Ammonia is a key ingredient in most fertilisers, enabling the world to feed more people. But ammonia production currently uses about 2 per cent of the world’s fossil fuel energy, so decarbonising ammonia production would have a significant impact on reducing climate change. And if we can get ‘green’ ammonia production right, then ammonia is being touted to have an even bigger role in reaching net zero – as a potential energy carrier.
Ammonia production in Australia
Ammonia (chemical formula NH3) is made by combining hydrogen and nitrogen. Around 410,000 tonnes of hydrogen per year1 is produced in Australia for the purpose of making ammonia, and it all currently comes from fossil fuels especially natural gas, producing carbon dioxide (a major greenhouse gas) as a by-product.
The ammonia production process is:
- Natural gas and water are converted into hydrogen and carbon dioxide, through a process called steam methane reforming. The carbon dioxide may be captured and stored or used (for making other fertilisers like urea or sold to the beverage industry to carbonate drinks), but usually it’s released into the atmosphere.
- Nitrogen can be introduced in the process via air used in the previous step, or it can be added after being separated from air in an air separation unit.
- The hydrogen and nitrogen are put together in a Haber Bosch reactor, named after the inventors of the process. The product is ammonia.
Another method of making the hydrogen (step 1) is by electrolysing water using an electrolyser. The electrolyser splits water into hydrogen and oxygen, a process that requires a lot of electricity (around 55 kWh per kg hydrogen). If the electricity comes from renewable sources, such as wind or solar, then we call the hydrogen ‘renewable hydrogen’ or ‘green hydrogen’. Thus, making ammonia from renewable hydrogen has a much lower carbon footprint.
Uses of ammonia
Most ammonia currently produced is for the purpose of making fertiliser. It can be applied directly to soil, but is often converted to urea, which as a solid crystal is very easy to store and apply. Ammonia can also be used to make combination fertilisers such as ammonium phosphate, which contains both the nitrogen and the phosphorus that many plants need.
Agriculture organisations such as the Grains Research & Development Corporation (GRDC) have shown strong interest in the development of green ammonia as a way of reducing the carbon footprint of farming. Fertiliser is one of the biggest consumable costs for farmers, so if renewable ammonia could also be made more cheaply than non-renewable ammonia, that would be a double win for farmers.
While ammonia’s main use in Australia is for fertiliser, it can also have other purposes, such as an ingredient in explosives used in mining. However it is for its hydrogen content that renewable ammonia is now being considered by experts around the world as a potential energy carrier, or fuel.
Ammonia as an energy carrier
Hydrogen can contribute to net zero greenhouse emission goals in numerous ways: it can be used as a fuel in vehicles, help to balance out renewable energy in electrical grids, and be a low carbon heat source for heavy industry to name but a few applications.
However, the storage and transport of hydrogen is a major challenge because it is a very small, light molecule. Hydrogen can be stored as a compressed gas, as a cryogenic liquid, or even within a solid structure, but each of these methods comes with its own set of problems, including the energy required to compress or liquefy the gas.
While ammonia is a gas at room temperature and pressure, it becomes a liquid at around 10bar pressure or by cooling it to –33oC temperature, so it can be converted to liquid much more easily than hydrogen can. Thus renewable hydrogen could be converted to renewable ammonia and liquefied, then transported to where it is needed via trucks, trains, and ships as we transport ammonia now. Once it reaches its destination, it could be converted back into hydrogen and nitrogen, and the hydrogen could then be used in a hydrogen vehicle, or to make electricity, or as a fuel etc.
Challenges
The biggest challenge at the moment is the cost of producing renewable hydrogen. Electrolysers are expensive to make, and they are also expensive to run because they use so much electricity. So electrolyser manufacturers and researchers around the world are racing to develop cheaper, more efficient electrolysers.
Safety is also a challenge. Ammonia is a toxic material, so careful regulation, training and engineering protections are required to keep the community safe. Ammonia has been in production for more than a century so none of these risks are new, but if we are going to produce a lot more ammonia and use it for new applications, then it’s important to make sure regulations and workforce training keep pace with the change.
What CSIRO is doing
We are also researching various aspects of ammonia, including ammonia production methods that are more efficient and/or use waste materials as input; and ways of converting ammonia back into hydrogen more easily so that the hydrogen can be used as an energy source where it’s needed. In addition, we are looking into ways of producing ammonia via simpler processes than the three steps described above, and also ways of using ammonia as an energy source directly (in internal combustion engines and solid oxide fuel cells) rather than converting it into hydrogen.
The CSIRO conducts a lot of research on the production of low-carbon hydrogen, including work to make more energy-efficient and cost-efficient electrolysers. We have licensed our Proton Exchange Membrane (PEM) electrolyser technology to our spinout company Endua, and licensed our tubular Solid Oxide Electrolysis technology to another spinout company, Hadean Energy.
We collaborate with industry to develop scientific solutions to their problems, including decarbonisation in energy and chemical use. For example, we have collaborated with the Grains Research & Development Corporation on developing technology for low pressure distributed scale production of green ammonia, and we are working with Bluescope Steel to trial our tubular Solid Oxide Electrolysis technology to produce hydrogen more efficiently for use in their steelworks. We also collaborate with researchers in Australian universities, and with hydrogen researchers around the world.
There are many different ways of using hydrogen and ammonia to combat climate change, and each method currently has its own challenges. CSIRO researchers are helping to develop hydrogen technology to support Australia’s growing hydrogen industry.
Please contact us if you would like to work with us on hydrogen or ammonia research and development.
Notes
- Data from State of Hydrogen 2022, Commonwealth of Australia 2022, Table 4, page 10.
