Navigating the Land-Energy Nexus for Carbon-Neutral Power Systems

Decarbonization efforts face a looming constraint around the globe: land availability for variable renewable energy (VRE) deployment, especially for densely populated and resource-constrained regions. Here, we develop an integrated framework coupling gridded renewable capacity expansion with spatial-temporal resolved power system optimization to quantify how land-use availability shapes electricity transition pathways for China. The country's carbon neutrality pledge by 2060 necessitates terawatt-scale VRE deployment in the world's largest power system, creating unprecedented land-use tensions that mirror challenges in many other countries. Our analysis reveals that stringent land-use policies limiting VRE siting could induce a 300 billion yuan (about 42 billion USD) increase in annual costs by 2060 versus less restrictive scenarios, a 4% increase that nonetheless maintains the technical feasibility of climate commitments. Land constraints trigger significant cascading adjustments: renewables would concentrate in resource-rich and less populated regions (+40% in northwestern China), intensifying inter-regional transmission demands (+22.5%). Conversely, more flexible land-use policies enable more demand-proximate solar deployment (+69% in north, south, central, and east China), with a 56% increase in energy storage over the stringent case. Our findings establish land availability as a critical determinant of power system transition globally, with policy decisions now creating irreversible path dependencies that shape infrastructure investments, system costs, and technology portfolios for decades.