When we scrap old sulphur hexafluoride (SF6) switchgear, how much of the gas counts as emitted under the Intergovernmental Panel on Climate Change (IPCC) method?
Without recovery, nearly all of it. IPCC Table 8.2 gives 0.93 (Europe) or 0.95 (Japan) of the nameplate charge as the fraction left at retirement and potentially emitted before recycling or disposal. Gas you recover with weighed cylinders comes off that, less small recycling losses.
The default for retiring equipment
Under the Tier 1 method, Equation 8.1, disposal emissions are the nameplate capacity of the retiring equipment times the fraction of SF6 remaining at retirement. Table 8.2 (sealed pressure, medium voltage) gives 0.93 for Europe and 0.95 for Japan. Table 8.3 (closed pressure, high voltage) gives 0.95 for both. The table footnote says this is "the fraction of the nameplate capacity potentially emitted before the equipment is recycled or disposed".
When you recover the gas
- For closed-pressure equipment the Guidelines count the nameplate capacity of retired units minus the SF6 recovered from them (Equations 8.7A and 8.7B).
- The Tier 2 form, Equation 8.2, multiplies the remaining gas by one minus the share of retiring equipment recovered x recovery efficiency x the share recycled, reused or destroyed. The Guidelines require country-specific factors for Tier 2, so a site with weighed cylinders should use the simple nameplate-minus-recovered form instead. That choice is our reading.
- Recycling losses are described as expected to be small, "on the order of less than one percent" of the gas fed in, but the Guidelines add: "However, these emissions may be higher if state-of-the art handling equipment and practices are not used." Destruction efficiency "may be as low as 90 percent", so up to 10 percent of gas sent to destruction could escape.
Why the evidence matters
The Guidelines warn that "the venting of just a few percent of the SF6 in retiring equipment will drive emission rates far above the minimum that is technically achievable". They suggest measuring gas by weighing cylinders before and after filling or recovery. Ask the contractor for the cylinder weights and the recycler's receipt, and keep them with the disposal record.
Do not count the same gas twice
If you already counted yearly use losses with a factor, the Guidelines (Table 8.1, example 1) say to subtract lifetime use emissions from the disposal figure: nameplate minus nameplate x use factor x lifetime. Equation 8.7B then multiplies that by (1 minus the fraction of retiring equipment whose SF6 is recovered x recovery efficiency).
Six kilograms of SF6 in panels retired after 35 years
- No recovery, Europe table: 6 x 0.93 = 5.58 kilograms of SF6
- No recovery, Japan table: 6 x 0.95 = 5.70 kilograms of SF6
- Contractor recovers 5.0 kilograms, weighed: 6 minus 5.0 = 1.0 kilogram vented, plus an example allowance of 1 percent of 5.0 lost in recycling = 0.05 kilograms, so about 1.05 kilograms
- With use losses already counted at the Europe factor: 6 minus 6 x 0.002 x 35 = 6 minus 0.42 = 5.58 kilograms, the same as 6 x 0.93
The 6 kilograms and the 5.0 kilograms recovered are examples. The 1 percent recycling loss is an example allowance; the Guidelines say recycling losses are generally expected to be less than one percent but may be higher without state-of-the-art handling equipment and practices.
What Senseible does here
Senseible reads fuel invoices and electricity bills into dated records. It does not read cylinder weights or recycler receipts, so keep those with your disposal file and add the SF6 kilograms to your inventory yourself.
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Last reviewed 2026-11-05. The Guidelines call Tier 2 country-specific; the site-level use of weighed recovery here is our reading of their mass-balance approach.