Grimsel 1E HPP

Grimsel 1E(xpansion) will eliminate the bottleneck between Lake Grimsel and Lake Räterichsbodensee (Grimsel 1 HPP). The design and optimisation of the plant comprises a 150 MW pump turbine with synchronous generator and full power converter with the following main points:

  • Hydraulic calculations and design of hydraulic components such as inlet/outlet structure each with an approx. 120 m2 cross-section, armoured transition areas up to Øi = 5.2 m, concrete-lined pressure tunnel and shafts up to Øi = 6.6 m
  • Central powerhouse 56 x 23 m2
  • Throttle valve Øi = 4.2 m in powerhouse 34 x 14 m2 with optimised inflow after bends
  • Design of access tunnel incl.  assembly cavern, turning areas, concrete pins, armoured gates, drainage, cleaning and ventilation
  • Construction workflow incl. lowering of lake level
  • Emergency scenarios and management

Main Data

  • Preliminary project with concession project
  • Construction project with building application
  • Tendering


    Kraftwerke Oberhasli AG, Innertkirchen


    IUB Engineering Ltd. and IM Maggia Engineering Ltd.

    Construction period


    Construction costs

    CHF 150 million

    Scope of services

    • Output 150 MW
    • Turbine operation QA = 100 m3/s, Pump operation QA = 90 m3/s
    • Gross head 83-183 (206) m