Energy Usage Survey of Dairies in the Southwestern United States

Abstract

A survey of 14 dairies in Texas and California was conducted to determine their total energy use on an annual basis. The goal of the survey was to evaluate the effect of production and management processes on energy consumption. The total energy used on facilities varied widely with the type of operation, e.g., pasture, open-lot, or hybrid (a combination of open-lot and free-stall) systems, as well as with the relative age of the facility. The on-farm energy supply sources included electricity, gasoline, diesel, propane, and natural gas. Total energy usage ranged from as low as 464 kWh per year per animal (kWh yr -1 hd -1 ) for a pasture dairy in Northeast Texas, to as high as 1,637 kWh yr -1 hd -1 for a hybrid facility in Central Texas. Where possible, the electricity usage at the dairies was allocated to four main energy sinks: the milking parlor, the animal housing areas, feeding, and manure management. Generally, milking and housing components dominated the electricity usage for hybrid dairies, with the milking parlor being the primary consumer of energy for the open-lot facilities. Newer dairies were more efficient in electrical energy use than older facilities. A significant amount of energy could be saved by upgrading facilities with newer and more energy efficient equipment. In addition, the estimated daily potential energy availability from manure (25.7 kWh d -1 hd -1 ) is much greater than the average daily on-farm energy requirement (3.2 kWh d -1 hd -1 ) indicating the possibility of adopting on-site manure to energy conversion systems. Analysis showed that renewable energy conversion systems with more than 15% conversion efficiencies could be considered for this on-farm energy production alternative.