Cost-effectiveness of environmental impact abatement measures in a European pig production system

Many emerging technologies and alternative farm management practices have the potential to improve the sustainability of pig production systems. The implementation of such practices is not always economically viable. The goal of this study was to assess the cost-effectiveness of such environmental mitigation strategies in pig systems, using an Environmental Abatement Cost analysis. We considered four pig housing (improved insulation, increased ventilation efficiency, frequent slurry removal, increased slurry dilution) and three manure management related abatement strategies (anaerobic digestion, slurry acidification, slurry separation), implemented as stand-alone and as a set of "pig housing-pig housing" and "pig housing-manure management" combinations. We calculated their annual equivalent value through a discounted cash flow analysis and then their annualised abatement potential through a cradle-to-farm gate life cycle assessment. The baseline system against which the analysis was conducted was a typical Danish pig production system, over a 25-year time horizon. The environmental impact categories considered were Non-Renewable Resource Use (NRRU), Non-Renewable Energy Use (NREU), Global Warming Potential (GWP), Acidification Potential (AP) and Eutrophication Potential (EP). Pig housing-anaerobic digestion combinations were the most cost-effective options for GWP, NRRU and NREU. Their abatement costs ranged from -(sic)0.237 to (sic)0.70 per tonne CO2 eq., -(sic)0.146 to (sic)0.36 per g Sb eq. and -(sic)1.75(-04) to (sic)3.11(-04) per GJ abated respectively. Anaerobic digestion was the most cost-effective stand-alone investment for GWP (-(sic)0.206 per tonne CO2 eq.), NRRU (-(sic)0.0493 per g Sb eq.) and NREU (-(sic)1.00(-04) per GJ), and slurry acidification for AP ((sic)303 per tonne SO2- eq.) and EP ((sic)1190 per tonne PO43- eq.) mitigation. Overall, measures for mitigation of GWP, NRRU and NREU required higher investments than for AP and EP, but also generated profit. The framework developed in this study can potentially aid decision making in the choice of environmentally and economically sustainable pig system modifications.