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Lighting constitutes a significant cost to farmers dealing with livestock. This is especially true for dairy operators who adopt long day lighting techniques to improve production. The cost of lighting on a typical dairy farm can be between 14 percent and 24 percent of overall energy costs. As such, savings in lighting costs can go a long way toward keeping money in a farmer's pocket, increasing profit margin or even allowing some expansion without added operational costs. Of all the technologies we'll be discussing in this series on efficiency options for dairies, energy efficient lighting options offer some of the best savings potential and payback times, making such improvements an attractive opportunity for producers looking to save energy and money.
How do you decide what lighting is appropriate for your operation? As the University of Wisconsin Extension puts it, "The best type of lighting is the one that provides the needed amount and type of light to perform a task or increase productivity at the minimum annual cost (operating and fixed costs)."
At present, the kinds of lighting most commonly used in dairies are T-12 fluorescent, incandescent lamps, or high intensity discharge (HID) lamps, such as mercury vapor or high-pressure sodium. At the outset, we can note there are proven, easily available upgrades to T-12 lamps (T-8s and T-5s); and incandescents will soon be difficult to replace due to federal legislation regarding the minimum efficiency requirements of light bulbs. HID lamps are efficient, but don't always produce the quality of light that dairy producers might want.

Fluorescents
Fluorescent lamps are quickly becoming the industry standard. Replacing incandescents with Fluorescents can reduce lighting costs up to 75 percent. Also, the lamps will typically last 6 to 10 times longer than incandescents. Upgrading from T-12 fluorescents to T-8s can also yield benefits. T-8 lamps provide around 15 percent more lumens and cost around 40 percent less to operate. T-8 ballasts are better suited to use in the cold and can start in temperatures as low as 0 degrees F, compared to 50 degrees F for a standard T-12. As many producers likely know, fluorescents do take a few minutes to warm up and start producing their full light capacity.

High Intensity Discharge (HID) Lamps
For dairy operations where color recognition is important, the metal halide (MH) lamp may be the best option for replacing mercury vapor (MV), the least efficient HID lamp. A 100-watt MH lamp replaces a 100-watt MV light and produces over 150 percent more lumens. (A High Pressure Sodium [HPS] light produces 250 percent more lumens, but renders an orange light less suitable for milking spaces.)

LEDs
The ultimate option for efficient, on-demand lighting, if not yet the best cost option, is light emitting diodes, or LEDs. LED lights use up to 30 percent less energy than CFLs and are 90 percent more efficient than incandescents. While currently more expensive, the longer lifespan of LED lights can make up for the initial cost as they last 5-10 times as long as a CFL bulb and up to 50 times as long as an incandescent. LEDs also benefit from their solid-state design, meaning they are much more durable and resistant to breakage, as well as practically unaffected by low temperatures or humidity, offering instant on-and-off light. The major drawback at present for LEDs is their cost. You might hesitate at a price 10 times the expense of a CFL lamp. But the savings come over an LED's long lifespan thanks to their energy efficiency.

Making your choice
The University of Wisconsin Extension recommends an average light level of 15 foot-candles at cows' eye level for dairy lighting. Meanwhile, treatment, feeding and breeding areas should have even more light: approximately 20 foot-candles.
Many dairy farmers are now moving to long-day lighting. Studies have shown that exposing cows to supplemental light during the short days of fall and winter, so that they get 16-18 hours of uninterrupted light and 6-8 hours of darkness, can increase milk production by about 5-16 percent. The result is an increase in annual profit of over $60 per cow. Thus, for long-day lighting, energy efficient lighting systems can be especially helpful. With the right upgrades, many dairy farmers can limit increases in their electric bills and realize a complete pay-back on their lighting investment within a year.
As you look into upgrading to more energy efficient lighting, don't overlook the rebates available from many local utilities. Utilities are required to have energy efficiency programs, and most see lighting upgrades as a great way to achieve energy savings goals. Utilities will generally provide a greater rebate for retrofits than when dealing with new construction, and rebates are typically based on a "per bulb" or "per watt saved" basis. One important note from the utilities: Make sure you contact them before purchasing or installing new lights in order to arrange a rebate.
For additional information on energy efficient lighting and other ways to save energy and money, contact your local electric utility or visit The Minnesota Project's website at http://mnproject.org/e-EE_ResourceCenter.html or contact us at 651-789-3330.
The Minnesota Project champions programs for the sustainable production and equitable distribution of energy and food in communities across Minnesota. In response to economic difficulties faced by Minnesota's dairy farms, The Minnesota Project was awarded funding from the Otto Bremer Foundation to provide dairymen and electric cooperatives with the resources they need to make dairy operations more sustainable, cost effective and profitable as the future promises increased input costs and competition.
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