Fload and coastal protection

Yedigöl and Aksu hydropower plants (Turkiye)

Wasserkraftanlagen Yedigöl und Aksu (Türkei)

The two high-pressure hydropower plants Yedigöl and Aksu are located on the Aksu River in north-east Turkiye. The two power plants are arranged in a cascade and each consist of a weir system with a headrace and sand trap, a pressurised water tunnel (excavation diameter 4.60 m) and an above-ground powerhouse. As a rule, the Yedigöl power plant discharges the headrace water directly into the headrace tunnel of the Aksu power plant.

The two pressurised water tunnels were excavated by mining. Due to the relatively good rock quality, only 15 % of the Yedigöl tunnel and 28 % of the Aksu tunnel had to be lined with a concrete shell (internal diameter 3.60 m). Due to the high water pressure and low rock cover, a steel penstock was laid in the lower part of the tunnels. The volume of water extracted from both power plants is 11 m³/s, which is converted into electrical energy by two Pelton turbines. With the available heads of 240 m and 295 m, the two power plants have an installed capacity of 23 MW and 27 MW and a forecast annual energy production of 56 GWh and 80 GWh respectively. The two power plants went into operation in 2011 and 2012 respectively.

Client: Borusan ENBW Enerji

Processing period: 2008 – 2012

Main data:
Yedigöl hydroelectric power station:
Weir system with sand trap
Headrace tunnel: approx. 4.5 km
DN 2000 steel pressure pipeline
Above-ground powerhouse with 2 Pelton turbines
Discharge water volume: 11 m³/s
Head: 240 m
Aksu hydropower plant:
Weir system with sand trap
Headrace tunnel: approx. 6.2 km
DN 2000 steel pressure pipeline
Above-ground powerhouse with 2 Pelton turbines
Discharge water volume: 11 m³/s
Drop height: 295 m

Services:
Review of the tender planning
Project optimisation and creation of a new tender planning
Review and approval of all execution documents
Construction supervision of the tunnelling work
Preparation and monitoring of a geotechnical investigation programme in the tunnels
Advising the client (owner's engineer)