Techno-Economic Evaluation and Configuration Design of Energy Storage Systems for Renewable-Rich Weak-Grid Regions

With the ongoing advancement of China’s “dual carbon” strategy, wind power and photovoltaic installed capacity have grown rapidly, making renewable energy a critical pillar for building a new-type power system. However, their inherent intermittency, variability, and uncertainty pose significant challenges to the secure and stable operation of modern power systems. As renewable energy capacity continues to expand, regions rich in renewable resources increasingly coincide with areas characterized by relatively underdeveloped grid infrastructure. This has resulted in insufficient renewable energy accommodation on the generation side and inadequate transmission capacity within the grid. Consequently, the integration of renewable energy faces growing challenges, including spatial mismatches between generation and demand, insufficient system flexibility, and increasing pressure on grid security and reliability. This study presents a systematic review combined with a quantitative techno-economic assessment of electrochemical energy-storage deployment in renewable-rich and weak-grid regions. Three representative electrochemical energy storage technologies, namely lithium-ion batteries, sodium-ion batteries, and all-vanadium flow batteries, are quantitatively evaluated using technical indicators and levelized cost metrics, including the levelized cost of energy (LCOE) and levelized cost of storage (LCOS). The results show that lithium-ion batteries exhibit the best overall techno-economic performance, with LCOE/LCOS values of 670/440 CNY kWh−1, compared with 660/840 CNY kWh−1 for sodium-ion batteries and 690/490 CNY kWh−1 for all-vanadium flow batteries. Additionally, a 10%/2 h energy storage system improves day-ahead power prediction accuracy, ultra-short-term prediction accuracy, and the correlation coefficient by 67%, 44%, and 18%, respectively. These findings establish a quantitative basis for linking energy storage technology selection with regional resource–grid conditions and operational requirements, thereby supporting coordinated source-grid-load-storage planning and cost-effective and reliable renewable energy integration in weak-grid regions.