Energy balance of waste management systems: A case study

摘要

Public policies for waste regulation can foster sustainable production systems in related fields. It is a common perception that waste to energy plants (WTE) are optimal solutions in terms of energy balance for dismissed materials, since they recovery part of the energy as electricity and heat. A few researchers state that there is an optimal threshold beyond whom separated collection of waste is of no use, since it results in a reduction of total energy recovered. This paper investigates the effects of the reduction of unsorted waste in terms of climate factors and energy balance. It is shown that energy saving density from recycling is higher than energy recovery from incineration, hence, source segregated recycling is a better option for waste management. The paper proposes a benchmark to assess the net energy balance of different waste management systems. A case study is reported, based on data of Emilia-Romagna, Italy, where unsorted waste was recently reduced of about 30% thanks to a dedicated waste tax and policies to promote waste separation and re-use. The case study is used to validate the proposed benchmark, while the method is general and can be used for different waste management systems and in different countries.