Mott MacDonald has previously conducted the feasibility, scoping studies and detailed design for the Tarbela V project, and also acted as lead consultant on behalf of the Water and Power Development Authority of Pakistan (WAPDA) for the Tarbela IV extension, it disclosed on 19 June.
The Tarbela V Extension project will increase the Tarbela powerplant’s total generating capacity from 4888 to 6300 MW with the aim of increasing seasonal power supply in Pakistan to meet rising demand. The project will involve the addition of a new plant at the end of an existing 43-year-old tunnel through the Tarbela dam, the largest earth-filled dam in the world. Unlike the four other tunnels, the fifth tunnel is situated within the left abutment of the dam. Using the tunnel for dual purpose, such as irrigation releases and power generation, has presented a unique set of challenges. Many of the challenges relate to its location between two large spillways, their associated plunge pools and a common discharge channel, Mott MacDonald said in a press statement. The project also includes the construction of a new associated 50 km-long, 500 kV transmission line and a 20 to 40 MW floating solar pilot project on the Tarbela reservoir, which will be the first in Pakistan.
It is the final planned expansion of the plant since it was originally commissioned in 1976.