SF6- and PFAS-free MV switchgear

Medium voltage (MV) gas-insulated switchgears (GIS) are key components in the electricity grid, where they play a vital role in safely controlling the flow of electricity during faults, maintenance, and regular operation. This technology is pivotal for a successful transition to an electrified zero-emission society, but it can also contribute to greenhouse gas emissions within the grid. Presently, most switchgears are filled with sulfur hexafluoride (SF6) as the insulation medium, which is known for being the most potent greenhouse gas to this date (24,300 times worse than CO2). Therefore, upcoming regulations from the EU will strictly regulate the use of SF6 and other F-gases. For MV switchgear at 12 and 24 kV, this means a deadline for use of SF6 in new installations from 2026. Another proposal is also under discussion and will regulate the use of PFAS (polyfluoroalkyl substances) in the EU. PFAS materials are informally called “forever chemicals”, which has been proven harmful to both the environment and to the human body when not being controlled. MV switchgears contain PFAS in the means of PTFE (polytetrafluoroethylene), which is used for constricting electrical arcs and controlling gas flow during current interruption. The proposed restrictions on PFAS can be put into effect as early as 2025 or 2026. In this project we aim to develop a three-position load break switch for 12 and 24 kV ratings, using high-pressure natural origin gases (NOG) as the insulation medium and with no switching components containing PTFE. Since both SF6 and PTFE have been considering the state-of-the-art in the MV GIS switching industry for decades, substantial innovative actions are required for achieving the same functional rating with technologically inferior materials. The project is a collaboration between ABB Electrification Norway AS, SINTEF Energy Reseach and NTNU, all partners with decades of experience with the relevant medium voltage technology topics.

ABB ELDS in Skien manufactures compact 12-40.5 kV gas insulated switchgears for the world market. Traditionally, these have used sulphur hexafluoride (SF6) gas as the electrical insulation and current interruption medium. However, SF6 is the most potent greenhouse gas known to date, with a global warming potential approximately 24,000 higher than CO2. Starting in 2009, ABB ELDS has made substantial investments in SF6-free technology and have successfully replaced SF6 for many products in its portfolio. Pending EU regulations on polyfluoroalkyl substances (PFAS), which are so-called "forever chemicals", have led to an urgent need for renewed R&D also on PFAS-free technology. Currently, ABB's SF6-free products use PFAS for two critical functional functions: insulation gas (non-SF6 F-gas) and Teflon (PTFE) arcing nozzles. As there are no direct substitutes for these, substantial innovative actions are required for achieving the same functional rating with technologically inferior materials. The number of switchgears also continue to grow in Norway and Europe, with projections indicating a doubling by 2050, so the need for climate-friendly switchgear has become paramount. The elimination of SF6 and PFAS in MV switchgear is thus a major innovation challenge which is critical for ABB Electrification Norway as an export company, as well as for the shaping of an environmentally friendly and sustainable future.