Explore GE Vernova
Resource Library
Get access to curated content, tools, and useful resources to help you face all your grid challenges.
Access the library
Electrification Businesses
Electrification Software
Power Conversion
Solar & Storage Solutions
Articles & Announcements
GE’s F35g, first SF6-free g3-gas-insulated substation to complete ENA assessment in the UK
GE’s F35g, first SF6-free g3-gas-insulated substation to complete ENA assessment in the UK

GE is proud to announce that the company has become the first manufacturer of high voltage (HV) gas-insulated substations (GIS) for SF6-free technology at voltages greater than 54 kV to successfully complete assessment by the Energy Networks Association (ENA). This marks a huge step forward for the power industry towards its ambitions to reduce emissions and achieve its net zero goal.

GE’s F35g GIS uses the company’s game-changing g3 (pronounced “g”- cubed) gas insulating and switching technology, which has a 99% less global warming potential compared to SF6, while delivering the same performance as a traditional SF6 circuit-breaker. As g3 products have the same dimensions, thus amount of raw material as SF6 equipment, there is no increase in emissions during the manufacturing process also.

The ENA operates the Switchgear Assessment Panel, which carries out the assessment of HV switchgear products. If a product is deemed compliant, they issue a Notice of Conformity (NOC) which details the compliance of equipment for use on United Kingdom’s transmission and distribution networks, with the relevant ENA specification. A NOC is intended to assist ENA member companies, which include a number of major T&D grid operators in the country, in meeting UK’s legislation on the selection of electrical plants and products.

GE Renewable Energy’s Grid Solutions business put forward the F35g 145 kV SF6-free GIS for ENA Assessment in 2018. The process started with getting two sponsors: Kevin Butter from Scottish Power, and Joe Helm from Northern Powergrid. GE’s F35g was approved in October 2021, with NOC 1159 being issued after a three-year rigorous process to complete the approval.

The ENA assessment allows all members to buy in confidence that GE can deliver SF6-free g3-GIS up to 145 kV that meets the functional and operational criteria required by the United Kingdom’s transmission and distribution networks.

This certification can be directly translated in the orders for the F35g GIS placed by several power utilities in the UK.
For more information on the assessment and the Energy Networks Association please go to the ENA website or contact your GE local sales rep.