Technologies for energy recovery from waste biomasses: A study about Tuscan potentialities

Biomass is a form of renewable energy that can be used to provide high energy outputs, to support and in same case replace conventional fossil fuel energy sources. There are many kinds of energy conversion processes in relation both with biomass chemical - physical characteristics and with the form in which the energy is required. In this work the potentialities for energy recovery of the waste biomasses derived from the agro industrial activities of the Tuscan region (Italy) are analyzed: in particular waste derived from food crops (cereals, beet, sunflower, olive tree, citruses, vineyard, ...), zoo technical activities, and wood. The data obtained are examined to make a comparison between the various energetic and economic results employing different kind of energy systems commonly used in biomass energy conversion. The technologies analyzed are the thermochemical processes combustion, gasification, Fischer Tropsch (FT) diesel fuel production and the biochemical process of anaerobic digestion. Each process requires a proper energy conversion plant. For the above mentioned processes, the conversion plants hypothesized are: for the direct combustion the steam turbine plant, for the gasification the Integrated Gasification Combined Cycle (IGCC), for FT biodiesel the compression ignition engine and for anaerobic digestion the gas engine. These conversion technologies were analyzed also from an economical point of view. This analysis was carried out by taking into account costs (harvest and collection, eventually pre-treatment, transportation cost) and incomes (energy saving and sale. Finally the environmental impact is considered studying the avoided emission of CO2 in relation with the avoided use of fossil energy for the power production.