Sulphur hexafluoride

Sulphur hexafluoride (SF6) is an extremely effective electrical insulant and has very significant advantages over alternative materials. It is non-flammable, a critical requirement in the high-voltage applications for which we use it, and because of its effectiveness, takes up less volume than an equivalent insulating volume of an oil alternative. Equipment filled with SF6 can leak and requires replacement.

SF6 is a greenhouse gas. In the UK, in its Guidelines for Company Reporting on Greenhouse Gas Emissions, the Government's Department of Environment, Food and Rural Affairs (DEFRA) defines one tonne as equivalent to approximately 23,900 tonnes of carbon dioxide.

Reported gas loss, as an absolute amount and percentage of inventory, increased to 19.6 tonnes (3.9%) in 2007/08 compared with 15.94 tonnes (3.3%) in 2006/07. The increase was due to several significant leaks in the UK.

Sulphur Hexafluoride losses
2007/08 (Tonnes)
 
SF6 losses
19.60
2006/07 (Tonnes)
 
SF6 losses
15.94
2005/06 (Tonnes)
 
SF6 losses
18.07
2004/05 (Tonnes)
 
SF6 losses
19.51
2003/04 (Tonnes)
 
SF6 losses
20.75
Key: UK  UKUS  US

2007/08 data excludes KeySpan.



Sulphur hexafluoride inventory
2007/08 (Tonnes)
 
SF6 inventory
501.24
2006/07 (Tonnes)
 
SF6 inventory
482.22
2005/06 (Tonnes)
 
SF6 inventory
477.49
2004/05 (Tonnes)
 
SF6 inventory
470.53
2003/04 (Tonnes)
 
SF6 inventory
466.97
Key: UK  UKUS  US

2007/08 data excludes KeySpan.