Case Study: Pathways from Forest to Energy in a Circular Economy at Lafões

The present case study deals with new pathways in demand for forest residues disposal in the Lafões region (Portugal), since this biomass is presently regarded as a residue and eliminated through open air burning. Different biomass-to-energy conversion systems have a high sustainability value and, thus, the energy potential of the biomass supplied by the forest of Lafões was assessed, using GIS-based methods and assumptions from the literature. The Lafões region produces large amounts of chicken manure from which energy can be recovered through anaerobic digestion. The energy potential held by the effluent of the several classes of the poultry industry of Lafões was assessed, using IPCC 2006 guidelines to estimate their biomass and methane production potential. Furthermore, integrated solutions were pursued. The present challenge is to explore complementarities between effluents for anaerobic digestion to achieve improved energy and waste management system performances. The complementarity between the residues from maritime pine forest management and from broiler production was assessed through bench-scale anaerobic co-digestion assays, leading to increased methane production when compared to those achieved with single substrate anaerobic digestion. This result highlights the interest of further research concerning complementarities between other effluents in the Lafões region.