EN30(1) Sulphur Hexafluoride Gas Inventory and Emission Rate

Calendar Year	2001	2002	2003	2004	2005	2006
In-Use Inventory (kg)	111,977	111,977	112,736	110,157	110,376	109,337
Emission Rate (as percentage of in-use inventory)	3.0	2.4	2.9	2.7	2.1	1.9

Sulphur hexafluoride gas is used to cool and insulate electrical equipment to prevent arcing and outages. It is also a powerful greenhouse gas, with a global warming potential 23,900 times that of carbon dioxide. To date, no commercially-viable substitute has been found. The emission rate shown includes all known losses, whether due to slow leaks, maintenance or accidents. Overall, the emission rate is improving due to enhanced materials handling training, better record-keeping, and as older equipment is replaced with new equipment with improved containment.