OPTIMAL PLANT SIZE AND FEEDSTOCK SUPPLY RADIUS: MINIMIZE THE PRODUCTION COSTS OR MAXIMIZE THE PROFITS ?

摘要

The biomass plant size is significantly affected both by negative and positive “economies of scale”. Asa result, an optimal plant size should be identified and, consequently, an optimal radius of the biomass supply basinshould also derived. Negative economies of scale are mostly related to biomass transport costs, while positiveeconomies of scale are observed with respect to plant capital costs, non-fuel operating costs and energy conversionefficiencies. In order to evaluate the economic viability of a biomass plant investment, two different objective criteriawere compared: “minimize” the total unit costs vs. “maximise” the profit, respectively. An integrated biomass-toenergyproduction system was properly modelled considering revenues and several cost components, thus allowingthe identification of the economic optimum scale for a biomass plant. The two approaches are not equivalent and donot lead to the same “optimal” results. A scaling procedure that brings cost to a minimum does not necessarily bringsprofit to a maximum. Results are also interpreted in view of strategic technological advancements that can generatemore profitable economic conditions, greatly influencing the size of the biomass plant to be set up.