Greenhouse gas emission abatement in Australian piggeries

As part of a national strategy to understand and reduce greenhouse gas (GHG) emissions from Australian piggeries, pork producers with a variety of production systems voluntarily participated in on-farm studies aimed at calculating their existing piggery baseline emissions and possible emissions reductions. For 55 Australian piggeries, representing 24% of Australian pork production, the PigGas Calculator (Kruger et al. 2013; Mills and Kruger 2014) was used to calculate total on-farm baseline GHG emissions and emissions’ intensities using Australia’s GHG accounting factors. The on-farm ‘business’ emissions boundary used included energy but excluded other pre-farm or post-farm emissions. Individual farm data relating to energy use, pig production parameters, manure management systems, land application practices and pork sales were collected from piggery records and observations at each farm were used in emissions calculations. In consultation with individual pork producers, the PigGas Calculator was then used to model feasible GHG abatement options for each farm. Abatement scenarios included changes in feed efficiency, housing, waste treatment methods, effluent and manure reuse and energy use.

On-farm baseline GHG emissions, average on-farm emissions intensities and potential abatements for the 55 piggeries were grouped by pig production system (Table 1). Total GHG emissions abatements ranged from 0–84% of the baseline on individual piggeries. Highest abatements of 75–84% were achieved on piggeries using covered anaerobic ponds to capture and burn methane in cogeneration systems. Abatement of 10% was achieved by improving feeding efficiency. Modifying waste treatment and reuse systems resulted in 15–25% abatement. Housing pigs in deep litter sheds resulted in about 40% abatement compared with housing in conventional flushed sheds.

Table 1.  On-farm total greenhouse gas emissions, average emissions intensities and potential abatements on 55 Australian piggeries

On-farm baseline emissions calculated from 24% of Australia’s pork production totalled 260,481 t CO₂-e/y with potential abatement of 54%, or 141,232 t CO₂-e/y. On a whole industry basis, maximum potential abatement is 588,467 t CO₂-e/y. It is also possible to reduce baseline emissions intensities by 51% from an industry average of approximately 3.9 to 1.9 kg CO₂-e/kg HSCW. These data provide evidence of the Australian pork industry’s capacity to reduce GHG emissions as it moves into a carbon-constrained future.