Oz dairy eyes energy savings
LOBBYING IS underway to gain Australian Government funding for a national programme to conduct energy assessments in dairies.
Gabriel Hakim, AgVet Projects, assessed energy use on 10 farms with automatic milking systems (AMS). He found that most AMS dairies had equipment unnecessarily large for the needs of automatic milking, wasting electricity.
"When building an AMS it can be tempting to reuse equipment from the existing dairy, but automatic milking can place quite different demands on equipment," he says.
For example, the milking equipment on AMS farms where cows move voluntarily runs at low capacity for up to 20 hours a day, versus conventional milking twice daily in intensive sessions.
"Operating equipment that is not sized correctly risks losing energy efficiency and using excess energy."
Many of the AMS dairies in the study had an oversize compressor and oversize vacuum pumps, and most had hot water systems suitable for a conventional dairy -- bigger than needed for an AMS.
"Operating oversize or over-capacity equipment wastes a lot of energy," Hakim says. "For example, if you are running a grossly oversize vacuum pump much of the energy can be used just driving the pump.
"The same is likely for compressors. Studies in other industries using compressed air have shown 30-50% of energy was used to service leaks and supply artificial demand and system inefficiencies. This warrants further investigation for AMS dairies."
When planning an AMS, Hakim recommends weighing the savings possible in capital outlay – by retaining existing equipment – against the longer term operating costs.
The FutureDairy project leader, associate professor Kendra Kerrisk, says although energy consumption was higher in AMS than conventional milking systems, it was a relatively small part of the overall economics of robotic milking.
"Higher energy cost doesn't mean AMS is uneconomic," she says. "In fact, although shed running costs are commonly reported to be higher, animal health and labour costs are much lower on many AMS farms."
The AMS energy study was funded through Dairy Australia's project Smarter Energy Use on Australian Dairy Farms, funded by the Department of Industry and Science as part of the Energy Efficiency Information Grants Programme.
