Farm energy audit can help conserve energy and lower costs

By DALE HILDEBRANT, For Minnesota Farm Guide
Saturday, February 2, 2008 1:21 PM CST

Chad Reisenauer, energy conservation coordinator for Basin Electric Power Cooperative.

GRAND FORKS, N.D. - Although commodity prices are better than they have ever been in many cases, input costs are also rising at a rapid pace. But that doesn't necessarily mean the cost of prodution has to go up.

With the cost of all forms of energy increasing at a rapid pace, farmers have the potential to lower their cost of production by performing an energy audit on their farm or ranch and identifying ways to lower energy use, which translates into lower costs.

During his presentation at Marketplace for Entrepreneurs in Grand Forks, Chad Reisenauer, Basin Electric Power Cooperative's energy conservation coordinator, outlined some areas that should be checked in a farm energy audit. These focus areas range from the farm home to the tractors and irrigator units running in the field.

“Farming is a very energy intensive business, it has been throughout its history,” he noted. “But earlier in our history we depended upon animal energy and the energy that came from those crops used to feed those animals. Now farmers are using a lot of electrical energy as well as petroleum in their operations.”

Two questions first need to be answered when performing an energy audit, according to Reisenauer. First, you need to know what the costs will be to implement a change that will result in energy savings; and secondly, what is the time frame that will be required to pay for that change.

He suggested that probably any project that has over a three-year period for payback should be given extra consideration, because of the length involved.

With those two factors in mind, Reisenauer listed several areas that are large energy users on some operations and what to look for when doing an energy audit.

- Irrigation. The average center pivot irrigation unit costs about $36 annually per acre in direct costs, such as costs of energy to run the system and an additional $12 per acre in repair and maintenance charges.

Many simple repairs and adjustments can lower the amount of energy used by irrigation system. These range from pump impellers being out of adjustment to dry bearings or worn out nozzles. He noted that improperly sized pumps, either too large or too small, can waste energy.

“You can't just go to a neighboring farmer's auction and pick up a pump,” he said. “Everything in an irrigation system needs to be sized for that particular system for the best results.”

He also cautioned that irrigation systems need to have their leaks fixed, since that not only wastes energy, but also interferes with the distribution of water across the field.

- Dairy farms. Seventy percent of the energy used on a dairy farm is used in the harvesting of milk, Reisenauer said - 25 percent each for heating water and cooling the milk and 20 percent for running the vacuum pump. And there are ways to decrease energy consumption in each of these areas.

The vacuum pump can be equipped with a variable speed drive that instead of running at 100 percent at all times, varies the pump's speed to match the vacuum demand.

In cooling the milk, many dairies are now using water-cooled plate coolers to initially cool the milk instead of relying on the compressor to do the entire job. This results in saving two ways, first, less energy is needed to cool the milk and the water going into the water heater is preheated by the milk.

Second, a scroll type compressor for milk cooling can be used rather than the traditional reciprocating type compressor and the heat generated by the compressor can be recovered and used to preheat water on its journey to the water heater.

Finally, in regards to dairy farms, Reisenauer indicated many operators are doing a practice called “long day lighting” in which cows are exposed to 16-18 hours of light a day, year round, relying on a combination of natural and supplemental lighting. Although this may consume slightly more energy for lighting, he indicated most dairy producers are experiencing production gains ranging from 5 to 15 percent more milk, which more than offsets the energy costs.

- Heated livestock water fountains. Other livestock producers can benefit as well from an energy audit, especially in the area of heated livestock water tanks. Reisenauer mentioned that 60 to 80 percent of the heat loss in a heated livestock waterer during the winter months comes from missing lids or lids that aren't closed. Additional energy is wasted by not having a tight seal around the foundation of the waterer and by having the water temperature set too high.

“The temperature on the thermostat only needs to be set from 32 to 35 degrees to prevent freezing,” he said. “I have heard of some cases where the thermostat was set as high as 50 to 60 degrees, and the heating elements were actually coming on in the summer, because the temperature of the incoming water was probably 55 degrees, which caused the heating elements to kick in.”

- Lighting. Two areas of lighting need to be addressed here - the outdoor security type yard lights and interior lighting in the farm buildings such as the barn and shop.

