Sulfur Hexafluoride (SF6) is a strong greenhouse gas (GHG), with a global warming effect 23,900 times greater than carbon dioxide, the most common GHG. SF6 also lasts in the atmosphere for 3,200 years after it is released. SF6 is an excellent insulator and it is therefore often found in gas-insulated switchgear (GIS), equipment used in high-voltage electrical systems to control the flow of electrical current. SF6 routinely leaks from closures and joints in GIS and is released into the atmosphere.
SF6 is used to insulate certain high-voltage electrical equipment called gas-insulated switchgear (GIS). This equipment is used in large electricity generation, transmission and distribution facilities, not in homes or other types of businesses. Specifically, the regulation defines GIS to include “switches, stand-alone gas-insulated equipment, and any combination of electrical disconnects, fuses, electrical transmission lines, transformers and/or circuit breakers used to isolate gas-insulated electrical power system equipment.”
Companies and municipalities that own, lease, operate or control gas-insulated switchgear (GIS) that contains SF6 and is located in Massachusetts are required to comply with 310 CMR 7.72. The regulation refers to these entities as “GIS owners.”
The current regulation includes the following requirements to minimize emissions of SF6 from GIS.
- For GIS purchased after January 1, 2015:
-The GIS owner must ensure that the GIS has a maximum annual leak rate of 1.0% for SF6, as represented by the GIS’s manufacturer (310 CMR 7.72(4)(a)).
-GIS owners must maintain their GIS in accordance with maintenance procedures or industry best practices that have the effect of reducing leakage of SF6 (310 CMR 7.72(4)(b));
-If, beginning with the second time that a GIS owner adds SF6 to a GIS unit, or group of commonly-owned, leased, operated, or controlled GIS, the GIS owner becomes aware that the annual average leakage rate for the new GIS equipment is greater than 1%, the GIS owner must inform MassDEP and describe actions that are expected to reduce the emission rate in the future. In such cases, GIS owners should use the form below (310 CMR 7.72(4)(c)); and
-All GIS owners must record, no less than annually, the amount of SF6 added to each piece of active GIS equipment (310 CMR 7.72(8)(b)).
- Upon removal of any GIS containing SF6 (regardless of its purchase date) from the ownership, lease, operation, or control of a GIS owner, the GIS owner must provide for the secure storage, re-use, recycling, or destruction of the SF6 (310 CMR 7.72(4)(d)).
- GIS owners who have in any year reported SF6 emissions from their GIS pursuant to US EPA’s GHG reporting regulation must meet an annually declining emission limit that reaches 1% or less by 2020, and they must report SF6 emissions from GIS to MassDEP each year. Only the two largest Massachusetts electric distribution utilities are covered by the federal requirement (310 CMR 7.72(5&6)).
- These same GIS owners (federal reporters) must also limit aggregate, company-wide SF6 emissions to the company-specific limits listed in the regulation (310 CMR 7.72(5)(b)).
- Gas-Insulated Switchgear Leak Rate Exceedance Reporting Form
Complete and submit this form only in the event of an exceedance that you are required to report under 310 CMR 7.72(4)(c).
- Gas-Insulated Switchgear Emissions Annual Reporting Form
GIS owners required to report GHG emissions to the U.S. Environmental Protection Agency (EPA) by 40 CFR Section 98.3-Subpart DD must submit this form by April 15 annually to MassDEP.
Please contact Jordan Garfinkle (firstname.lastname@example.org) if you have questions or need additional information about the requirements of 310 CMR 7.72: Reducing Sulfur Hexafluoride Emissions from Gas-Insulated Switchgear.