.3% leakage rate discussed above and a 1.5% conversion of nitrogen in ammonia to N2O in the environment,
the emissions would be an order of magnitude lower than the level estimated to negate low-carbon ammonia’s
climate benefits.

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65

There is still much to be learned about the environmental impacts of increased ammonia use, but the mechanisms
for tracking and limiting these impacts are known. The key to minimizing the impact of increased ammonia
use on air quality, water quality, and human health and safety will be leak detection, regular measurement andmonitoring, and more reliable guidance for where emissions must be limited or avoided altogether based on local
atmospheric and aquatic ecosystem conditions.

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pnas.2121998119 (2022).
35 Niels deVries. Safe and effective application of ammonia as a marine fuel (Student Thesis). Delft University ofTechnology; TU Delft Mechanical, Maritime and Materials Engineering (Marine Technology). http://resolver.tudelft.
nl/uuid:be8cbe0a-28ec-4bd9-8ad0-648de04649b8 (2019).
36 Sanjay B. Shah, Philip W. Westerman & Jactone Arogo. Measuring Ammonia Concentrations and Emissions from
Agricultural Land and Liquid Surfaces: A Review. Journal of the Air & Waste Management Association 56, 945-960,
https://doi.org/10.1080/10473289.2006.10464512 (2006).

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37 US Environmental Protection Agency (EPA). 2017 National Emissions Inventory: January 2021 - Updated Release,
Technical Support Document. US Environmental Protection Agency (EPA) Office of Air Quality Planning and Standards,
Air Quality Assessment Division, Emissions Inventory and Analysis Group. https://www.epa.gov/sites/default/
files/2021-02/documents/nei2017_tsd_full_jan2021.pdf (2021).
38 S. Bittman, S. C. Sheppard & D. Hunt. Potential for mitigating atmospheric ammonia in Canada. Soil Use andManagement 33, 263-275, https://doi.org/10.1111/sum.12336 (2017).
39 L. Zhang et al. Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates. Atmos. Chem.
Phys. 18, 339-355, https://doi.org/10.5194/acp-18-339-2018 (2018).
40 Casey D. Bray et al. Ammonia emissions from biomass burning in the continental United States. Atmospheric
Environment 187, 50-61, https://doi.org/10.1016/j.atmosenv.2018.05.052 (2018).
41 Rong Ma et al. Mitigation potential of global ammonia emissions and related health impacts in the trade network.
Nature Communications 12, 6308, https://doi.org/10.1038/s41467-021-25854-3 (2021).
42 Andrzej Sapek. Ammonia Emissions from Non-Agricultural Sources. Polish Journal of Environmental Studies 22, 63-70(http://www.pjoes.com/Ammonia-Emissions-from-Non-Agricultural-r-nSources,88952,88950,88952.html)(2013 ).
43 Ramón A. Alvarez et al. Assessment of methane emissions from the U.S. oil and gas supply chain. Science 361, 186-188
https://www.science.org/doi/10.1126/science.aar7204 (2018).
44 International Energy Agency. Ammonia Technology Roadmap. (IEA, Paris, 2021 https://www.iea.org/reports/
ammonia-technology-roadmap).
45 Paul Wolfram et al. Using ammonia as a shipping fuel could disturb the nitrogen cycle. Nature Energy, https://doi.
org/10.1038/s41560-022-01124-4 (2022).

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Chapter 7

RESEARCH AND DEVELOPMENT
The research and development (R&D) needs for safely and sustainably scaling up low-carbon ammonia are focusedin four major areas:

1. Developing deep integration schemes with renewable energy, particularly solar, windand biomass, which tend to occur in areas far from ammonia markets.
Production of low-carbon ammonia could be an integral part of a low-carbon economy, but today ammonia
production is not well integrated with non-fossil sources of electricity and heat. While the use of dispatchable
low-carbon energy sources—such as hydro, nuclear and geothermal—is relatively straightforward, utilizing solar
and wind power for ammonia production will require R&D to develop intermittent operation schemes. The
appropriate balance among strategies that enhance the operational flexibility of ammonia production, strategies
that buffer variable power production through energy storage, and strategies that store produced hydrogenremains unclear and likely depends strongly on local grid conditions, the cost of energy and hydrogen storage, andammonia demand.
The potential for using biomass as a hydrogen source through biomass carbon removal and storage (BiCRS)
methods, as outlined in the 2021 ICEF Roadmap, is an important option for ammonia production. Biomass-based
systems can also provide required heat and power. Developing integrated biomass-based ammonia production,with efficient heat integration and tolerance of heterogeneous biomass feedstocks, requires significant R&D andprocess engineering.
The availability of large amounts of variable renewable power and biomass is often largest in regions that arefar from centers of ammonia demand. This implies that green ammonia production will be accompanied bylong-distance bulk transportation from these resource-rich regions to key markets. (In some cases, smaller-scale,
distributed low-carbon ammonia production may be preferable given these constraints.) While a large amountof planned low-carbon ammonia production is located in developing countries, projects are also being pursued
in countries such as Sweden, Spain and Chile. For blue ammonia, the availability of pore space for CO2 storage
may similarly be far from ammonia demand centers. Because of these factors, R&D is needed to improveunderstanding of the optimal global-level logistics of production, transportation and distribution of low-carbon
ammonia, which may differ significantly from conventional ammonia infrastructure.
Finally, these large-scale integrated efforts need careful evaluation of the carbon intensity of all parts of the
supply chain to ensure that integrated efforts are in fact more carbon- and energy-efficient than separated
processes. This need for full life-cycle analysis exists throughout the various futures for ammonia (as fertilizer,
fuel or hydrogen source) and most effectively will include direct comparison to the alternative ways of making,transporting and using ammonia in a clean energy economy. These global-scale evaluations need to consider the
local advantages that can accrue from heat integration or use of novel resources, such as biomass.

