Operations

Green Ammonia: The Hydrogen Carrier Explained

How green ammonia works, why it is emerging as the hydrogen trade fuel, and where major projects are underway.

Green ammonia may become the practical way to move green hydrogen around the world. Denser than pure hydrogen and shipped via existing infrastructure, ammonia could enable international clean energy trade. This guide covers the technology, projects, and outlook.

What ammonia is

Ammonia (NH3) is a nitrogen hydrogen compound. Currently 180 million tonnes produced annually, mostly for fertiliser. Second most produced chemical globally. Well established global shipping and storage infrastructure.

Green vs other ammonia

ColourHydrogen sourceNotes
Grey (99% of current production)Natural gas reformingHigh CO2 emissions
BlueNatural gas plus CCSLower emissions if CCS good
GreenRenewable powered electrolysisNear zero emissions
PinkNuclear powered electrolysisLow emissions

How ammonia is made

The Haber Bosch process combines nitrogen (from air) with hydrogen at high temperature and pressure over a catalyst. Very mature industrial technology. Green ammonia uses renewable powered electrolysis for hydrogen input. See our companion article on green hydrogen.

Why ammonia as hydrogen carrier

AttributeAmmoniaPure hydrogen
Density at storage conditions~120 kg H2 per m3 (liquid)~40 kg H2 per m3 (700 bar)
Liquefaction conditionsMinus 33 C at atmospheric pressureMinus 253 C
Existing infrastructureYes (fertiliser trade)Limited
Global handling experienceExtensiveLimited
ToxicityToxic (concern)Not toxic
Key insight. The strongest case for ammonia is trading hydrogen internationally. Existing LPG carriers can be adapted for ammonia. Existing ammonia terminals in major ports. Storage well understood. This makes ammonia the practical solution for exporting solar rich regions (Middle East, Australia, Chile) to importing hydrogen demand centres (Japan, Korea, Europe).

Applications for green ammonia

  • Direct fertiliser replacing grey ammonia (biggest current market).
  • Hydrogen carrier for international trade.
  • Shipping fuel (industry decarbonisation).
  • Power generation (co firing or dedicated).
  • Industrial process feedstock.
  • Rail and heavy transport fuel (potential).

Major projects announced

ProjectLocationScale
NEOM Saudi ArabiaSaudi Arabia1.2 MTPA green ammonia by 2027
H2 Green Steel SwedenSwedenSteel plus ammonia integrated
Fortescue Future IndustriesAustralia, globalMulti MTPA global portfolio
Air Products NeomSaudi Arabia1.2 MTPA export ammonia
Yara Norsk HydroNorwayGreen ammonia at existing plant
Woodside EnergyAustraliaMultiple projects
Uniper Nord PoolGermanyImport terminal

Ammonia as shipping fuel

International Maritime Organization (IMO) targeting decarbonised shipping. Ammonia among the leading candidates alongside methanol. Multiple engine manufacturers (MAN, Wartsila) developing ammonia engines. First commercial ammonia ships expected late 2020s.

Power generation from ammonia

Japan and Korea planning ammonia co firing at coal power plants as decarbonisation transition. Marubeni, JERA, and IHI leading. Dedicated ammonia power plants at pilot stage.

Cost trajectory

USD 800 to 1,500
per tonne green ammonia today
USD 200 to 400
per tonne grey ammonia today
USD 400 to 600
green ammonia target 2030

Technical challenges

  • Ammonia conversion back to hydrogen requires energy.
  • Ammonia combustion produces NOx emissions requiring controls.
  • Toxicity requires careful handling.
  • Fugitive emissions from leaks (nitrous oxide is greenhouse gas).
  • Direct use requires new engine or turbine designs.
  • Fertiliser vs energy competing demand.
Common trap. Fugitive ammonia emissions could produce nitrous oxide (N2O), a potent greenhouse gas 300 times stronger than CO2. Full lifecycle emissions accounting is essential. Poorly managed ammonia leakage could undermine climate benefits.

Emerging global trade

ExporterImporter
Middle East (solar plus wind)Europe, Asia
Australia (solar plus wind)Japan, Korea
Chile (wind)Global via Panama
Norway (existing infrastructure)EU
North Africa (solar)Europe

Policy support

US IRA hydrogen production tax credit (up to USD 3 per kg) applies to green ammonia production. EU import demand supported by ETS pricing. Japan H2 basic plan targets 3 million tonnes hydrogen imports by 2030. Korea has similar targets.

Renewable siting matters

Green ammonia project economics depend heavily on renewable electricity costs. Sites with world class solar plus wind (Neom, Pilbara Australia, Chilean Atacama) most competitive. Higher electricity cost regions likely importers rather than producers.

Storage and transport

Ammonia can be shipped as refrigerated liquid at atmospheric pressure or pressurised at ambient temperature. Standard fertiliser transport equipment adaptable. Ports of Rotterdam, Antwerp, Singapore, Los Angeles all preparing.

Regulation

Growing regulatory attention. Safety standards for storage and shipping evolving. Emissions requirements for combustion. Standardisation efforts through ISO and industry associations.

Where green ammonia is going

  • First large scale export projects online 2026 to 2028.
  • Shipping fuel deployment growing late 2020s.
  • Power generation co firing expanding.
  • Fertiliser decarbonisation slower.
  • Trade flows establishing.
  • Cost reduction with scale.

Frequently asked questions

Why ammonia not just hydrogen?

Denser and easier to ship internationally.

Is it dangerous?

Toxic. Requires careful handling but industry has 100+ years experience.

Can we burn ammonia?

Yes with new engine or turbine designs.

Who leads production?

Middle East, Australia, and Chile developing large export projects.

What is the fuel use?

Shipping fuel most promising near term.

How much is invested?

Hundreds of billions of dollars in announced projects globally.

Is ammonia zero carbon?

Green ammonia near zero. Depends on hydrogen source.

Does fertiliser still dominate?

Yes currently. Energy uses growing.

How is it shipped?

Refrigerated ammonia carriers. Similar to LPG ships.

Where can I read more?

IEA Global Hydrogen Review, Ammonia Energy Association, project developer sites.

Summary

Green ammonia is emerging as the practical hydrogen carrier for international trade. Existing shipping infrastructure, well understood storage, and dense hydrogen content make it the leading candidate. Multiple mega projects underway in Middle East, Australia, Chile. Shipping fuel, power co firing, and fertiliser decarbonisation are the main applications. Cost currently 2 to 3 times grey ammonia; falling. Watch NEOM commissioning as major inflection point.

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