One of the major concerns leading to reduction in delivery of power and hence loss of revenue from solar photovoltaic (PV) plants is the deposition of dust on the panel surface. Solution to this problem lies in cleaning the panels frequently. Both events dust accumulation and cleaning entail cost which become significant as the size of the plant becomes large. Plant management often encounters a question as to what must be the periodicity of cleaning the panels that ensures maximum delivery of power to the grid. This study answers this question by determining optimum cleaning periodicity on the basis of maximum net energy delivered. The methodology is illustrated by an example of a 40 MWp PV plant. It is demonstrated that the optimum periodicity of cleaning for a 40 MWp PV plant comes out to be 7 days at which the annual energy delivered by the plant will be maximum at 60.53 GWh /year. The proposed methodology is simple, accurate, has a general applicability with no dependence on the capacity of the plant. However, the methodology requires experimental data on the rate of degradation in the output due to dust and dirt accumulation on the panels at the plant site.
Keywords Dust accumulation loss of PV arrays, optimum cleaning periodicity, dust, module soiling