Question to the Department for Environment, Food and Rural Affairs:

To ask Her Majesty's Government whether they will consult the National Grid and other electricity suppliers about the use of the greenhouse gas sodium hexafluoride as an insulation material in medium and high-voltage electrical installations, including switchgear; in particular about leaks of gas into the atmosphere, the extent of this problem and its global impact; and whether they will publish their findings.

We have interpreted this question as referring to sulphur hexafluoride (SF6).

In the EU Fluorinated Greenhouse Gases Regulation (2014), equipment containing sulphur hexafluoride (SF6) is subject to containment provisions, including leak checking obligations, a requirement to repair any detected leakages without undue delay and the need to use appropriately qualified personnel to perform these tasks. The Regulation also prohibits the intentional release of F-gases into the atmosphere, where the release is not technically necessary for the intended use.

The EU F-gases Regulation requires that the Commission publish a report by 1 July 2020, assessing whether cost-effective, technically feasible, energy-efficient and reliable alternatives exist, which make the replacement of SF6 possible in new medium-voltage secondary switchgear. It also requires that a comprehensive review of the EU F-gas regulation, including a consultation process, is published by December 2022.

All requirements of the Regulation, including the above, will be retained in UK law after EU exit.