Partial curtailment to firm photovoltaic generation dispatch

Growing utility-scale photovoltaic (PV) generation brings new challenges in short-term operational management. Their variable and somewhat unpredictable generation adds to supply-demand imbalance, while displacing the conventional generation generally used to provide frequency regulation. One possible solution is for variable renewable energy plants to reduce their variability within dispatch intervals. With suitable incentives, these plants can be partially curtailed to maintain a reduced yet firmer output. This study investigates the potential of utility PV plants to provide firmer dispatched generation according to varying solar resource availability. It uses historical 4-second SCADA output from a number of Australian utility PV plants. The level of partial curtailment for reasonably stable dispatch generation is found to be the second standard deviation of the output uncertainty. The high uncertainty in PV plant output under common weather conditions makes firm dispatch challenging to achieve even if the weather conditions are known and involves significant curtailment levels.