Optimizing solar photovoltaic plant siting in Liangshan Prefecture, China: A policy-integrated, multi-criteria spatial planning framework

• Introducesa novel framework for integrating policies and multi-criteria evaluations within national spatial planning constraints. • Develops hydro-solar complementary assessment criteria to address limitations in current literature on single energy site evaluations. • Harnesses fuzzy TOPSIS and GIS technology to pinpoint optimal PV locations. • Assesses PV plant site suitability in Liangshan, revealing desirable areas for PV locations (DAPs). The development of solar photovoltaic (PV) energy is essential for China to meet its ’dual-carbon’ goals and shift towards cleaner energy sources. Site selection, a key early step, often neglects land spatial planning constraints and suffers from subjective decision-making ambiguity. This study introduces a novel framework for identifying optimal sites for PV plants within China’s spatial planning. Through two screening stages and three decision-making processes validated in Liangshan Prefecture (LS), where solar and hydro resources are abundant. Criteria such as orography, climate, economy, and hydro-solar complementarity are evaluated to determine PV land suitability. Utilizing the triangular fuzzy number TOPSIS method and GIS technology, the study identifies the desirable areas for PV installations (DAPs). The study highlights that 59.66% of LS’s land is unsuitable for PV, with the remaining areas classified as highly suitable (0.56%), moderately suitable (2.31%), suitable (3.94%), and weakly suitable (33.52%). The DAPs are predominantly located in Huili, Yanyuan, and Huidong counties, while areas like Dechang and Xichang show potential for hydro-solar complementarity. Above all, the methodology aims to improve PV solar power generation efficiency, support local spatial planning and deliver economic and environmental benefits.