Biogas and fatty acids produced from agricultural biomasses for industrial use.

The Swedish Industrial Biogas Commission is calling for 10 TWh of biogas/year (via digestion and gasification; by 2030). Current production is about 2 TWh/year, mainly from waste and sludge. The supply of organic waste is not sufficient to produce the required biogas.Agriculture has significant amounts of residual biomass that can be digested (mainly manure and straw). With this fact taken into account, this project report also assumesthat smaller parts of the arable land can be used for growing nitrogen-fixing grass/clover ley for biogas production, perhaps in combination with the production of protein feed for agriculture and fatty acids for industry in a biorefinery concept.It is possible to use manure, straw and ley with smaller amounts of waste in the western part of Sweden (Västra Götaland, Skåne and Halland) to produce 3.5 to 5 TWh of biogas/year in large biogas plants (approx. 100 GWh/plant and year) for use in industry. Co-production of fatty acids and biogas is also possible, e.g. at least 16 plants are needed to cover identified industrial needs.There are good opportunities for Bio-CCS, partly at the biogas plant, when biogas becomes biomethane, and partly in the industry where biomethane is used. Negative emissions possible, corresponding reduction of climate gases when biomethane replaces natural gas (5 TWh biomethane with CCS can reduce CO₂ emissions by about ¾ for the chemical and refinery industry segment). CO2 can also be used for production of emethane (Bio-CCU), but electricity shortages are a likely bottleneck.The price of natural gas (including tax) compared to biogas with existing subsidies is estimated to be relatively similar. The current subsidy system is directed towards manure digestion, which only produces about 1/5 of the potential biogas from agricultural biomass, which is why subsidies need to be modified to produce the biogas in demand. Fatty acids can also be produced using primarily pasture and waste via a biological process at a similar price level as today's fossil-based production method.A future investment in building biorefineries, which generate renewable commodities can be one solution for the industrial green transition, with agricultural biomasses, but this can also contribute to the green transition of the agriculture. Difficulties with the studied system is that it is large with many actors, significant investment is needed to be realized, and clear incentives are needed to become an actor in the system also includingthe farmers, and there are technical and biological uncertainties in function. A clear question is who is prepared to take the lead in realizing this?