What Are the Main Emission Sources in the Fertilizer Sector? And What Are the Opportunities?

The fertilizer sector in Brazil is a significant source of greenhouse gas (GHG) emissions, primarily due to the intensive use of synthetic nitrogen fertilizers such as urea. When applied to the soil, these fertilizers release nitrous oxide (N₂O), a gas with a global warming potential approximately 298 times higher than that of carbon dioxide (CO₂). According to the Greenhouse Gas Emissions Estimation System (SEEG), the use of synthetic fertilizers ranks among the top emission sources in Brazil’s agricultural sector and has been increasing in recent years.

In addition to direct field emissions, the industrial production of these fertilizers also contributes to GHG emissions due to energy consumption and fossil fuel combustion. Transportation and distribution—often via high-carbon-intensity modes like diesel trucks—add indirect emissions throughout the product lifecycle.

The growth in nitrogen fertilizer use in Brazil has outpaced the expansion of planted area, indicating increased input intensity per cultivated hectare. This trend reinforces the need for strategies to mitigate emissions in the sector. Emission sources vary across the fertilizer value chain and are distributed among the three GHG Protocol scopes (Scopes 1, 2, and 3).

Scope 1 (Direct Emissions):

  • Stationary Combustion: For companies directly involved in fertilizer production—especially ammonia and urea—large volumes of natural gas are used, generating CO₂ emissions through methane reforming (Haber-Bosch process); diesel combustion in boilers and fertilizer dryers.
  • Industrial Process Emissions: Emissions from nitric acid production and phosphate rock reactions with acid release nitrous oxide (N₂O), a GHG far more potent than CO₂; Phosphate rock (carbonates) reactions also generate CO₂.
  • Mobile Combustion: Diesel consumption in mining trucks (for extraction operations), internal distribution fleets, tractors, and loaders at manufacturing plants.
  • Fugitive Emissions: Natural gas (CH₄) leaks in ammonia units; diffuse CO₂ emissions from internal processes; refrigerant gas (HFC) leaks from office and plant air conditioning systems.

Scope 2 (Indirect Energy Emissions):

  • Purchased Electricity: Electricity consumed in factories, mines, and offices is a significant emission source, especially if sourced from non-renewable grids. Some operational units already use renewable energy (wind and solar) produced on-site.

Scope 3 (Other Indirect Emissions):

  • Category 1 – Purchased Goods and Services (Upstream): Imported urea, ammonia, nitrates, and third-party-supplied phosphoric acid, as well as plastic bags. This is the largest share for blending operations.
  • Category 4 – Upstream Transportation and Distribution: Maritime shipping of imported fertilizers (fuel combustion in vessels); domestic transport of raw materials from ports to factories (trucks, trains).
  • Category 9 – Downstream Transportation and Distribution: Delivery of fertilizers from factories/ports to cooperatives and farms via third-party logistics (trucks); regional distribution by local partners.
  • Category 11 – Use of Sold Products (Downstream): Application of nitrogen fertilizers releasing N₂O in soils (nitrification/denitrification processes); CO₂ emissions from urea hydrolysis; indirect emissions from post-application management.
  • Category 12 – End-of-Life Treatment of Sold Products: Disposal or improper burning of 50 kg plastic bags or 1-ton big bags used for fertilizer delivery, emitting fossil CO₂. Although smaller in impact, many companies have adopted returnable and recycled packaging solutions.

Challenges and Opportunities for the Fertilizer Sector

The fertilizer sector faces the challenge of reducing GHG emissions generated both during industrial manufacturing and through product use in agriculture. Fertilizer production consumes significant energy and releases CO₂, while field application can generate even more potent GHGs like nitrous oxide.

Fortunately, there are viable pathways to reduce these emissions. Technological innovations and more sustainable practices already allow for cleaner fertilizer production and more efficient use, significantly lowering the sector’s climate impact.

Below are concrete examples of emission reduction opportunities—ranging from industrial process improvements to agricultural techniques that prevent waste and unnecessary emissions:

Emission Reduction Opportunities:

Scope 1:

  • Energy Efficiency Improvements: Investing in more efficient processes and energy cogeneration can reduce fossil fuel consumption at plants.
  • Fuel Optimization: Expanding the use of biofuels in company vehicles and forklifts can reduce fossil fuel dependence and GHG emissions.
  • N₂O Abatement Technologies: Using catalysts in nitric acid plants can cut N₂O emissions by up to 90%.
  • Green Hydrogen Transition: Though a costly investment, replacing natural gas with green hydrogen in ammonia production can nearly eliminate CO₂ emissions.

Scope 2:

  • Use of Renewable Energy: Procuring renewable energy (wind and solar) for industrial operations can reduce indirect electricity emissions.
  • On-site Renewable Generation: Investing in on-site energy production, such as solar panels at facilities, also contributes to decarbonization.

Scope 3:

  • Promoting Local Production: Increasing domestic fertilizer production with a lower carbon footprint can reduce emissions associated with importing raw materials (considering both maritime and domestic transportation).
  • Using More Efficient Fertilizers: Expanding the production of controlled-release fertilizers and nitrification inhibitors can significantly reduce N₂O emissions in agricultural use. One example: a company achieved approximately a 20% reduction in annual emissions by adopting controlled-release fertilizers (Coruripe case).
  • Promoting Best Agricultural Practices Across the Value Chain: Training farmers and buyers to apply fertilizers efficiently, avoiding over-application, helps reduce field-use emissions.

By implementing cleaner technologies and more efficient agricultural practices, the fertilizer sector can significantly reduce its carbon footprint while aligning with climate goals.

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