Application of SF6-free technology in the Swedish transmission system – overview of the challenges and strategic decision

Switchgear (GIS) technology in the Swedish transmission system. The background emphasizes environmental concerns, driven by SF₆'s high global warming potential and the EU's F-Gas

Regulation (2024/573), which prohibits new SF₆ GIS commissioning after 2032. Concurrently, rapid electrification and urban growth in Stockholm necessitate significant grid expansion, demanding sustainable and reliable high-voltage solutions. The paper's goal is to present

Svenska kraftnät's strategic decision to adopt SF₆-free GIS for the first time, along with the technical complexities arising in ongoing projects.

The methodology involved an extensive two-year evaluation. This included assessing SF₆-free 420 kV GIS manufacturers, reviewing completed type tests, analysing the implications of the

F-Gas Regulation (including project timeline risks beyond 2032), international benchmarking and conducting economic viability studies. Strict technical specifications were developed, requiring a Global Warming Potential (GWP) ≤ 1000 and full type test certification for all procured equipment.

Key results confirm the technical maturity of SF₆-free GIS, proven up to 145 kV and ready for 420 kV. Svenska kraftnät's decision to procure SF₆-free 420 kV GIS prevents a 50% increase in its SF₆ inventory. While initial equipment costs are higher, total project costs increase only 10-20%, offset by expected long-term operational savings. The paper underscores that type test certification is crucial for validating new technologies, ensuring environmental goals without compromising power system reliability and safety. The paper emphasizes the need for diverse, proven technical solutions to facilitate a resilient energy transition.