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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.

Knowing the latitude of Nine Mile Falls will help estimate average peak sun hours for your area. The latitude is used to accurately estimate the time of sunrise and sunset, thus giving you the total hours of daylight each day. Once you know the total hours of daylight, you can estimate the amount of peak sun hours based on a number of variables such as weather, time of year, the angle of the solar panel.

There are a few ways to increase average peak sun hours per year for your solar power system. One way is to use a tracking mount solar panel instead of a fixed tilt solar panel. A 1-axis mount will track the sun throughout the sky from sunrise to sunset, giving your panel a more efficient facing direction towards the sun throughout the day. A 2-axis solar panel will track the sun in the sky throughout the day, but also change and follow the angle of the sun in the sky throughout the year. Both of these axis system solar panels will produce higher average peak sun hours than a fixed solar panel.

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.

Using the latitude of Nine Mile Falls along with historical data of sunlight and weather patterns we can estimate that a fixed mounted solar panel will receive an average of 4.4 hours per day in this area. That number can be increased with better technology including add a 1-axis or 2-axis tracking mount, which would increase the average peak sun hours per day to 5.5 hours and 6 hours, respectively.