2. Increasing life-cycle energy efficiency and reducing capital intensity.
Conventional ammonia synthesis plants are highly optimized, with well-engineered approaches to heat integrationand energy efficiency. Low-carbon ammonia production will require renewed attention to these issues and new
approaches to efficiently reuse produced heat. For example, the Haber-Bosch synthesis loop itself is exothermic,
which could potentially enable heat integration with green hydrogen production using solid oxide electrolysis cells(SOECs), which operate at high temperature. In the case of blue ammonia, carbon capture systems require heatfor sorbent regeneration, which could also benefit from heat integration. R&D activities in this area include fullNovember 2022

CHAPTER 7l69system analysis of heat integration opportunities across a variety of low-carbon ammonia plant configurations andcorresponding process design.
Improved catalysts could also provide improved energy efficiency, although current catalysts are highly optimized
and will be economically difficult to replace. However, some promising concepts have emerged, such as more
efficient use of expensive ruthenium and cobalt catalysts and the use of cocatalysts to weaken the nitrogen triple
bond. Increasing catalyst resistance to poisoning will also improve overall efficiency. R&D is needed to improvecatalyst design; improved catalysts could increase per-pass ammonia conversion efficiency, thus improving thecapital efficiency of the reactor.
Reducing the operating temperature for ammonia synthesis is a high-profile target for R&D. Along with catalyst
improvement, process changes such as removing ammonia continuously from the reactor could improve efficiency
and reduce required operating temperature.
Direct electrolytic production of ammonia has not been utilized to date because of its poor selectivity forammonia over hydrogen evolution at the cathode, in addition to energy loss due to the evolution of oxygen at
the anode. However, recent progress in areas such as lithium-mediated electrochemical ammonia synthesis isencouraging, and this general area should continue to be a focus of R&D.1,2
One of the most direct ways to improve ammonia production is to reduce the cost and carbon footprint ofhydrogen electrochemical production. R&D opportunities in this space have been outlined in a number ofpublications, including NREL,3 IRENA,4 US DOE5 and IEA.6 Key areas for innovation include increasing the lifetime ofcatalysts and systems for hydrogen evolution and reducing manufacturing and material costs.

3. Ensuring that we understand and can manage any safety and environmental
risks.
Ammonia has clear safety hazards that are well understood by industry and appear manageable in most industrial
settings. However, consideration of the additional issues presented by transportation and large-scale use as astationary fuel is needed. While crop and livestock production remain the dominant sources of ammonia in air
and water, novel uses of ammonia can exacerbate these environmental impacts. The degree to which increased
ammonia production and use impacts air and water quality is a function of the overall scale, leakage rate, andlocal air and water chemistry. Local environments may experience increased atmospheric PM2.5 concentrations as
a result of ammonia leakage. The impact of additional ammonia emissions, especially to the aquatic environment,
needs evaluation, both as a function of local environmental impacts and as an overall examination of likely
leak rates. Although there are no red flags at this time, with possible large-scale increases in global ammonia
production, transportation and use, it is important to confirm that global climate effects will truly be limited.
Ammonia can interact with other pollutants, including NOx, to form harmful fine particulates in the air. Given thepotential for synergistic effects between ammonia and NOx emissions in terms of secondary particle formation,
the net effects of ammonia combustion on NOx emissions must be further studied, monitored and controlled.
This synergistic effect between NOx and ammonia is particularly concerning in areas with poor air quality, given thepotential for even greater damage to human health. However, R&D is needed to identify areas where increasing
the level of ambient ammonia might trigger significant additional PM2.5 formation. Many agricultural areas alreadyhave more ammonia than NOx, implying that increased ambient ammonia would not lead to increased PM2.5
formation. This issue is extremely important and should be resolved before large-scale ammonia infrastructure isexpanded, especially in seaports, which tend to have low ammonia levels, and where PM2.5 levels could increase
with ammonia leakage. R&D should focus on improving understanding of where new ammonia use is likely toresult in significant increases in PM2.5 formation, including the role of NOx and SOx. A closely related R&D topic
is determining whether there are classes of areas where ammonia usage should be avoided because of a highpotential for significantly increasing air pollution.
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R&D should also evaluate the levels of overall ammonia leakage that are likely to result from increased ammonia
use, with both modeling and measurement of existing facilities. The devices and systems required to make thesemeasurements must be developed and demonstrated to have appropriate sensitivity levels. In general, ammonia
does not tend to persist in indoor air (especially in facilities with well-managed ventilation systems), but themechanisms by which it is removed from outdoor air need to be reexamined with global impacts in mind. Aquatic
impacts are of particular interest and may require new levels of sensitivity.
These ecological (as opposed to climate) impacts are one of the most concerning for large-scale utilizationof ammonia as an energy carrier. Immediate attention to realistic leakage rates and the impacts of theseemissions, coupled with an ability to measure and eliminate leaks on an active basis, must be given to a variety ofenvironments and regions. Ammonia leakage impacts may be quite different in different places, depending on leakrate and local environment: these differences could range from small to significant. Substantial R&D is warranted.
The second major possible impact of ammonia use as an energy carrier is NOx production from burning it as
a fuel. While our roadmap makes it clear that fuel-cell use is much more efficient, there is current interest in
using ammonia as a combustion fuel. Rates of NOx production need to be evaluated, and effective engines andpollution-control equipment must be developed to ensure that levels of NOx emissions are extremely low. For
ocean applications, NOx may have ecological impacts on plankton blooms and other aquatic life. This is anotherhigh priority area of research but may not be as localized as the ammonia leakage impacts. Closely linked to theecological aspects are the possibility that marine exhaust could change cloud formation and albedo, thus affecting
climate.
Research on the combustion characteristics of ammonia, either as neat fuel or as an additive, should be
conducted under a variety of conditions. Particularly since ammonia affects flame speed, the details of individual
uses need to be carefully examined. Engines using ammonia require attention for both overall efficiency andfundamental pollution control.
Hazards to human health and safety are well understood because of existing industrial and agricultural usesof ammonia, but R&D for design of safe, large-volume transportation options is warranted. Safety systems onboard ships carrying large amounts of ammonia deserve special attention. A study indicating that lubricating
oil contamination can reduce the lower flammability limit to 8% suggests that, in cases where contamination
or intentional blending of ammonia with other substances will take place, safety standards should be updated
accordingly based on the behavior of these mixtures.7 R&D should therefore include a broad-ranging assessmentof the interaction of ammonia, both neat and mixed, with combustion and engine systems.

