Sulfur hexafluoride (SF
6) is a man-made gas. It is used in electrical equipment and also in applications including arc furnaces, window insulation, car tires and sports shoes. It is one of the six greenhouse gases listed in the Kyoto Protocol.
The amount of SF6 that escapes to the atmosphere is minute, compared with emissions of carbon dioxide (the main greenhouse gas). Even though SF6 has a global warming potential some 25,000 times greater than carbon dioxide, SF6 probably accounts for only about 0.1 percent of mankind’s contribution to the greenhouse effect.
Like many other manufacturers, ABB uses SF6 as an insulator in high-voltage electrical equipment. The gas has excellent insulating and arc-quenching properties, which enable much more compact equipment designs than would otherwise be possible. Land use, energy consumption, losses and waste are all considerably reduced, while recyclability is increased.
Our Life Cycle Assessments indicate that with proper precautions, these advantages outweigh the environmental impact of leakages of SF6 to the atmosphere.
In normal use, our products emit hardly any SF6. The gas is contained in closed systems – in many cases sealed for life. Our current products guarantee leakage rates below 0.5 percent per year and the next generation should lose less than 0.1 percent per year.
Accidental escapes of SF6 – due to mistakes during manufacturing, installation, maintenance and decommissioning – are a bigger problem than leaks. To minimize them, ABB uses strict tracing and inventory systems and efficient handling procedures, in line with the recommendations of environmental agencies. To this end, ABB plays a leading role in the international organizations responsible for developing quidelines for SF6, including CIGRE, CAPIEL and NEMA. We also take back old products for dismantling and recycling under controlled conditions.
ABB has continuing research programs into alternatives to SF6, and we make SF6-free products available whenever feasible.
References:
“SF6 in the Electric Industry, Status 2000”
(Cigré Study committee No. 23) P.O’Connel et al,
Electra No. 200, February 2002, pp 16–25
www.cigre.org
“Recommendations for SF6 gas handling”
(Cigré Study committee No. 23)
www.cigre-b3.org
“Environmental Sustainability Dossier”
CAPIEL, September 2001