Application of Wind Energy to Great Plains Irrigation Pumping

We investigated application of dedicated wind energy systems without energy storage for irrigation in the Great Plains. Major uses of irrigation energy were identified as pumping for surface distribution systems, which could be supplied by variable flow, and pumping for sprinkler systems using constant flow. We developed a computer program to simulate operation of wind-powered irrigation wells. Pumping by wind turbine systems was simulated for two variable and two constant flow operational modes in which auxiliary motors were used in three of the modes. Using the simulation program, we made a comparison among the four modes of well yields and maximum pumping rates as a function of drawdown in atypical well. The program also was used to determine monthly well yields using a 250 m2 swept area wind turbine system in each mode if located at Columbus, Nebr.; Garden City, Kans.; and Amarillo, Tex. Irrigation required for various crops at these locations was then matched to monthly water yields. Such management practices as preplant irrigation, limited irrigation, or crop combinations were compared to determine how they affected the amount of annual capturable wind energy used. Last, we computed the percentage of fossil fuel replaceable by wind energy for the most efficient constant and variable flow modes of the wind powered systems. We concluded that wind powered systems could supply half or more of the Great Plains irrigation energy demand using the present mix of sprinkler and surface distribution systems. However, in the variable flow modes that used little or no auxiliary energy, two wells would be required to yield amounts of water similar to a continuously pumped well. Proper irrigation management is important to maximize wind energy use. Fully irrigated summer crops with preplant irrigation will use 30 to 60 percent of the annual, capturable wind energy, depending on crop and location. Fully irrigating equal areas of corn and winter wheat will use 70 to 85 percent of the wind energy, depending on location. With limited irrigation, 50 to 100 percent of the wind energy can be used, depending on practices followed.