How to handle waste that can be burned, e.g. wood and plastics (in all stages of LCA, especially in End of Life)?
Waste that can be burned is dealt with in LCA by “system expansion”. See Fig. 7.6. The basic idea is to add an extra step to the chain (the blue step in Fig. 7.6), where the waste is burned, either in a electrical power plant or in a municipal waste incinerator. To calculate the gross heat, the Lower Heating Value of the waste has to be applied (ISO 14044). The following efficiencies are to be applied in the eco-costs system (the best practice in Western Europe): – 45% to convert the LHV to electricity in a power plant for use in manufacturing plants (medium voltage, i.e. 1 KV to 35 kV, power supply in the range of 160 kWh to 40.000 kWh) – 25% (= 55% of 45%) to convert the LHV to electricity in a municipal waste incinerator, medium voltage – 95% to convert heat input to heat output. The moisture content (MC) in wood must be evaporated, leading to the following net LHV values: – 20 MW per kg dry wood (this is an average for softwood, the LHV for hardwood is approx. 10% higher) – 17,3 MW
