With emission reporting now being mandatory for many SF6 users, reports of nameplate discrepancies have become quite common. This paper will identify the different types of emissions, discuss the possible reasons for some of the inaccuracies, as well as the difficulty faced by both SF6 users and regulatory agencies alike while trying to gather accurate data. A simple method to determine the exact amount of SF6 in a vessel at any given time will also be discussed.
Nameplate; amount of SF6 (in kg or lbs) that is contained in the equipment when properly charged, as indicated by the OEM. GIE (Gas Insulated Equipment); any equipment, which as its dielectric or arc quenching medium, uses SF6 . Phantom Emissions; any accounting-only emission that didn’t actually occur.
The Mandatory Greenhouse Gas Reporting Rule (40 CFR Part 98) subpart DD applies to users of medium to high voltage SF6 insulated transmission and distribution electrical equipment, and subpart SS applies to Original Equipment Manufacturers (OEM‘s) of that equipment. The US Environmental Protection Agency (EPA) now requires users with in service SF6 nameplate capacity of at least 17,820 lbs to report their gas emissions annually. Certain States - most prominently the State of California through its Air Resources Board (CARB) - have enacted similar mandatory reporting regulations. With the increase of different entities now having to track and monitor their SF6 emissions, so have the reports of nameplate discrepancies leading to so called 'phantom emissions'