A large photovoltaic installation
Solar panels are most effective when at the proper angle, known as the angle of declination, and, in the Northern Hemisphere, when facing south. Although they can be installed parallel to a building’s flat roof, or parallel to the ground, they will not achieve their full potential in terms of energy generation. Instead, angled roofs or angled solar mounts allow panels to reach higher levels of efficiency.
Roof mounts like this are examples of fixed solar installations.
Many solar installations are fixed installations, meaning they are in fixed positions. Such installations should be oriented at the proper angle of declination to absorb the greatest amount of sunlight. These panels are set either at one angle throughout the year or on a system that allows them to be repositioned throughout the seasons for maximum exposure to sunlight. The latter type considers varying changes in the earth’s tilt throughout the year.
Your location on Earth determines your angle of declination.
Declination means the angular distance of a point north or south of the equator. Your angle of declination is basically equal to your latitude. The angle of declination is important to helping solar panels reach their maximum efficiency. By using the angle of declination and some simple calculations, you can find the best angle for installing solar panels in your location.
Calculating Angle of Declination and Proper Orientation
Simple calculations allow you to figure out the proper angle of declination throughout the year.
The best orientation for solar panels is facing south and at the angle of declination. Using your angle of declination to calculate the best angle of orientation for fixed solar installations isn’t too difficult. Latitude is equal to the angle of declination. That’s the angle at which a fixed installation should be installed. Also, solar angle calculators exist to give you the best angle of declination for a solar system in your region.
Winter Vs. Summer Angles
In the U.S. and Northern Hemisphere, because Earth rotates on its axis, the sun appears farther north in the sky in summer than it does in the winter. To get more out of photovoltaics throughout the year, their angle of orientation needs to match the sun’s position in the sky.
To counteract that–particularly as you move further from the equator–panels can be adjusted seasonally. In the summer months, as the sun moves north in the sky, reducing the panels’ angle of orientation by 15 degrees allows the maximum amount of sun to hit the panels. And in the winter months, when the sun moves south, increasing the panel’s angle by 15 degrees higher than the angle of declination allows them to receive the maximum amount of sunlight in the winter.
This solar panel is mounted on tracker system.
A more efficient alternative to fixed photovoltaic systems are systems mounted on solar trackers. Such systems position the solar panels to face the sun throughout the day, matching the sun’s angles as it moves across the sky. Solar trackers are panels attached to a moveable frame powered by a motor, which moves the panels to match the sun’s trajectory. They act much like a sunflower that follows the sun throughout the day.