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Frequent Questions
- What is the goal of this partnership?
- How do SF6 emissions contribute to global climate change?
- How is SF6 used in the U.S. electric power industry?
- How will the SF6 partnership help my company?
- What can the electric power industry do to reduce SF6 emissions?
1. What is the goal of this partnership?
To collaborate with the electric power industry to identify and implement cost-effective operational and technical solutions to reduce U.S. SF6 emissions.
2. How do SF6 emissions contribute to global climate change?
SF6 is the most highly potent greenhouse gas known to-date. Over a 100-year period, SF6 is 23,900 times more effective at trapping infrared radiation than an equivalent amount of carbon dioxide (CO2). SF6 is also a very stable chemical, with an atmospheric lifetime of 3,200 years. As the gas is emitted, it accumulates in the atmosphere in an essentially un-degraded state for many centuries. Thus, a relatively small amount of SF6 can have a significant impact on global climate change.
3. How is SF6 used in the U.S. electric power industry?
SF6 is a non-hazardous, inert gas that is used both as an arc quenching and insulating medium in high-voltage switchgear, circuit breakers and gas insulated substations. SF6-insulated equipment is predominantly used in the transmission system that manages the high voltages carried between the generating stations and customer load centers. The largest use of SF6 occurs in high-voltage circuit breakers. Here, in addition to providing insulation, SF6 is used to quench the arc formed when an energized circuit breaker is opened.
Disconnectors and ground switches use SF6, primarily, for insulation, and individually, they contain only slightly less SF6 than a circuit breaker. These devices are used to isolate portions of the transmission system where current flow has been interrupted (using a circuit breaker). Gas-insulated substations also use a significant amount of SF6. GIS installations house SF6-insulated circuit breakers, busbars, and monitoring equipment.
Several factors affect SF6 emissions from electrical equipment, such as the type and age of SF6 containing equipment (e.g., older circuit breakers can contain up to 2,000 pounds of SF6, while more modern breakers contain less than 100 pounds), and the handling and maintenance protocols utilized by electric utilities.
4. How will the SF6 partnership help my company?
- Save Money
Purchasing SF6 can be expensive, so reducing emissions saves money. Since 1999 our SF6 partner companies have saved $2.5 million dollars from the avoided gas loss alone. - Increase Grid Reliability
Use of improved SF6 equipment and management practices helps protect system reliability and efficiency. - Protect the Environment
SF6 is the most potent greenhouse gas known. It is 23,900 times stronger than carbon dioxide and stays in the atmosphere 3,200 years. The partnership’s tracking and reporting protocol enables companies to better organize, estimate, and document the impact their SF6 emission reduction activities.
EPA also sponsors a biennial International SF6 Conference where partner companies, equipment and gas suppliers, governments and others can stay informed of the latest developments.
5. What can the electric power industry do to reduce SF6 emissions?
All companies should develop an SF6 emissions reduction strategy. The first step is to develop an inventory of SF6-using equipment and estimate current emissions. The EPA partnership inventory protocol provides a user-friendly tool to facilitate this process. The second step is to develop and implement a company-wide policy for managing the leak-rates of current equipment and to ensure the proper handling of SF6.