Automobiles in dense traffic

Annual SF6 emissions are equivalent to the yearly CO2 emissions produced by approximately 100,000,000 cars 

SF6 – the most potent greenhouse gas in the world

SF6 is the most potent greenhouse gas in existence - it is 23,500 times worse than CO2 in terms of its global warming effect (1). Its annual emissions are comparable to the yearly CO2 emissions produced by approximately 100 M cars (2). Furthermore, it is a synthetic gas for which neither a natural sink exists nor an effective disposal method is at hand, making its accumulation in the atmosphere virtually irreversible. On top of this, the gas is extremely long-lived: SF6’s atmospheric lifetime is 3,200 years, which is well beyond CO2‘s 100-200- year lifetime (3). Finally, in a business as usual scenario, SF6's globally installed base is expected to grow by 75% - based on 2019 levels - by 2030 (4).

 

Transmission pilon line against blue sky

SF6 is widely used in the energy industry

Despite being such a significant contributor to global warming, SF6 is widely used in the energy industry due to its excellent electrical properties. To be more precise, of all the SF6 produced, 80% is used in the electrical industry (5), as an insulating medium for gas insulated switchgear (GIS).

 

SF6 emissions, however, are not well-understood:  research shows that up to 80% of SF6 emissions are not reported at all (6). One reason for this is that some countries who are driving the increase in emissions, do not report their SF6 emissions to the United Nations Framework Convention on Climate Change (UNFCCC). Another reason is that developed countries that do report emissions to the UNFCCC are likely to be underestimating their emissions (7).

 

SF6 is increasingly a subject of regulation

Because of its environmental impact, SF6 is increasingly being discussed by regulatory bodies. The EU F-gas regulations in 2006 and 2014 (in the framework of its F-Gas Regulation No. 517/2014), have further strengthened the restriction of SF6 usage in the switchgear industry. Further revision of regulation in 2022 will assess new technologies on the market and whether it is possible to further restrict SF6's usage.

 

In the USA, SF6 emissions from electrical equipment are reported to be much higher than in European countries and the Air Resource Board of California has regulated allowable yearly emissions from 10% in 2010 to 1% in 2020. This may result in further stringent restriction of SF6 usage in the coming years.

 

Sources

(1) Greenhouse Gas Protocol, 2016. "Global Warming Potential Values". Available here.

(2) Regarding the 100 million cars, the average emissions of new cars is around 118g/km (2a). As cars have an average mileage of 15,000km, this means that the average car emitts 1,777kg. If one considers SF6 emissions (which is equivilant to 184,680,000 tonnes of CO2), they are equivilant to around 100 million cars.

(2a) EU Commission, 2018. 'Reducing CO2 emissions from passenger cars'. ​European Commission. Available here.

(3) ABB, 2016. "AirPlusTM - An alternative to SF6 as an insulation and switching medium in electrical switchgear". Available here.

(4) BBC 2019. "Climate change: Electrical industry's 'dirty secret' boosts warming". Available here.

(5) EPA, 2021. "Sulfur Hexafluoride (SF6) Basics" Available here.

(6) Levin, I. et al. 2010. "The global SF6 source inferred from long-term high precision atmospheric measurements and its comparison with emission inventories".  Atmos. Chem. Phys., 10, 2655–2662. Available here.

(7) Rigby, M. et al. 2010. "History of atmospheric SF6 [SF subscript 6] from 1973 to 2008".  Atmospheric Chemistry and Physics 10.21 (2010) : 10305-10320. Available here.