Nearly 40 years ago, President Carter proclaimed the dawn of the solar age. But that proclamation may have been a little premature.
Quick Facts: Solar Electric
Updated January 20, 2014
- A home solar system is typically made up of solar panels, an inverter, wiring (meter and disconnect switch) and support structure.
- A typical rooftop solar electric system is connected to the utility grid and relies upon the grid infrastructure for backup power. It will not operate in the absence of utility power.
- A modest PV system will pay for itself during the life of the equipment, generally several times over.
- Solar increases the value of your home.
- Solar equipment helps protect you from rate increases and fuel cost uncertainties.
- Use of solar helps decrease air pollution problems related to burning fossil fuels.
- Solar Energy is measured in kilowatt-hours. 1 kilowatt = 1000 watts.
- To figure the cost of a photovoltaic system the system size is multiplied by the installed cost per watt. A 1 kW system that costs $4 per installed watt would cost $4,000 (1,000 x $4 = $4,000).
- Larger systems have a lower cost per watt.
- Solar energy systems qualify for state and federal tax credits and exemption from state sales tax. The cost of a solar system is further reduced by a state tax credit (25 percent up to $1000) and a federal tax credit (30 percent).
- A one kilowatt solar system that cost $4,000 to install would be reduced by a $1000 state tax credit and $1200 federal tax credit. The out-of-pocket cost would be $2800.
- A solar energy system generates units of energy measured in kilowatt-hours. One kilowatt-hour (kWh) is the amount of electricity needed to burn a 100 watt light bulb for 10 hours.
- A 1 kilowatt home solar system will generate approximately 1,680 kilowatt-hours per year in Arizona. The average Arizona utility electric rate is $0.12 a kilowatt-hour – meaning the energy offset by a 1 kilowatt solar system is equal to $201.60 (1680 x $0.12 = $201.60).
- If a 1 kW photovoltaic system cost $2800 to install (after incentives), and saves $201.60 a year in electricity costs – the payback period would be 14 years.
- A typical Arizona home generally has an electric utility service rated at 200 amperes. This generally limits the size of the inverter to about 8,000 watts without extra costs. An inverter rated at 8,000 watts can generally use a photovoltaic array rated at up to 10,000 watts (10 kilowatts).
- If the photovoltaic array is in an area without shadows, or must face other than South, the performance will be affected.
- In one hour more sunlight falls on the earth than what is used by the entire population in one year.