Projects

Alakopru Dam and Hydropower Project

Alaköprü Project consist of a multiple-purpose reservoir having an active storage of 86.5 hm³ being responsible for potable water demand of Northern Cyprus, irrigation demands and energy production.
 

Project Information

Client: Boyut Group Energy

Location: Mersin

Status: In Progress 

 

Key Features

Installed Capacity 32 MW

Multi-purpose Reservoir

Energy Tunnel

 

Summary

Alaköprü HEPP is located in Southwest Region within the border of Anamur district of Mersin province over the creek of Dragon. Powerhouse is adjacent to the Alaköprü Dam has a catchment area of 210 km2 along this river and diverts water to Alaköprü HEPP.

 

Alaköprü Project consists of a multiple-purpose reservoir having an active storage of 86.5 hm³ being responsible for potable water demand of Northern Cyprus, irrigation demands and energy production. Dam diverts the water via 260 m long energy tunnel to the branch where the water demands of the project divert. Prosem Engineering’s scope was to design the energy purpose of the project. Reservoir simulation was carried out in order to determine the optimum turbine capacities and to define the operation rules in order to maximize energy revenues while ensuring the non-energy purposes of the project. Revised feasibility report was prepared as a result of the process and electromechanical equipment contractual works started accordingly. Although the final designs for the energy tunnel were complete and were not in the scope of Prosem Engineering, the rock cover confinement requirements for the tunnel were re-evaluated and it was concluded to elongate the length of steel lining.

 

 

Aydinlik Hydropower Project

By this way, high cost of the dam body as well as the unwanted social and environmental effects of this dam is eliminated.
 

Project Information

Client: Odabaşı - Bal Electricity

Location: Batman

Status: In Progress

 

Key Features

Installed Capacity 49 MW

Cascade Diversion Type

Project Formulation

Daily Pondage 

 

Summary

Aydınlık HEPP is a diversion type cascade hydroelectric facility that has been planned to use the potential between 1050 m and 800 m of Aydınlık Creek. The project is already in the planning stage. In the former feasibility report, Aydınlık HEPP project was composed of two hydropower plants and one dam. In this case, the project had a lot of adverse social and environmental effects and also the cost of the project was very high. Therefore, to minimize these effects and to improve the project economy, a new project formulation was developed by Prosem Engineering.

According to this new formulation, Aydınlık HEPP consists of three cascade diversion type projects. Instead of the big reservoir storage proposed in the former solution, projects are planned to have daily pondage. By this way, high cost of the dam body as well as the unwanted social and environmental effects of this dam is eliminated.

 

Akin Hydropower Project

Two equal power Francis type units, by means of the advantage of having daily tanks in the projects, can be used without energy loss.
 

Project Information

Client: Güngör Energy

Location: Giresun

Status: Completed

 

Key Features

Diversion Type

Total Installed Capacity 18 MW

Disk-shaped Headpond

Long Tunnel

 

Summary

Akın HES Project is a diversion type hydroelectric power station which evaluates Ahırlı Creek’s (Pazarsuyu) head level between the altitudes of 655 m and 550 m. Assignments of planning, optimization and formulation as well as the financial analysis of the project are prepared by Prosem Engineering.

Akın HES makes use of the energy potential of Ahırlı Creek’s head level between the altitudes of 655 m and 550 m . The currents which are converted by a regulator structure will be transmitted to the head pond through 2470m long and 5m in calibre transmission tunnel. The topography of the region, where the forebay is to be built, is highly inclined. Therefore, the head pond is planned as disk shaped and its diameter is determined to be 15.00m. In this project, the transmission tunnel is designed to be used as a daily tank and a significant benefit is procured due to the long length of the tunnel. Two equal power Francis type units, by means of the advantage of having daily tanks in the projects, can be used without energy loss.

 

Bingol - 2 Hydropower Project

Bingöl – 2 is located in a very high seismicity area of Turkey with a peak ground acceleration estimated around 0.5 g, close to the vicinity of faults
 

Project Information

Client: Odabaşı - Bal Electricity

Location: Bingöl

Status: In Progress 

 

Key Features

Diversion Type

Total Installed Capacity 27 MW

Reinforced Concrete Steel Cylinder Pipe (RCCP) 

 

Summary

Bingöl - 2 HEPP is a diversion type hydropower facility which makes use of the head between 1 180 m and 1 095 m of Göynük Stream. The construction of the project commenced in 2012 and the HEPP is going to be in commercial activity in 2014.

Bingöl – 2 is located in a very high seismicity area of Turkey with a peak ground acceleration estimated around 0.5 g, close to the vicinity of faults. In the original design, 12 km long trapezoidal channel located in slopes was planned. Prosem Engineering investigated the site area and consulted specialists; consequently the former design was replaced with a buried and pressurized reinforced concrete steel cylinder pipe (RCCP) with the diameter of 4.1 m near the river in order to eliminate the risk of slope stability failures which might have been triggered by an earthquake event. The RCCP was chosen to Steel, HDPE and GRP alternatives because of its lower cost and in situ fabrication eliminating hauling expenses. The weir was moved downstream in order to increase the active storage which increased peak energy production; also this resulted in a shorter length of conveyance around 8 km.

 

 

Ceviz Hydropower Project

As a result of the formulation studies committed by Prosem, the project was converted to a single project with one weir, a pressurized conveyance system and a powerhouse.
 

Project Information

Client: Arsan Construction

Location: Eskişehir

Status: In Progress 

 

Key Features

Diversion Type

Total Installed Capacity 4 MW

GRP Pipeline

Pressurized Conveyance System

 

Summary

Ceviz HEPP is a diversion type hydropower project located over the Gürleyik Creek within the borders of Eskişehir province. The project will use the head between 582 and 470 m elevations releasing tailwater to Sarıyar Dam reservoir which is under operation since 1956.

Ceviz HEPP is located between the altitudes of 582 m and 470 m of Gürleyik Creek. In earlier studies, the project was composed of two parts as Ceviz-1 Weir&HEPP and Ceviz-2 Weir&HEPP. In this formulation, there were two weirs, long conveyance lines, two head ponds, penstocks, and two power plants. As a result of the formulation studies committed by Prosem, the project was converted to a single project with one weir, a pressurized conveyance system and a powerhouse.

In the final formulation, the project is composed of a 12 m high weir to ensure daily regulation, 3.6 km pressurized GRP pipeline and a powerhouse.

The penstock of the project is designed to be constructed with GRP pipes and near to the powerhouse, a standpipe will be installed in order to limit the pressure rise in the penstock. There will be two sets of Francis turbines inside the powerhouse.

 

 

Derince Dam

By changing the dam type, the face slopes of the dam will be more steeper and accordingly the fill material will be decreased.
 

Project Information

Client: State Hydraulic Works (DSİ)

Location: Mugla

Status: Completed

 

 

Key Features

Reservoir

Irrigation

Concrete Face Gravel Fill Dam

 

Summary

Derince Dam was designed as clay core compacted gravel fill dam previously. But at the project site there is a lot of problem to obtainin clay material. Therefore, Derince Dam should be designed without any need of clay material.

Clay core is the impervious layer of the dam. The new dam type was determined as concrete face gravel fill dam. In this type, the impervious layer would be the concrete face and thus there will be no need to use clay material in the dam design anymore.

Derince Dam has a height of 52 m from thalweg and 62.80 m from the foundation. At the top of the dam there is a parapet of 3 m height. The crest elevation of the dam is 122.00 m.

 

Koyunbaba Dam

The final design of the dam revised and the detailed design prepared according to the revised final design.
 

Project Information

Client: State Hydraulic Works (DSİ)

Location: Cankiri

Status: Completed

 

Key Features

Large Reservoir

Irrigation

Concrete Face Gravel Fill Dam

 

Summary

Koyunbaba Dam was designed as a concrete faced gravel fill dam. At the construction stage problems came up due to the subsurface water elevation.

The final design of the dam had to be revised and a detailed design had to be prepared according to the revised final design. Prosem Engineering has taken charge of this work.

Koyunbaba Dam has a height of 48.75 m from thalweg and 59.00 m from the foundation. At the top of the dam there is a parapet of 3.50 m height. The crest elevation of the dam is 841.85 m.

 

 

 

Bagistas II Dam and Hydropower Project

Income maximisation, reservoir operation rules, riverbed excavation.
 

Project Information

Client: Unit Investment N.V.

Location: Erzincan

Status: Completed

 

Key Features

Total Installed Capacity 50 MW

Income Maximisation

Reservoir Operation Rules

Riverbed Excavation

Basin Hydrology 

 

Summary

Prosem has served consultancy to Unit International N.V. for several projects. Hydraulics, hydrology, optimization and operational studies are conducted and tailwater excavation optimization and feasibility reports are prepared for projects of 69 MW total installed capacity.

Two equal capacity Pelton Turbines were selected for Hunut-II Project.

For Bagistas II Dam & HEPP Project that is in operation within Iliç district of Erzincan province, a riverbed excavation about 5.700 m long will be included. The recent project firm has performed a study for this excavation, Prosem has evaluated this study by means of hydraulic aspects. At the downstream of the project, Adatepe Bridge is located on Karasu River and at the left coast, the railway lies along the river. Prosem has performed a study in order to determine the route and the cross-sections of the excavation and the hydraulic calculations without any damage to the bridge and the railway by ensuring the minimum excavation volume. In the scope of other two diversion type projects, Prosem has performed water supply and operational studies while preparing feasibility report for one of them.

 

Cambasi Hydropower Project

One of the solutions includes substantial reduction in reinforcement and concrete quantities in energy tunnel rock trap region by utilizing advanced design methodology.
 

Project Information

Client: NVS Construction

Location: Trabzon

Status: Completed 

 

Key Features

Total Installed Capacity 40 MW

Energy Tunnel

Riverbed Diversion 

 

Summary

Çambaşı HEPP Project is located at Ögene & Haldizen Creeks' basin in the Eastern Black Sea Region within the borders of Trabzon city. Çambaşı HEPP makes use of the head between 582 m and 311 m.

Çambaşı HEPP project is owned by Enerji SA company, which is the largest energy production company of Turkey. Construction works are granted to NVS Construction. Prosem Engineering prepared alternative solutions to the difficulties encountered by contractor in the riverbed diversion and the energy tunnel and presented the results to both the owner and the contractor.

One of the solutions includes substantial reduction in reinforcement and concrete quantities in energy tunnel rock trap region by utilizing advanced design methodology.

 

 

 

Tufekcikonagi Hydropower Project

The water transmission line placed under or near the existing roads as much as possible to minimize the negative environmental effects.
 

Project Information

Client: B. Ergunler Construction

Location: Bursa

Status: Cpmpleted

 

Key Features

Diversion Type

Installed Capacity 5 MW

4 Diversion Weir

Forebay with Pondage

 

 

Summary

Tüfekcikonagi Hydropower Project is located in Marmara Region within the border of Inegol district of Bursa province over the creek of Sacmali. Karaburun, Biçki, Uçuncu and Bogakaya Weirs along the branches of this river, divert water to Tüfekçikonagi HEPP using the head between elevations 962.50 m and 615 m of Saçmalı Creek.

The surroundings of the construction site are very steep and covered by extensive vegetation. This facility, which consists of relatively small hydraulic structures in order to be in compliance with the topography, has a significant production capacity due to the high head it makes use of. The water collected by different branches of the Saçmali Creek by four above mentioned weirs is conveyed to forebay through GRP pipes - 0.50 m and 0.80 m in diameter and 2 680 m in length - and U-PVC pipes- 0.90 m and 1.20 m in diameter and 2 040 m in length. The water transmission line placed under or near the existing roads as much as possible to minimize the negative environmental effects. Due to the fact that it is not practical to store water in the four weirs separately, a forebay as large as the topography allows is designed with a reservoir possessing 16 800 m3 daily storage capacity, thereby making it possible to increase the energy output at peak hours with the help of two Pelton type turbines.

 

Telli Hydropower Project

An economical design of penstock was achieved by taking the advantage of the use of Pelton type turbines which are able to keep pressure rise at a reasonable level.
 

Project Information


Client: Aksar-Nazar Energy

Location: Giresun

Status: Completed

 

Key Features

Diversion Type

Installed Capacity 9 MW

Long Penstock

Transient Analysis

Environmentally Conscious Design

 

 

Summary

The construction of Telli Hydropower Project is in operation since 2012. Project makes use of the head between 665 m and 455 m of Akdere Creek.

 Telli 1 Weir

Telli 1 Weir

Penstock, one of the most important components of the project, is made of steel pipe with a length of 3.037 m and diameter of 1.70 m. The penstock was placed such that the first 2 312 m of it will be laid under the nearby village road and the reaming 725 m part will be placed in a tunnel coated by concrete. The penstock is connected to the power plant via the bifurcation at the tunnel exit, thereby eliminating the need for forebay which in turn reduces the negative social and environmental effects as well as the total cost. An economical design of penstock was achieved by taking the advantage of the use of Pelton type turbines which are able to keep pressure rise at a reasonable level.

 

Aksar Weir and Nazar Hydropower Project

The new formulation composes of a single weir which has daily reservoir and pressurized tunnel together with surge chamber.
 

Project Information

Client: Akşar - Nazar Energy

Location: Bitlis

Status: Completed

 

Key Features

Diversion Type

Installed Capacity 33 MW

Reservoir

High Diversion Weir

Power Tunnel

Surge Tank

Transient Analysis 

 

Summary

Aksar Weir and Nazar Hydropower Project are located in Eastern Anatolia Region within the border of Hizan district of Bitlis province over the creek of Sutopu. Aksar Weir has a catchment areaof 1,000.10 km2 along this river and diverts water to Nazar HEPP.

According to the feasibility report that was prepared in 2005, Akşar Weir and Nazar HEPP was composed of two diversion weirs, a conveyance channel having a length of 10.5 km, forebay, penstock and power house.It was determined that construction of the conveyance channel above the ground is inappropriate in terms of economical and environmental aspects considering field observations and office studies that were conducted by Prosem Engineering. Revised feasibility report was prepared by modifying the formulation which minimizes the cost of expropriation as well as negative social and environmental impacts. The new formulation composes of a single weir which has daily reservoir and pressurized tunnel together with surge chamber. The tunnel which has an inner radius of 4.00 m with modified horse-shoe cross-section and a length of 7,500 m is designed as coated due to geological and hydraulic reasons. The thickness of concrete cover and the amount of reinforcement have been determined considering the hydrostatic pressures over the tunnel. Steel coating has been used at the regions where the hydrostatic pressure was not carried by rock mass over the tunnel and at the regions between the surge chamber shaft and the powerhouse. In order to keep the pressure rises at reasonable levels, surge chamber, having an upper tank with a radius of 15 m and a height of 21 m, was designed at the closest location to the power house considering the suitability of the location in terms of geological and topographical aspects. As a result of all the modifications, a storage of 150 000 m³ has been obtained and the energy production has been shifted to peak hours. Two Francis turbines of equal capacity have been erected in powerhouse. Another turbine having 300 kW capacity has been constructed within the weir in order to take the advantage of the energy of the first water flowing into the creek.

Hemsin Hydropower Projects

Thanks to the projects being the run-of-the river type hydroelectric facilities, the negative environmental effects of the project is minimized.
 

Project Information

Client: BM Holding

Location: Rize

Status: Completed

 

 

Key Features

Run-of-River Type

Installed Capacity 3 MW

Cascade Projects

Pondage Storage

High Weir

 

 

Summary

Hemsin Hydropower Projects are three-level cascade run-of-the river hydroelectric facilities that are located in Black Sea Region within the border of Hemşin district of Rize province over the stream of Hemşin. The construction of Hemsin I and Hemşin III projects started within the last quarter of 2011.

Hemsin HEPPs make use of the head between 345.00 m and 285.00 m of Hemşin Stream for energy generation. There is no conveyance line in both projects and the water collected by weirs is transmitted to the powerhouse via the penstock nearby the weir body. Hemşin III diversion weir is constructed at a thalweg elevation of 335 m. In order to generate the production planned for Hemşin III, up to 11 m deep and 450 m long excavation is carried out along its downstream. Similarly for Hemşin I with a thalweg elevation of 288.50 m and normal water level of 300 m, an excavation 4 m in depth and 150 m in length is carried out along its downstream.

Thanks to the projects being the run-of-the river type hydroelectric facilities, the negative environmental effects of the project is minimized. Additionally, with the lake areas and stepped spillway structures created within the project, a contribution is made to landscape works planned within the context of urban regeneration projects.

 

Angutlu I - II Hydropower Projects

To reduce waterhammer effect “Pressure Relief Valves (PRV)” are installed in the power house instead of building a surge tank.
 

Project Information

Client: Turkerler Construction

Location: Giresun

Status: In Progress

 

Key Features

Diversion Type

Installed Capacity 24 MW

Power Tunnel

Transient Analysis

Pressure Relief Valve

Flap Gate

 

 

Summary

Angutlu I - II Hydropower Projects are cascade hydropower schemes which are located in Black Sea Region within the border of Dereli district of Giresun province over the creek of Aksu. Angutlu–I weir has a catchment area of 722 km2 along this river and diverts water to Angutlu–I HEPP whereas Angutlu–II weir with a catchment area of 782.00 km2 diverts water to Angutlu–II HEPP.

Both projects have a similar formulation in that in both projects the flows taken by water intake structures are conveyed through power tunnels to the power plants that contain two big and a small Francis type turbine. Angutlu-II weir which is located at the downstream of Angutlu-I HEPP and near the city center of Dereli is designed for Q500 flood discharge of 680.94 m3/s by installing five units of 8.0 m width flap gates on the spillway.

In Angutlu I - II Hydropower Projects w rhich are located in close vicinity of the city center where bulding stock has a considerable density, the conveyance lines are planned as pressurized tunnels taking the probable expropriation costs into consideration. Since the flows are transmitted directly to the powerhouse via energy tunnels, there was no more need for constructing a forebay and penstock. Besides, to reduce waterhammer effect “Pressure Relief Valves (PRV)” which ensure savings both from cost and space are installed in the powerhouse instead of building a surge tank. In this manner, the negative environmental effects and construction and expropriation costs are reduced to the least possible extent thereby ensuring the smooth and rapid construction of the project facilities. The transient analysis related with the waterhammer effect and adaptation of the PRVs to the system are also carried out by Prosem Engineering.

 

Akdere Hydropower Project

The solution developed by Prosem Engineering reduced the undesirable social and environmental effects as well as cost of expropriations considerably.
 

Project Information

Client: B.Ergunler Construction

Location: Bursa

Status: In Progress 

 

Key Features

Diversion Type

Installed Capacity 8 MW

Long GRP Penstock

Transient Analysis

 

Summary

Akdere Hydropower Project is a diversion type hydropower project and located in Marmara Region within Inegol district of Bursa province over the creek of Akdere using the head between 500 m and 360 m.

According to the first feasibility report prepared in 2008, the project was designed such that it is composed of two diversion weirs, transmission channel, forebay, penstock and power plant. After carefully reviewing the project with the support of the office and field studies of Prosem Engineering, it is seen that by eliminating one weir, designing the transmission channel as GRP pipeline and burying it near the stream bed and transmitting the water directly to the turbines through this pipeline, the project would become faster, more economical and feasible. The projects have been changed accordingly and revised feasibility report has been prepared. These modifications reduced the undesirable social and environmental effects as well as cost of expropriations considerably. In order to keep the pressure rises at reasonable levels in GRP pipeline, “Pressure Relief Valves” (PRV) will be installed inside the powerhouse. It will be possible to generate energy at low regimes of flow with two large and one small Francis type turbines installed in the powerhouse.

 

Devecikonagi Dam and Hydropower Project

In order to maximize the energy generation, the highest possible head is achieved by keeping the operating water level same as flood level with a five radial gate-controlled-spillway.
 

Project Information

Client: BM Holding

Location: Bursa

Status: Completed

 

 

Key Features

Total Installed Capacity 29 MW

RCC Dam

Run-of-River Type

Pondage Storage 

Reservoir

Irrigarion

Large Radial Gates

Semi-Indoor Powerhouse

Vertical Kaplan Turbine

Riverbed Excavation

 

 

Summary

Devecikonagi Dam and Hydropower Project is a storage regulation type hydroelectric development that is constructed over Emet Stream. The construction of the project started in September 2010 and the project is in operation since 2012. Kizkayasi Dam and HEPP are going to be constructed at the upstream of Devecikonagi Dam and HEPP project.

RCC Dam

Due to the facts that the body of the dam is RCC (Roller Compacted Concrete) and 40 m high from foundation. The spillway is designed for Q500 flood discharge which is 2,545 m3/s. In order to maximize the energy generation, the highest possible head is achieved by keeping the operating water level same as flood level with a five radial gate-controlled-spillway. Dam reservoir is 660.000 sq.m in area and 6.2 M cu.m in volume at the operating water level, 95 m. The dam has an active storage of 1.9 M cu.m to carry out the daily regulation. The crest length of the body constructed within the scope of the project is 298 m including spillway and the total RCC volume is about 60.000 cu.m.

Semi Indoor Powerhouse

The semi indoor powerhouse located on the toe of the dam contains three Kaplan type turbines; two of them have equal hydraulic capacities of 57.5 m3/s and the other one has 5 m3/s.

Energy from Irrigation Water

Low capacity turbine was designed to supply water needed for Dolluk-Gulluce Irrigation Project constructed by the State Hydraulic Works as well as to generate energy using this water.

Riverbed Excavation

At the tailrace of Devecikonagi Dam, a riverbed excavation is carried out up to 7 m depth to reduce the downstream water level, thereby reducing the amount of inundated agricultural lands which in turn reduces the negative social effects as well as expropriation cost and increases the amount of energy production.

Vizara Hydropower Project

The project constructed in fast manner and economical solution has been achieved.
 

Project Information

Client: Yılmaz Ulusoy Holding

Location: Trabzon

Status: Completed

 

Key Features

Total Installed Capacity 9 MW

Concrete Gravity Dam

Pondage Storage 

Long Penstock

Transient Analysis

Environmentally Conscious Design

 

Summary

Vizara Hydropower Project is a diversion type hydropower project that is currently in operation. Vizara HEPP makes use of the head between 1545 m and 1270 m of Manahoz Creek.

 Vizara Dam

Vizara Dam

Cost Effective Solutions

The project has designed with 4 km long and 1.4 m diameter buried penstock which diverts the water directly from the dam to powerhouse. By this way, the project constructed in fast manner and economical solution has been achieved. A cost-effective, long penstock design is performed with the use of two equal capacity Pelton type turbines which minimize waterhammer effect.

Daily Regulation Pondage and Concrete Dam

The project can shift its energy production to peak hours thanks to the five-hour capacity reservoir behind the 26 m high concrete dam.

Environmentally Conscious Design

water conveyage system + powerhouse architecture


Mavi Hydropower Project

The project is composed of weir structures, concrete lined tunnel, cylindrical forebay, penstock and a power plant.
 

Project Information

Client: Cese Energy

Location: Trabzon

Status: Completed

 

Key Features

Total Installed Capacity 12 MW

Pondage Storage

High Diversion Weir

Cylindrical Forebay

Semi-Indoor Powerhouse

 

Summary

Mavi Hydropower Project is a diversion type hydropower facility over the Hamsiköy Stream and makes use of the head between 894 m and 706 m. The construction of the projects has commenced in 2010 and Mavi Hydropower Project is expected to go into operation in 2013.

The project is composed of weir structures, 3.738 m long concrete lined tunnel, circular forebay, 236 m long penstock and a power plant. The type of conveyance line is determined as tunnel, thereby minimizing the negative social and environmental effects and expropriation costs. A circular forebay which is 12 m in diameter and 18.15 in length is designed within the scope of the project. The selection of the circular forebay in such a steep topography reduced the excavation amount, which in turn reduced the total cost. With the use of daily regulated 84.000 m3 water storage behind the weir and inside the tunnel, it is aimed to shift the energy production to the peak hours. The semi indoor type powerhouse has two equal capacity Francis turbines.

Arpa Hydropower Project

The type of water conveyance is designed as tunnel-shaft-pressurised tunnel, which minimizes the negative social impacts and the cost of project.
 

Project Information

Client: BM Holding

Location: Artvin

Status: Completed

 

Key Features

Diversion Type

Total Installed Capacity 33 MW

High Pressure Power Tunnel

Steel Fiber Reinforced Concrete (SFRC)

Pressure Tunnel Lining with Drainage Holes

100m Shaft

Transient Analysis

 

Summary

Arpa Hydropower Project is a diversion type hydroelectric facility that makes use of the head between 1005 m and 660.60 m of Arpa Creek for energy generation. The project is in operation since 2012.

 Arpa Power Station

Arpa Power Station

Project Formulation

The project consists of 1.670 m long open channel flow tunnel, octagon forebay, 100 m deep vertical shaft, 1.750 m long steel fiber reinforced lined energy tunnel, emergency valve chamber, 600 m long penstock inside the tunnel, 230 m long penstock outside the tunnel, powerhouse and tailrace channel. The type of water conveyance is designed as tunnel-shaft-pressurised tunnel, which minimizes the negative social impacts and the cost of project. The forebay which is located at a steep topography is designed as octagonal and linked with 100 m long vertical shaft from the center. This design reduced the amount of the excavation significantly. 282 m long access tunnel connecting to the intersection of shaft and pressurized tunnel has been designed for reducing the construction time of pressurized tunnel by executing the excavation works through two faces simultaneously. A watertight gate that can sustain 100 m of water pressure was placed at the intersection of shaft and energy tunnel and also can be used for maintenance purposes during operation.

Cost Effective Solution in Pressure Tunnel

The tunnel was required to be lined due to the hydraulic and geological requirements. Steel fiber reinforced concrete has been used in the horseshoe-shaped tunnel, which eliminates the use of reinforcement, shortened the construction process, reduced the cost and increased the durability of the tunnel. At the locations where the hydrostatic pressures reach around 300 m and the rock mass over the tunnel cannot resist this pressure, steel penstock which is fixed by support masses have been employed. Considering that the system is pressurized and the considerable volume of water accumulated in the tunnels, an emergency valve was constructed in the tunnel.

Yedigol and Aksu Hydropower Projects

The power tunnels are designed as unlined.
 

Project Information

Client: Makyol-Ismil Joint Venture, Borusan - Enbw

Location: Ispir 

Status: Completed

 

Key Features

Diversion Type

Installed Capacity 52 MW

Cascade Projects

Unlined Power Tunnel

 

 

Summary

Yedigol and Aksu Hydropower Projects are cascade diversion type hydropower facilities over Aksu Stream. Yedigol Project has commenced to commercial activity in 2011 whereas Aksu Project in 2012.

IMG_0434.JPG

Projects make use of the head between 1.598 m and 1.057 m of Aksu Stream for energy generation. The flows of Aksu Stream taken by tyrolean-type weirs are conveyed to powerhouses through energy tunnels. The tunnels are designed mostly without concrete lining except the parts where reinforced concrete lining is required. The total length of the tunnel for Yedigol is 4.800 m whose last 350 m is made up of steel penstock inside the tunnel, similarly the last 400 m of 6.400 m long Aksu energy tunnel is also made up of steel penstock. Both facilities have two equal capacity Pelton type units.

Since the powerhouse final design projects are prepared with poor soil investigations, the thick alluvial layer that is discovered during excavation of power plants necessitated the modification of the design of projects. In this respect, Prosem Engineering has relocated the Yedigöl powerhouse and compulsorily designed the Aksu powerhouse with pile foundation above alluvium. The architectural and final design projects of both powerhouse buildings together with the application projects of whole structures are prepared by Prosem and has been controlled and approved by the consultant firm HPI (Germany).