Solar Systems for Watering Cattle
Drawing power from the sun makes water available in distant pastures.
Watering beef cows on remote pastures is easier for Jason Zahn since he replaced aging windmills with solar pumping systems 10 years ago.
Zahn, who ranches near Towner, North Dakota, installed the solar units through a leasing program offered by his local electrical provider, Verendrye Electric Cooperative (VEC).
“The windmills I’d been using were getting old and had problems,” says Zahn. “Because the pastures are located nearly 2 miles from the nearest electrical power line, connecting the wells to electrical service would have been expensive for the co-op.”
He waters 350 cows from each of three wells. At each well, a high-powered ½-hp. submersible pump is plugged into a solar array. The pumps can draw 25 gallons of water per minute from a depth of 18 feet.
The solar array powering each pump is made up of two 120-watt panels. These measure 2×4 feet and are designed to follow the sun. No batteries are used for backup power.
One of the two solar units is stationary; the second unit can be lifted from its base and moved to another well site in the back of a pickup.
Because the pumping systems are designed to permit water to drain back down the pipe when the pump shuts off, they can be used in cold weather.
“At the well site with the stationary solar unit, I’ve pumped water as late as December and as early as the middle of March,” says Zahn.
The tank at each well site is sized to hold a three-day supply of water for the number of cattle in the pasture. Tanks are fitted with floats to switch pumps off and on.
“I recommend sizing water tanks to hold 60 gallons of water per cow-calf pair; that amount should provide a three-day supply of water for each pair,” says Allen Kersten, VEC member services technician. “Sizing tanks to store that amount of water provides some insurance for a long spell of cloudy weather, when the solar units produce less power.”
Each of Zahn’s tanks is sized to hold a 40-gallon supply of water per cow-calf pair. The big tanks can store 14,000 gallons. Though the storage capacity is slightly lower than the cooperative’s recommendations, Zahn’s cattle have never run out of water.
Solar panels have given him no trouble. One submersible pump failed after 10 years, and he had it rebuilt.
He pays the co-op a year-round fee of $20 per month for each unit. The fee covers any servicing the unit might need due to unexpected damages.
The smaller solar-powered submersible pumping units the co-op typically installs cost its member-producers $17 a month.
“Our standard system is a quad pump capable of pumping 4 gallons of water per minute, or 3.1 gallons per minute from a depth of 100 feet,” says Kersten. “That pump is typically powered by two 65-watt solar panels and can supply water to a herd of 90 pairs.”
For such a system, the approximate cost for member-producers looking to purchase the solar panels and submersible pump outright from the co-op would come to about $3,500.