IEEE PVSC 49
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SPLTRAK Abstract Submission
Uncertainty in Annual Energy Resulting from Uncertain Irradiance Measurements
Clifford W Hansen1& Aaron Scheiner2
1Sandia National Laboratories, Albuquerque, NM, United States
/2Rutgers University, New Brunswick, NJ, United States

We report an analysis quantifying the contribution to uncertainty in annual energy projections of uncertainty in ground-measured irradiance. Uncertainty in measured irradiance is quantified for eight instruments by the difference from a well-maintained, secondary standard pyranometer which is regarded as truthful. We construct a statistical model of irradiance uncertainty and apply the model to generate a sample of 100 annual time series of irradiance. The sample is propagated through a common performance model for a reference photovoltaic system to quantify variation in annual energy. The results show that the instruments vary from the reference by a few percent (standard deviation of 1-2%) but the uncertainty in annual energy is on the order of a fraction of one percent.