HOCHTIEF successfully delivered Glendoe Hydro Electric Scheme, a 100MW capacity hydroelectric power station south of Loch Ness. Water is collected in a new reservoir, impounded by a dam over 1km long, then transferred through an 8km power tunnel to a turbine housed in an underground cavern. The drop from the reservoir to the turbine is over 600m, making Glendoe the most efficient hydro scheme in the UK.

Key features:

  • 1km long, 35m high rock fill dam
  • Aqueduct system: 8km tunnel, 4.5km pipeline
  • 8km power tunnel
  • 1.2km power station access tunnel
  • Additional access and service tunnels
  • Power Cavern, 38m long, 18m wide, 32m high, 250m underground
  • Single 100MW Pelton Turbine
  • 650km3 excavation
  • 207km3 structural concrete
  • 45km of access roads

Using sophisticated drilling jumbos and the latest explosives and detonation systems, we safely and efficiently excavated the power cavern 250m underground, modifying the excavation sequence to achieve early completion.

Working closely with the client to optimise solutions, we installed a single 100MW Pelton Turbine, using robust design to maximise its efficiency while minimising capital cost. We also modified the aqueduct tunnel, using cut and cover sections at river crossings to maximise the catchment used and optimise the scheme’s output.

We built the 1km long, rock-filled dam using both rock excavated from the aqueduct tunnel and from a quarry within the reservoir area. To minimise the scheme’s impact on the landscape, the dam was shaped to suit the local topography, the control building was set into the hillside and the intake tower was finished with smooth columns and textured panels to enhance its appearance.

We continuously monitored the programme, resequencing and adopting continuous shift working to drive progress. We completed the scheme over two months early and achieved a CEEQUAL Excellent rating.