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Reduce Electricity Use To Boost Profits

01 August 2009

With operating costs for South Dakota dairies at approximately $14 per one hundred pounds of milk, electricity alone represents 30 cents per 100 pounds of milk, explains Jarett C. Bies, Associate Writer for the South Dakota State University.

That's according to South Dakota Cooperative Extension Dairy Specialist Alvaro Garcia, who said producers who want to reduce electric bills have to understand what exactly that 30 cents pays for.

"If a producer wants to save money, it makes sense to concentrate in those areas that use the most electricity," Garcia said. "The area with the greatest electricity use is milk harvesting, which includes cooling, pumps, and other equipment."

Garcia said these systems use 42 per cent of the total cost, or nearly 13 cents per hundred pounds of milk. The next highest cost is lighting that costs 7 cents per hundredweight.

"Ventilation comes next, again roughly about 7 cents per hundredweight, and the remaining 3 cents are split almost equally between water heating, manure handling, and feeding equipment," said Garcia. "One way to save is to change the type of compressors used. Switching from reciprocating to scroll-type compressors can reduce energy use by 20 per cent, and the total savings will amount to 1.5 cents per 100 pounds of milk."

Other steps Garcia suggests include addressing pumping milk and washing the system.

"Pumps account for nearly 20 per cent of the electricity used for milk harvesting, and when these pumps have a variable-speed drive installed, they can bring a 1-cent savings per 100 pounds," Garcia said. "The use of this technology requires an upfront investment and several years of repayment, depending on number of cows milked."

Dairy producers who pre-cool milk through a well-water plate cooler can save nearly 40 kilowatt hours per cow annually or another 1.6 cents per 100 pounds of milk at current electricity prices.

"The areas where significant savings can be achieved are lighting and ventilation," said Garcia. "Switching from incandescent to fluorescent lights that produce similar intensities of light can save nearly 4 cents per 100 pounds of milk produced."

Garcia said producers should evaluate how efficiently their air-movement systems inside barns work as well.

"Air movement represents another potential area for electricity savings, because large-diameter, large-bladed fans run at slow speeds are more efficient. They move more air with similar energy usage," said Garcia. "The key is to compare efficiency, looking at the amount of cubic-feet-per-minute/per watts used."

Garcia said that since standard alley fans generally range from 1/3 to 1 1/2 horsepower, figuring the equivalent in improved-efficiency fans is important.

"It takes 6 or 7 standard alley fans to move 125,000 cubic feet of air per minute," he said. "You can move the same amount of air with a high-volume, low-speed fan and only use a 1-horsepower motor."

Regardless of the type of fan used, Garcia said it is important to have thermostats that start the fans only when ambient temperatures increase above 70 degrees Fahrenheit.

Although some more-efficient technologies require an initial investment before they produce savings, there are methods to reduce electricity bills, Garcia said.

"Fluorescent lights are a good example of a strategy producers can employ in increments without incurring huge out-of-pocket expenses all at one time," Garcia said. "By addressing these areas a producer can save almost 5 cents per one hundred pounds of milk produced."

July 2009

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