Mühleberg Ost Substation, GIS - Building and Transformer Stations

The new substation replaces two old open-air facilities with a space-saving and modern indoor facility. The new facility consists of two main buildings for the 220 kV and the 380 kV systems, upstream transformer station, a new access road for heavy goods vehicles upto 450 t as well as a cable tunnel for 380 kV connecting sections.

The two GIS buildings are connected via an underground cable vault. The sealed basement floors are partly below groundwater level. The load-bearing structure of the two buidings consists of pre-fabricated concrete elements while the façade is made of metal.

The transformer systems are located outside the buildings. Physical infrastructure constructed includes sealed concrete troughs with piled foundations, tension frames and foundations of the transformer stands, skidways as well as installation site.

Main Data

  • GIS building:
    • 220-kV : 50m x 14.50m x  9m
    • 380-kV : 36m x 14.50m x 11m
  • Transformer trays: 155m2
  • Access road: 6000 m2
  • Cable tunnel: 350 m2


BKF FMB Energie AG, Engineering Kraftwerke, Bern


IUB Engineering in consortium

Construction period


Construction costs

CHF 7.5 million

Scope of services

  • Building, transformer system project
  • Tendering
  • Construction management of overall project