ELECTRIFICATION IN MOTION

RTE, France's electricity transmission operator, has chosen to replace sulfur hexafluoride (SF₆)- a greenhouse gas whose global warming potential is about 24,000 times greater than that of CO₂ - across its entire high-voltage network, using GE Vernova's SF₆-free g³ technology, part of GRiDEA solutions to decarbonize the grid. The decision makes RTE the first transmission system operator in the world to do so across its complete range of high-voltage substations. 

The gas inside the grid

For decades, a potent greenhouse gas has been quietly doing its job inside the metal enclosures of high-voltage electrical substations. It is called sulfur hexafluoride, or SF₆, and it insulates the equipment that keeps electricity flowing safely at the voltages required to run a national grid. It works extremely well. It also has a global warming potential roughly 24,000 times that of carbon dioxide.

Now, France is moving to change that.

RTE, the sole operator responsible for France's high-voltage electricity transmission network, has signed a framework agreement with GE Vernova to eliminate SF₆ across its full range of high-voltage substations. These substations use a design called gas-insulated switchgear, or GIS, where SF₆ serves as the insulating medium inside sealed metal enclosures - allowing the equipment to be compact and reliable even at very high voltages. The technology replacing SF₆ is called g³ - GE Vernova's SF₆-free insulating gas solution.

The agreement covers a very large range of voltage level used on France's network, from 72.5 kV to 420 kV. It is considered one of the most ambitious agreements of its kind globally, and it makes RTE the first transmission system operator in the world to choose SF₆-free technology across its complete GIS range.

Thomas Veyrenc, RTE’s Managing Director for Economics, Strategy and Finance, views this collaboration with GE Vernova as a concrete expression of industrial policy, fully aligned with the strategic vision set out in RTE’s 2025 Grid Development Plan (SDDR). The agreement creates a virtuous cycle: French industrial capabilities are mobilized to manufacture the equipment required for the decarbonization of RTE’s grid infrastructure, and the latter is in turn deployed across the country to support France’s decarbonization and electrification objectives, as well as strengthen its digital and industrial sovereignty.

What is g³ and how does it replace SF₆? 

The technology at the center of this agreement is called g³ - GE Vernova's SF₆-free insulating gas solution. It is designed to do everything SF₆ does in high-voltage equipment, but with a global warming potential reduced by about 99%. Critically, it is intended to achieve this without any compromise on equipment performance or physical footprint, which matters because substations operate in constrained environments and cannot easily be redesigned around a different technology.

g³ is part of GE Vernova's GRiDEA product range, designed to help grid operators decarbonize their high-voltage substations while meeting the performance and reliability standards that transmission infrastructure demands.

Where is g³ developed and manufactured? 

For GE Vernova, the agreement also reflects a broader industrial ambition - one rooted in France. Philippe Piron, CEO of GE Vernova's Electrification segment, describes the agreement as a signal of shared commitment to building electrical infrastructure that is both more sustainable and more sovereign.

The g³ technology is the product of research carried out at GE Vernova's R&D center in Villeurbanne, with development and manufacturing based at the company's plant in Aix-les-Bains - a site with more than 100 years of industrial history and more than 1,000 employees. That R&D effort has also received support from the European Union - a recognition, in Philippe's view, of GE Vernova's role in the European energy sovereignty strategy.

More broadly, GE Vernova employs around 8,000 people across 15 sites in France - a footprint that gives the company's commitment to the energy transition an industrial weight beyond the technology itself.

Frequently asked questions

What is SF₆ and why is it used in power grids? Sulfur hexafluoride, or SF₆, is a gas used to insulate and break current in high-voltage electrical equipment inside substations. It is highly effective at preventing electrical faults in compact, sealed enclosures. However, it has a global warming potential about 24,000 times that of carbon dioxide, making it one of the most potent greenhouse gases in use in industrial infrastructure.

What is a gas-insulated substation? A gas-insulated substation, or GIS, is a type of high-voltage electrical substation where the key components are enclosed in sealed metal housings filled with an insulating gas. This design makes substations more compact and reliable than open-air alternatives and is widely used on high-voltage transmission networks.

What is g³ technology? g³ is GE Vernova's SF₆-free insulating gas solution for high-voltage switchgear. It is designed to match the performance of SF₆ while reducing the global warming potential of the insulating gas by about 99%. It was developed at GE Vernova's R&D center in Villeurbanne, France, and is manufactured at the company's plant in Aix-les-Bains.

What is RTE? RTE, or Réseau de Transport d'Électricité, is France's electricity transmission system operator. It is responsible for operating, maintaining and developing France's high-voltage transmission network - the largest in Europe at approximately 100,000 kilometers. RTE is the sole transmission system operator in France.

Why does this agreement matter? The agreement between RTE and GE Vernova covers every voltage level on France's high-voltage network, from 72.5 kV to 420 kV, making it one of the most ambitious efforts globally to eliminate SF₆ from grid infrastructure. It makes RTE the first transmission system operator in the world to choose SF₆-free technology across its complete range of gas-insulated switchgear. As other grid operators face similar pressure to decarbonize their infrastructure, the agreement is likely to be closely watched across the industry.

Note : This transaction is expected to be recorded as an order by GE Vernova’s Electrification segment by the end of 2026.