Reducing emissions from farming: Green ammonia is vital

The UK Government announced its aim to bring all greenhouse gas emissions to net zero by 2050 back in June 2019 and many industries rose to the challenge with their own commitments to emissions reduction. Agriculture was no exception, with the publication of the NFU's net zero by 2040 pledge.Commentators agree the net zero by 2040 pledge is an ambitious one and will require all farming sectors and ancillary industries to play their part in reducing emissions.The production and use of nitrogen fertiliser is recognised as a significant contributory factor to the industry total, so the fertiliser production industry is working hard to meet its own reduction targets.Anke Kwast, vice-president of Yara's Climate Neutral Roadmap states that fertiliser production accounts for 1.5% of global emissions and a further 1.5% comes from the application and use of fertiliser.She says: "When looking at greenhouse gas emissions for the production of wheat, we can see that one-quarter of emissions come from the farming element of the supply chain.Of this proportion, 30-40% of emissions are from the soil, and 25-30% is related to fertiliser production."So both problems must be addressed.Yara has developed emissions abatement technology which reduces the nitrous oxide emissions of its fertiliser production by more than 90%.This means fertilisers produced using this process have less than half the carbon footprint of other fertilisers."There is scope to reduce the carbon footprint of making ammonia, the precursor of AN and urea by switching to green ammonia."This technique is carbon neutral and is in fact turning the clock back to 1905, when the first fertilisers were manufactured in this way Electrolysis"Electrolysis of water was used until 1991, when it became cheaper to extract the hydrogen from natural gas."Green ammonia is not compatible with urea production because urea is made by reacting ammonia with carbon dioxide and because green ammonia is fossil fuel free, there is no carbon dioxide available."This process is powered by renewable energy sources and the nitrogen obtained from the air using an air separation unit.Green ammonia is then synthesised from nitrogen and hydrogen via the Haber-Bosch process."Yara is now working with partners to invest in this pioneering process and is establishing a 100MW wind power electrolysis green ammonia manufacturing plant, which will save 100,000 tonnes of carbon dioxide each year and has the potential to make enough green ammonia to fertilise an area of 0.5 million hectares." Ms Kwast says improving nitrogen use efficiency is also vital if net zero targets for agriculture are to be met.Yara is developing a range of tools for farmers to help them produce more food per unit of nitrogen applied.