Nebraska Utility to Test Solar Powered Irrigation System

Patented in 1952 by Frank Zybach of Strausburg, Colorado, center pivot irrigation systems have turned out to be, well, a pivotal invention for agriculture, so much so that their spread has raised concerns about ongoing, rapid loss of natural ecosystems and biodiversity.

Providing electrical power to more than 30,000 center pivot irrigation systems across Nebraska (the largest producer and user of center pivots in the U.S.), the state's largest utility, the Nebraska Public Power District (NPPD), is launching a project to test the feasibility of using solar photovoltaic (PV) energy to power them, the Journal Star reported last week.

Food and clean energy: Solar powered irrigation

Improving water efficiency by some 85-95 percent, center pivot irrigation systems have enabled farmers around the world to do a lot more with a lot less man and mechanical power as well as a lot less water. This has led to vast new areas of land being cultivated. Today, more than 40 percent of world food supply is grown on irrigated cropland, with China, the U.S. and Pakistan accounting for more than half the worldwide total, according to The Groundwater Foundation.

An estimated 42,000 center pivots now irrigate approximately 63 percent of the 8 million acres of irrigated farmland in Nebraska, the world capital for this agricultural technology, according to a Groundwater Foundation Rainmaker's Gallery article by David Howe.

The largest power utility in the nation's only not-for-profit, public power state, NPPD is keen to evaluate the feasibility of using solar energy to power center pivot irrigation systems, nearly all of which are powered by electricity, propane or diesel fuel. Its 2013 Integrated Resource Plan calls for the utility to source 10 percent of its native load from renewable resources by 2020.

NPPD's pilot project entails installing a solar PV array capable of generating up to 25 kilowatts of electricity, about 25 horsepower (hp), enough to supply at least some of the power a local center pivot requires -- on about 1/10th of an acre of land near a center pivot system somewhere in the state, the Journal Star's Algis J. Laukaitis reported. Center pivots in Nebraska require anywhere from 25-125 horsepower to pump water through a system's pipes and propel its wheels across fields, NPPD's sustainable energy manager Dave Rich told Laukaitis.

Upon approving the project, NPPD's board allocated $25,000 to carry it out. NPPD also intends to invest $14,000 from a USDA Energy for America Program grant and a $24,000 federal tax credit to get the project rolling.

NPPD needs to find a willing participant among Nebraska's farmers, one who's willing to contribute $17,000 to the project. The state-owned utility is also looking to bring in other utilities from its wholesale customer base as project partners.

The solar panels' estimated lifespan is 25 years. With a 30 percent federal tax credit, NPPD estimates the payback period for a non-pilot project to be anywhere from eight to 24 years, according to the Journal Star's report.