Q643. Should we report the SF6 and PFC emissions from a substation located at a power plant subject to subpart D under subpart DD?  If so, would the SF6 and PFC emissions be reported under the same report as the subpart D emissions or as a separate report?

A643. It is possible that you would be required to report emissions under subpart DD, but subpart DD emissions must always be reported as a separate facility from the subpart D emissions in e-GGRT.  If the substation is located on your property but is part of an electric power system that is owned, serviced, or maintained by an electric power transmission or distribution entity (see definition in 98.308), then emissions would be reported by the transmission and distribution entity and not by your power plant.  The power plant is required to report emissions under subpart DD only if: (1) the equipment is owned by your facility and is not serviced or maintained by an electric power transmission or distribution entity, and (2) the total nameplate capacity of SF6- and PFC-containing equipment that is owned by the power plant and that is located at that site exceeds 17,820 pounds (see 98.301.b).  If both criteria are satisfied, you must register and report DD equipment as a separate facility from the subpart D facility and submit separate reports for each facility.