Life cycle emissions of greenhouse gases associated with burning animal wastes in countries of the European Union

摘要

Burning animal wastes for the production of electricity is stimulated in the European Union because of the 'climate neutrality' of its life cycle. In doing so fossil fuel inputs in animal husbandry and the N_2O and CH_4 emissions associated with animal husbandry are neglected. Here types of relatively fossil fuel efficient animal husbandry in the European Union are analysed without neglecting such inputs and emissions. The burning of pig derived animal meal, a single-output process, was found to be associated with an emission of greenhouse gases equivalent to 33 x 10~2-44 x 10~2 g CO_2/kilowatt-hour (kWh). In most cases, however, animal wastes can be viewed as outputs from a multi-output production process. If system expansion is not possible, one may allocate multi-output process emissions on the basis of financial value or on a physical basis. Allocating on the basis of energy content of outputs of animal husbandry the burning of manure from poultry, dairy cows and pigs was estimated to generate between 6.3 x 10~2 and 19.5 x 10~2 g CO_2 equivalent per kWh. When allocating on the basis of financial value, burning manure in the Netherlands corresponds with net-sequestration, as the monetary value of manure is negative. For chicken manure a net sequestration was found of 2.5 x 10~2-3.9 x 10~2 g CO_2 equivalent/kWh. Thus life cycle emissions of burning animal waste are extremely sensitive to the allocation principle favoured. One may extend the life cycle for instance by including indirect effects such as the substitution of carbon that is lost to agriculture due to burning animal wastes. Such an extension may well lead to a changed emission in terms of CO_2 equivalent emitted per kWh.