By Liz Morrison

Hog producers: Pay attention to energy costs!

Energy is a significant expense that you can control, said Jay Harmon, professor of agricultural and biosystems engineering at Iowa State University. He spoke at the 2017 Midwest Farm Energy Conference in June, held at the West Central Research and Outreach Center in Morris, Minn..

From 2013 to 2016, the median cost of fuel and power on sow farms was $20.39 per liter and $1.98 per head on wean-to finish farms, according to FinBin, the University of Minnesota’s farm financial database. “We encourage people to think about this,” Harmon said. “Many energy savings can be implemented with very little expense.”

Sleepy Eye, Minn.-based Christensen Farms manages 464 nursery, wean-to-finish and finish sites. LP and electricity make up the company’s largest and most volatile operating expense, said Adam Barka, environmental resource manager at Christensen Farms, who also spoke at the energy conference.

However, energy costs vary sharply among similar operations, he said. At two comparable sites within the company, for example, electricity use per pig space varied 56%, and LP use varied 200%.

“That’s all about management,” Barka said. “Often, it’s the little things that separate the farms that use less energy from the farms that use more.”

To boost your operation’s energy efficiency, start by monitoring energy use, Harmon said.

“If you don’t keep track of what you use, it’s hard to tell if you’re doing great or have a great opportunity to improve,” he said.

Ventilation is by far the largest source of energy loss in swine facilities, Harmon said. A well-managed ventilation system provides good air quality without excessive energy loss from the building.

Ventilation energy losses are often caused by incorrect furnace controller settings, he said. For example, when the heater shuts off too close to the setpoint — that’s the line between the heating and cooling cycles — the temperature in the room may overshoot the setpoint. That prompts the fans to increase ventilation, thereby exhausting the heat that was just added. There go your energy dollars.

Improper controller settings in swine barns can waste a lot of energy, as this example shows. The left side of the graph shows the furnace run time when it was set to come on 2 degrees F below the setpoint, and turn off at 1 degree F below the setpoint, explains Jay Harmon, an agricultural engineer at Iowa State University. The right side of the graph shows how the furnace stopped running when the shutoff temperature was changed from 1 degree below the setpoint to 1.5 degrees F below the setpoint. This change saved 3.75 gallons of LP fuel per day per furnace. For more on-farm energy savings tips, go to farmenergy.exnet.iastate.edu. Additional source: “Managing swine ventilation controller settings to save energy” by Jay Harmon, Iowa State University, farmenergy.exnet.iastate.edu/publications.

Small changes in the controller settings can have a big impact on energy consumption, Harmon said. In one case study, reported by Brumm Swine Consultancy in North Mankato, Minn., just a half-degree change in the heater shutoff settings saved nearly 4 gallons of LP fuel per day per furnace.

One easy way to tell if you have a problem?

“Listen!” Harmon said. “If the furnace runs, and then the minimum ventilation fans begin to increase speed after the furnace has shut off, the offset needs to be larger.”

Other ways to improve energy efficiency in hog barns include proper sizing of ventilation fans and using variable-speed fans, Harmon said. Good fan and shutter maintenance saves energy bucks, too, he added.

Barka also suggested some simple and inexpensive energy conservation tactics:

• Put plastic or bubble wrap inside curtains.
• Make sure inlets are functional and soffit openings are not clogged.
• Keep fan blades clean.
• Eliminate leaks around doors and holes in the ceiling.
• Keep curtains in good shape.
• Add ceiling insulation.

For more on-farm energy savings tips, go to farmenergy.exnet.iastate.edu.

Morrison writes from Morris, Minn.