The Low-Load Trap in Hydrogen Systems: A Nested RIS-PTE Framework for Regional Synergy in China’s Yangtze River Delta

While decarbonizing heavy-duty port logistics is a critical imperative for regional environmental sustainability, the large-scale transition to green hydrogen in industrial clusters is systematically constrained by a “low-load trap”, where localized resource scarcity and fragmented demand create a self-reinforcing cycle of high costs. While existing techno-economic frameworks typically treat hydrogen infrastructure as isolated nodes, this study transcends these spatial limitations by theorizing the structural transition of such environmental-energy systems through a newly proposed “Nested RIS-PTE” framework (Regional Innovation System embedded with Policy-Technology-Economy flows). Taking China’s Yangtze River Delta as a representative laboratory, we simulate how the spatial-functional coupling of inter-provincial levers, Shanghai’s R&D, Jiangsu’s manufacturing, and Anhui’s energy, and converges in Zhejiang’s application hub to dismantle entrenched cost barriers. Results demonstrate that this regional synergy drives a non-linear Levelized Cost of Hydrogen (LCOH) reduction from 55.5 RMB/kg to a critical parity threshold of 30.6 RMB/kg. Beyond simple cost-cutting, we reveal a “Denominator Effect” triggered by a “Port-Corridor” strategy, which provides a mechanistic pathway for infrastructure to transcend the utilization bottleneck—elevating rates from a stagnant 36% to a commercially viable 75%. By identifying the exact techno-economic tipping points for heavy-duty commercialization, this study offers a replicable theoretical blueprint for resource-deficient yet market-rich urban agglomerations worldwide to unlock hydrogen economies and accelerate deep decarbonization through coordinated spatial governance.