Replacing SF₆ in electrical gas-insulated switchgear: Technological alternatives and potential life cycle greenhouse gas savings in an EU-28 perspective

To date, atmospheric concentrations of sulfur hexafluoride (SF₆) are the most potent among the greenhouse gases identified by the Intergovernmental Panel on Climate Change (IPCC) and are still rising. In the EU-28, SF₆ has been banned from several applications, however, an important exception is gas-insulated electrical switchgear (GIS) for which cost-effective and environmentally sound alternatives were unavailable when the F-Gas regulation was last revised in 2014. To date, after some recent innovations, we argue that the phasing out of SF₆ could spur the accelerated development of alternatives with a lower carbon footprint. In the EU-28, the SF₆ amount in switchgear is unclear. In this paper, we estimated the SF₆ amount to be between 10,800 and 24,700 t (with a mode at 12,700 t) in 2017, resulting in 68 to 140 t of annual emissions from operational leakage only, corresponding to 1.6 to 3.3 Mt of CO₂-eq. We additionally calculated the potential greenhouse gas savings over the lifecycle of one exemplary 145 kV gas-insulated switchgear bay upon replacing SF₆ by decafluoro-2-methylbutan-3-one (C5-FK) and heptafluoro-2-methylpropanenitrile (C4-FN) mixtures. Projecting these results over the EU-28, a phase-out scenario starting from 2020 onwards could reduce the carbon footprint by a median of 14 Mt of CO₂-eq, over a period of 50 years. Extrapolation to medium voltage could be assumed to be of a similar magnitude.