Notice on SP Transmission's Interruption and Insulation Gas Exceptional Event claim
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Electricity transmission companies are financially incentivised to reduce the leakage of Insulation and Interruption Gases (IIG), which are used in some transmission equipment. Some IIG, such as sulphur hexafluoride (SF6), are potent greenhouse gases. Some leakage of IIG is expected from normal operating assets, therefore a target quantity of IIG (measured in kg) leaking from all network assets is set for each company. Each company is then rewarded or penalised through a revenue adjustment based on how it performs each year against the target.
If an IIG leak occurs on a company's network due to an event that it believes was beyond its reasonable control then the company may make a case to the Authority to designate it an Exceptional Event and for all or some of the quantity of IIG leaked during the event to be excluded when we calculate the company's revenue reward or penalty.
This letter sets out the Authority’s intention to issue a direction in relation to SP Transmission's claim for an IIG Exceptional Event that occurred on its network on 14 June 2023. The Authority is satisfied that the event is an Exceptional Event and proposes to issue a direction to exclude 226kg of sulphur hexafluoride related to the event when calculating SP Transmission's ALEt term for regulatory year 2023/24.
Respond name
James Mackintosh
Respond email
Main document
[Consultation on minded-to decision for an Insulation and Interruption Gas Exceptional Event Claim for Scottish Power Transmission (SPT) at Hunterston Converter Station [PDF, 109.60KB]
](https://www.ofgem.gov.uk/sites/default/files/2023-10/SPT%20Hunterston%20consultation%20FINAL.pdf)