The transition to a net-zero economy would involve more than the simple upscaling of renewable energy resources alone. This would need the support of solutions that would enable the storage, transport, and utilisation of clean energy effectively in those sectors that have challenges associated with the reduction of carbon footprint and require a constant energy demand pattern. This changing landscape of the energy sector includes green ammonia as one of the major facilitators of a net zero transition.
Green ammonia has a system-level role as it uses renewable electricity to produce a carbon-neutral energy carrier that can be stored on a massive scale and transported over long distances. In this regard, green ammonia ensures that renewable energy is utilised in various sectors such as shipping, power generation, and agriculture beyond fulfilling electricity needs. Thus, with the emergence of green hydrogen, green ammonia is rapidly being accepted as backbone infrastructure in a net-zero world.
Hydrogen is still at the focal point of international plans to fight climate change. As reported by the International Energy Agency, clean hydrogen could represent up to 10% of total final energy demand in 2050. Hydrogen is believed to be able to substitute fossil fuels in the areas of industry-related heat, transport, and grid services, especially in sectors that are difficult to abate. Green ammonia is an extension of hydrogen in the sense that it offers a stable way to transport hydrogen’s energy.
Green ammonia is produced by the reaction of green hydrogen obtained from the electrolysis of water using renewable electricity and nitrogen obtained from the air. One of the greatest advantages of green ammonia is the fact that it is easy to liquefy at relatively low pressure or by moderate cooling. This makes its storage and transportation economically viable. Also, the use of the ammonia can be direct as a fuel source, or it can be converted back to hydrogen for the generation of electricity in a fuel cell.
The maritime industry is one of the most prominent demand contributors to green ammonia. The maritime transport sector is responsible for almost 3% of annual carbon dioxide emissions, but available alternatives to fossil fuels remain scarce.
The use of ammonia is being mooted as a zero-carbon marine fuel, with various engine manufacturers and ship-owners already carrying out trials. The ambitions to reduce carbon emissions targeting the maritime industry from the International Maritime Organisation are likely to hasten its development, with various studies projecting that the demand from the maritime industry alone is likely to increase ammonia usage between three to six times by 2050.
Green ammonia can also facilitate the integration of net zero energy systems as a long-duration energy storage technology. Green ammonia can be fired in existing thermal power plants or repurified into hydrogen for use in hydrogen-fueled gas turbines as it can provide stability to the power system while abundant renewable energy integration. This will be critical as the projected growth in global electricity demand by 2050 stands at more than 70%.
However, ammonia has wider uses other than in the energy sector. Currently, the production of ammonia consumes about 2% of energy generated from fossil fuels. The production of green ammonia would therefore help in reducing emissions that come with fertilizer production, which is increasing due to agricultural growth. Emphasising green ammonia in India, therefore, fits well with their National Green Hydrogen Mission plans, which support fertilizer security and also make India a clean energy hub in the future.
One of the benefits of green ammonia is that there is already existing infrastructure. Large-scale storage terminals, pipelines, and transport vessels are already being used because of the long-term use of ammonia in fertilizers. Although there are issues regarding cost, efficiency, and safety, the pace of progress in electrolysers, the use of renewable energy sources, and the development of ammonia cracking techniques makes the future for green ammonia look increasingly bright. In a collective cumulative fashion, these advances make the use of green ammonia an indispensable piece of a net-zero energy system puzzle.
