Girdwood Solar Power Information & Peak Sun Hours
Solar Green Energy Summary for Girdwood, Alaska
Fixed Tilt Sunlight Hours: 2.5 hours per day
1-Axis Tilt Sunlight Hours: 4.3 hours per day
2-Axis Tilt Sunlight Hours: 5.2 hours per day
The average peak sun hours of Girdwood is a crucial measurable component needed to efficiently implement a solar power system in a home or business. Put simply, peak sun hours are the hours of sunlight a day that are strong enough to be efficiently absorbed by solar panels and eventually turned into usable electricity. Not every minute of sunlight during a day is strong enough to be useful to a solar power system. Think about just minutes after the sunrises, which officially counts towards total hours of sunlight, but is usually too weak to be counted in peak sun hours because the strength of the solar insolation is not strong enough near the horizon to be absorbed and turned into electricity at an efficient rate. Times during the day like this, where the sun is out but not strong enough, are not counted as peak sun hours. In other words, the amount of peak sun hours in a location will theoretically always be less than total sunlight hours for a given day.
The equator has a latitude of zero while Girdwood has a latitude of 60.9. Any city located on the equator will receive the most sunlight throughout the year because the sunlight arrives at a perpendicular 90 degree angle to the earth at the equator. The further you are from the equator the more your daily sunlight hours can vary.
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.
The sunrise and sunset is very predictable every day, but things like cloud coverage and weather are less predictable and vary daily and annually. If a location that is usually very sunny experiences a huge increase in storms and cloud coverage in a given year than the average peak sun hours for that day or year will probably decrease. Tall objects such as trees and buildings can block out the sun during high solar insolation times, so be sure to strategically place your solar panels to get better efficiency.
We can use previous years of data to estimate the amount of peak sun hours in Girdwood. A fixed tilt mount for example will receive 2.5 average hours per day. For more efficiency for your system in Girdwood you could use a 1-axis tracking mount and increase your daily peak sun average to 4.3 hours, or even further with a 2-axis panel to get an average of 5.2 hours.