Energy Consumption and Greenhouse Gas Emissions in Fertiliser Production

The fast growing population of the world needs food, and fertilisers are among the most important elements to secure sufficient food production. Today, fertiliser production consumes approximately 1.2% of the world’s energy and is responsible for approximately 1.2% of the total emission of the greenhouse gases in the world, consisting of 0.3% of pure CO₂, 0.3% as N₂O and 0.6% as flue gas CO₂. Increased focus on energy issues during the last 25-30 years has already caused a positive downward trend both for energy consumption and greenhouse gas emissions.

Theoretically, global energy consumption by the fertiliser industry can be reduced by almost 40% and the greenhouse gas emissions by almost 60% through implementing new technology. This is positive in view of a ongoing replacement of old technology over the next decades. The specific energy consumption in the West European fertiliser industry is approximately 15% lower than the global average. In West Europe, the fertiliser industry consumes 0.9% of the total energy consumption and emits 1.8% of the CO₂/N₂O emissions. Lower energy consumption is mainly due to higher energy cost and higher emissions are due to different product ranges (more AN versus urea).

A product building block model has been developed. This model links energy consumption and greenhouse gas emissions to the building block products. All kinds of fertilisers can be divided into these building blocks, and consequently energy consumption and greenhouse gas emissions can easily be estimated for all kind of fertilisers. The main energy requirement for production of fertilisers is linked to the nitrogen component; 94% for N, 3% for P₂O₅ and 3% for the K₂O component on a global basis. Production of the most common phosphate fertilisers (DAP/MAP and SSP/TSP) with modern technology releases excess energy due to the huge surplus energy formation in modern sulphuric acid processes.

Tore K Jenssen, Hydro Agri ASA, Oslo, Norway.

Gunnar Kongshaug, late of Hydro Agri ASA, Oslo, Norway.

28 Pages, 5 Figures, 12 Tables, 2 References.