Development status and future key technology prospects of cascade hydro-pump-storage-wind-photovoltaic multi-energy complementary system: a case study of China

• CHMCS, a new energy form meeting NPS flexibility needs, is studied. China's use of hydropower flexibility for HPSPS integration is summarized from resource endowment, tech traits, watershed integration, and hydropower’s multi-scale flexibility. • With China's electricity spot market advancing, this paper analyzes key technical challenges like system state evolution and collaborative decision-making under "physical operation-market trading" interaction, based on CHMCS-HPSPS integrated modeling. • Research on key technologies includes multi-scale flexible response, system evolution, benefit quantification, human-machine hybrid decision-making, digital twin control, and quantum-blockchain scheduling, refining CHMCS theory and tech systems. As a new form of energy organization that supports the large-scale flexible resource demand of Chinese new power system, cascade hydro-pumped-storage-wind-photovoltaic multi-energy complementary system (CHMCS) has received widespread attention. Yet, there is a pressing need for in-depth research on its operational decision-making theories and technologies. To compensate for this limitation, this article innovatively constructs a three-dimensional framework of “policy technology market”, which has the unique advantage of systematically coupling macro environment and micro operation, and comprehensively coordinating the coordinated evolution of multidimensional factors. Based on this framework, this article summarizes the new demands and related operational decision-making technologies for the development of CHMCS in China in the new era. Firstly, analyze the new trend of CHMCS participating in market operation under the new pattern of NPS and electricity market construction in China, discuss the necessity of constructing CHMCS through the integration of pumping and storage in some regulating hydropower stations, and analyze its characteristics, advantages, development status, and problems; Secondly, focusing on the technical dimension, analyze the key challenges currently faced in operation: hierarchical aggregation modeling and external characteristic characterization of power plants with different regulatory capabilities, participation in market trading game decision-making and precise control of operating status, scientific quantification of dynamic compensation contributions and rational allocation of benefits, etc. Meanwhile, summarize the current status and shortcomings of literature review research. Finally, suggestions are made for policies and market mechanisms that support development, and prospects are given for key technologies that promote their synergistic effects in the ESM environment. The “policy technology market” trinity is coordinated to provide reference for the development of CHMCS in China.