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Uncertainty Calculation Method for Photodiode Pyranometers
A. Forstinger, S. Wilbert, A. Driesse, B. Kraas
PV Systems – Modelling, Design, Operation and Performance
Subtopic: Solar Resource and Forecasting
Event: 38th European Photovoltaic Solar Energy Conference and Exhibition
Session: 5BO.6.6
ISBN: 3-936338-78-7
0,00 EUR
Document(s): presentation


Solar irradiance ground measurements are of crucial importance for the monitoring of largescale PV plants and solar resource assessments. Photodiode pyranometers are widely used for such applications, especially at remote locations. Rotating Shadowband Irradiometers (RSI), which use silicon photodiode pyranometers, provide a robust measurement of the global horizontal (GHI), diffuse horizontal (DHI) and direct normal irradiance (DNI) and are low cost and low maintenance. Because the used silicon photodiode pyranometers have a wavelengthdependent spectral response, the broadband irradiance measurements depend on the actual solar radiation spectrum. The spectrum changes with atmospheric conditions, such as current water vapor, temperature and aerosol optical depth and location parameters like altitude. For all measurements, a provision of uncertainty for each measurement point is crucial for proper utilization of the data. The presented method aims to estimate an uncertainty for each measurement of photodiode pyranometers.