Abstract |
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, taken together, purchased over 80 percent of all SF6 produced worldwide. 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 life cycle. SF6 can also be accidentally released during equipment installation, servicing, or de- commissioning. SF6 has been identified by the Intergovernmental Panel on Climate Change (IPCC) as a highly potent greenhouse gas that contributes to climate change. According to the IPCC, SF6 is 22,200 times more effective at trapping infrared radiation than an equivalent amount of carbon dioxide (CO2) over a 100-year period. Additionally, it has an atmospheric life of 3,200 years; its accumulation in the atmosphere is virtually irreversible. Measurements taken from 1978 through 1996 indicate that SF6 concentrations are increasing in the atmosphere at a rate of 7 percent per year. In 2002, SF6 emissions from the U.S. electric power industry totaled 589 metric tons. This paper discusses the SF6 Emissions Reduction Partnership for Electric Power Systems, a forum for the industry and EPA to share information on ways to reduce SF6 emissions. The efficiency of SF6 management can be improved through cost-effective operational improvements and equipment upgrades. These opportunities fall into four categories: SF6 inventory tracking systems, SF6 recycling, improved leak detection technology, and SF6 management training programs to improve operation and maintenance practices. |