SSEN Transmission orders first 420 kV g3 gas insulated switchgear

GE’s 420 kV gas-insulated products using g3, pronounced “g cubed”, have been selected by SSEN Transmission for their new SF6-free 400 kV Kintore substation on the northeast coast of Scotland.

With the financial support of the European Union in the framework of its ‘LIFE’ program for climate change mitigation, GE’s team of experts is developing an innovative 420 kV circuit-breaker. This circuit breaker uses GE‘s g3 Green Gas for Grid insulating and switching gas instead of the traditional SF6, listed as the worst gas by the Kyoto Protocol in terms of global warming potential.

SSEN Transmission, leading the way in environmentally responsible system operation

In the UK’s next transmission price control framework, RIIO-T2, which covers the period from April 2021 to March 2026, SSEN Transmission has set five ambitious goals. One of these goals is a science-based commitment to deliver a one-third reduction in its greenhouse gas emissions, which is consistent with a 1.5 °C pathway critical to achieving net zero targets. One of the ways in which it will achieve this goal is to change the gases used to operate its critical transmission infrastructure.

SSEN Transmission joined our LifeGRID project earlier this year. Since then, the transmission system operator has worked closely with GE to help best specify the performance of the new SF6-free circuit breaker.

To support their decarbonization goals, SSEN Transmission selected the g3 solution and awarded a contract to GE’s Grid Solutions at the beginning of December for the manufacturing and delivery of the world’s first SF6-free 420 kV g3 gas-insulated substation at Kintore in Aberdeenshire. The 420 kV g3 substation is SSEN Transmission’s fourth g3 order. Last year, SSEN Transmission ordered the construction of a 1-km long g3-gas insulated line (GIL) at its New Deer substation, as well as a 145 kV g3-gas insulated substation (GIS) and a 420 kV g3 gas-insulated busbar for its Fort Augustus site.

The installation of GE’s nine bays of 420 kV g3 GIS and roughly 2 km g3 GIL at Kintore supports SSEN Transmission in getting closer to its carbon reduction targets by building the transmission infrastructure necessary to connect and transport large quantity of renewable energy. It also prevents the addition of about 350,000 tons of CO2 equivalent on the Scottish grid.

Finally, this contract is a major milestone of our project as it will help us to reach stage 4 of LifeGRID: cooperating with a high-voltage network operator to set up a pilot. This is a major step before we can replicate the technology in other European transmission networks.

Press release

Stages of the project

Stage 1 > Preparatory actions
Stage 2 > Developing the key components of the SF6-free high-voltage switchgear
Stage 3 > Replicating the technology for other bay components
Stage 4 > Cooperating with a high-voltage network operator to set up a pilot
Stage 5 > Preparing for adoption on all European high-voltage networks