California regulations governing the sulfur hexafluoride (SF6) gas used in gas insulated equipment (GIE) since the 1950s have proven to be a complex topic to tackle throughout the years, and they’re about to become even more so. But California's ultimate aim is simple: to eliminate the use of SF6, the most potent greenhouse gas known to humans.

In California, electrical switches and breakers used in electrical transmission and distribution are the primary source of SF6 emissions, which have a carbon intensity that is 22,800 times stronger than carbon dioxide (CO2) and an atmospheric life of 3,200 years.

The California Air Resources Board (CARB) began clamping down on SF6 use in 2010, when mandates, as part of the Assembly Bill 32 (AB-32), called for greenhouse gas emissions to be reduced to 1990 levels by 2020. When that goal was met four years early, a new law was passed requiring emissions be cut to 40% below 1990 levels by 2030. New proposed SF6 regulations call for the gradual reduction of SF6, leading to its elimination from new switchgear installations after Jan. 1, 2025, and reducing total SF6 emissions to 0.49% of nameplate capacity for existing switchgears by 2049 and beyond.

The proposed regulations are expected to go into effect at the beginning of 2021. At that time, GIE owners and operators will face stringent, mandatory record keeping, monitoring and reporting obligations from CARB, with penalties of up to $10,000 per day per violation for noncompliance.

For instance, the proposed regulations require all SF6 GIE equipment owners and operators to notify CARB at least 30 days before SF6-insulated equipment is installed, decommissioned, repaired or modified. The proposed regulations also change how nameplate capacities, emission rate limits, container tracking and SF6 gas usages are calculated, adding complexity to record keeping, monitoring and reporting. But there are ways to offload some of these responsibilities.

Consider SF6 usage tracking. The only way to calculate SF6 emissions in switchgear accurately is to calculate the difference in the cylinder’s volume before and after the gas from it is transferred into the GIE equipment.

The procedures on how cylinders are weighed, the scales employed and the accuracy required leave little margin for error. Cylinders stored on-site, for example, must be weighed at the start and end of each calendar year. To minimize reporting responsibilities, work with vendors who maintain the cylinders off-site and take responsibility for SF6 documentation and recording.

If SF6 does begin to leak from the switchgear, it’s beneficial to be notified immediately because of the severe emissions limits. Pressure monitors installed on equipment can alert operators to pressure drops or deviations in gas levels, allowing for quick response. Procedures also can be put in place to monitor and record levels that both meet compliance requirements and minimize disruption to day-to-day operations.

As part of a complete phaseout program, CARB also proposed to ban the acquisition of some new SF6 GIE equipment beginning in 2025, based on voltage class. That phaseout would continue through 2031. In addition, CARB recommends any existing GIE equipment that undergoes major maintenance or repairs be replaced with non-SF6 GIE equipment. One way around this will be to obtain a technical infeasibility exemption. To obtain a technical infeasibility exemption, an owner must demonstrate that the non-SF6 GIE equipment for a specified application is unavailable, incompatible with existing processes at the facility, or not suitable based on safety or reliability specifications.

Achieving compliance will likely require a third-party consultant who is well-versed in the complex nuances of SF6 requirements and experienced in negotiating solutions with CARB. Qualified firms can help applicants comply with current regulations as well as design and install new switchgear needed to replace noncompliant systems.


Know how to work with regulatory staff when new regulations — beyond SF6 reporting requirements — from agencies like CARB are announced.

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