In the gumbo soil country of South Dakota there is not much water underground, so when rancher Oliver Romey's stock dams went dry in 1990 he had a hard time finding a new source of water. When he found water on his land, the well was 1.5 miles (2.4 km) from the power line. Extending the line to power his pump would have cost $18,000. So, like many people in the area, Romey hauled water to his cattle in tank trucks each day. After two seasons of hauling water, he read about solar-powered pumping provided by the Northwest Rural Public Power District.

The Northwest Rural Public Power District, along with many utilities around the country, offers customers the choice of running new power lines or installing a PV system. PV water pumping is particularly popular in rural areas because, although the electricity is used as it is generated, the water can be stored in tanks and reservoirs. (Storing water is much cheaper than storing electricity.)

Twenty PV modules generate 1600 watts of dc electricity to power a centrifugal pump at this South Dakota ranch. (Photo: Rural Electric Nebraskan)

Now, Romey's PV system pumps water through 5.6 miles (9 km) of pipeline to four stock tanks that supply over 150 head of cattle. And with the new pipeline, he can graze cattle on two fields that he could not use before.

Are PV pumping systems reliable?

Yes! A recent survey of more than 250 PV-powered pumping installations by The Electric Power Research Institute (EPRI) found PV to be a very reliable source of power for pumping systems. In fact, the PV modules are the most reliable parts of the systems; none of the systems in this study experienced module failures. The pumps experienced operational and maintenance problems common to all pumping systems.