California Curtails 4.5 Million MWh of Clean Power as Grid Bottlenecks Worsen

Power curtailments continue to rise in California despite a range of initiatives to ease congestion, as new clean power generation outpaces new grid capacity, Reuters reported this week. Some 4.5 million megawatt-hours of solar and wind power were curtailed in California in the first half of 2026, compared with 3.77 million MWh in the same period a year earlier — a 19 percent jump that underscores the state's transmission bottleneck even as it smashes clean-energy records.

Too Much Sun, Too Few Wires

Curtailment — paying generators to shut down or be limited because the grid cannot carry their output — typically spikes on sunny spring days when solar production peaks and demand is low. California's duck curve has grown more pronounced each year as utility-scale solar capacity compounds, and interconnection queues now stretch years behind schedule. Battery storage has become the state's primary shock absorber, with utility-scale storage capacity growing at roughly 70 percent annually, according to the Climate Tech and Clean Energy weekly report — but storage saturation is also being reached in some pockets of the grid, analysts note.

The waste has a price: every curtailed MWh represents forgone revenue for generators and a missed emissions reduction, and the state's grid operator has warned that without accelerated transmission buildout — including new high-voltage lines through the Central Valley and upgraded interties — curtailments could exceed 10 percent of annual renewables output within three years, according to the Reuters analysis.

Federal Pushback and the Storage Bridge

California's experience is being watched nationally as other states build out renewables faster than their grids can absorb them. Federal permitting reform and the FERC Order 2023 interconnection overhaul were designed to address queue backlogs, but transmission siting remains a multi-year hurdle. In the meantime, storage is doing the heavy lifting: developers added gigawatts of new battery capacity in the first half, and the California Independent System Operator says batteries now routinely absorb the midday solar peak — a bridge that buys time, but only until the next congestion point appears.