RENEWABLE POLK COUNTY (WI): Peterson/Stewart Home

Owners: Jeff Peterson & Nancy Stewart

Location: 750 Round Lake Rd., Luck, WI 54853

Phone: 715-472-2728

Email: peterson [at] lakeland.ws

Installed: April, 2009

Components: 8 Sharp 187-watt PV modules, Fronius inverter

This grid-tied photovoltaic system is rated at 1.5 kW, though output has at times surpassed that level. The array is fixed in orientation at 10 degrees west of true south to provide optimum output during times of peak system load. Angle from horizontal is adjustable to account for seasonal variations in the sun's position in the sky. Owners make those adjustments themselves four times a year.

Maximum daily output is 10 kW hours -- greater than homeowners' normal consumption. Polk-Burnett Electric Cooperative (PBEC) provides net metering, so excess production is compensated at the retail rate. Expectation is for this system to provide about 40% of electric needs over the course of a year. Electric bills, formerly $70-$80 per month, have been reduced by $20-$25 per month.

Total installed system cost was approximately $15,000. A 20% incentive from PBEC and anticipated federal tax credits of 30% effectively cut that cost in half. Still, payback at current electric rates is 20+ years. This will, of course, be shortened any time electric rates increase.

Photo: Mounting pole set in rebar-reinforced concrete capable of withstanding 100 m.p.h. winds.

Photo: Installer Kris Schmid attaching ground wires.

Photo: Lightning arresters, inverter, circuit breaker inside garage.

Photo: Display shows current production in watts per hour.

Photo: New meter under old measures outgoing kilowatts. Monthly credit from PBEC is based on difference between top reading (incoming) and bottom reading.