Greener options for power equipment beyond SF₆

Sulphur hexafluoride (SF 6 ), a synthetic fluorinated gas, is highly regarded for its chemical stability, non-flammability, and outstanding electrical insulating properties.

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It is primarily used in high-voltage electrical equipment such as gas-insulated switchgear (GIS), circuit breakers and transformers. Nevertheless, SF₆ is recognised as one of the most potent greenhouse gases, projecting a global warming potential (GWP) of 23,500 relative to CO2 over 100 years and an atmospheric lifespan of around 3,200 years. The gas's prolonged persistence and high GWP exacerbate its environmental effects even at minimal atmospheric concentrations (about 10 parts per trillion in 2020).

Why SF6 gas is widely used in the power sector

Before diving into its applications, it is important to understand why SF₆ is so widely used in the electrical industry. Key properties include:

High dielectric strength: SF₆ is approximately 2.5 times more effective than air at insulating voltage

Excellent arc-quenching capabilities: It efficiently extinguishes arcs in circuit breakers

Chemical stability: SF₆ is nonreactive and stable over a wide range of temperatures and pressures

Non-flammability: It does not support combustion, making it safe in electrical applications

Thermal conductivity: Provides efficient heat dissipation These properties make SF₆ ideal for medium and high-voltage electrical equipment, especially in environments where safety, space and reliability are critical.

Applications of SF₆ in the power sector

Gas-insulated switchgear (GIS):

One of the most common uses of SF₆ is in gas-insulated switchgear. In GIS systems, electrical conductors are encased in a sealed environment filled with SF₆ gas, which acts as an insulator and arc extinguisher.

Benefits:

Compact design, reducing substation footprint High reliability and low maintenance Ideal for urban and restricted spaces like underground substations.