Breaking Free from Ammonia for True Sustainable Farming
The demand for decarbonized synthetic nitrogen fertilisers is growing as the agricultural sector faces increasing pressure to manage its carbon footprints. In fact, the European Union is set to implement carbon taxes starting in 2026, specifically targeting fertilisers through the Carbon Border Adjustment Mechanism (CBAM), a move to incentivize more countries to commit to the net-zero 2050 goal.
Ammonia (NH3) is the primary source of nitrogen in the synthetic fertilisers, and it is synthesized from nitrogen and hydrogen gases under high pressure and temperature conditions through a process known as the Haber-Bosch process. The manufacture by this process alone accounts for 1.5% of global carbon emissions corresponding to 483 million tonnes of carbon dioxide equivalent (CO2e).
The main source of carbon emissions associated with the Haber-Bosch process is the production of hydrogen from natural gas. Thus efforts to reduce the carbon footprint of this process have centred on using hydrogen produced through electrolysis powered by renewable energy sources, called “green hydrogen”.
The use of green hydrogen is not a new concept for ammonia production. For example, in the early 20th century, the Merano plant in Italy had a daily production capacity of 50 tons of ammonia and relied on hydro-electric power for production of hydrogen by electrolysis. For economic reasons, electrolysis use was phased out from the 1960s onward in favour of steam methane reforming, a common method to obtain hydrogen from natural gas today.
While using green hydrogen may reduce carbon emissions in ammonia manufacturing, it does not address the root cause of carbon emissions associated with fertilisers. Throughout the lifecycle of nitrogen fertilisers, the carbon emissions result from the manufacture, transportation, and application. The majority of these emissions occur during the application of the fertilisers on farmland, accounting for 2.5% of global carbon emissions (829 Mt CO2e). This figure is nearly twice as high as the emissions generated during the manufacturing phase (483 Mt CO2e).
Ammonia-based fertilisers, such as urea, require a nitrification process, carried out by soil bacteria, to convert ammonia into nitrate (NO3). This nitrification process produces nitrous oxide (N2O) as a by-product – a greenhouse gas with 300 times the warming potential of carbon dioxide. Also ammonia-based fertilisers can easily volatilize into the atmosphere, contributing to air pollution and acid rain.
Transitioning from ammonia-based fertilisers to nitrate-based ones may significantly reduce carbon emissions because nitrate-based fertilisers such as calcium nitrate are already in the nitrate form, eliminating the need for the nitrification process in the soil. Therefore, they have a lower direct impact on nitrous oxide emissions compared to ammonia-based fertilisers. nitrate fertilisers are less prone to volatilization compared to ammonia-based fertilisers.
In addition, nitrate-based fertilisers provide a more readily available form of nitrogen for plants, which can result in more efficient nutrient uptake, reducing the overall amount of fertiliser applied. The better water solubility of nitrate-based fertilisers enhances their compatibility with precision agriculture practices.
At Debye, we’re rethinking nitrogen fertilisers, and we’re on a mission to initiate a paradigm shift from ammonia-based fertilisers to nitrate-based ones.
We invite you to follow us on this exciting journey as we work to decarbonize and decentralize the production of nitrogen fertilisers, aiming to achieve our dual objectives of combating climate change and enhancing food security in developing countries.
