Explanation of “Average Peak Hours”
 As the sun rises, the array starts to produce power right away. However, due to the atmosphere, the angle of the sun, clouds, etc, the system will not produce peak power until somewhere around noon. As the sun starts to go down, the array then also begins to reduce its production. So, even though there might be ten or more daylight hours in the day, you will never get peak production for more that a few hours per day.
The peak hours of performance is calculated by how much total power was produced by our solar array, over the span of days, and divided by the power that our system should produce at peak output. (“total power output” divided by “the number of days running”) to produce “average total power per day”. (“average total power per day” divided by “peak power of system”) gives us how many “PEAK” kilowatt hours were produced per day during that time frame.
The reason this is important is because it will enable anyone who is considering a solar installation to get an idea of what the system of any given size can be expected to produce over a given length of time. Obviously weather changes, and the farther away from Grantsburg, Wisconsin that you get means the less accurate that the prediction will be. It is primarily posted here to aid anyone in the local area in making their sizing decisions, and to also track how accurate my original predictions were. I originally based the size of our array on our power usage, (which over many years has averaged about 40 kilowatts per day), and a predicted average daily output of 4 peak output hours per day. Added to the equation is the fact that according to our research we can expect the solar panels to produce approximately 20% less power in two years. The panels are then supposed to hold that output for many years to come… (approximately 20 years or more).
So, to put it all together, “10.8 kilowatts”, (the rated size of our system) TIMES “4 peak hours per day” TIMES “0.8” (to reflect a 20% drop in production) EQUALS “34.56” kilowatts per day. As time goes on we’ll see how accurate these predictions are. If you have any questions or comments please click the link below to send me an email.
|