Ammonia is a key ingredient in most fertilisers, enabling the world to feed more people. But ammonia production currently uses about 2 per cent of the world’s fossil fuel energy, so decarbonising ammonia production would have a significant impact on reducing climate change. And if we can get ‘green’ ammonia production right, then ammonia is being touted to have an even bigger role in reaching net zero – as a potential energy carrier.
Ammonia production in Australia
Ammonia (chemical formula NH3) is made by combining hydrogen and nitrogen. Around 410,000 tonnes of hydrogen per year1 is produced in Australia for the purpose of making ammonia, and it all currently comes from fossil fuels especially natural gas, producing carbon dioxide (a major greenhouse gas) as a by-product.
The ammonia production process is:
- Natural gas and water are converted into hydrogen and carbon dioxide, through a process called steam methane reforming. The carbon dioxide may be captured and stored or used (for making other fertilisers like urea or sold to the beverage industry to carbonate drinks), but usually it’s released into the atmosphere.
- Nitrogen can be introduced in the process via air used in the previous step, or it can be added after being separated from air in an air separation unit.
- The hydrogen and nitrogen are put together in a Haber Bosch reactor, named after the inventors of the process. The product is ammonia.
Another method of making the hydrogen (step 1) is by electrolysing water using an electrolyser. The electrolyser splits water into hydrogen and oxygen, a process that requires a lot of electricity (around 55 kWh per kg hydrogen). If the electricity comes from renewable sources, such as wind or solar, then we call the hydrogen ‘renewable hydrogen’ or ‘green hydrogen’. Thus, making ammonia from renewable hydrogen has a much lower carbon footprint.
Uses of ammonia
Most ammonia currently produced is for the purpose of making fertiliser. It can be applied directly to soil, but is often converted to urea, which as a solid crystal is very easy to store and apply. Ammonia can also be used to make combination fertilisers such as ammonium phosphate, which contains both the nitrogen and the phosphorus that many plants need.
Agriculture organisations such as the Grains Research & Development Corporation (GRDC) have shown strong interest in the development of green ammonia as a way of reducing the carbon footprint of farming. Fertiliser is one of the biggest consumable costs for farmers, so if renewable ammonia could also be made more cheaply than non-renewable ammonia, that would be a double win for farmers.
While ammonia’s main use in Australia is for fertiliser, it can also have other purposes, such as an ingredient in explosives used in mining. However it is for its hydrogen content that renewable ammonia is now being considered by experts around the world as a potential energy carrier, or fuel.
Ammonia as an energy carrier
Hydrogen can contribute to net zero greenhouse emission goals in numerous ways: it can be used as a fuel in vehicles, help to balance out renewable energy in electrical grids, and be a low carbon heat source for heavy industry to name but a few applications.
However, the storage and transport of hydrogen is a major challenge because it is a very small, light molecule. Hydrogen can be stored as a compressed gas, as a cryogenic liquid, or even within a solid structure, but each of these methods comes with its own set of problems, including the energy required to compress or liquefy the gas.
While ammonia is a gas at room temperature and pressure, it becomes a liquid at around 10bar pressure or by cooling it to –33oC temperature, so it can be converted to liquid much more easily than hydrogen can. Thus renewable hydrogen could be converted to renewable ammonia and liquefied, then transported to where it is needed via trucks, trains, and ships as we transport ammonia now. Once it reaches its destination, it could be converted back into hydrogen and nitrogen, and the hydrogen could then be used in a hydrogen vehicle, or to make electricity, or as a fuel etc.
Challenges
The biggest challenge at the moment is the cost of producing renewable hydrogen. Electrolysers are expensive to make, and they are also expensive to run because they use so much electricity. So electrolyser manufacturers and researchers around the world are racing to develop cheaper, more efficient electrolysers.
Safety is also a challenge. Ammonia is a toxic material, so careful regulation, training and engineering protections are required to keep the community safe. Ammonia has been in production for more than a century so none of these risks are new, but if we are going to produce a lot more ammonia and use it for new applications, then it’s important to make sure regulations and workforce training keep pace with the change.
What CSIRO is doing
We are also researching various aspects of ammonia, including ammonia production methods that are more efficient and/or use waste materials as input; and ways of converting ammonia back into hydrogen more easily so that the hydrogen can be used as an energy source where it’s needed. In addition, we are looking into ways of producing ammonia via simpler processes than the three steps described above, and also ways of using ammonia as an energy source directly (in internal combustion engines and solid oxide fuel cells) rather than converting it into hydrogen.
The CSIRO conducts a lot of research on the production of low-carbon hydrogen, including work to make more energy-efficient and cost-efficient electrolysers. We have licensed our Proton Exchange Membrane (PEM) electrolyser technology to our spinout company Endua, and licensed our tubular Solid Oxide Electrolysis technology to another spinout company, Hadean Energy.
We collaborate with industry to develop scientific solutions to their problems, including decarbonisation in energy and chemical use. For example, we have collaborated with the Grains Research & Development Corporation on developing technology for low pressure distributed scale production of green ammonia, and we are working with Bluescope Steel to trial our tubular Solid Oxide Electrolysis technology to produce hydrogen more efficiently for use in their steelworks. We also collaborate with researchers in Australian universities, and with hydrogen researchers around the world.
There are many different ways of using hydrogen and ammonia to combat climate change, and each method currently has its own challenges. CSIRO researchers are helping to develop hydrogen technology to support Australia’s growing hydrogen industry.
Please contact us if you would like to work with us on hydrogen or ammonia research and development.
Notes
- Data from State of Hydrogen 2022, Commonwealth of Australia 2022, Table 4, page 10.