GIS-BASED SUSTAINABILITY ASSESSMENT OF BIOENERGY CHAINS IN A MEDITERRANEAN AREA: COMPARING ENVIRONMENTAL AND ECONOMIC PERFORMANCES OF A LARGE-SCALE POWER PLANT WITH SMALL-SCALE COGENERATION SCHEMES

摘要

Environmental and economic performance of bioenergy chains are key issues for defining thernsustainability of forest biomass-based bioenergy chains. In the study area, Tuscany Region (central Italy), forestrnsurface is 50.1% of the total land area which could provide up to 1.65 Mt year-1 of firewood and 0.77 Mt year-1 ofrnresidues from wood harvesting according to a recent study. A GIS-based evaluation of potential bioenergy chains atrnregional scale was carried out within the Biopower in Tuscany Project considering two alternative scenarios, namelyrnCHP scenario (Combined Heat-Power) supposed sourcing small heat-power plants, assumed to be developed in 55rndifferent existing industrial sites within the study area and Large-scale Power Plant (LSP) scenario, which supposedrnusing all potentially available biomass to feed a single LSP, sited in an existing electric facility. In both cases therneconomic and environmental feasibility of supplying biomass was evaluated considering only local forest resources.rnIn the two scenarios, wooded areas were allocated to the plants by means of a cost-distance allocation functionrnallowing: 1) in CHP scenario, to estimate a biomass supply in the surrounding areas of each plant, based on thernminimum distance of biomass road transport; 2) in LSP scenario, to define a potential biomass supply according tornincreasing road distances to the power plant. Forest areas from the Tuscany Forest Inventory (TFI) and Corine LandrnCover (CLC2006), were classified according to accessibility (distance from roads, terrain slope and topographicrnconstrains), forest management (high forests and coppices) and productivity (annual biomass increment). Costs andrnGHG emissions associated with the production of woodchips were estimated for each forest type based on differentrnforest chain schemes. Costs and GHG emissions for handling and delivering wood chips were estimated consideringrnmechanical work in the forest and road transport by truck considering distances from each forest area to thernassociated plants. Final results provide an overview on the sustainability of producing electricity from local forestrnbiomass at the second level of the EU Nomenclature of Territorial Units for Statistics (NUTS 2).