4. Ensuring that energy and climate impacts of ammonia use are wellunderstood.
Hydrogen production, ammonia combustion and increased emissions from ships over the open ocean all havesecond-order climate effects that need to be evaluated. In many cases, these are tradeoffs (e.g., methanol vs.
ammonia) whose climate impacts should be more carefully quantified than has been done to date. These are
not so much questions of the direct impacts of ammonia usage as outlined in the previous R&D descriptions but
rather assessments of the overall system impact and comparisons to the alternative means by which services
could be obtained. These are questions principally of analysis, and not research, but they are pressing andimportant.
When considering the round-trip efficiency of ammonia used as a transport fuel or used in ammonia-fired turbines
for power generation, R&D is necessary to understand how energy is converted along the supply chain and how
leakage could contribute for the full cycle of production and use. The same context is required to evaluate theenvironmental impacts of global schemes for use of ammonia as an energy transport method. Immediate R&D
should be conducted on the benefits of ammonia versus hydrogen or other energy carriers like methanol. A fullNovember 2022

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life-cycle and environmental-impact assessment needs to be done to consider these questions and questions we
do not even know we should be asking today. For example, it remains unclear at what point in an energy system
it would make sense to crack ammonia to hydrogen for use as a fuel. Further, unless this and related issues areanalyzed at the system level, local decisions could be made that lock in undesirable outcomes.
As ammonia gains attention for use as maritime fuel and consideration as a fuel for stationary power, there
are significant system questions to be asked about energy uses that may be quite different from the existing
agricultural transport and use of ammonia. These questions include evaluation of the critical infrastructure needs
for low-carbon ammonia, such as pipelines or reforming stations to turn ammonia back into hydrogen (cracking).
The most efficient places in the transport chain should be evaluated. Are centralized or local facilities betterfor energy and the environment? And do those answers vary by region? Evaluating current ammonia-handlingfacilities and their cost and environmental impact may give insight into that problem. Tracking existing shipping
can point out places to examine environmental impacts. Pipeline transport and storage of ammonia should be
evaluated in terms of the energy value and issues of safety and environment. A related question is whether it ispossible to convert existing LNG facilities to handle ammonia. Life-cycle assessment approaches that are uniform
and, to the extent possible, technology neutral, need to be developed to make these evaluations.
Demand for ammonia is currently predicted to grow 40% for just conventional usage by 2050, and required energy
use would increase significantly. Realistic and publicly available assessments of ammonia demand should be
developed at a regional scale to help governments plan for ammonia use and regulation.
Technology to enable ammonia use in energy systems will need significant R&D if it is to be added to existing
systems. This includes ammonia combustion needs and challenges, spark versus compression engines, and otherengine design issues. How would NOx controls be added to stationary power sources fueled by ammonia? What
are the most efficient ammonia-cracking methods, and can they be integrated with other activities to be moreenergy efficient?
Finally, what application areas are likely to adopt low-carbon ammonia the earliest? Immediate R&D on thecommercial and policy drivers that will increase ammonia use in energy systems should be done to inform
regulators, policy makers and researchers working on the questions listed above. Questions such as the possibleamount of fuel-switching in existing facilities are currently hard to evaluate and deserve immediate attention.

REFERENCES
1

Runbo Zhao et al. Recent progress in the electrochemical ammonia synthesis under ambient conditions. EnergyChem 1,
100011, https://doi.org/10.1016/j.enchem.2019.100011 (2019).

2

Channing K. Klein & Karthish Manthiram. Sustainable ammonia synthesis: Just around the corner? Joule 6, 1971-1973,https://doi.org/10.1016/j.joule.2022.09.001 (2022).

3

Ahmad Mayyas et al. Manufacturing Cost Analysis for Proton Exchange Membrane Water Electrolyzers National
Renewable Energy Laboratory (NREL/TP-6A20-72740). https://www.nrel.gov/docs/fy19osti/72740.pdf (2019).

4

IRENA. Green Hydrogen Costreduction: Scaling Up Electrolysers to Meet the 1.5°C Climate Goal. International
Renewable Energy Agency. https://irena.org/-/media/Files/IRENA/Agency/Publication/2020/Dec/IRENA_
Green_hydrogen_cost_2020.pdf (2020).

5

US Department of Energy. Advanced Liquid Alkaline Water Electrolysis Experts Meeting (Summary Report). US
Department of Energy (DOE) Office of Energy Efficiency & Renewable Energy (EERE) Hydrogen and Fuel Cell
Technologies Office. https://www.energy.gov/sites/default/files/2022-04/liquid-alkaline-electrolysis-expertsmeeting-report.pdf (2022).

6

International Energy Agency. Electrolysers. International Energy Agency. https://www.iea.org/reports/electrolysers(2022).

7

D L Fenton et al. Combustion characteristics review of ammonia-air mixtures. Annual meeting of the American Societyof Heating, Refrigeration and Air-Conditioning Engineers, Inc. (ASHRAE) (CONF-950624-; Journal ID: ISSN 0001-2505).
pp. 476-485 (https://www.osti.gov/biblio/215705) (San Diego, California, United States, 1995)

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Chapter 8

POLICY
Policy support will be essential to substantially increase production anduse of low-carbon ammonia.
At present, barriers to the growth of low-carbon ammonia are significant.
• Production costs are high.
• Infrastructure for distributing low-carbon ammonia is inadequate.
• Financing barriers limit the private capital available for project

development.
• Markets rarely value low-carbon attributes in fuels or other products.

