Geotechnical Investigations for the Pumped Storage Plant Goldisthal, Germany

The pumped storage plant Goldisthal is located on the upper course of the river Schwarza in Southern Thuringia and has an installed capacity of 1,060 MW.

The upper reservoir was constructed on Farmdenkopf Mountain as a circular rockfill ring dam with asphaltic concrete surface sealing, providing an effective storage capacity of 12 x 106 m3, incorporating a bell-mouth intake structure. The intake is connected to the cavern powerhouse by twin 6.2 m diameter steel lined pressure tunnels, 820 m long.

The main underground power cavern (137 m long, 26 m wide and 49 m high) houses four 265 MW pump-turbines, generators, and spherical valves, together with ancillary equipment, and is accompanied by a separate transformer cavern. Two units are conventional fixed speed hydro units, and the other two are double fed induction machines plus cycloconverters for adjustable speed control.

From the powerhouse cavern, two 8.2 m diameter tailrace tunnels run 275 m to the outlet structure on the lower reservoir. The lower reservoir is formed on the Schwarza River by the construction of a 67 m high asphalt faced rockfill dam, which itself incorporates a mini hydropower facility.


Vattenfall Europe Generation AG + Co. KG (VE-G), Berlin

Services Period1991 – 2004
Technical Data
  • Pump turbines:
  • Rated capacity - turbine operation:
4 x 269 MW
  • Rated discharge - turbine operation:
4 x 103.3 m³/s
  • Rated gross head:
301.65 m
  • Rated capacity - pump operation:
4 x 257 MW
  • Rated flow - pump operation:
4 x 80 m³/s
  • Rated head:
306.7 m
  • Effective reservoir volume:
  • Upper reservoir:
12 x 106
  • Lower reservoir:
19 x 106
  • Pressure tunnels (2 No.), D/L:
6.2 m / 820 m
  • Tailrace tunnels (2 No.), D/L:
8.2 m / 275 m

Feasibility study including geotechnical field/laboratory investigations:

  • Evaluation of previous four exploratory adits and in-situ and laboratory tests performed prior to 1990
  • Additional investigations consisting of:
    • Dilatometer tests
    • Borehole slotting tests
    • Water pressure tests
    • Large scale (60 x 60 x 120 cm) true triaxial test on prismatic rock mass sample
    • Miscellaneous laboratory tests

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