From ecological indicators to photovoltaic planning: A graded suitability framework and long-term potential on the Qinghai–Tibetan Plateau

The Qinghai–Tibetan Plateau (QTP) is one of China's most resource-rich regions for utility-scale photovoltaic (PV) development, but abundant solar radiation alone is insufficient for defining rational development priorities in this ecologically fragile and topographically complex region. Existing studies often rely on static resource indicators, binary ecological exclusions, or suitability mapping that is weakly linked to long-term development potential. To address these limitations, this study develops an ecologically constrained, integrated and reproducible framework for utility-scale PV planning on the QTP. The framework integrates five dimensions—climate resource endowment, construction and operation suitability, ecosystem importance, ecological sensitivity, and socio-economic suitability—and combines hierarchical Bayesian estimation of global horizontal irradiation, stability analysis of irradiation supply, entropy-based weighting, and fuzzy Gamma aggregation. Long-term PV development potential is then estimated as an ecologically constrained technical potential under two nested planning scenarios. The results show that PV suitability on the QTP is highly spatially differentiated and cannot be inferred from radiation conditions alone. High-grade suitable land is concentrated mainly in Qinghai and Xizang, whereas the southern and southeastern Plateau are more strongly constrained by ecological sensitivity, land-use conflict, and complex terrain. Under the conservative scenario, the retained PV potential is 6.39 TW of installable capacity and 11.86 PWh·yr −1 of annual generation; under the long-term scenario, these expand to 18.61 TW and 33.95 PWh·yr −1 . Qinghai and Xizang together account for over 87% of both scenarios, indicating a clear two-tier structure in which a spatially concentrated near-term core is complemented by a broader high-suitability long-term reserve. These estimates should be interpreted as ecologically constrained upper bounds rather than deployment targets. The framework provides a transparent and policy-relevant basis for phased PV development on the QTP.