Methane utilisation on dairy farms

On dairy farms, enteric fermentation in ruminants and the handling of manure and slurry cause unwanted greenhouse gas (GHG) emissions. In contrast, anaerobic digestion (AD) through engineered systems yields biogas or biomethane as a renewable energy with negative net GHG emissions. The production and utilisation of methane-rich renewable gas represents an important pathway to achieve net-zero GHG emissions for dairy farms. This chapter explains how AD for biogas and biomethane production and methane utilisation can be implemented on dairy farms and how this contributes to achieving net-zero GHG emissions. Renewable methane from dairy manure and slurry could reduce global net GHG emissions by at least 1%, and AD systems on dairy farms can increase this potential by using co-substrates. However, it is estimated that less than 10% of this potential is currently being exploited. The chapter also outlines promising lines of research.