Direct and indirect CO2 emissions from ammonia production and use by scenario

Notes: STEPS = Stated Policies Scenario; SDS = Sustainable Development Scenario; NZE = Net Zero Emissions by 2050 Scenario. Ammonia used as an energy carrier is not included.

A portfolio of mitigation options

Like the wider energy system, the fertiliser sector cannot rely on one technology or mitigation lever alone to make progress on its climate goals – it must pull on all levers that can make a difference to allow its transition to zero emissions to take place as quickly as possible. However, the relative importance of different mitigation options evolves over time.

More efficient use of nitrogen fertilisers is an important strategy pursued to reduce the overall quantity of ammonia demand in the Sustainable Development Scenario and Net Zero Emissions by 2050 Scenario. Around 20% of the cumulative emission reductions from ammonia production to 2050 in the Sustainable Development Scenario are made possible by avoiding the production and use of up to 25 Mt of fertilisers in that year (14% of today’s global annual production) compared with the Stated Policies Scenario, while delivering the same agricultural output. Strategies within the agricultural sector involve minimising nutrient losses by applying fertilisers at efficient rates and with appropriate timing and placement, often aided by precision agriculture technologies and specialised fertilisers. Outside agriculture, measures are also taken to improve material efficiency, such as increased plastics recycling and reuse (see Chapter 2, “The outlook for demand and production” for more details).

Energy efficiency is a win-win strategy to enhance competitiveness in an industry that is as energy-intensive and exposed to international trade as the fertiliser industry. The amount of process energy required to produce a tonne of ammonia from natural gas on average globally was about 40% higher in 2020 than BAT energy performance levels. The remaining gap is narrow and producers exploiting it in some regions face practical (e.g. physical constraints on existing assets) and economic barriers that are overcome in the Sustainable Development Scenario. The adoption of BAT, improved operating and maintenance routines, and increased levels of process integration lead to all regions achieving BAT energy performance levels for each process route in the period 2040-2050 in the Sustainable Development Scenario.

The type of feedstock determines the lowest amount of process energy required per unit of output: even with BAT, coal-based ammonia production is around 15% more energy intensive than natural gas-based production (and twice as emissions intensive). Thus, a shift towards the natural gas-based route, as takes place in the Sustainable Development Scenario, contributes to further lowering energy intensity, beyond the progression towards BAT energy performance levels for each process route. Conversely, some innovative near-zero-emission routes require additional equipment beyond the core ammonia production process, which increases the energy demand per unit of output even if BAT is adopted. For instance, 3.5 GJ/t CO2 (or 2.4 GJ/t ammonia) are needed to capture CO2 from flue gases resulting from the combustion of fuels in ammonia production compared to the overall 28 GJ of process energy needed per tonne of ammonia in best performing natural gas-based plants today. After accounting for these opposing trends, overall technology performance improvements deliver 24% of the cumulative emission reductions in the Sustainable Development Scenario.

A further 10% of cumulative emission reductions in the Sustainable Development Scenario stem from shifts towards less CO2-intensive feedstocks and fuels. A shift at the global level from coal to natural gas-based routes is the main contributor, stemming primarily from an underlying regional dynamic in which coal-intensive Chinese ammonia production decreases and production in natural gas-intensive regions increases. In the Sustainable Development Scenario existing energy distribution infrastructure repurposed to the extent possible facilitates the delivery of low-carbon fuels. Gaseous biofuels and hydrogen are injected into natural gas distribution grids to lower their overall CO2 intensity by 5% on average globally by 2050, which constitutes an indirect form of fuel switching.