Determining Uncertainty in I-V Translation Equations

Photovoltaic energy yield predictions rely on methods that estimate outdoor performance under arbitrary conditions based on a set of reference measurements. The uncertainty in these predictions has direct economic impacts on both the perceived feasibility of new systems and the energy market value. A common approach uses a set of translation equations such as those proposed in IEC 60891. Previous work examining the performance of the standard translation methods has not addressed the important issue of uncertainty. This is due to both a lack of comprehensive test data, and the scope of the problem resulting from flexibility in the way these methods can be applied. We used synthetic data to characterize the behavior of these standard translation methods in the presence of input uncertainty. The inputs and their uncertainty can then be mapped to the prediction uncertainty over a wide range of conditions.