Government policies can play a central role in overcoming these andother barriers. Indeed government policies have played a central role inrecent years in the growth of several clean energy technologies, including
solar power, wind power and electric vehicles. Policies broadly similar to
those that have accelerated the deployment of these technologies could(with some differences and adjustments) do the same for low-carbon
ammonia.
In the past several years, national hydrogen strategies have proliferated,recognizing the central role hydrogen can play in decarbonization.1 Manyof these hydrogen strategies contain policies directly relevant to lowcarbon ammonia, including research and development funding, budget
support for infrastructure development, public partnerships and more.
Some of these hydrogen strategies already address low-carbon ammonia(such as the Japanese government’s target of 3 million tons (Mt) of low-carbon ammonia demand by 2030), butthat is not universal.2
One simple step governments could take is to highlight low-carbon ammonia more centrally in their nationalhydrogen strategies. Ammonia will often be the best hydrogen carrier and, as a result, should always be
considered as governments develop these strategies. National hydrogen strategies can highlight the potential forbusinesses in a number of sectors to use low-carbon ammonia.
Inter-ministerial coordination will also be important. Policies on low-carbon ammonia may involve energy
ministries, environment ministries, agriculture ministries, labor ministries, transport ministries, finance ministries
and others. Some governments have well-developed tools for coordinating among these different departments;
other governments have less well-developed tools. Engaging stakeholders with a broad range of interests andexpertise in the most efficient manner will lead to better policy making.
One central point: governments should promote the optimal use of low-carbon ammonia within a broad portfolio
of decarbonization strategies—not simply strive for the maximum use of low-carbon ammonia everywhere.
Low-carbon ammonia will provide a compelling decarbonization strategy in some sectors but not in others.
In agriculture and shipping, for example, the potential for low-carbon ammonia to contribute to emissions
reductions is already clear. (See Chapter 5 – Uses of Low-Carbon Ammonia.) In other sectors, the potential is lessclear. The sectors and sub-sectors that will benefit the most from low-carbon ammonia will emerge with time, as
technologies and markets develop in the years ahead. Governments should help low-carbon ammonia overcome

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CHAPTER 8l73market barriers and provide the enabling environment for it to scale, while always proceeding based upon analysis
with respect to optimum decarbonization strategies.
Policymakers have sometimes focused support on a particular “color” of ammonia over others. While this is basedon a desire to accelerate decarbonization, reliance on color-based descriptors of ammonia (such as green or blue)
as a basis for policy support risks sub-optimal or even counterproductive results. Life-cycle carbon emissions
within each color category can vary significantly, and there is no guarantee that ammonia labeled green, blue orother is actually contributing significantly to decarbonization. Policy support for accelerating low-carbon ammonia
should be based on a technology-neutral approach that measures life-cycle carbon intensity.
A number of policies could help low-carbon ammonia reach its full potential. We consider those policies in four
categories below.

A. DEMAND-SIDE POLICIES
Government policies can play a central role in building demand for low-carbon ammonia.
1. Carbon pricing. Historically, manufacturers of conventional ammonia have been able to externalize theclimate change costs of their product, venting carbon dioxide (CO2) into the atmosphere for free. Carbon
pricing corrects this market imperfection by charging emitters (including manufacturers of conventionalammonia) for their CO2 emissions. This allows low-carbon ammonia to compete in the marketplace on amore level playing field against conventional ammonia.
Carbon pricing programs come in two broad categories—carbon taxes and emissions-trading programs.
Under carbon tax regimes, emitters are charged for every ton of CO2 emitted. Under emissions trading
programs, the right to emit CO2 requires a permit. Governments give or sell these permits to emitters, who
may then trade the permits among themselves. Under many emissions trading programs, governments
gradually reduce the number of permits (often called emissions allowances), thereby reducing total
pollution.
Roughly 36 jurisdictions around the world have carbon tax programs. Emissions trading programs for CO2
are now in place in the European Union, China, California, the northeast United States and Canada, among
other places. In general, prices under these programs have been too low to motivate significant increases indemand for low-carbon products.3,4
2. Low-carbon fuel standards. A low-carbon fuel standard requires fuel sellers to reduce the life-cycle carbon
intensity of their fuels over time. California has the world’s leading low-carbon fuel standard.5
Low-carbon fuel standards could help significantly to bring low-carbon ammonia to market. Ammonia
produces no greenhouse gases when burned, and low-carbon ammonia—by definition—produces very
little heat-trapping gasses during the manufacturing process. Low-carbon ammonia can be an importantcompliance option for a range of industries facing low-carbon fuel standards.
3. Power plant CO2 emissions standards. Emissions standards can require power plants to reduce their CO2
emissions over time. Compliance strategies can include fuel shifting and/or co-firing with a clean fuel suchas low-carbon ammonia. Japanese power plants are increasingly using low-carbon ammonia to help
achieve emissions targets.6
4. International Maritime Organization (IMO) guidelines. The IMO is a specialized agency of the United
Nations responsible for improving the safety of international shipping and preventing pollution from ships.
In 2018, the IMO’s Marine Environment Protection Committee (MEPC) adopted a resolution setting forthan Initial Strategy for reducing greenhouse gas emissions from ships. The Initial Strategy calls for peaking

