EPA's SF6 Emission Reduction Partnership: Maximizing the Benefits of SF6 Emission Reductions for Electric Utilities

First manufactured in 1902, sulfur hexafluoride (SF6) is a fluorinated compound with an extremely stable molecular structure. This structure makes it far superior to oil or air in its insulation properties, dielectric strength, and arc quenching abilities. Electric equipment manufacturers and utilities therefore rely heavily on SF6 in transmission systems. In 2001, electric utilities and electrical equipment manufacturers (OEMs), taken together, purchased over 80 percent of all SF6 produced worldwide (1). Under ideal conditions, SF6 would remain contained within transmission equipment. In reality, however, SF6 is inadvertently emitted into the atmosphere as leaks develop during various stages of the equipment’s lifecycle. SF6 can also be accidentally released during equipment installation, servicing, or de-commissioning.