Life Cycle Assessment of electricity production from refuse derived fuel: A case study in Italy

Biomasses and bio-waste have an important role in decarbonizing the European energy mix, the latter contributing to the transition towards a circular economy. In particular, Refuse Derived Fuel (RFD) - a biofuel obtained from dry residue of waste - appears a really interesting energy option. In this framework this study aims at assessing the environmental profile of electricity generation from RDF in Italy, comparing two different kinds of RDF production and combustion plants. The functional unit is 1 kWh of net electricity from RDF delivered to the grid. Two Italian plants are examined: one located in Ravenna (RDF is produced in a direct flow treatment plant) and the other one in Bergamo (RDF is produced in a unique flow treatment plant and electricity is generated in a cogenerator). Results show that, comparing the plants, it is not possible to identify an option for RDF production or electricity generation characterized by lowest impacts for all the examined impact categories. However, cogeneration process and the avoided burdens due to the valorisation of ferrous metals and dry fractions during RDF production can reduce most of the environmental impacts. A dominance analysis reveals that chimney direct emissions generated during RDF combustion significantly contribute to some impact categories, as well as electricity consumption during RDF production. Furthermore, disposal of incineration wastes is a relevant contributor to human toxicity and freshwater eutrophication. The eco-profile of electricity from RDF is compared with electricity from the Italian grid and from multi-Si PV. The comparison highlights that electricity from RDF performs worse for relevant environmental impact categories such as climate change, human toxicity and photochemical oxidant formation. On the other hand, electricity from RDF performs better than electricity from the grid and from photovoltaic for resource depletion, an impact category of growing importance in the framework of circular economy.