From Fertilizer to Future Fuel: The growing role of green ammonia
Green hydrogen has been making headlines in Tasmania recently – that’s hydrogen created using renewable energy, which is then converted into electricity or heat with no emissions.
But it’s not the only future fuel gaining prominence, as industries grapple with reliable energy alternatives to fossil fuels. Hydrogen’s comrade ammonia is also having a moment.
Best known as an agricultural chemical, ammonia has been predominately used as an industrial fertilizer. Now, green ammonia is increasingly viewed as an important piece in the energy transition puzzle.
“Similarly to fossil fuels, ammonia is both a chemical energy carrier and a potential fuel, where energy is released by the breaking of chemical bonds,” describes global producer Yara. “Crucially, ammonia has the advantage of not releasing any carbon emissions if used as a fuel, and its green credentials can be enhanced even further if sustainable energy is used to power the production of ammonia.”
What is ammonia, and how is it made?
Not all ammonia is created equal.
Ammonia – NH3 – is made when hydrogen produced by water electrolysis and nitrogen from the air are reacted under high temperature and pressure. This is known as the Haber-Bosch process.
There are four types of ammonia – brown/grey, blue, green and turquoise – and the difference lies in how it’s made.
As described by C&EN, the ammonia industry has informally adopted a color scheme to describe the carbon intensity of the different methods for making ammonia. The system also applies to hydrogen.
Why is green ammonia significant?
With more than 180 million tonnes produced annually, ammonia is the second-most widely produced commodity chemical worldwide. Around 80% of global ammonia production goes into fertiliser and 20% into industrial products.
Currently, most ammonia is grey/brown, made from hydrogen produced using steam methane reforming (SMR). This hydrogen is then fed into the Haber process. SMR is extremely energy-intensive, and accounts for approx. 90% of ammonia-related CO2 emissions – around 1.8% of global carbon dioxide emissions.
A shift to green ammonia will therefore massively reduce the environmental impact of industrial agriculture, and will be crucial for achieving global net-zero emissions targets. There will also be a place for blue ammonia, where SMR hydrogen production emissions are captured and stored.
Producing green ammonia at scale becomes even more imperative given its untapped potential as an alternative to fossil fuels. “Up to this point, we have made a business by selling the nitrogen value of the molecule,” says Tony Will, CEO of CF Industries, the world’s largest ammonia producer. “What’s really exciting about this is now there is an opportunity and a market that values the hydrogen portion of the molecule.”
Energy storage: ammonia is easily stored in bulk as a liquid at modest pressures (10-15 bar) or refrigerated to -33°C. This makes it an ideal chemical store for renewable energy. There is an existing distribution network, in which ammonia is stored in large refrigerated tanks and transported around the world by pipes, road tankers and ships.
·Zero-carbon fuel: ammonia can be burnt in an engine or used in a fuel cell to produce electricity. When used, ammonia’s only by-products are water and nitrogen. The maritime industry is likely to be an early adopter, replacing the use of fuel oil in marine engines.
Hydrogen carrier: there are applications where hydrogen gas is used (e.g., the PEM fuel cells in hydrogen cars). However, hydrogen is difficult and expensive to store in bulk, needing cryogenic tanks or high-pressure cylinders. Ammonia is easier and cheaper to store, and transport and it can be readily “cracked” and purified to give hydrogen gas when needed.
Positioning Tasmania to capitalise on green ammonia potential
Tasmania’s ambitions to become a world-leading green hydrogen hub should naturally lead into opportunities around green ammonia production and use. There are scores of applications: it could benefit the state’s agriculture sector, dramatically reduce heavy industry emissions, and improve the viability of more renewable energy projects.
Ammonia offers easy storage and export of the energy generated by variable renewables. This would allow us to tap into our abundant wind and wave resources, which aren’t currently practical energy sources because of a lack of effective grid integration or energy storage and transport options.
Flow on effects would include a new knowledge industry for the state, with the potential to become a world leader in green ammonia research, technology development and innovation.
What are the barriers and opportunities?
Green ammonia technology is relatively new, expensive and unproven. While many chemical companies are making leaps and bounds with green ammonia technology, it’s not yet competitive with conventional ammonia. Green ammonia costs up to four times as much to produce, and many pilot technologies are yet to prove viable, or scalable.
Green ammonia as an alternative fuel is also very much a fledgling market. While the shipping industry has been flagged as an early adopter, ammonia-fuelled engines are still in the pilot phase.
On the flipside, while the costs are high, green ammonia could also be incredibly lucrative. CF Industries estimates it could fetch US$2,200 per metric ton in the alternative energy marketplace, about eight times as much as conventional ammonia. Not to mention the market potential: “ammonia taking even a relatively small portion of marine applications, let alone overall hydrogen applications, and you’re talking about more than doubling the current production capacity of global ammonia,” says Tony Will.
What are some of the major ammonia projects in Australia?
In Tasmania, Fortescue Future Industries’ (FFI) proposed plant at Bell Bay would produce green ammonia, as well as hydrogen. FFI is aiming for an annual production capacity of 250,000 tonnes. The company has already signed a memorandum of understanding with Japanese engineering firm IHI Corporation and its local arm IHI Engineering Australia, assessing the economic and technical feasibility of a green ammonia supply chain between Tasmania and Japan. Origin Energy, which is also involved in the Bell Bay project, has signed a similar agreement with Japanese shipping company Mitsui OSK Lines.
A BP study released last month identified Western Australia’s mid-west region as a promising production site, and says there is strong demand from both local and export customers. But while the study found green hydrogen and ammonia production is technically feasible at scale, it hinges on significant government support. This includes building transmission lines, expanding ports, providing incentives and setting emissions targets. BP is also conducting a feasibility study into producing green hydrogen at its Kwinana refinery, south of Perth.
In July an international consortium revealed plans for a 20m tonne/year green ammonia mega project, the Western Green Energy Hub (WGEH) in south east Western Australia. To put that into perspective, 20m tonnes a year is roughly equivalent to the entire current global seaborne ammonia market.
The Australian Renewable Energy Agency (ARENA) has awarded a massive $42.5 million to Yara Pilbara and ENGIE for one of the world’s first industrial-scale renewable hydrogen plants at Yara’s existing ammonia plant. It will produce up to 625 tons of renewable hydrogen and 3,700 tons of ‘green’ ammonia per year, and is scheduled for completion in 2023.
In South Australia, work is underway on the H2U Eyre Peninsula Gateway Hydrogen project. Due to be completed in 2022, the plant will be capable of producing 40,000 tonnes of green ammonia annually.
On the research front, earlier this year a team from the University of Sydney and UNSW revealed a new method of producing hydrogen without high pressure or temperature, eliminating emissions and the need for fossil fuels in the ammonia production chain. “And once it becomes available commercially, the technology could be used to produce ammonia directly on site and on demand – farmers could even do this on location using our technology to make fertiliser – which means we negate the need for storage and transport,” says Dr Emma Lovell, from UNSW’s School of Chemical Engineering.
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