More consistent water application can mean greater water and power savings for large- or small-scale farmers.
According to Luke Robison, manager of Shasta View Irrigation District in Malin, Ore., when Shasta View installed a variable frequency drive at its seven-pump district station, it allowed them to stabilize water pressure and reduce water fatigue on the delivery system.
He said the device, installed with help from an Energy Trust of Oregon cost-share program, reduced the district’s operating pressure by nearly 20 percent and reduced irrigation costs by about $60,000 annually.
Robison noted the pressure reduction didn’t make less water available, but it allowed water managers to distribute the water more efficiently. He said the VFD works like a cruise control, automatically compensating for pump variation and changes in pressure.
Robison said Energy Trust covered roughly half of the $216,000 project.
Doug Heredos, Energy Trust program manager for agriculture, said the Shasta View project is considered larger than average, but it’s not uncommon for the organization to pay 50 percent of VFD projects.
Energy Trust’s irrigation incentives are designed to encourage farmers to grow crops more efficiently with less energy, he added. Water savings can be an additional benefit, along with labor and fuel savings.
“Oftentimes, the water, labor and fuel savings are just as valuable to the grower as the energy efficiency benefits,” Heredos said.
Seus Family Farms owner Scott Seus, said he has installed in several on-farm VFD pumps on his wells in Oregon and California.
“That’s where you save because you can fine tune the settings,” he said.
“Instead of the old way, which was just go turn on a switch and what you get is what you get, you can change the setpoint to how many gallons per minute you are pulling,” Seus said. “You only draw out of the ground what you are actually using.”
Farmer Gary Derry said in most cases one VFD provides enough to flexibility to achieve farm goals. He explained that the pump can be programmed to compensate for full-demand or partial deliveries, depending on farm needs. Derry said most irrigation systems run on maximum pressure, meaning water is commonly over-pumped.
“You only have one speed — it’s on or off,” Derry said. “With the variable speed you’re more consistent with what you do pressure-wise and water delivery-wise.”
Derry noted that even with a cost-share program, VFDs are expensive to buy and maintain. He advised understanding immediate farm needs and long-term goals before investing in large projects like these.
Most Energy Trust customers work directly with local irrigation vendors, according to Heredos. He said the collaboration helps farmers identify the size and type of VFD they need and it helps ensure it will meet the efficiency standards to qualify for an Energy Trust incentive.
Seus said for farmers, electricity and water will always be inextricably linked.
“We benefit by producing better crops, by using better distribution uniformity, and using the water where it’s needed, when it’s needed — with the lowest cost of energy,” he said.