Soon, Nebraska's crops may rely on sunshine in more ways than one. The state's largest utility, the Nebraska Public Power District, recently announced a pilot project to test the feasibility of powering the more than 30,000 center pivot irrigation systems across the state using solar photovoltaic energy.
Nebraska farms rely primarily on groundwater for irrigation, a process that requires a lot of energy to pump water up from underground onto fields above. (That pumping has also led to significant groundwater loss in parts of the state.) Today nearly all of Nebraska's center-pivot irrigation systems are powered by electricity, propane or diesel fuel. That presents a big market for NPPD, which is trying to reach its goal of ten percent of its power generation from renewable energy resources by 2020.
The pilot project would help farms install solar panels - requiring about a tenth of an acre of land - designed to generate up to 25 kilowatts of electricity, which is equal to about 25 horsepower. Since most center pivots need 25 to 125 horsepower to operate, the proposed solar installations could provide anywhere from 20 to 100 percent of the power needed. Funds from NPPD, the USDA and a federal tax credit will help to defray the costs so that farmers and ranchers who want to participate will contribute only $17,000. Without the subsidies, a farmer would have to pay $80,000 for the same solar system with a payback period of about 24 years, so participating farmers will see significant savings.
While we're always happy to see solar energy encouraged on farms, other major farm states like Idaho have shown that simply turning off irrigation systems for a few hours a day can lead to big energy savings. Some technologies, like drip irrigation, are more energy and water efficient. And of course, large industrial monocrops like those found in Nebraska can have serious consequences for water supplies, through both groundwater loss from intensive irrigation and pollution through over application of pesticides and fertilizers (many of which are derived from fossil fuels).
Powering irrigation with solar is a good match. There are even solar-powered soil moisture sensors, which can help farmers avoid over-watering, thereby saving unnecessary pumping costs and helping to prevent leaching of fertilizers.
But farmers should think no differently than homeowners when it comes to energy use: focus first on how to be more energy - and water - efficient, and then look towards renewables.