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greenhouse gas emissions from ships as soon as possible, steadily reducing greenhouse gas emissions
intensity of shipping in the years ahead and cutting total annual greenhouse gas emissions from shipping by
50% by 2050.7
Ammonia has significant potential to help the shipping industry achieve these goals (see Chapter 5 – Uses of
Low-Carbon Ammonia), but that will require the IMO to develop guidelines on several topics.
Guidelines on the safe handling of ammonia on ships are essential. Risks to personnel and marine life in theevent of release should be addressed. Work on this topic is already underway by an IMO subcommittee,
with a target completion date of 2023 for the first stage.8 These guidelines will need to be continuallydeveloped and elaborated in the years ahead.
Guidelines on life-cycle assessments of greenhouse gas emissions from ammonia fuels will also be essential.
Initial work on this topic is underway by an IMO subcommittee as well.9
5. Government procurement. In many countries, government procurement makes up more than 10% of
GDP.10 This spending provides an important opportunity to jumpstart markets for new products with publicbenefits, such as low-carbon ammonia. First, government purchase contracts can provide manufacturers
with an assured market, which can be especially important in securing debt capital. Second, government
purchases can help establish standard technical specifications for new products, which can help catalyze
efficient supply chains.
Governments are major purchasers of bunker fuels and other products in which low-carbon ammonia
could play a role. Coast Guards around the world provide a perfect opportunity to begin scaling up the useof low-carbon ammonia, in part because Coast Guard vessels often return for refueling to the same port
where they launched. As a result, the operators of most Coast Guard vessels powered by ammonia would
not be constrained by the lack of low-carbon ammonia infrastructure at remote locations.11,12 Establishingstrong preferences for low-carbon ammonia in government procurement could help jumpstart markets andpromote low-carbon ammonia as a climate solution.

B. SUPPLY-SIDE POLICIES
1. Government Support for R&D. National governments spend at least $30 billion annually on R&D for clean
energy technologies. These programs have played important roles in developing countless technologies inrecent decades.13
As set forth in Chapter 7, R&D on a range of topics are important for low-carbon ammonia to reach its fullpotential. Priority topics include the following:— Electrochemical reduction of nitrogen to ammonia— Integration of ammonia production with renewable energy sources— Better catalysts for ammonia production to reduce temperatures required for operation— Reducing CO2 emissions from blue hydrogen production— Climate change impacts of ammonia leakage
Much of this research involves fundamental science or pre-commercial topics that private companies
have little incentive to fund. As a result, government funding for research on these topics will be essential.
National governments, including those in the United States, Japan, the European Union, Russia and China,
have historically provided most of the support for fundamental science and pre-commercial research.

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In June 2021, ministers from more than 20 countries announced Mission Innovation 2.0, pledging “a decadeof innovation to catalyze increased investment in clean energy research, development and demonstrations
to deliver affordable clean energy solutions by 2030.”14 Member governments include Japan, the UnitedStates, China, the United Kingdom, Germany and Saudi Arabia. The resulting increase in government R&D
budgets in these countries in the years ahead offers an opportunity to increase R&D funding for low-carbon
ammonia.
2. Loan guarantees. Cutting the cost of debt capital can help make a project financially viable. Government
loan-guarantee programs seek to do this by reducing risk to lenders, resulting in lower borrowing costs.
The US Department of Energy’s loan-guarantee programs helped launch the utility-scale solar industry
in the United States, among other successes. Loan guarantees for the capital expenditures required for
manufacture of low-carbon ammonia could significantly speed deployment.

C. ENABLING POLICIES
1. Accelerated permitting processes. For low-carbon ammonia to play a significant role in decarbonization,
significant new infrastructure will be needed. New and expanded ports and pipeline networks will beessential. Although requirements vary significantly from jurisdiction to jurisdiction, such infrastructure
typically requires regulatory approvals and permitting. Policies that give priority to low-carbon projects andrecognize the public interest in expeditious review processes would help facilitate scale-up of necessary
facilities.
In many jurisdictions, environmental and occupational safety permits may be required for operation ofammonia facilities. These permitting procedures may often be important for public health and safety. They
may also help minimize the risk of accidents that could tarnish the industry’s reputation and slow its growth.
Clear and uniform environmental and occupational standards, applied in a transparent and expeditious
manner, can help support growth of the low-carbon ammonia industry.
2. Public-private partnerships. Public-private partnerships play an important role in the development ofports in many countries. One standard model is for a public sector agency to own the port land and be
responsible for developing the port, with private entities responsible for port operations.15 National legal
frameworks that facilitate establishment of such public-private partnerships for ports designed to handle
low-carbon ammonia could help accelerate the development of critical infrastructure.
Related to this, some government programs provide grant or debt financing to port developers. In the
United States, for example, the federal government’s Port Infrastructure Development Program provides
planning grants, as well as operational and capital financing, to assist with port development.16 Suchprograms can de-risk and accelerate development of critical infrastructure for low-carbon ammonia.
3. Life-cycle emissions methodologies. Widely accepted methodologies for evaluating the life-cycle
greenhouse gas emissions of low-carbon ammonia can play an important role in growing the industry.
Buyers will want assurances with respect to the low-carbon attributes of their ammonia, and government
agencies will need to establish eligibility criteria to determine whether ammonia supplies qualify forfavorable treatment under low-carbon incentive programs. This issue will arise soon in the context of theEuropean Union’s Carbon Border Adjustment Mechanism, which will cover imports of ammonia to theEuropean Union.17 Reliable, transparent methodologies for evaluating life-cycle emissions for ammonia canalso help reduce confusion and mislabeling associated with the current ad hoc system of colors (e.g. blue,
green, etc.) that do not truly capture the full emissions impacts of different ammonia production methods.

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A growing body of research explores this topic globally.18-20 Government funding is essential to support
this work. Governments can also help by convening key stakeholders in expert dialogue and by recognizing
consensus results in regulatory programs.

D. REGULATORY ISSUES
1. Water and air quality regulations. Governments around the world regulate ammonia to protect water andair quality.21,22 Some of these regulations focus directly on ammonia; others focus more broadly on nitrogen
pollution (for which ammonia is often the principal source).
Low-carbon ammonia is identical to the conventional ammonia for which these regulations were developed.
(The difference is in the production method, not the final product.) As a result, regulations developed
for conventional ammonia should be mostly applicable to low-carbon ammonia. However, novel uses ofammonia may create new risks. Regulators should be attentive to these as the industry develops
2. Worker health and safety regulations. Governments around the world regulate ammonia to protect
worker health and safety. A 2016 study identified dozens of worker health and safety regulations related toammonia globally.23 These regulations are designed to address two principal types of hazards: those related
to loss of containment and those related to rapid phase change.
As noted just above, low-carbon ammonia is identical to the conventional ammonia for which theseregulations were developed. However, many of the use cases for low-carbon ammonia may be quite
different than those for conventional ammonia. (Conventional ammonia is rarely used as a bunker fuel,for example, or to co-fire coal in power plants.) As new use cases for ammonia are developed in the years
ahead, attention to worker health and safety considerations will be essential. In the shipping sector andelsewhere, this may require new analyses as ammonia begins to be used at a large scale in new ways.

