Shadow analysis is the assessment of the site of installation of the solar PV modules for the casting of shadows. This technical analysis is of utmost importance before proceeding with installation because casting of shadows on a solar PV module has considerable impact on its efficiency and shelf-life. The effect of shading is to reduce the photo current per unit area of the cell.
A shadow falling on a solar PV module blocks the flow of solar energy and eventually, the modules generate hotspots and are damaged through rise in temperature. The shading could be of nearby trees, buildings or even inner-row shading of the installed PV module array. The efficiency of a PV module at any time reduces in direct proportion to the area of the shadowed part of the module, therefore it becomes highly important to conduct shadow analysis during the feasibility study and designing a rooftop solar power plant.
The shading experienced in solar PV plants can be identified as follows:
- Self-shading – the shadow that occurs on a PV module due to another PV module.
- Shading due to near objects – the shadow that occurs due to nearby objects which may be present within the vicinity or rooftop, around the installed PV modules. Some of these may affect the plant for a certain time of the day or for the entire day depending on their location, height, distance from the solar module. There may also be shadows that are cast due to newly built high-rise buildings, towers etc. which are at times unpredictable.