China's 2,260-km UHV line now covers 20% of Chongqing peak power demand

For climate and energy professionals, China's 2026 summer grid test is less about one city and more about whether high-voltage transmission can turn distant renewables into a reliability asset. Chongqing's peak load now gets roughly 20% from a single Hami-Chongqing UHV line, with over 70% clean energy, making it a real-world case for decarbonizing reliability.

China's 2026 summer peak is testing whether years of grid modernization can keep pace with extreme heat. State media reported in mid-August that sweltering heat and high humidity had driven electricity demand in megacities to record highs, with the focus falling on Chongqing, a southwestern municipality of more than 30 million people. Chongqing's role as an automotive and electronics manufacturing hub means any grid failure would ripple well beyond air conditioning. The centerpiece of the response is the Hami-Chongqing ultra-high-voltage direct current line, a 2,260-kilometer energy artery that entered service in June 2025. Rated at ±800 kilovolts, the line can transmit up to 6 million kilowatts at peak, roughly one-fifth of Chongqing's maximum load. More than 70 percent of the power originates from clean energy sources in Hami, Xinjiang Uygur Autonomous Region. According to Shuai Hong, deputy chief engineer of the power dispatch and control center of State Grid Chongqing Electric Power Company, externally purchased electricity now accounts for about one-third of the city's total grid load, and the UHV line is 'our strongest source of confidence.'

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Chongqing's peak load now gets roughly 20% from a single Hami-Chongqing UHV line, with over 70% clean energy, making it a real-world case for decarbonizing reliability.

The strategic significance goes beyond one city. UHV technology moves electricity over very long distances with lower losses than conventional transmission, making it possible to connect renewable-rich western regions to demand-heavy eastern and central urban centers. In Chongqing's case, the Hami corridor converts distant wind and solar resources into dispatchable summer capacity. The report also highlights energy storage and virtual power plants as complementary measures, indicating a more flexible grid rather than a simple supply expansion. That flexibility is critical because peak air-conditioning demand is sharp and short, often exceeding what local generation can deliver cost-effectively. By importing clean power at scale, Chongqing can reduce pressure on local thermal plants and potentially avoid the most expensive and carbon-intensive peaking resources.

The operational context is sobering. The sources note that rolling blackouts in response to summer crunches are 'not yet a distant memory.' This is a clear reference to prior episodes when extreme heat collided with insufficient capacity, forcing industrial curtailments and public disruption. The 2026 experience therefore is not merely a technical milestone but a resilience test. The ability to secure one-third of load from outside the municipality, with one UHV line covering roughly 20 percent of maximum demand, marks a structural change. It suggests China is moving from reactive crisis management toward a more planned interprovincial balancing system. However, reliance on a single long-distance artery also creates concentration risk: if the Hami-Chongqing line were disrupted or Hami's renewable output sagged, Chongqing would still need local reserves, storage, and demand response to maintain stability.