4th Extension Hydropower Project has been completed adding 1307 MW of energy to the national grid. This project included addition of 3 units, to the Tunnel no.4 at Tarbela, each with a capacity of 470 MW. The project will provide 3.84 billion units of electricity on the average to the National Grid per annum. Annual benefits of the project have been estimated at Rs. 30 billion. The project will pay back its cost in just three years. Since commissioning, Tarbela 4th Extension Hydropower Project has contributed 632 million units of low-cost electricity to the system during the test run.
The 1st and 2nd unit became operational on September 8 and 13 respectively while the 3rd unit became operational on 5th October 2018. As a result of this extension project 1307 MW have been added to Tarbela upgrading it from 4378MW to 4888MW.
