The most common use for SF6, both domestically and internationally, is as an electrical insulator in high voltage equipment that transmits and distributes electricity. Since the 1950’s the U.S. electric power industry has used SF6 widely in circuit breakers, gas-insulated substations, and other switchgear used in the transmission system to manage the high voltages carried between generating stations and customer load centers.
Several factors affect SF6 emissions from electric power systems, such as the type and age of the SF6 containing equipment (e.g. older circuit breakers can contain up to 2,000 pounds of SF6, while modern breakers usually contain less than 100 pounds), and the handling and maintenance procedures practiced by electric utilities. Because of its long life span and high GWP potency, even a relatively small amount of SF6 can have a significant impact on our climate.
The SF6 Emission Reduction Partnership is one of EPA’s voluntary industry programs aimed at reducing greenhouse gas emissions. The Partnership’s primary objective is to reduce SF6 emissions via cost-effective technologies and practices. Through improvements in the leak rate of new equipment, refurbishing of older equipment, and the use of more efficient operation and maintenance techniques, utilities often find economical solutions to reduce SF6 emissions.
The electric power industry uses roughly 80% of all SF6 produced worldwide. Ideally, none of this gas would be emitted into the atmosphere. In reality significant leaks occur from aging equipment, and gas losses occur during equipment maintenance and servicing. With a global warming potential 23,900 times greater than CO2 and an atmospheric life of 3,200, one pound of SF6 has the same global warming impact of 11 tons of CO2. In 2002, U.S. SF6 emissions from the electric power industry were estimated to be 14.9 Tg CO2 Eq. For more information on the U.S. SF6 emissions from electric power systems see Sources and Emission on the High GWP home page.
Opportunities for Electric Power Systems
The electric power industry has an enormous opportunity to help reduce the nation’s SF6 emissions through cost-effective operational improvements and equipment upgrades. With an average cost of $9.00 per pound, the SF6 emission reduction of partner companies from 1999-2002 totals $2.5 million dollars.
EPA works to share information on best management practices and technical issues that can help reduce emissions. EPA also sponsors SF6 conferences where partners and others from the industry can stay informed of the latest developments in this area. The most promising and cost effective options to reduce SF6 emissions are:
- Leak Detection and Repair
EPA estimates that if consistently and aggressively implemented in the U.S., SF6 emissions could be reduced by 20%.
- Use of Recycling Equipment
EPA estimates that SF6 recycling could eliminate 10% of total related emissions from the U.S. electric industry.
- Employee Education/Training
Making employees aware of the environmental impact of these emissions and establishing a corporate policy for managing SF6 is critical. “You can’t manage what you don’t measure!”
More detailed cost information is available at EPA’s High GWP Projections and Mitigation page.
Commitment and Responsibilities
Partners agree to:
- Estimate current annual SF6 emissions;
- Annually inventory emissions of SF6 using an emissions inventory protocol;
- Establish a strategy for replacing older, leakier pieces of equipment;
- Implement SF6 recycling;
- Ensure that only knowledgeable personnel handle SF6; and
- Submit annual progress reports.
EPA assists partners by:
- Acting as a clearinghouse for technical information on successful strategies to reduce SF6 emissions;
- Providing partners with recognition for their achievements in reducing SF6 emissions;
- Serving as a credible repository for data on the emissions reduction achievements of the partners; and
- Working to obtain commitments from all electric power system operators to join the partnership.