REFERENCES
1

KPMG. National hydrogen strategies: An update on recent progree in the hydrogen markets. https://home.kpmg/xx/
en/home/insights/2021/08/national-hydrogen-strategies.html (Accessed September 2022).

2

Reuters. Japan aims to boost ammonia fuel demand to 3 mln tonnes a year by 2030. https://www.reuters.com/
article/japan-energy-ammonia-idUSL4N2KE2HE (2021).

3

WorldBank. State and Trends of Carbon Pricing 2022 (License: CC BY 3.0 IGO). The World Bank. https://
openknowledge.worldbank.org/handle/10986/37455 (2022).

4

C2ES. Carbon Tax Basics. Center for Climate and Energy Solutions. https://www.c2es.org/content/carbon-tax-

basics/#:~:text=A%20number%20of%20countries%2C%20regions,had%20carbon%20tax%20since%202008(Accessed September 2022).

5

CRS. A Low Carbon Fuel Standard: In Brief (R46835). Congressional Research Service. https://sgp.fas.org/crs/misc/
R46835.pdf (2021).

6

Katsumori Matsuoka. Will Japan run on ammonia? . Chemical and Engineering News (C&EN). https://cen.acs.org/
business/petrochemicals/Japan-run-ammonia/100/i14 (2022).

7

International Maritime Organization (IMO). Greenhouse Gas Emissions. International Maritime Organization. https://www.imo.org/en/OurWork/Environment/Pages/GHG-Emissions.aspx (2020).

8

IBIA. IMO to develop guidelines for safe use of ammonia. International Bunker Industry Association. https://ibia.
net/2022/05/04/imo-to-develop-guidelines-for-safe-use-of-ammonia/ (Accessed September 2022).

9

Aly Shaw & Tristan Smith. An overview of the discussions from IMO MEPC 78. UMAS. https://www.u-mas.co.uk/
wp-content/uploads/2022/06/MEPC-78-overview-UMAS.pdf (2022).

10 Erica Bosio & Simeon Djankov. How large is public procurement? World Bank Blogs. https://blogs.worldbank.org/
developmenttalk/how-large-public-procurement (2020).

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11 US Naval Institute. World’s Coast Guards. US Naval Institute. https://www.usni.org/taxonomy/term/300 (Accessed
September 2022).
12 Julio Friedmann. Time for the Ammonia Coast Guard! Carbon Wrangler. https://carbonwrangler.medium.com/
time-for-the-ammonia-coast-guard-bd9b7593428b (Accessed September 2022).
13 International Energy Agency. Special Report on Clean Energy Innovation: Accelerating technology progress for asustainable future (at p. 36); In: Energy Technology Perspectives 2020. International Energy Agency (IEA) Directorate
on Sustainability, Technology ad Outlooks (STO); Energy Technology Policy Division. https://iea.blob.core.windows.

net/assets/04dc5d08-4e45-447d-a0c1-d76b5ac43987/Energy_Technology_Perspectives_2020_-_Special_
Report_on_Clean_Energy_Innovation.pdf (2020).

14 Mission Innovation. Mission Innovation launches a decade of clean energy innovation to accelerate achieving theParis Agreement Goals. Mission Innovation. http://mission-innovation.net/2021/06/02/decade-clean-energyinnovation-mi-6/ (2021).
15 The World Bank. Public Private Partnerships in Ports / Port Reform. https://ppp.worldbank.org/public-privatepartnership/sector/transportation/ports (Updated 2021).
16 US Department of Transportation Maritime Administration. Port Infrastructure Development Program Grant
Information. https://www.maritime.dot.gov/ports/port-infrastructure-development-program (Accessed
September 2021).
17 Julian Atchison. EU policy developments: CBAM & rules for emissions accounting. Ammonia Energy Association. https://www.ammoniaenergy.org/articles/eu-policy-developments-cbam-rules-for-emissions-accounting/ (2022).
18 Mohammed Al-Breiki & Yusuf Bicer. Comparative life cycle assessment of sustainable energy carriers including
production, storage, overseas transport and utilization. Journal of Cleaner Production 279, 123481, https://doi.
org/10.1016/j.jclepro.2020.123481 (2021).
19 Luis F. Razon & Agustin Valera-Medina. A Comparative Environmental Life Cycle Assessment of the Combustion ofAmmonia/Methane Fuels in a Tangential Swirl Burner. Frontiers in Chemical Engineering 3, https://doi.org/10.3389/
fceng.2021.631397 (2021).
20 Chris Lawson. Quantifying the emissions footprint of the nitrogen industry. Ammonia Energy Association. https://www.
ammoniaenergy.org/paper/quantifying-the-emissions-footprint-of-the-nitrogen-industry/ (2021).
21 US Environmental Protection Agency (EPA). Aquatic Life Ambient Water Quality Criteria for Ammonia - Freshwater 2013.
Regulations.gov. https://www.regulations.gov/document/EPA-HQ-OW-2009-0921-0058 (2013).
22 David R. Kanter et al. Gaps and opportunities in nitrogen pollution policies around the world. Nature Sustainability 3,
956-963, https://doi.org/10.1038/s41893-020-0577-7 (2020).
23 Mark Fecke, Stephen Garne & Brenton Cox. Hazards 26: Review of Global Regulations for Anhydrous Ammonia
Production, Use, and Storage. IChemE: Institution of Chemical Engineers. https://www.icheme.org/media/11771/

hazards-26-paper-34-review-of-global-regulations-for-anhydrous-ammonia-production-use-and-storage.pdf(2016).

