Energy and greenhouse gas balances for a solid waste incineration plant: a case study

Energy and greenhouse gas balances for a waste incineration plant (Reno–Nord I/S, Aalborg, Denmark) as a function of time over a 45-year period beginning 1960 are presented. The quantity of energy recovered from the waste increased over time due to increasing waste production, increasing lower heating value of the waste and implementation of improved energy recovery technology at the incineration plant. Greenhouse gas (GHG) balances indicated progressively increasing GHG savings during the time period investigated as a result of the increasing energy production. The GHG balances show that the Reno–Nord incineration plant has changed from a net annual GHG emission of 30 kg CO2-eq person−1 year−1 to a net annual GHG saving of 770 kg CO2-eq person−1 year−1 which is equivalent to approximately 8% of the annual emission of GHG from an average Danish person (including emissions from industry and transport). The CO2 emissions associated with combustion of the fossil carbon contained in the waste accounted for about two-thirds of the GHG turnover when no energy recovery is applied but its contribution reduces to between 10 and 15% when energy recovery is implemented. The reason being that energy recovery is associated with a large CO2 saving (negative emission).