In a significant stride towards global decarbonization, Hitachi Energy and the State Grid Corporation of China (SGCC) have successfully commissioned the world’s first SF6-free 550 kV gas-insulated switchgear (GIS). The groundbreaking technology was activated on May 29, 2026, at a substation in Yuxian, Wuhan, China.
This development tackles the challenge posed by sulfur hexafluoride (SF6), a powerful greenhouse gas with a global warming potential 24,300 times greater than carbon dioxide. Historically, eliminating SF6 from essential extra-high voltage equipment like 550 kV GIS was considered a difficult task.
Hitachi Energy’s innovative EconiQ® solution utilizes an eco-efficient gas mixture composed of 86.5% CO2, 10% O2, and 3.5% C4-FN. This alternative gas achieves a remarkable 99.2% reduction in insulation gas emissions over a 40-year service life when compared to traditional SF6-based GIS systems.
The collaboration directly supports SGCC’s commitment to lowering carbon emissions and aligns with China’s overarching “Strategic Dual Carbon” goals. This project sets a precedent for the sustainable modernization of high-voltage infrastructure across the nation.
The successful implementation of this commercial SF6-free 550 kV GIS demonstrates the technology’s scalability and reliability in demanding operational settings. It provides a vital reference for grid operators and policymakers worldwide navigating the transition to greener energy infrastructure.
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