Environmental impact comparison between a 220 kV gas-insulated substation and a 220 kV air-insulation substation

This paper presents the environmental comparison of Air Insulated and Gas Insulated switchgears for a specific 220 kV project. The study evaluates the impact of the two technologies on 18 environmental indicators. Results confirm that the GIS substation has a lower environmental impact than the AIS one on the majority of environmental indicators. This is due to electricity losses that are four times lower with GIS than with AIS. However, it is more impacting on global warming indicator due to higher quantities of SF6 used in GIS. The sensitivity analysis shows that the source of electricity generation, taken to model electrical losses during the 40 years of service life, has important consequences on the results: the more the electricity mix chosen has a strong environmental impact (when coming mainly from hard coal plant for example), the more the environmental comparison will be in favor of the GIS technology.