A Life cycle assessment (LCA) approach to evaluate energy intensity and related environmental impact in dairy farms

The usage of fossil fuels on a large scale started with the Industrial Revolution and it has been constantly raising since then, as well as the resulting emission of carbon dioxide (CO2) into the environment. The objective of this study was to determine, through a partial life cycle assessment approach, the energy demands and the resulting Carbon Footprint in milk dairy production. The main study, which involved 285 Italian dairy farms, showed an average diesel consumption of 0.040 kg and 0.075 kWh of electricity per kg of milk produced. Total annual carbon dioxide emission, related to the energy use corresponded to 0.156 kg CO2-eq per kg of milk. Final results showed that 79% of the on-farm energy emissions were due to the use of diesel and 20% for the electricity supply. The results obtained from the study were used to develop two linear models for predicting diesel and electricity consumption in dairy farms. Moreover, 4 conventional and 4 organic farms, located in California, USA, were analyzed to define the use of direct energy and the related environmental load. The results for conventional and organic farms showed annual diesel consumption about 0.0071 and 0.0164 kg per kg of milk sold, respectively. The electricity purchased accounted for 0.043 and 0.189 kWh per kg of milk, for conventional and organic respectively. Emissions of carbon dioxide associated to the energy usage were: 0.035 kg CO2-eq per kg of milk per conventional farms and 0.103 kg CO2-eq per kg of milk for the organic system.