Home » Solar Turbine » Illinois » Eureka

It goes without saying that throughout the year the amount of sunlight in any given day is going to vary. The time of year and weather will have a strong influence on daily sunshine. Looking at the average amount of peak sunshine hours in a day during an entire year stretch is a valuable exercise when trying to determine the amount and type of solar panels you need to install to power your business or your home. 4.7 peak sun hours means that in Eureka on average there are 4.7 hours a day where the sun is strong enough for solar panels to harness its energy. This number is less than the amount of total sunlight hours in a day because there are times during the day (ex. sunrise and sunset) where the sun is not strong enough to benefit solar panels.

Knowing that the latitude of Eureka is 40.7 can be helpful for understanding total sunlight hour variance. As you approach the equator latitude approaches zero. The closer the latitude is to zero, the more consistent the daily sunlight hours are throughout the year. Total sunlight hour consistency simply makes planning for your solar power needs easier, but it is certainly not a requirement.

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 40.7 for Eureka. 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.

The sun is a great ball of gas that rises and sets every day that the earth rotates while in orbit around the sun. Barring any major disasters this is a very predictable occurance every day. Latitude helps predict this even more, narrowing it down to the minute for sunrise and sunset. But some things aren’t as predictable that will greatly influence the efficiency of solar panels. Weather and cloud coverage for example can greatly diminish peak sun hours on any given day. Thick storm clouds will block a high percentage of the sun's rays, resulting in lower output of your solar panels. Weather needs to be factored into deciding when to use your system, or how much output one expects to get.

Using the latitude of Eureka along with historical data of sunlight and weather patterns we can estimate that a fixed mounted solar panel will receive an average of 4.7 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 5.9 hours and 6.3 hours, respectively.