Towards energy-efficient small dairy production systems: An environmental and economic assessment.

Abstract Around 64% of the cow raw milk produced in Europe is collected from small dairy systems. However, the available literature focusses on assessing the energy consumption of industrial raw milk production dairy systems and overlook small dairy systems which often include the farming and processing stages within their system boundaries. To cover this gap, this study energetically audited nine small dairy systems located in the north-west of Spain. These facilities perform conventional dairy farming and processing activities. As result, this study presents reliable energy consumption data, Key Performance Indicators and it also suggest custom-made energy efficient improvements to reduce the systems’ energy consumption, costs and enhance their products’ environmental performance. To produce pasteurized cow milk, small dairy systems consume 2.1 MJ/kgm which causes emissions of 0.2 kg CO2eq/kgm. While the energy consumed to produce sheep milk cheese (7.4 MJ/kgm) generates emissions of 0.58 kg CO2eq/kgm. Diesel is a thermal energy consumption hot spot at the agricultural stage since it is highly used to power agricultural machinery. At the cow facilities, the diesel usage rate is 0.8 MJ/kg ECM; while the sheep facilities have a usage rate of 2.5 MJ/kgECM. The agricultural and processing equipment consumes most of the electricity (85%) where the lamps and the cold chambers are the main electric equipment consumption hot spots at the processing stage since they respectively demand up to 10% and 30% of the total electricity consumed. To optimize the energy demand due to lighting, the use of LED lamps was highly recommended as a specific and straight forward improvement action for all the facilities. Another improvement is the implementation of energy consumption monitoring/management systems to optimize the equipment's operational time and energy demand such is the case of the cold chambers compressors. These two improvements showed to be profitable for the facilities and both can reduce up 5% of the electricity consumption and thus, reduce its related emissions and costs by a 5% and 6% respectively.