Hydel Generation

As a consequence of partition of the Indo-Pakistan Sub-Continent in 1947, India and Pakistan became two independent sovereign states. Hydel generation capacity of only 10.7 MW (9.6 MW - Malakand Power Station & 1.1 MW - Renala Power Station) existed in the territory of Pakistan. With the passage of time, new Hydel Power Projects of Small and Medium capacities were commissioned including the first water storage dam and power house at Warsak due to which country's Hydel capability raised to about 267 MW uptill 1963. The Irrigation System which existed at the time of partition in 1947 was divided between the two countries without any regards to the irrigation boundaries which resulted in an international water dispute which was finally resolved by signing of the Indus Water Treaty in 1960 under the aegis of World Bank. The Treaty assigned three Eastern rivers (Ravi, Beas and Sutlej) to India and three Western rivers (Indus, Jhelum & Chenab) to Pakistan. It also provided construction of replacement works called Indus Basin Projects (IBP) to compensate for perpetual loss of Eastern rivers' water. The works proposed under the Treaty included two multipurpose dams i.e. Mangla Dam on Jhelum river and Tarbela Dam on Indus river having the provision of power generation. These were commissioned in 1967 & 1977 respectively. However, their capacities were subsequently extended in different phases.

Hydel Generation Capacity

The total capacity of 13 No. Hydel Stations as of today is 6443.56 ~ 6444 MW which is 37.10% of total installed generation capacity of WAPDA. During 2007~2008, aggregate energy sharing during the year was 33.32%. The Hydel Generation Capacity was reduced from 6463.16 MW to 6443.56 MW due to decommissioning of Jabban Hydel Power Station after a fire incident in November, 2006.
Seasonal Variations of Hydel Generation
The seasonal variations of reservoir levels and consequent reduction in Power outputs of storage type hydel projects in Pakistan are very pronounced. Tarbela with maximum head of 450 ft. experiences variation of 230 ft. while Mangla has 162 ft. variation against the maximum head of 360 ft.
The lean flow period of Tarbela reservoir is from November to June when the Capability reduces to as low as about 1350 MW against the maximum of 3692 MW during high head period i.e. August to September (15% permissible overloading on Units 1~10).
Lean flow period of Mangla reservoir is observed from October to March when the minimum generating capability is 500 MW. The capability rises to as high as 1150 MW during 'high head' period (15% permissible overloading).
In all, WAPDA's Hydel generating capability varies between the two extremities of 2414 MW and 6746.0 MW over the cycle of a year.
Statistics
The next few pages provides information about the salient features of WAPDA Hydel Stations, their locations, statistical data etc. which are titled as under: