Kale Hydropower Project

The first hydroelectric project that uses Pressure Relief Valves in Turkey.

Project Information

Client: Asa Energy

Location: Rize

Status: Completed


Key Features

Diversion Type

Total Installed Capacity 10 MW


Transient Analysis

Pressure Relief Valve

Long Penstock



Kale Hydropower Project started to operate on February 2010 and since then it is the first and only hydroelectric project that uses Pressure Relief Valves in Turkey. The project mainly consist of Tascami Weir which takes water at elevation of 309 m on Gurgen Creek, a conveyance tunnel that diverts the water to Kale Weir which is located on Kale River, Kale Weir, a long penstock, pressure relief valves and a powerhouse that has three equal capacity Francis Turbine units. Penstock is one of the most important components of the project with its remarkable length. It is a spiral welded and buried steel pipe having a length of 3.530 m and a diameter of 2 m. In the project, six “Pressure Relief Valves” having a diameter of 400 mm have been used in order to keep the pressure rises due to the long penstock and Francis type turbines at a reasonable level.

Kale Weir

Kale Weir

Socially and Environmentally Friendly Solution

The power house of the project is located at a place where the settlement is dense and tea agriculture is widespread. If a classical diversion type hydropower project was to be adopted, a forebay or a surge tank and related access roads would have been constructed. The negative environmental and social impacts of these constructions have made a classical divergence type design impossible. The most feasible solution among the studied alternatives was to lay a penstock under the existing village road that runs parallel to the river and convey the water to the turbines via this buried penstock.

Cost Effective Result

With this approach, the project has become applicable, the environmental and social impacts have been reduced to the least possible extent and a considerable cost saving has been ensured. The high pressure rises due to the long penstock and Francis type turbine have been prevented by using the “Pressure Relief Valves” and an economical penstock design has been achieved by keeping the pressure rises at a reasonable level. Manufacturing and laying of pipes and putting the road with the improvements into service were accomplished in a period as short as four months.