Obfelden–Samstagern grid upgrade worth CHF 170m under construction

Swissgrid is upgrading the existing 150 kV line between Samstagern (Richterswil), Thalwil, Kilchberg/Waldegg (Zurich) and Obfelden to 220 kV in stages, split into six sub-projects with overhead-line and underground-cable sections plus new substations in Thalwil and Waldegg. The first construction stage (Schweikrüti–Sihlhalden) was completed in October 2023, and the second stage (Sihlhalden–Kilchberg) has been running since spring 2025 through the end of 2026. According to Swissgrid, work on all sections, including dismantling of the old line, is expected to be completed by 2033; total construction costs are around CHF 170 million.