Estimation of solar panel efficiency in the presence of curtailment

While solar power typically exhibits a linear relationship with solar irradiance, solar curtailment (intentional power reduction to match load) can disrupt this relationship. Consequently, solar panel efficiency estimation based on curtailed solar power may be inaccurate. This paper presents four methods for detecting solar curtailment samples: net load thresholding, clustering and thresholding, quantile regression, and piecewise efficiency estimation. The proposed methods include two specifications: one requires the time series of net load, while the other requires solar power and irradiance data. The effectiveness of the proposed methods is shown on two datasets with different load characteristics. The findings show that the suggested methods are effective in various aspects, depending on the application.