Teams from SSEN Transmission and their supply chain partner GE Vernova have celebrated progress in the installation of SF6-free circuit breaker technology at the Kintore substation in Aberdeenshire, Scotland. This development is part of ongoing efforts to eliminate the powerful greenhouse gas sulphur hexafluoride (SF6) from electricity grid infrastructure.

Staff involved in the project toured the site where GE Vernova's SF6-free 420 kV g3 gas insulated switchgear (GIS) and gas insulated busbar (GIB) are being installed. This equipment will be a crucial component of the substation's upgrade to 400 kV operation, supporting national ambitions for clean energy transmission.

SF6, while highly effective as an insulator and switching medium in electrical switchgear, is a potent greenhouse gas, significantly more impactful than carbon dioxide. This has led to global initiatives aimed at phasing out its use.

GE Vernova's innovative g3 technology replaces SF6 with an alternative insulating gas, resulting in a 99% reduction in the gas's contribution to carbon emissions, while maintaining the same dimensions and performance levels. SSEN Transmission is among the first transmission operators globally to adopt this technology, having placed the world's first order for the 420 kV g3 GIS.


Installation of GE Vernova's 420 kV g3 GIB is already underway, with the delivery of the 420 kV g3 GIS expected in the coming months. Additionally, the company has supplied a separate 16-bay 145 kV g3 GIS, which has been installed as part of the Kintore Phase 3 – 132 kV Asset Replacement Project and is set to enter the commissioning phase soon.

While the g3 equipment is capable of operating at higher voltages (420 kV and 145 kV), it will be used on SSEN Transmission's 400 kV and 132 kV network, aligning with the company's broader decarbonisation goals. SSEN Transmission was the first transmission operator worldwide to receive accreditation from the Science Based Target initiative for its carbon reduction targets, which are consistent with achieving net zero emissions.

Kevin Hutton, Senior Project Manager at SSEN Transmission, commented: "It was a pleasure to join colleagues involved in this innovative project for a tour of Kintore substation, where world-first g3 technology will form an important part of vital upgrades to the transmission network that will deliver clean, renewable energy to homes and businesses across the UK."

He added, "GE Vernova's 145 kV GIS has already been delivered and installed, and for many of those involved it was the first time they've had the opportunity to see the equipment on site, where installation of the new GIB is taking place ahead of the arrival of the 420 kV GIS. As one of the first transmission operators in the world to use this technology we are immensely proud of the work we're doing to remove SF6 from our network, decarbonising our operations in line with our science-based carbon reduction target. The installation of this technology is another big step towards the full energisation of Kintore substation in 2026."

Bertrand Portal, Power Transmission Marketing Leader at GE Vernova's Grid Solutions business, said: "The world's first 420 kV SF6-free contract with SSEN Transmission has been instrumental in advancing our g³ GIS program. We would like to highlight the outstanding contributions of the SSEN Transmission team in the specification and development of our new SF6-free GIS. We are honored to advance this partnership collaboration while spearheading efforts to reduce greenhouse gas emissions and encourage even greater industry cooperation to support the transition to a more decarbonised future."