Investigation of Dust-Related Energy Losses in Rooftop Solar PV Systems: A Case Study in Chittagong Town

Abstract

The accumulation of dust on rooftop solar photovoltaic (PV) systems is a critical factor that reduces the overall energy output, particularly where the dust accumulation rate is higher. This thesis investigates the impact of dust accumulation on the efficiency of rooftop solar photovoltaic (PV) systems in Chittagong City in four key locations which represent different types of environmental conditions throughout the city, Likes- CUET is located in a semi-urban area, AECC is located in an industrial area, BPDB is located in a commercial area and NMI is located in an EPZ area respectively, focusing on how dust reduces solar light transmittance and, consequently, energy output and analyzes the elemental composition of the dust contributing to it. Dust samples were collected from these four locations, and analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) spectroscopy, and UV transmittance tests. And also set up two 550wp solar panels on the rooftop of the CUET’s professor building block to investigate the real scenario of degradation of efficiency in a regular clean panel and unclean panel. The SEM and EDX analyses revealed significant variations in dust composition: CUET samples showed high carbon content (13.09% to 62.71%) with high light absorbing properties which originate from vehicular emissions, burning fossil fuel and industrial activities, while NMI samples had high oxygen that often bound with other elements in the form of oxides (e.g., silica as silicon dioxide, calcium oxide, iron oxide, aluminium oxide) (41.74% to 44.92%). The AECC location showed the highest silicon (commonly present as silica (SiO₂) in sand) content (up to 38%), which correlated with a notable decline in transmittance. BPDB locations also varied, with silicon, iron, and calcium being prominent in certain locations. These elements significantly affected solar transmittance, reducing the panels' energy output. The study found that dust accumulation can reduce solar light transmittance by 10% to 42%, depending on the dust composition, location and also seasonal variation — in the dry season solar transmittance is lower and in the wet season is higher. Energy output data from two 550 Wp solar PV systems at the CUET location showed the highest efficiency drop of 21.28% in April due to dust accumulation. The findings highlight the necessity for regular cleaning and maintenance of solar panels, especially in environments like Chittagong where dust accumulation is prominent. Based on the analysis, cleaning intervals and methods tailored to each location’s dust composition are recommended to optimize energy output. This research provides practical insights into improving the performance of rooftop PV systems, contributing to enhanced renewable energy efficiency in urban settings.