Photovoltaic cleaning frequency optimization under different degradation rate patterns

Abstract

Dust accumulation significantly affects the performance of photovoltaic modules and its impact can be mitigated by various cleaning methods. Optimizing the cleaning frequency is therefore essential to minimize the soiling losses and, at the same time, the costs. However, the effectiveness of cleaning lowers with time because of the reduced energy yield due to degradation. Additionally, economic factors such as the escalation in electricity price and inflation can either compound or counterbalance the effect of degradation. The present study analyzes the impact of degradation, escalation in electricity price and inflation on cleaning frequency and proposes a methodology than can be applied to maximize the profits of soiling mitigation in any system worldwide. The energy performance and soiling losses of a 1 MW system installed in southern Spain were analyzed and integrated with theoretical linear and nonlinear degradation rate patterns. The Levelized Cost of Energy and Net Present Value were used as criteria to identify the optimum cleaning strategies. The results showed that the two metrics convey distinct cleaning recommendations, as they are influenced by different factors. For the given site, despite the degradation effects, the optimum cleaning frequency is found to increase with time of operation.

Monitoring photovoltaic soiling: assessment, challenges, and perspectives of current and potential strategies

“…The higher the losses, the more the profits are ideally possible through soiling mitigation. Moreover, additional factors, such as degradation and electricity price, can impact the revenues of soiling mitigation ( Micheli et al., 2020d ) and therefore affect the capital available for soiling monitoring.…”

“…In addition to the variability of soiling, it should be noted that also the variability of electricity price, operational and labor costs, discount rate, and taxes can affect the profitability of soiling mitigation (Al-Housani et al, 2019;Alzubi et al, 2018;Fathi et al, 2017;Jones et al, 2016;Micheli et al, 2020dMicheli et al, , 2021Stridh, 2012). For these reasons, several models have already been presented to optimize the soiling mitigation strategy (i.e.…”

Analysis and mitigation of nonuniform soiling distribution on utility‐scale photovoltaic systems

“…It should be noticed that there is no accepted methodology in the literature to remove the effects of artificial cleanings from a soiling profile. So a procedure similar to that employed for different sites in previous works 20,38,49 was established and employed. The methodology is based on the procedure commonly used to model the effect of cleanings on an unmitigated soiling profile.…”

Comparative Analysis of Change-Point Techniques for Nonlinear Photovoltaic Performance Degradation Rate Estimations

“…For example, This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ assuming an installation that does not experience inverter clipping, the energy recovery from cleaning is reduced with time due to degradation, therefore, cleaning frequency would vary depending on Rd patterns and other financial metrics [16]. However, in the case of high dc/ac ratios, significant levels of soiling can be tolerated in the early years of the PV plants due to clipping, while in later years soiling can actually have more impact as the system degrades and clips less often.…”