Biomass has the potential to play a significant role in the world energy scenarios due to its abundance and to the neutral contribution to the CO2 balance when it is used as fuel. Several thermo-chemical processes can be used to produce fuels from biomass. Pyrolysis can be considered a densification process in which the biomass is converted to solid and liquid fractions which may be transported and used for energy production. Nevertheless, the environmental and economic feasibility of a bio-energy supply chain based on this technology and its compatibility with the territory are to be intently investigated. Practical guidelines can be drawn only in a life cycle perspective. The aim of the present study was to perform a LCA study on alternatives biomass-to-electricity (BtE) supply chains based on the slow pyrolysis densification process. Three environmental indicators were included in the assessment: life cycle energy demand, emission of greenhouse gases and land occupation. The application considered co-combustion of coal with solid and liquid products obtained from the slow pyrolysis of different biomass species. Raw biomass co-combustion with coal was selected as comparative scenario. With reference to the set of indicators considered, the co-combustion of the pyrolysis products seems to yield lower environmental burdens than direct co-combustion when long transport distance (i.e. hundreds of kilometres) or high renewable power capacity (i.e. dozens of MWel) are requested. Useful indication for the potential implementation of bio-energy projects on the territory can be obtained from the results of the analysis. The study is moreover a reliable basis for further investigations on other environmental and economic issues and on alternative biomass utilisation routes.
Life cycle modelling and environmental impact assessment of energy production supply chains based on a biomass pyrolysis densification process
CORDELLA, MAURO;COZZANI, VALERIO;SANTARELLI, FRANCESCO
2010
Abstract
Biomass has the potential to play a significant role in the world energy scenarios due to its abundance and to the neutral contribution to the CO2 balance when it is used as fuel. Several thermo-chemical processes can be used to produce fuels from biomass. Pyrolysis can be considered a densification process in which the biomass is converted to solid and liquid fractions which may be transported and used for energy production. Nevertheless, the environmental and economic feasibility of a bio-energy supply chain based on this technology and its compatibility with the territory are to be intently investigated. Practical guidelines can be drawn only in a life cycle perspective. The aim of the present study was to perform a LCA study on alternatives biomass-to-electricity (BtE) supply chains based on the slow pyrolysis densification process. Three environmental indicators were included in the assessment: life cycle energy demand, emission of greenhouse gases and land occupation. The application considered co-combustion of coal with solid and liquid products obtained from the slow pyrolysis of different biomass species. Raw biomass co-combustion with coal was selected as comparative scenario. With reference to the set of indicators considered, the co-combustion of the pyrolysis products seems to yield lower environmental burdens than direct co-combustion when long transport distance (i.e. hundreds of kilometres) or high renewable power capacity (i.e. dozens of MWel) are requested. Useful indication for the potential implementation of bio-energy projects on the territory can be obtained from the results of the analysis. The study is moreover a reliable basis for further investigations on other environmental and economic issues and on alternative biomass utilisation routes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
