Evaluation of the solar irradiance variability in Brazil using satellite-based Variability Score

One of the main barriers to increase the solar energy share is its intermittency. In this work, we compared ground observations in different timescales (1-, 5- and 30-minutes) with satellite effective cloud cover coefficient variability, with 30-minutes time resolution. The smallest discrepancies happen when analyzing the same timescale (30-minutes), where the Pearson correlation for all sites was up 0.94. However, when the frequency of the solar irradiance measurements increased, the correlation decreased. A solution may be the use of downscaling methods, which may be a topic for future work. The most important result achieved in this study was the development of a simple methodology for evaluating the surface solar irradiance variability using only the cloud cover obtained from visible satellite imagery. The results denoted that the proposed methodology is an interesting alternative to evaluate the solar irradiance variability over large areas with satisfactory accuracy, where no ground data is available.