Many of the outdoor “all night” yards lights are mercury vapor lamps which produce 32 lumens per watt of power, Reisenauer noted, while high pressure sodium lights emit 95 lumens per watt and metal halide give off 60 lumens per watt.

Going by these figures, the high pressure sodium would be the way to go, but many object to the yellow light emitted by those bulbs, so he suggested that farmers check into the metal halide light as an alternative, which gives off a light similar to what a mercury vapor bulb does.

He also said some farmers and ranchers are going to a half-night light controller, where the light is on for the first portion of the night is then shut off after midnight or 1 a.m., since there is little activity in the yard during those hours.

For interior lighting, Reisenauer suggests phasing out incandescent bulbs and going with T8 fluorescent bulbs and converting T12 fluorescent fixtures to T8, since the T8 bulbs give off 15 percent more lumens per watt of power, their ballasts are 40 percent more efficient, the bulbs start at temperatures down to zero degrees and the bulbs have a 60 percent longer life than the T12 bulbs.

- Grain drying. In order to conserve energy, he suggested that harvest should be delayed as long as possible to allow for natural drying in the field. Keeping the drying floors and columns in a dryer bin clean are also important, since it allows for a better flow of air.

Finally, farmers should continually monitor the moisture level of the crop to guard against over-drying, since drying the crop too much not only requires more energy, but also lessens the weight of the crop being sold, resulting in less crop income.

Drying installations also use high horsepower electric motors, which are a large user of energy. Simple maintenance like keeping the motor clean, and maintaining the proper belt tension and alignment can increase efficiency. If belt replacement is necessary, use a cogged version for less slippage and use the proper size and type of motor for the application.

If possible, use a variable-speed drive and if a motor burns out, consider replacing the unit instead of having the old one rewound. Rewinding a motor usually lowers the efficiency of the unit, Reisenauer noted. Rewinding an older motor can result in an efficiency of only 80 percent, whereas a new motor can be up to 94 percent efficient.

This is another time, when the cost of the more efficient motor needs to be weighed against the cost of rewinding a motor that is less efficient and determine the length it would take to invest the extra money in a new motor.

- Powered farm implements. Tractors and other self-propelled farm equipment need to also be evaluated in the farm energy audit. Are the tires properly inflated? Both under- and over-inflation can be costly, he noted. And is the tractor properly ballasted? All too often the ballast load of a tractor is added for just a few jobs where maximum traction is required, resulting in hauling around an extra weight the rest of the time, which lowers efficiency.

If working conditions permit, on lighter loads shift up and throttle down, making sure that by doing so the engine isn't over loaded. Keep your tractors tuned up, and in the case of diesel powered equipment, make sure you are using the right blend of diesel fuel.

Winter blends of diesel fuel have less energy units per gallon than those blended for warmer temperatures, so make sure you don't carry over a large inventory of winter blend into the spring, when temps are warmer.

- The farm home. Take a look around the farm home. Consider upgrading the insulation in the structure and seal openings against air infiltration.

Consider other options for heating and cooling. For instance, using a geo-thermal type heat pump for heating has an efficiency rating of 300 percent and an air source heat pump is 200 percent efficient. Both require a large investment to install, and again the owner needs to pencil out the repayment time, Reisenauer said.

Consider changing incandescent light bulbs in the house over to screw-in compact fluorescent bulbs, which will not only use 75 percent less energy, but prolong the time needed to change bulbs, since they last from 6 to 10 times longer than a standard incandescent bulb.

Insert rubber gaskets under the cover plates of wall switches and outlets and if the water heater needs replacement consider switching to a high efficiency model. An insulating blanket can be put around your present water heater as a means of conserving energy, and Reisenauer suggests setting the water heater thermostat at no more than 120 degrees.

Finally, when purchasing new appliances for the home, you should buy only Energy Star appliances, which are designed to save energy.

For more information on an energy audit on your farm, contact your local rural electric cooperative. They might not actually do energy audits, but they could refer you to a business that can provide such a service. You can also contact Reisenauer at Basin Electric Cooperative by calling 701.355.5710 or dropping him an email at chard@bepc.com.

Comments »

Comment on this story

Comments will be approved within 48 hours

Name:

Email: (optional)

Comments:

Image Verification: (Case sensitive)