Lexington Solar Power Information & Peak Sun Hours
Solar Green Energy Summary for Lexington, Virginia
Lattitude: 37.7825
Sunlight
Fixed Tilt Sunlight Hours: 4.6 hours per day
1-Axis Tilt Sunlight Hours: 5.8 hours per day
2-Axis Tilt Sunlight Hours: 6.5 hours per day
Peak sun hours is one of the most important criteria to examine when considering installing a solar power system. Peak sun hours are different than total sunlight hours in a day because the strength of the radiation of the sun varies throughout the day. For example, during sunrise and sunset the solar insolation from the sun is less powerful than at noon. For a moment of sunshine to be considered a peak sun hour the intensity needs to be at least 1 kilowatt per square meter. This means that a square meter of your solar panel should be receiving 1 kilowatt of energy from the sun. This number is used because it is an amount of light that allows a solar panel to produce output efficiently and not under perform due to lack of sunlight power.
The latitude at the equator of the earth is zero degrees. This is where sunlight strikes the earth most directly. Due to the earth's curved shape, sunlight hits at a various angles depending on location. As latitude increases, the further you are located from the equator and more variance you see in sunlight hours. The latitude of Lexington is 37.8.
A tracking mount will increase the average peak sun hours for a solar power system. Think about a panel that is tracking the sun in the sky vs a panel that is fixed and not moving: you will see a higher efficiency ratio of productions. A 1-axis mount will track the sun from East to West from sunrise to sunset and move on a single axis of rotation. A 2-axis mount will track the Sun from East to West the same as a 1-axis mount would, but it will also track the angle of the sun in the sky as it slowly varies season to season. A 2-axis mount is more necessary in high latitude regions where the angle of the sun in the sky changes dramatically between each equinox.
Another reason to consider average peak sun hours is because weather can dramatically affect the day-to-day output of solar panels. It goes without saying that a dark stormy day will produce less output than a clear sunny day. Looking at a yearly average helps account for these daily variables.
In Lexington the average yearly peak sun hours for a fixed tilt non-tracking solar panel mount is 4.6. This is for a fixed panel mounted at an angle that is equal to the latitude of the location for the entire year. The amount of peak sun hours increases to 5.8 hours if you are using a 1-axis panel, and to 6.5 hours if you upgrade to a 2-axis solar panel.