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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.

The equator has a latitude of zero while Johnson has a latitude of 46.6. 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.

Since a fixed solar panel is set in one position it is ideal to place it at an angle that will expose the panel to the most sunlight throughout the year. This angle is generally the same angle of your latitude which is 46.6 for Johnson. You do not need to strategically place a 1-axis or 2-axis panel as much as you do a fixed panel. A 1-axis panel follows the movement of the sun during the day. Additionally, a 2-axis panel also adjusts for the suns various positions in the sky throughout the year.

There are more variables than latitude that can change average peak sun hours. Weather patterns and geography will influence solar insolation that reaches your system. Thick grey storm clouds for example will block out a lot of the sun to the point where there may be no peak sun hours in the middle of the day when the sun is usually very powerful. Trees and mountains can deflect the sunlight, so be sure your solar panel is selectively placed.

By taking the latitude of Johnson one can get a close estimate of the amount of average peak sun hours per day for the geographical area. It varies with technology and the type of solar panel mount you use, but for a fixed mount solar panel in Johnson one can expect close to 4.3 average peak sun hours per day. With a 1-axis tracking mount you would get 5.1 hours per day, and 6.9 hours per day with a 2-axis tracking mount that tracks the sun everywhere in the sky.