Q852. What equipment should be included as new or retired equipment each year for Subpart DD?
A852. Subpart DD uses a mass balance methodology to calculate facility emissions and uses the terms “new” and “retired” to describe equipment added to or removed from active use. To correctly determine a facility’s emissions, EPA recommends including equipment as “new” if the equipment was not energized at the beginning of the year and is energized at the end of the year. EPA recommends including equipment as “retired” when removed from active use (decommissioned or out of service at the end of the year). The EPA interprets the term “retired” to mean that the equipment is energized at the beginning of the year but not energized at the end of year. Prior to installation, SF6 that is inside partially-filled electrical equipment that has been purchased by the facility (i.e., the title has been transferred to the facility) is recommended to be counted as part of the mass balance input §98.306(h) "SF6 with or inside new equipment purchased in the year" as well as the mass-balance input §98.306(g) "SF6 stored in containers at the beginning and end of the year” (assuming the equipment still has not been installed by the end of the year). Once equipment is in active use, this gas should no longer be counted as part of the “SF6 stored in containers at the beginning and end of the year” (see EPA’s response to comments in EPA-HQ-OAR-2009-0927-0237). For reporting years 2017 and later, both new and retired equipment should have separate totals for hermetically sealed-pressure equipment and other than hermetically sealed-pressure equipment.