Thailand, Nan: Hitachi Energy and the Electricity Generating Authority of Thailand (EGAT) will complete the world’s first 550 kV eco-efficient gas retrofill on existing high-voltage assets originally designed for sulphur hexafluoride (SF₆).
The project will use Hitachi Energy’s EconiQ high-voltage technology to upgrade 130 m of 550 kV gas-insulated lines at the Nan Substation. The work is scheduled for completion in December 2026.
According to Hitachi Energy, the project will replace SF₆ with an eco-efficient gas mixture without modifying or replacing the primary equipment. This approach is intended to reduce environmental impact while maintaining full grid performance and reliability.
The upgrade is expected to eliminate around 800 kg of SF₆, avoid 97 t of CO₂-equivalent emissions and deliver a more than 95 % reduction in CO₂-equivalent impact.
Hitachi Energy said the project demonstrates how existing high-voltage infrastructure can be upgraded to support decarbonisation goals while minimising operational disruption.
EGAT said the project supports Thailand’s wider energy transition and its pathway towards net-zero emissions by 2050.
The retrofill also aligns with Hitachi Energy’s global roadmap for SF₆-free high-voltage technologies, as utilities look for practical ways to reduce greenhouse gas emissions from existing grid assets.
Source: Hitachi Energy
