LAHORE Tarbelas 4th extension project was approved by Central Development Working Party (CDWP) in its meeting on Friday. This development has taken place within a short span of one week after the inauguration of Mangla Dam raising project and foundation stone laying ceremony of Diamer Basha Dam project, WAPDA stated. 1410-megawatt (MW) Tarbelas 4th extension project is part of low-cost power generation strategy being implemented by Wapda on priority. This strategy not only aims at adding a sizeable quantum of electricity to the national grid but also improving the ratio of low-cost hydel electricity in the overall system to stabilize the power tariff. According to the statement, generation capacity of Tarbela Hydropower Station would rise to 4,888MW after addition of 1410MW units as part of 4th extension project. On completion, Tarbelas 4th Extension Hydropower Project would provide about 3.84 billion units of low-cost electricity to the national grid per annum. Annual benefits of the project have been estimated at about Rs.30.7 billion. The project would pay back its cost in just three years. The project would also be instrumental in saving foreign exchange on import of almost one million tons of furnace oil annually, required for the equivalent generation of electricity from thermal sources. The project would also provide a cushion to undertake rehabilitation and upgradation of the existing Tarbela Power House during the lean period. As per the further details of the project, at present pre-qualification of the contractors for Tarbelas 4th extension project is in process and expected to be completed soon. Afterwards, the project would be ready to launch. The project would be constructed with an estimated cost of $935 million. The WAPDA stated that it had already arranged the finances required for the project through the World Bank. Project includes installation of three units of 470MW each at Tarbela Dam on existing tunnel-4, being used for irrigation releases. The main dam, intake and tunnel already exist. Only construction of the powerhouse, penstock, extension of the switchyard and installation of electrical and mechanical equipment are to be undertaken for the project.