Dairies, pay attention to electric bill


BROOKINGS, S.D. — Dairymen pay close attention to their feed bills. And they should, since feed is a major expense on the dairy farm.

But what about your electric bill? There might be some ways you could shave some dollars off your electricity use.

Shouldn’t ignore

In South Dakota, for example, electricity alone represents 30 cents per 100 pounds of milk. 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 percent of the total cost, or nearly 13 cents per hundred pounds of milk (using South Dakota figures). The next highest cost is lighting, which 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.

Check compressor

One way to save is to change the type of compressors used, Garcia said.

“Switching from reciprocating to scroll-type compressors can reduce energy use by 20 percent, and the total savings will amount to 1.5 cents per 100 pounds of milk.”

Other steps to watch

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

“Pumps account for nearly 20 percent 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, he added.

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.

Lights, fans

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, because air movement represents another potential area for electricity savings.

Compare efficiency

Large-diameter, large-bladed fans run at slow speeds are more efficient, for example. 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.”

Invest in thermostat

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.

He estimates that by addressing these areas, a producer can save almost 5 cents per 100 pounds of milk produced.

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