Solar Spectral Irradiance Analysis and Modeling: A Case Study in the Black Hills Area

Understanding solar spectral irradiance is critical for photovoltaic (PV) forecasting and power systems operation, especially with the increasing distributed energy resources (DERs). Multiple solar spectral irradiance simulation models and databases have been developed and applied to determine PV power output. The Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS), developed by the National Renewable Energy Laboratory, is one of the most popular tools to simulate global solar spectral irradiance. To ensure the accuracy of solar PV output forecasting using spectral irradiance, solar spectral irradiance measured by a robust preconfigured spectrometer in the Black Hills Area is analyzed, and a datadriven model is developed to enable absolute irradiance conversion using irradiance intensity to avoid extra time and costs for absolute irradiance calibration of light spectrometers based on SMARTS solar spectral irradiance. In addition, a rooftop grid-tie solar system on the South Dakota Mines campus is utilized to validate the model and implement it for real-world solar applications. This case study provides an example to help researchers and engineers better understand the correlations among simulation solar spectral irradiance, actual measured solar irradiance, and solar system power output.