Are Primary Agricultural Residues Promising Feedstock for the European Bioeconomy?

Abstract

The Bioeconomy Strategy of the European Commission, launched in 2012, aims to develop the production and use of biomass within the European Union as a strategy to limit the consumption of fossil carbon while fostering jobs and growth. The quantification and timely reporting of biomass flows are crucial for the monitoring of such a strategy. Within this framework, the present work focuses on the quantification of primary agricultural residues in the European Union, which could be a potential feedstock for the biobased material and bioenergy sectors. Harvest indices, or residue-to-product ratios (RPRs), determined at crop level, are used in the calculation of primary agricultural residues. Building on RPR functions of yield, we acknowledge a relationship between primary crop residue quantity and crop yield. Finally, we estimate that 395 million tonnes of dry matter (Tdm) of primary agricultural residues was produced in Europe in 2013 from more than 130 crop commodities, of which 297 million Tdm should be left in the fields for the maintenance of ecosystem services (using conservative assumptions) and 29 million Tdm is collected for agricultural use. Consequently, 69 million Tdm is collectable as feedstock for the biobased material and bioenergy sectors. Collectible residues are mainly composed of cellulose (42%) and sugar and starch (10%). The production of primary agricultural residues is concentrated in the major cereal-producing countries and is stable over time. Nevertheless, a wider adoption of ad hoc harvesting machinery, the optimization of logistic processes, and the maturation of the new biobased value chains could help to take advantage of the current production of agricultural residues.