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Chapter 9

FINDINGS AND
RECOMMENDATIONSFINDINGSFINDING 1: Low-carbon ammonia could produce significant greenhouse gas reductions in key sectors this decadeand deep reductions in some sectors by 2050. Low-carbon ammonia could have applications inagriculture, transportation and power. Two key sectors stand out: fertilizers and maritime shipping.
Current supply chains for ammonia production and transport are large and able to grow. The
substantial existing market for conventional ammonia provides experience, standards and immediatemarket opportunities for low-carbon ammonia (notably in fertilizer production). The potential toreplace fossil fuels with low-carbon ammonia at scale is not limited globally by natural resources or
critical minerals (although local limits can be substantial).
FINDING 2: There are no technical barriers to producing low-carbon ammonia in large volume before 2030.
Low-carbon ammonia can be produced from low-carbon hydrogen production (e.g., blue, green, biohydrogen) and Haber-Bosch process synthesis. Green hydrogen production faces manufacturing limits(for electrolyzers) and siting constraints (for transmission and generation of zero-carbon electricity)that must be addressed to scale rapidly. Blue hydrogen supply is chiefly limited by CO2 transport andstorage access and can be accelerated by adding carbon capture to existing ammonia production units
and new projects. Local factors—such as the availability and price of low-carbon electricity, natural gas
prices and proximity to CO2 storage—will determine the relative cost of blue and green ammonia indifferent locations.
FINDING 3: Cost is the chief barrier to deployment. The use of low-carbon ammonia for fertilizer production
would raise the cost of food and fiber production. When used as a fuel, low-carbon ammonia would
cost substantially more than natural gas, coal, diesel or even hydrogen on an energy-density basis. It
would also require additional capital expense to retrofit existing assets, such as engines and turbines.
To achieve widespread deployment, production costs must be substantially reduced. This can beachieved through a combination of cost reductions and demand-support policies, such as incentives
and mandates.
FINDING 4: Safety and environmental risks from ammonia scale-up will require attention and management. The
large global ammonia industry today has deep experience in managing the safety risks of ammonia, as
well as many of the key environmental risks. Preventing large uncontrolled releases will continue to be
essential, requiring robust safety measures and worker training. In general, more gradual releases are
relatively easily detected because ammonia has a strong aroma at low levels, allowing operators andcommunities to identify leaks before they pose a significant human health or flammability concern.
(Unpopulated locations require automated sensors.) Ammonia emissions can impact air quality andhuman health by contributing to the formation of fine particulate matter (PM2.5) in some regions,particularly in urban and industrial areas without other background ammonia emissions sources.
Novel uses are likely to cause a small increase in global ammonia emissions. More research is needed
to understand the impact of ammonia emissions on air quality.
FINDING 5: Global low-carbon ammonia trade will require infrastructure investment and more ships. Although
there are a substantial number of ammonia terminals and long-haul ships today, more infrastructure
will be necessary for use of low-carbon ammonia to grow. This need is particularly acute in regions ofNovember 2022

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new supply (e.g., Chile, North Africa, northwest Australia) and new demand (e.g., Singapore, North
Sea). While no technical barriers prevent scale-up, there will likely be issues with siting, permitting andconstruction of new docks, storage and pipelines. Building such infrastructure often involves long leadtimes.
FINDING 6: Before low-carbon ammonia can deliver substantial abatement of greenhouse gas emissions, morework on applications is a priority. Ammonia use is the least mature component of low-carbon
ammonia value chains and therefore the area that would most benefit from investment in innovation.
Potential applications span all major emitting sectors.
• Fertilizer provides the most immediate and one of the largest applications for low-carbon ammonia.

Use of low-carbon ammonia requires little or no operational changes.
• Shipping is a very high-impact application with high decarbonization potential. Some use can begin

today by blending in existing ships and engines (with some modification of maritime architecture).
High levels of blending and fuel substitution require additional innovation to scale.
• Power-sector applications require advances in blending and feed systems, combustion science,ammonia fuel cells, environmental hazard management and improved efficiency of use.
• Heavy-industry applications require the same advances as power sector applications, with special

focus on ammonia as a low-carbon fuel for producing steel, cement, glass and chemicals/refining.
In some cases, it may prove easier to use hydrogen reconstituted from ammonia rather than to use
ammonia directly.
• Low-carbon ammonia for transport applications, such as trucks, trains and aircraft, could become

useful but face a wider set of competing technology options and may prove less important.
A long-lived, substantial innovation program focused on ammonia use in many sectors with manytechnology pathways could help identify the most promising early pathways and most profoundopportunities for decarbonization. Even then, analysis, practical experience and input costs may
determine that low-carbon ammonia is not cost competitive for many applications.
FINDING 7: Very few countries have policies that support low-carbon ammonia today. While roughly 35 nations
have low-carbon hydrogen policies (mostly production and use), very few have policies tailoredto the potential or the specific requirements of ammonia. This includes a lack of policies focusedon ammonia infrastructure, innovation, supply creation or specific economic applications (e.g., inagriculture, shipping or power). Few countries today have supporting policies of sufficient scale anddurability to overcome the economic hurdles. (Japan provides an important exception, supporting
industrial transition to ammonia fuels, infrastructure support, international policy for low-carbon
production and a green-premium for low-carbon ammonia supply.) Because the low-carbon attributes
provide the key rationale for low-carbon ammonia, life-cycle accounting and standards will underlie
market structures and investments. Without policies that close the cost gap or value the low-carbon
attributes (such as those in Japan), the market will remain small and stagnate.
FINDING 8: Low-carbon ammonia trade could have geopolitical implications. Because low-carbon ammonia can beproduced in many geographies and help decarbonize many sectors, its trade may create new bilateralenergy and investment relationships. Like liquified natural gas (LNG), low-carbon ammonia requires
special infrastructure and could be traded with bilateral agreements and investments. Nations
may increase their production and import of low-carbon ammonia as part of their broader climate
strategies. Since many potential suppliers lie in the Global South and are not traditional petrostates,
there is an opportunity for new global energy players to emerge, counterbalancing traditionalenergy suppliers. Developed countries may choose to redress some North-South inequities throughdevelopment investment in low-carbon ammonia in these countries.
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RECOMMENDATIONSRECOMMENDATION 1:
Governments should support investment in new low-carbon ammonia supplies. Governments should
consider fast-track permitting for early demonstration projects for low-carbon ammonia production as a meansof accelerating learning and greenhouse gas reductions. Nations and provinces without the appropriate mix ofnatural resources for primary production should pursue investments in regions hosting the appropriate resourcesand governance structures for speed, scale and cost, possibly as bilateral agreements. Analysis may reveal specificrecommendations for investment that also achieve important national and regional geopolitical goals and provide
a vector for sustainable development, energy access and wealth-creation in developing regions. Quantitative lifecycle emissions accounting—rather than qualitative green/blue designations—is essential to ensure production istruly low-carbon. Further, life-cycle emissions accounting must eventually be codified in standards and regulations.

