how to assess the feasibility of your rooftop for solar PV system

Before performing a detailed site survey, a client prefers to do the feasibility check by considering the following parameters:


Shadow Test: To collect the maximum sunlight during the day, the panels should be faced to the South as much as possible. The roof must be checked from the shadow of the trees and of the neighbouring roofs and walls. In case there is some shadow on the roof, a detailed analysis of time and direction of sunlight needs to be evaluated to estimate the energy received by the rooftop. 

Rooftop Type: The load carrying capacity of the roof should be checked. Solar panels with structure typically weigh 15 kg per sq. meter.  This weight varies with technology and type of structure.


Sizing of Solar system: Size of the solar system depends on the available rooftop area for installation of panels. This can be calculated by dividing the entire roof area by each panel area and multiplying it by the panel’s rated output. For estimate purposes, 70% of rooftop area can be used for panel’s installation.


Size of the solar system = Panel’s rated output* (rooftop area/ each panel area)*70%


System Output: The panel output and hence the system output is defined by the Capacity Utilization Factor which defines the panel efficiency and the solar radiation incident on the panel. Typically, for India the CUF for solar plants is estimated at 19%.


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