Agricultural residues as feedstocks for biofuels production
Field residues such as straw of grain crops and processing residues such as husks, chaff, cobs or bagasse can be used for biofuel production. 139 million tonnes of crop residues (See Wasted - Europe's Untapped Resource: An assessment of advanced biofuels from wastes and residues). Such biofuels are generally considered sustainable as they use waste materials from food crop production, and do not compete with food crops for land.
Conversion of agricultural residues to advanced biofuels
A number of conversion technologies can be used with agricultural residues. For example, conversion of:
Wheat straw or corn stover to cellulosic ethanol via pretreatment, hydrolysis and fermentation
Wheat straw and other agricultural wastes to Btl via various thermochemical pathways.
Innovative conversion pathways based on catalysis and biotechnology can also be used to convert agricultural and other cellulosic wastes to drop-in biofuels.
Mobilisation of agricultural residues
Optimising removal of above-ground biomass residues is compulsory to maintain yields and soil fertility, in practice that means that 20 to 25 % of the residues can be taken off the fields. In September 2013, research commissioned by Poet-DSM Advanced Biofuels and carried out over 5 years by Iowa State University and USDA, showed that the use of cobs, leaves, husk and some stalk to produce cellulosic ethanol does not have a detrimental effect on soil health. For the Poet-DSM Project Liberty facility it was determined 1 ton per acre, 20-25%, of residual biomass could be removed.
The research suggests that, in general, fields with yields above 175 bushels per acre could remove up to 2 tons of biomass per acre, without any need for additional nitrogen or phosphorous applications. However a small additional amount of potassium may be of benefit in some conditions.
In February 2016 the IEA-webinar “Mobilising Sustainable Energy Supply Chains” was held.
In May 2016 the IEA-workshop “Mobilising sustainable bioenergy supply chains: opportunities for agriculture” was held in Rome collaboration with GSE, FAO and IRENA. Subjects were:
- Biomass perspectives and mobilisation
- Discussion / debate on assumptions behind biomass perspectives
- Case studies and strategies showing synergies in food and energy production
- Biogas and applications
- Interactive discussion with the audience on strategies and good practices of biomass mobilisation in agriculture
View the PresentationsSee also Mobilising Cereal Straw in the EU to Feed Advanced Biofuel Production