Medium voltage The European Commission’s latest proposal on Fluorinated Greenhouse Gases (F-gases) aims to significantly reduce the use of Sulphur Hexafluoride (SF6)—a highly potent greenhouse gas—in medium voltage (MV) gas-insulated switchgear (GIS). By 2030, the proposal seeks to cut SF6 usage in MV GIS by two-thirds compared to 2014 levels.
Despite this ambitious target, current EU regulations provide no oversight on SF6 inventories or emissions in the MV segment, whereas high voltage (HV) switchgear are subject to strict regulatory controls. Given that the installed volume of SF6 in MV switchgear matches that of HV switchgear, this regulatory gap raises important questions. Why is SF6 in MV equipment overlooked, and how can better inventory tracking and emission controls contribute to reducing its environmental impact?
This article explores the pressing need for stricter SF6 monitoring and regulation in MV switchgear and how it could drive the adoption of sustainable alternatives.
SF6 is the most potent greenhouse gas known today, with a Global Warming Potential (GWP) of 25,200. This means that just 1 kg of SF6 has the same warming effect as 25,200 kg of CO2. Additionally, SF6 remains in the atmosphere for approximately 3,200 years, making even small emissions a long-term environmental threat.
Currently, global SF6 emissions amount to around 8,000 tons annually, equating to the yearly CO2 emissions of 100 million cars. Worse still, projections indicate that by 2030, SF6 usage in switchgear will have grown by 75% compared to 2019 levels.
While SF6 is widely used in HV and MV electrical switchgear, transformers, and substations due to its exceptional insulating and arc-quenching properties, its disposal is highly challenging and costly. A 2020 report by the California Air Resource Board (CARB) emphasized that SF6 recycling is common, yet actual destruction of the gas remains rare due to the expense and difficulty involved. As a result, nearly all SF6 in use today will persist in either electrical equipment or the atmosphere for centuries.
Given these risks, it is crucial to establish stronger oversight on SF6 use, particularly in the growing MV segment.
Despite the lower per-unit SF6 volume in MV switchgear, the sheer number of MV installations results in an SF6 inventory nearly equal to that of HV switchgear.
Currently, EU regulations apply only to GIS containing at least 6 kg of SF6. Since most MV switchgear contains less than this threshold, it falls outside regulatory oversight. In contrast, HV switchgear is subject to strict controls, including:
This disparity is based on the assumption that HV switchgear contributes more significantly to SF6 emissions due to:
While these justifications are valid, they fail to account for the cumulative SF6 emissions from the vast number of MV switchgear units, making the lack of MV regulation a critical oversight.
Despite lower per-unit emissions, the total SF6 inventory in MV switchgear is equal to that of HV switchgear. However, no tracking or reporting requirements exist for SF6 in MV equipment.
A study by the Fraunhofer Institute found that SF6 leakage rates in MV switchgear vary widely:
Between 2010 and 2020, SF6 emissions from HV switchgear declined from 6 to 5 tonnes, while emissions from MV switchgear increased from 1 to 1.5 tonnes.
Though MV switchgear is designed to be maintenance-free, minimal leaks (0.1% per year) still occur over its 40-year lifespan.
SF6 from decommissioned MV switchgear is typically recycled at manufacturing plants, yet there is no reporting on emissions from the recycling process.
SF6 destruction is extremely difficult and expensive, and the emissions generated during this process are not accounted for in any inventory.
Looking ahead, MV switchgear installations are projected to increase by 40% by 2050, driven by:
Since renewable energy integration primarily occurs at MV levels, the need for SF6-free alternatives will become more urgent. Without proper oversight, continued reliance on SF6 in MV switchgear will significantly hinder decarbonization efforts.
Given the environmental risks, MV switchgear should be included in Articles 6 and 7 of the European Commission’s F-Gas Proposal, covering:
By tracking and reporting SF6 emissions, regulators can:
Exempting MV switchgear from SF6 reporting requirements was historically justified by practicality, given the large number of MV units. However, with MV GIS accounting for 50% (and rising) of all SF6 emissions, this regulatory gap is no longer acceptable.
To achieve a climate-friendly energy sector, tracking, reporting, and reducing SF6 emissions in MV switchgear must become a priority. Strengthening oversight will not only limit environmental damage but also promote the widespread adoption of SF6-free alternatives, ensuring a more sustainable energy future.