Green fertilisers - sustainable production of mineral nitrogen from renewable sources

The project started in 2007 and finished in 2008.

Agricultural production must be based on energy and nutrients from renewable resources to become long term sustainable. The largest energy consumption (ca 2,5 TWh) in Swedish agriculture is linked to the production of nitrogen fertilisers, of which 95% originates from non-renewable fossil sources.

Nitrogen fertilisers are produced from ammonia made in the Haber-Bosch process where nitrogen gas and hydrogen is reacted. The nitrogen is extracted from surrounding air and the hydrogen is presently generated from natural gas.

Modern technique however, opens for hydrogen produced from gasified agricultural biomass (such as straw or Salix) or by electrolysis of water with electricity produced from biomass or for example wind power. Well-designed systems make sustainable manufacture of nitrogen fertiliser possible, an opportunity that gives new perspectives for future food production.

The aim of the study was to analyse systems with potential sustainable nitrogen fertiliser production. Energy balance and environmental impact from a life cycle perspective, land requirement, effect of biomass choice, effect of scale and costs will be quantified for the different systems. Further, the systems potential of implementation in different time perspectives etc will be analysed and discussed. The study is based on LCA methodology and a system analysis calculation model based on the graphic interface in Simulink/Matlab, which previously has been developed and used within the group.

The project was financed by the The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planningy.

Participating from the Department was Åke Nordberg (then at JTI) and Serina Ahlgren.

External partners were JTI.