The Ulog dam and hydropower scheme is under construction on the river Neretva, in the Republika Srpska, Bosnia and Herzegovina.

This greenfield construction consists of a 53 metre high arch dam which will create a reservoir with a total storage capacity of 6.44 Million cubic metres (m³). The reservoir is designed to have a water level at 641 metres above sea level (m asl) and thus the reservoir is expected to cover a surface area of 79.6 hectares and have a length of 4.9 km.

A headrace tunnel of 2.5 km in length with a 3.5 m diameter will lead to a water intake, surge shaft, and penstock which will supply a flow of 17.5 cubic metres per second (m³/s ) to the 2 Francis turbines in the powerhouse. The hydropower scheme is designed to have a total installed capacity approximately 35 Megawatts (MW), which includes small Hydro Power Plant (SHPP) with an installed capacity of 0.178 MW located just downstream of the dam which discharges a guaranteed ecological flow,

The electrical components include a 110 kV step-up transformer and a 110 kV switchyard located on the powerhouse roof.

The energy generated annually is expected to total approximately 85’000 MWh which will be fed into the grid over two 110 kV single system overhead transmission lines (Ulog OHTL) which will be built and connected to the regional 110 kV OHTL running from Gacko to Nevesinje.

The project has been registered under the Clean Development Mechanism (CDM) of the United Nations Framework Convention on Climate Change (UNFCCC), where the project was confirmed to contribute to the sustainable development of Bosnia and Herzegovina by reducing greenhouse gas emissions (estimated at 87’846 tons of Carbon dioxide per year) and other pollutants compared with business as usual scenario and creating local employment during the construction and operation of the hydro power plant.

Gruner’s services on the Ulog dam and hydropower scheme

Gruner Balkans’s task on this project is to provide the Owner’s Engineer services, including approval of the Contractor’s design (The EPC contractor is Sinohydro Corporation Limited) and providing technical assistance to the Client for the design and works supervisions on site. The site supervision services include the supervision of the execution of the works, Quality Control (QC), and monitoring of Health Safety and the environment (HSE) during the construction period.

Back to overview