Field Assessment of the DustIQ Optical Soiling Sensor Performance Under the Harsh Conditions of Desert Environments

Soiling of photovoltaic (PV) modules can lead to energy yield losses of more than 1% per day due to shading of sunlight. PV systems in desert regions are particularly affected but are also increasingly installed due to economic attractiveness of PV in areas with high solar irradiation. The process of soiling of PV modules in desert climates is promoted by the high dust concentrations and rare rain events. However, it is physically complex and only partially analyzed and understood. In this work, we report on the field assessment of the DustIQ optical soiling sensor performance for PV-soiling measurement under harsh conditions of a desert environment. DustIQ was installed in a hot, sunny, and dusty climate in the Outdoor Test Facility, managed by Qatar Environment & Energy Research Institute, located in Doha (state of Qatar). Our results over a period of 19 months show that despite some discrepancy in the soiling measurements that were more pronounced during certain periods of time, globally, a good fit was noticed between the values recorded by the Dust sensors and those measured through conventional clean/soiled reference module pair method. A mismatch of less than similar to 0.01 %/day between the light transmission loss estimated by the DustIQ sensor and from a PV array is identified. We demonstrate thus the feasibility of Dust IQ to be deployed in different geographical locations and its potential in measuring wide range of PV-soiling in commercial-scale PV installations.