Coordinated capacity configuration and techno-economic assessment of a grid-connected hydro–wind–solar–pumped storage complementary system for long-distance UHVDC power transmission

Abstract

Against the background of the global low-carbon energy transition, long-distance power delivery from large-scale wind and photovoltaic bases to remote load centers has become an important pathway for improving renewable energy utilization. However, hydro–wind–solar–pumped storage complementary systems for ultra-high-voltage direct current power delivery still face two key challenges. The first is the difficulty of formulating stable transmission profiles. The second is the mismatch between generation-side capacity and grid-side transmission capacity. To address these challenges, this study develops a source–grid coordinated optimization framework with transmission corridor capacity treated as a rigid engineering constraint. Photovoltaic installed capacity and transmission corridor capacity are defined as the core decision variables. A multi-timescale dual-layer dispatch model is incorporated into the proposed framework. The CRITIC–GLDS multicriteria decision-making method is further integrated to identify the economically optimal scheme within the technical feasibility domain. A clean energy base in the upper reaches of the Yellow River, comprising 2320 MW of hydropower capacity and 4200 MW of pumped storage capacity, is selected as the case study. The results show that stable transmission profiles can be generated under a 95% export plan fulfillment rate constraint. The economically optimal matching relationship between transmission corridor capacity and photovoltaic installed capacity is approximately 1:2.5. The preferred configuration is identified as 18 GW photovoltaic capacity and 8 GW transmission corridor capacity. Under this configuration, the levelized cost of electricity is 256.62 RMB/MWh, the transmission corridor utilization rate is 61.78%, and the renewable energy utilization rate is 91.11%. This study provides decision support for the long-distance transmission of large-scale renewable energy bases and source–grid coordinated planning.