Atmospheric Intelligence for Hybrid Power Advancements: Volume 2 (Whole Sky Image Percent Cloud and Sun Analyses)

Author(s):

Gail Vaucher, Hailey Goodman, Brian Wang, and Michael Lee

Abstract:

Tactical and civilian environments depend heavily upon consistent and reliable electrical power. Solar fuel gleaned from photovoltaic (PV) technologies hold potential as a hybridized power resource. To determine the PV power contribution, knowledge of solar radiation is required. Clouds are major inhibitors of solar radiation. Whole Sky Imagers map clouds and other filters of irradiance as the radiation traverses from space onto a PV panel. Analyzing and quantifying clouds from a whole sky image was the research’s goal. The method used included image analysis preparation (non-cloud feature extraction), isolating clouds, and percent cloud calculation. In the course of isolating clouds, a strong link was found that matched the sun-corona footprint with sky type, cloud layers, and cloud types. Red, green, blue thresholding was the primary approach for isolating both sun-corona and clouds, from blue sky. Multiple analysis functions were explored to see if they could improve the detailing. A sample of eight image analysis functions are described in the report, along with a summary of their usefulness to the cloud cover algorithm development. The research conducted has contributed to the hybridized power integration by further bridging the gap between the whole sky image analysis and PV power prediction.