The effect of cleaning photovoltaic panel surfaces using a cleaning robot on panel efficiency: An experimental study

The increasing population, industrialization, and technological advancements in today's world have led to a continuous rise in energy demand. To meet this growing demand, fossil fuels (petroleum, coal, and natural gas) have been used as the primary energy sources for many years. However, in addition to having limited reserves, fossil fuels pose significant disadvantages, such as contributing to environmental pollution and increasing greenhouse gas emissions, which in turn drive climate change. Therefore, transitioning to clean, renewable, and environmentally friendly energy sources has become inevitable for a sustainable future. Renewable energy sources (RES), such as solar, wind, hydroelectric, and biomass, are of strategic importance both in terms of reducing environmental impacts and ensuring energy supply security. In this context, increasing investments in renewable energy and reducing dependency on fossil fuels are considered critical requirements for both economic development and environmental sustainability. Among RES, solar energy holds a significant position, and its share in total energy production is increasing worldwide. Solar energy systems consist of photovoltaic (PV) panels and thermal energy collectors. While PV panels convert sunlight directly into electrical energy, thermal energy collectors use sunlight to produce hot water or steam. These systems are not only environmentally friendly but also crucial for a sustainable energy supply. The efficiency of PV panels depends on various factors such as solar irradiance, temperature, panel orientation and tilt angle, panel type, surface cleanliness, shading, inverter quality, cable connections, wear over time, and regular maintenance. When panel surfaces become dirty, the amount of absorbed radiation decreases, resulting in a reduction in output power. The aim of this study is to determine the increase in energy production achieved through the cleaning of PV panel surfaces using direct measurements. For the cleaning of 199,440 panels at the Aşağı Kaleköy Auxiliary Solar Power Plant located in Bingöl Province, two robots with a daily cleaning performance of 1–3 MW are used. Two arrays, each consisting of 27 adjacent panels with identical characteristics, were selected. Over a three-month period, one array was cleaned weekly using a cleaning robot, while the other was left uncleaned. Continuous current and voltage measurements were taken from both arrays. The results showed that output power increased by up to 7.59% as a result of panel surface cleaning.