Sulphur hexafluoride (SF6) is an extremely effective electrical insulator and has 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.
Reported gas loss, as an absolute amount and (percentage of inventory), was 15.76* tonnes (2.2%) in 2010/11 compared with 13.98 tonnes (2.2%) in 2009/10.
SF6 is also a greenhouse gas and one tonne is equivalent to approximately 23,900 tonnes of
carbon dioxide.
In 2010/11, SF6 leakage accounted for around 3.9% of our total scope 1 and 2 greenhouse gas emissions.
* Restated from 15.31 tonnes