Accuracy of Potential High Limit Estimation for Solar Plants in the Southeast US

Flexible solar operation, where solar photovoltaic (PV) plants follow up- and down-regulation signals, has signifi-cant potential to improve integration of solar into power grids. To optimize operation, it is important to accurately estimate the potential maximum power output, or potential high limit (PHL), of a plant in real time during periods where output has been reduced. As the PHL cannot be directly measured while a plant is curtailed, and it is driven by highly variable weather and plant conditions, model-based estimation methods are subject to errors. An estimation method using a subset of a plant as a reference has been developed by NREL. Here, we evaluate a version of that method using data from several utility-scale plants in the Southeast US spanning up to a full year.