Since the late 1960s, because of its remarkable insulating properties, sulfur hexafluoride (SF₆) was the most widely used gas in switchgear and metering equipment in high-voltage electrical substations, the “strategic nodes” of power grids. The electricity transmission industrý accounts for about 80% of the world’s SF₆ use.

Nevertheless, it has been listed as a greenhouse gas. SF₆ is estimated to contribute 23,500 times more emissions than CO₂, if leaked, and can remain in the atmosphere for up to 3,200 years.

GE’s alternative to SF₆ gas, which is used as an insulating and switching gas, is the g³ gas. It is the result of ten years of research and development by its teams in France, Germany and Switzerland, in collaboration with the 3M group. The g³ gas mixture consists of carbon dioxide, oxygen, and 3M™‘s Novec™ 4710 dielectric fluid from the fluoronitrile range. Fluoronitrile was identified by GE R&D experts as the most suitable additive to CO₂ and O₂ to achieve the targeted environmental benefits of an alternative to SF₆ without compromising on technical performance and equipment footprint. The global warming potential (GWP) of the g³ gas used in GE’s equipment is more than 99% lower than that of SF₆. In terms of technical performance, high voltage equipment insulated with g³ gas offers the same level of performance as products insulated with SF₆. They have the same physical size and operate in the same environmental conditions (down to -30°C). A recent European Commission report concluded that switchgear using fluoronitriles may be the only alternative to SF₆ when space is a constraint (e.g. in urban areas).

Tests on a 420 kV, 63 kA gas-insulated g³ substation circuit-breaker are underway and will demonstrate that g³ technology can be applied to all other high-voltage levels of European power grids.

Eventually, when all g³ products are available, 10,000 tons of SF₆ will no longer be added to the electrical networks each year. In addition, the g³ gas can be used to replace SF₆ in particle accelerators.