Quantification and extraction of power loss patterns in hydro-photovoltaic-pumped storage integrated energy bases

The flexibility of conventional hydropower stations and pumped storage power stations is regarded as a promising approach to integrating more intermittent photovoltaic (PV) power into the grid. However, directly implementing medium- and long-term operations of hydro-PV-pumped storage integrated energy bases (HPPEBs) is challenging due to the daily regulation capability of pumped storage power stations, an aspect that has been infrequently studied. To tackle this issue, a short-term operation model is developed to quantify power loss, including energy loss caused by the efficiency of pumped storage units and power curtailment due to load demand and channel capacity. Then, an accurate method for calculating power generation in HPPEBs during mid- and long-term operations is proposed, considering the short-term power loss patterns. A HPPEB located in the Lancang River Basin is selected as a case study. The results indicate that: (1) power generation is overestimated in the direct medium- and long-term operation, leading to higher water levels in the cascade reservoirs; (2) both energy loss of pumped storage and power curtailment exhibit a significant linear correlation with hydropower output, with coefficients of determination above 0.85 for each PV output range; (3) the proposed method can accurately calculate medium- and long-term power generation, with errors in total and daily power generation amounts of 0.06% and 1.22%, respectively, during the validation period. From the hydropower perspective, this study quantifies the short-term power loss patterns, providing a practical tool for the accurate mid- and long-term operation of HPPEBs.