RECOMMENDATION 2:
Governments should launch a set of public-private partnerships to plan, develop and finance key
infrastructure for low-carbon ammonia production, transportation and use. The economies of scale in ammonia
drive very large projects with large capital requirements. Dedicated policies to stimulate low-carbon ammonia
infrastructure investments must feature prominently in policy design and legislative process since dedicatedinfrastructure is needed for ammonia production, transportation, use and health/risk management. Public-private
partnerships would reduce risk and crowd in private capital for key infrastructure projects, including electrictransmission lines, CO2 transportation and storage, ammonia fueling and storage systems, and pipeline upgrades.
In particular, ports for import, export and bunkering—especially industrial ports—represent chokepoints for tradeand deployment and should receive immediate focus for retrofit, new construction and permitting.

RECOMMENDATION 3:
Governments and industries should invest heavily in innovations for use of low-carbon ammonia. New
innovation programs should include a mixture of foundational science (e.g., combustion chemistry), appliedscience (e.g., fuel mixing) and pilot demonstrations across power, industrial, transportation and chemical sectors.
A combination of material science, simulation, engineering and system analysis could provide the crucial insights
to enable commercially viable use. Absent these investments, there will be no market for ammonia as a fuel,limiting ammonia-based decarbonization to the fertilizer market.

RECOMMENDATION 4:
Government regulators should take steps to prevent safety and environmental problems in the ammonia
trade. The most immediate action should be to launch monitoring programs for hydrogen and ammonia
production, use and transport, with a focus on fueling systems. Monitoring should serve as the basis for amending
and upgrading regulations regarding leakage tolerances. Facilities should manage “unacceptable risks” associatedwith ammonia production, transportation and trade. Analysis should assess potential local risks, including
increased air and water pollution, and health effects on communities. As low-carbon hydrogen and ammonia
production increases, operators and regulators should work together to ensure minimal leakage—ideally less than
0.5% of production—beginning with active monitoring of pilots and new developments.

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RECOMMENDATION 5:
Key governments should institute supporting policies to drive ammonia into wider use as a fuel and feedstock.
Firm policies supporting production and use and valuing low-carbon attributes will prove essential to growing
supply, transportation and use, including a mixture of incentives, procurements and regulations. Initial projects
and policies should focus on overcoming cost barriers. Market pull mechanisms, such as incentives, grants andprocurement (e.g., “buy clean” initiatives), should be based on quantitative assessments of life-cycle carbon
footprint for goods and services where ammonia is currently used and could serve as a low-carbon feedstock or
fuel. Due to the long-lived nature of commercial ammonia-related assets, long-term commitments (i.e., offtakes,
financial terms) may be needed to achieve deployment breakthroughs.

RECOMMENDATION 6:
Policy incentives for low-carbon ammonia should be based on carbon intensity rather than ammonia “color”(such as green or blue). Carbon emissions from ammonia production methods labeled as “green” or “blue” canvary dramatically. Ammonia labeled green can have higher carbon emissions than ammonia labeled blue or even,in some cases, conventional fossil-based ammonia. While the color system can be a useful qualitative descriptor,
it should not be used as a proxy for carbon intensity. Policy incentives for low-carbon ammonia should be basedon the full life-cycle carbon intensity of a batch of ammonia (including upstream emissions from fugitive methane,
grid power emissions and land-use change), not on the type of production method.

RECOMMENDATION 7:
Business and governments should support local, national and international data-gathering and data-sharing.
Since the low-carbon ammonia enterprise is in its earliest stages and since many commercial applications have
not yet commenced, there is an opportunity to avoid potential failure, risks and capital misallocation throughdata gathering and sharing. Business should expect to monitor emissions from the production and use ofammonia—especially for projects that receive public sector grants and subsidies. This should apply to production,transportation, conversion, and use cases and projects. Governments may choose to compel such data gatheringand sharing from business. They may also wish to construct and manage federated data sites that host information
for future scholars and practitioners.

RECOMMENDATION 8:
Business, governments and training institutions should focus on human capital development. The scarcity
of human resources will greatly limit the speed and scale of low-carbon ammonia deployment. Expertise isneeded in the trades (welders, pipefitters, builders, subsea workers), designers (architects), high technology(engineering, sensors, novel electrolyzers), regulation (permitting, inspection, oversight) and governance (finance,
law, international affairs). Skills can be built through apprentice programs, certification processes, short courses,
executive education and dedicated curricula. Sectors should begin at once and should simultaneously explore
possible collaborations to speed and strengthen human capital development.

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Low-Carbon Ammonia Roadmap

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DISCLAIMER
Roger Aines and Corinne Scown contributed to the technical evaluations
but not the policy recommendations in this document.

CITATION
Cite report as: David Sandalow, Roger Aines, Zhiyuan Fan, Julio Friedmann, Colin McCormick, Ann-Kathrin Merz
and Corinne Scown, Low-Carbon Ammonia Roadmap (ICEF Innovation Roadmap Project, November 2022)

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