Tom Jespersen Energy Adviser

Verendrye Electric Service Area Serve parts of 6 counties around Minot 15,000 meters First PV system installed in 1991 Currently have installed 244 PV systems PV Systems are leased by the Membership

Why PV water pumping? Rural area has a density of 1 meter per mile of line. Overhead line now cost $20,000 per mile. Water pumping is a low usage load less than 500 kwhs per year. PV pumping systems are relatively inexpensive to install.

Lease of PV Systems Lease the power supply only---All above ground equipment Customer needs to purchase the pump Keeps Verendrye in the power supply business

Water Pumping Rule #1---Keep it simple for reliability Use Module direct to pump system, no batteries Use large stock tank for storage, 2-3 day water supply Cattle drink less on cloudy days when the system pumps less Normally a cow/calf pair will drink 20 gallons per day

Typical PV Pumping System Uses 2 solar modules Voltage/Current controller Tracker Disconnect Switch Float on/off switch DC 24 volt pump

Solar Modules Most are 60 to 100 watt modules. Goal is a 20 Year Warranty Large J-box for easy connections Heavy duty aluminum frame

Pump Controllers Maximize the daily output of the pump while providing protection for the motor. The controller circuitry trades voltage for amperage to allow the pump to start earlier in the morning or on partial sun days. Protects the pump from reverse polarity, surges and limits both amperage and voltage. Cost in the $250 range

Passive Trackers Operates by the moving liquid between sealed frame members. No drive motors, gears or pistons to wear out. Ideal for water pumping systems during long summer days. Increases the amount of electricity produced 25-40% during the summer months. Cost in the $500 range for a two module system.

Pumps Most are 24 volt DC diaphragm pumps Operate on low power output days Small easy to install Pump water from 100 feet with reasonable flow rates Relatively inexpensive about $750 per pump Diaphragm will need to be rebuilt after 10 years of pumping

Misc Equipment Disconnect switch Ground rod Float switch Pipe Rope Mounting pole