Shading analysis is a very crucial step in finalizing panel locations in distributed Photo Voltaic (PV) solar installation. The extent of the rooftop area required by a solar PV plant is a factor of panel efficiency and extent of shading. Any kind of shading is detrimental to the performance of the entire solar PV plant. Solar panels are mostly arranged in strings to meet voltage requirements. A shade in one panel not only reduces the efficiency of that panel but cuts short supply from entire string.
A shadow falling on a panel blocks the flow of solar energy and eventually, the panel gets damaged through heating. The efficiency of a panel at any time reduces in direct proportion to the area of the shadowed part of the panel. Sometimes even panels not in shadow zone get heated as they try to compensate for the power loss. Most often the damaged panels are not covered under warranty, adding to the operations cost of the plant.
Shade created by movable objects such as trees and similar objects can be avoided by removing them to create a shade-free area. However, in the case of immovable objects such as fixed structures, we need to leave surrounding areas falling in the shadow zone.
For a rooftop solar project, objects such as parapet walls, staircase and small columns can be a source of shadow. While placing panels, care also needs to be taken for inter-row shading caused by panels themselves and hence panels are placed at an appropriate inter-row distance.
Manual examination of shadow region is difficult as shadow pattern not only changes throughout the day but also varies at different times of the year. This is because the angle of elevation (angular height of sun) and Azimuth angle (movement of the sun across the year) together define the shadow length and shadow position.
Nevertheless, there are programmed tools available for locating panels which use coordinates as input and work with Google to get a detailed survey of the area including different objects which can create shadows.
The user is given the option to define different areas as keep-away areas and the software come up with the surrounding shadow region where panels cannot be placed. These softwares use optimal inter-row spacing between panels and produce result on how much capacity plant can be accommodated in the demarcated area. Tentative placement of panels is also produced as output. Finally a report is generated with detailed analysis of expected generation for a year and other performance parameters.
To conclude, for a typical PV plant, getting rid of shaded regions is one of the most critical criteria for enhancing ROI (Return on Investment) from a solar power plant. At Amplus, our in-house design team working from the corporate office uses highly sophisticated software tools to finalize positioning of panels with more than 90% accuracy. We don’t rely on a single software but analyze the results from different tools as well as use our expertise through different projects to further increase the efficiency of our PV plants.