The energy demand in Nepal is growing continuously. The country aims to meet this growing demand with hydropower and make the most of the country’s unique geographic characteristics to do so. The Himalayan state has many rivers which have to overcome a great altitude difference on the way to their mouth. For the development of a new hydroelectric power station in the Himalayas, the Nepal Electricity Authority (NEA) once again called on the expertise of Lahmeyer International. Following the start of construction of the upstream Upper Tamakoshi Hydroelectric Project, the contract for the downstream Tamakoshi V cascade project was awarded to Lahmeyer.
Challenging hydropower project in a seismically active zone
For this new and highly challenging project in a very seismically active zone, Lahmeyer submitted a convincing proposition in technical terms. In cooperation with Tractebel India, TEAM Thailand and Total Management Services (TMS) Nepal as sub-consultants, the hydropower specialists have been working on the detailed designs and tender documents since spring 2017. Other subcontractors are carrying out field investigations. The fact that Lahmeyer is also involved in the construction of the upstream Upper Tamakoshi hydropower station makes coordination of both construction projects easier.
Hydro power plant supplies energy for peak times
The lower cascade project does not need its own dam, because the works water comes directly from the tailrace tunnel of the Upper Tamakoshi hydropower station. It has a tailrace tunnel with a length of 8.1 km; the head will be about 160 m. Three Francis turbines will generate a total output of around 95 MW based on a flow rate of 66 m³/s. This will enable them to deliver the urgently needed energy – most importantly at peak times.The fact that the location is in an earthquake zone is one of the biggest challenges of the project. Concerning the plant design, Lahmeyer furthermore has to consider the possibility of a glacial lake outburst flood.
The Company
As an international company of consulting engineers, Lahmeyer offers a wide range of planning and consultancy services. The main fields of activity are complex infrastructure projects in the Energy, Hydropower and Water Resources Sectors as well as in Building and Transportation. With origins dating back to 1890, the company has grown into one of the leading international companies with project experience in 165 countries. Since December 2014, Lahmeyer belongs to Tractebel, and thus is part of the ENGIE Group.