Petaluma Solar Power Information & Peak Sun Hours
Solar Green Energy Summary for Petaluma, California
Lattitude: 38.2423
Sunlight
Fixed Tilt Sunlight Hours: 5.9 hours per day
1-Axis Tilt Sunlight Hours: 7.2 hours per day
2-Axis Tilt Sunlight Hours: 8.4 hours per day
Peak sun hours are a vital measurement to understand when considering the installation of solar panels. Peak sun hours are not the same as total sunlight hours because not every hour of sunlight during the day has enough strength and solar insolation to qualify as a peak sun hour. The rule of thumb is that a peak sun hour is when the intensity of the sun that is hitting your solar panel is providing at least 1,000 watts per square meter. This is an arbitrary number, but it is a number where most solar panels will be producing an efficient output and not underperforming due to sunshine that is not strong enough or direct enough.
The latitude of the location is important for measuring peak sun hours. The latitude determines how much overall sunlight there will be in a day. With a given latitude, time and date, one can accurately determine when sunrise and sunset will occur. Areas with latitudes closer to the equator will have a more consistent range of solar insolation throughout the year. Whereas areas closer to the poles will have a greater variance during the summer and winter months due to their higher latitudes.
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.
Looking at latitude, average peak sun hours and various data can obviously help when planning for your solar power needs. The one thing you can never fully account for is changing weather. Storms, rain, cloud coverage all have an impact on solar panel capabilities.
Since we know the latitude of Petaluma we can take the average amount of total sunlight hours and estimate that with a fixed solar panel there would be an average of 5.9 peak sun hours per day. 7.2 hours per day with a 1-axis tracking mount that tracks the sun from sunrise to sunset, and 8.4 hours with a 2-axis tracking mount that tracks the sun everywhere in the sky.