Dranesville Solar Power Information & Peak Sun Hours
Solar Green Energy Summary for Dranesville, Virginia
Lattitude: 38.9955
Sunlight
Fixed Tilt Sunlight Hours: 4.8 hours per day
1-Axis Tilt Sunlight Hours: 6.1 hours per day
2-Axis Tilt Sunlight Hours: 6.3 hours per day
Peak sun hours are a vital measurement to understand when considering the installation of solar panels. Peak sun hours are not the same as total sunlight hours because not every hour of sunlight during the day has enough strength and solar insolation to qualify as a peak sun hour. The rule of thumb is that a peak sun hour is when the intensity of the sun that is hitting your solar panel is providing at least 1,000 watts per square meter. This is an arbitrary number, but it is a number where most solar panels will be producing an efficient output and not underperforming due to sunshine that is not strong enough or direct enough.
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 Dranesville is 39.0.
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.
Climate in your geographical region is a major factor that will influence average peak sun hours per year. If you live in a region that does not have a lot of completely sunny days, then cloud coverage will greatly influence solar insolation on any given day. Mountains and trees may also contribute to lower solar insolation if they block the sun from your panels at any given point of the day.
We can take the latitude of Dranesville and use that number to know the amount of total sunlight hours in the region from sunlight to sunset and estimate that with a fixed solar panel, Dranesville will receive 4.8 average peak sun hours per day. This number can be increased to 6.1 hours by using a 1-axis tracking mount, or 6.3 hours from a 2-axis tracking mount.