Agricultural energy efficiency tour: replacing inefficient irrigation systems

M. Charles Gould<gouldm@msu.edu>, and Aluel S. Go, Michigan State University Extension - August 09, 2017

Grand Valley Farm energy efficiency tour highlights multiple energy efficiency practices including center pivot system and low elevation spray application.

After conducting a Michigan Farm Energy Audit, Grand Valley Farm, the host site for the Aug. 17 agricultural energy efficiency tour, found it could cut energy expenses by more than 50 percent by replacing two traveling guns with a more energy efficient center pivot system. The two installed center pivots use a Berkley Model, 75 horsepower irrigation pump with a flow of 1,200 gallons per minute. This 75 horsepower pump replaced the 125 horsepower pump from the previous system and included a variable frequency drive to accommodate flow and pressure variations. Table 1 documents the electricity of the two traveling guns used before the new system. Assuming a $0.14 per kilowatt hour rate, the total yearly operating expense for the two traveling guns was $58,220. In Table 2, the electricity usage for the installed center pivot system is shown. The total electricity used is less than a third of the consumed electricity of the old system. This led to a total expense of $25,343, less than half of the original expense. Overall Grand Valley Farm achieved a 56 percent energy reduction.

Table 1 – Traveler Rigs Electricity Usages

Irrigation System	Pumping Rate (gpm)	Total Dynamic Head	Water Horsepower (WHP)	Electricity Rate (kWh/hr)	Operating (hours)	Electricity Usage (kWh/yr)	Cost @ $0.14/kWh
Traveler 1	650	383	62.8	71.0	2,841	201,554	$28,218
Traveler 2	650	407	66.8	75.4	2,841	214,305	$30,003
		Totals			5,681	415,859	$58,220

Table 2 – Center Pivot Electricity Usages

Center Pivot	Pumping Rate (gpm)	Total Dynamic Head	Water Horsepower (WHP)	Electricity Rate (kWh/hr)	Operating (hours)	Electricity Usage (kWh/yr)	Cost @ $0.14/kWh
Full Circle	1,200	247	74.7	84.4	771	65,099	$9,114
Full Circle	1,050	268	71.1	80.4	456	36,631	$5,128
3/4 Circle	1,200	264	80.0	90.4	453	40,990	$5,739
3/4 Circle	1,050	282	74.8	84.5	453	38,297	$5,362
		Totals			2,134	181,018	$25,343

Not only did the farm reduce their energy expenses with the center pivot system, the system also reduced water loss from evaporation and wind using low elevation spray application (LESA). The entire system is low pressure, with the center pivot operating at 50 psi and the end gun at 30 psi. The higher efficiency allowed by this application system has allowed Grand Valley Farm to see a 30 bushel per year increase in their corn yields. It is estimated that the new system is allowing 99 percent of the pumped water to reach the crops. Achieving the proper hydration for the crops led to higher yields within the first years of operating the new system.

Grand Valley Farm applied for and received a U.S. Department of Agriculture (USDA) Rural Education Achievement Program (REAP) grant that covered 25 percent of the total cost of the irrigation system, plus they received an energy savings rebate from Consumers Energy. These funding opportunities are still available and information on how to access grant, low interest loans, and rebate funding information will be shared with participants during the energy efficiency tour.

The event will start with a light dinner at 6 p.m. followed by a tour of the farm’s irrigation system and other energy efficient practices including a new grain drying system, lighting improvements, and a solar thermal hot water heating system. Registration information can be found at https://events.anr.msu.edu/AgEETour_GrandValleyFarm. There is no cost to attend this event but registration is requested so we can get an accurate meal count. Questions about the tour can be directed to Charles Gould at 616-994-4547 or gouldm@msu.edu. Reference to commercial products or trade names does not imply endorsement by Michigan State University Extension or bias against those not mentioned.

Data in this article comes from a publication entitled Farming for Efficiency: A Case Study - Grand Valley Farms by Kara Dean, Breanna Earls and Aluel Go with the Michigan Farm Energy Program.

Additional articles in this series:

Agricultural energy efficiency tour: grain dryer system on Michigan farm

Solar thermal system part of Michigan agriculture energy efficiency tour

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).