An analytical method to evaluate curtailment of hydro–photovoltaic hybrid energy systems and its implication under climate change

Identifying power curtailment is essential for system reliability, especially in hydro–photovoltaic (PV) hybrid energy systems (HPESs) exposed to future climate variability. However, the relatively low temporal resolution of climate projections challenges the effectiveness of current numerical simulation methods for evaluating the curtailment rate of HPESs. This study derives an analytical method based on daily hydropower and PV power rather than the commonly used hourly data in numerical methods, to reduce reliance on the temporal resolution of climate inputs. A short-term operation model is constructed to verify the effectiveness of the derived power curtailment function. A long-term operation model incorporating the analytical power curtailment function is then established to analyze variations in future curtailment rates using climate information projections. Results of a case study in the Yalong River Basin validate the accuracy of the derived PV curtailment function. Compared with the reference period, future hydropower and PV power will increase in most climate scenarios with substantial variances, whereas the PV curtailment rate exhibits an overall increase in the near future (+2.49%) and a larger increase in the far future (+5.53%). The most noticeable increases in future PV curtailment rates occur in June, July, and October (+3.15%, +5.47%, and +3.11%). The proposed analytical method provides valuable insights for the risk evaluation of HPESs by coupling the short-term power curtailment rate with mid- and long-term climate variations.