Renewable energy curtailment in a high-penetration linear power system: Technical drivers, nodal price decoupling, and equivalent storage requirements in Chile

Renewable energy curtailment has emerged as a critical barrier to the decarbonization of power systems with high penetration of variable renewable energy (VRE). This study quantifies the technical and economic drivers of renewable energy curtailment in Chile's National Electric System (SEN), a geographically linear grid of approximately 3100 km, using operational data from the national grid operator for the period 2022–2025. Curtailment rates, nodal marginal costs, and spatio-temporal generation patterns were examined by technology (solar PV and wind), region, and season to characterize systemic congestion dynamics. Results show that renewable energy curtailment escalated from 6.38% (1471 GWh) in 2022 to 18.49% (6044 GWh) in 2025, with solar PV disproportionately affected (21.59%) relative to wind (13.28%). Transmission congestion in northern regions (Antofagasta and Atacama) caused structural price decoupling, with nodal marginal costs collapsing to zero during peak generation hours. Spring and summer together accounted for 49.5% of high-stress curtailment events (29.5% in spring and 20.0% in summer). A novel Equivalent Energy Storage Capacity (EESC) metric translates curtailed energy into actionable storage requirements, revealing a 1825 MW infrastructure gap between installed BESS capacity and operational needs. These findings demonstrate that mitigating renewable energy curtailment requires coordinated planning of grid expansion, multi-scale storage deployment, and electricity market reform.