The annual production incentive can be estimated by multiplying the system rating times the number of full sun hours of the area where the solar system will be installed. Eastern Washington receives about 1,200 full sun hours per year. Annual income for a 1,000 watt (1 kilowatt) system using Washington-made solar modules would therefore range from:
Estimated Annual Income with Washington-made inverter, but not Washington solar modules:
1 kW x 1200 hours/Year x State Incentive, $0.18/kWh = $216/Year
Approx. Simple Payback = ($7,000 - $2,000 tax credit) / $216/Year = 23 years
Estimated Annual Income with Washington-made solar modules & inverter:
1 kW x 1200 hours/Year x State Incentive, $0.54/kWh = $648/Year
Approx. Simple Payback = ($7,000 - $2,000 tax credit) / $648/Year = 8 years
Washington's production incentive is authorized through June 30, 2020.