How to Prevent Solar Panels From Shading One Another

Shading of solar panels can seriously effect their effieciency.

When installing a photovoltaic (PV) array system, it is very important to determine whether it will receive uninterrupted sunlight for as long as possible. External elements near any proposed solar installation, such as other buildings and trees, must be analyzed for the shadows they make as the sun travels across the sky. Even a small amount of shading can significantly decrease the efficiency of a PV module. Inter-row shading, particularly on flat roof installations, occurs when one row of solar panels shades an adjacent row of panels, and can prove to be just as detrimental to a successful operational solar system.

Things You'll Need

• Latitude of location
• Tape measure
• Angle measuring device

Instructions

1. Calculate the optimum tilt of your solar panels to maximize the capture of direct sunlight. For all installations north of the equator, solar panels should face due south and must be tilted from the horizontal to a degree equal to the latitude where they are installed. Factor in seasonal adjustments by adding 15 degrees in the winter and subtracting 15 degrees in the summer.

2. Measure the height of the top of the first row of PV modules. To allow for seasonal adjustments it is best to calculate the height of the winter tilt.

3. Multiply this height by three and use this distance to calculate the minimum spacing between rows before installing the array

Tips & Warnings

• Crystalline silicon solar panels are more susceptible to shading than thin-film modules, because the thin-film cell structure crosses the full length of the module requiring more shading for the same effect.

• In the southern half of the United States closer spacing may be possible, but even at the lowest latitudes the spacing should not be less than two times the height of the top of the adjacent module.

• In most cases it is better to use a lower tilt angle in order to prevent inter-row shading.

• Always take due care when working with live electrical currents,

References

• BIPV Malaysia: PV Array System Design for Proper Operation and Site Installation