Learn about Solar Power Topics
Which topic would you like to learn about regarding solar power? Choose from the items above. Were you trying to learn about all of the solar projects that the City is working on instead?
Solar Photovoltaics (PV)
What are Solar Photovoltaics (PV)?
Different than the solar hot water systems that use the sun's energy to heat water, solar electric or photovoltaic (PV) technology uses the sun's energy to make electricity. Learning from the word itself, the prefix "photo" means "produced by light," and the suffix "voltaic" refers to "electricity produced by a chemical reaction." PV technology produces electricity directly from the electrons freed by the interaction of sunlight with certain semiconductor materials, such as silicon, in the PV module. The electrons are collected to form a direct current (DC) of electricity. The basic building block of PV technology is the solar "cell." Many cells may be wired together to produce a PV "module," and many modules are linked together to form a PV "array." PV modules sold commercially range in power output from about 10 watts to 300 watts, and produce a direct current like that from a car's battery.
The sun's energy is free - it just takes some equipment to capture it. Homes and businesses can use Solar Photovoltaic (PV) systems to generate their own electricity. The cost of the PV panels, a key component, is falling ever closer to $1 per watt. In 2015, installed cost for complete PV systems runs about $3.50 -$4 per watt, or $3,500-$4,000 per kilowatt (kw). A 30% Federal tax credit that helps reduce cost is available through December 31, 2019. And the City of Tallahassee offers residential loans for solar PV at 5% interest, 10 years term, no down payment.
Most residential rooftop PV systems are sized from 2 to 5 kilowatts - A kilowatt is 1,000 watts. Individual PV panels come in a wide range of sizes, most frequently about 230 watts per panel. Panels are wired together in rooftop arrays. Roof coverage is about one square foot per 10 watts, so 1,000 watts (one kw) of arrayed panels covers about 100 square feet.
Solar photovoltaics and Tallahassee
At Tallahassee's latitude, with our annual average sun, clouds, humidity, pollen, length of day, and other factors, PV systems facing south with a 30-degree tilt produce about 1,314 kilowatt-hours (kwh) of electricity per year, for each kw (1,000 watts) of rooftop PV panels. In 2011, City of Tallahassee charges about $0.12 per kwh for residential electricity, including taxes. At that electric rate, a 1 kw system produces about $157.68 worth of electricity per year ($13.14 per month).
Call 891.4YOU (4968) and ask to speak to someone in the Energy Services department to learn more about this technology.