Life cycle impact assessment of various treatment scenarios for sulfur hexafluoride (SF6) used as an insulating gas

A life cycle environmental impact assessment was conducted for sulfur hexafluoride (SF6) used as an insulating gas in electrical devices. Eight scenarios with a variety of SF6 treatment processes were considered. For each scenario, the life cycle power consumption was determined and an inventory analysis of pollutants and toxic materials was conducted. The scenarios were compared in terms of their life cycle environmental impacts, such as power consumption, global warming, acidification, eutrophication, generation of photochemical oxidants, and generation of substances toxic to human health. The power consumption is significantly reduced by the use of a gaseous mixture of SF6 and nitrogen in comparison to when pure SF6 is used, because the power consumption required for producing SF6, which is the major power consumption process, can be reduced according to the amount of SF6 replaced by nitrogen. On the other hand, larger amounts of the pollutants associated with the transportation process will be generated for the scenarios using gaseous mixtures with smaller SF6 contents in the insulating gas. The reuse of spent SF6 after purification can also reduce the power consumption. The calculated environmental impacts were unified with two types of environmental indexes using Eco‐Indicator 99 and LIME (Life‐cycle Impact assessment Method based on Endpoint modeling), and the scenarios were evaluated and compared.