Hydro Electrical Power

Rivers flowing over earth's surface posses large amount of energy. Proper utilization of this energy for the benefit of the human being could assure an almost inexhaustible source of energy. But in spite of tremendous developments in construction technology the total utilization of power from water is merely a fraction of the total available power potential. Hence the compelling need for the utilization of this resource.

Water power resources are constituted by the integration of the products of river flows and the differences in elevation along the river courses. This, however, represents the maximum potential that can be developed and can be regarded as the theoretical power potential. Only a part of the theoretical power potential is capable of actually being exploitable. This limitation comes out of practical and economical constraints. The river flows in Pakistan are subject to wide variations over the year on account of fluctuations in the monsoon and to some extent variations in the seasons. It would thus be necessary that these fluctuations in the river flows are regulated so as to derive dependable or firm power from hydroelectric schemes. The regulation is achieved by providing storage reservoirs. Thus the topographical conditions of a river valley scheme in affording reservoir capacity constitutes the major constraint that limits the firm power available from the scheme. Reservoirs are created by building regulating dams. The drop in level along the course of the river is availed of by running water conducting system. When a dam is built the resultant reservoir will submerge land. In a developing country like Pakistan river valley projects have to be invariably multi-purpose projects catering to irrigation and flood-control besides power generation. In any cases irrigation takes first priority.

The following aspects require careful consideration while planning a hydel power project:

• Power of the river or portion of river.

• Geographic situation of existing power plants, both hydel and thermal and the existing transmission network.

• Nature and magnitude of load.

• Topographical conditions of the river valley and the river bed play an important role in deciding upon the types and location of the plant.

• Geology of the site will greatly influence the general layout.

• In designing low-head plants, existing and possible reservoir capacity should be reckoned with.

• Power generation should be other purposes viz., irrigation, water supply, navigation, etc. Considerable reduction will result from a multipurpose utility.

• Development plans for the entire river should be prepared before the location of the individual plants is decided so as to ensure optimum exploitation of the resources.

MEConsult has taken the lead by being at the forefront of the Pakistan Private Power Generation Program. Some of its comments have been incorporated in the new hydel power policy. MEConsult has identified a section of the Indus Valley approximately 300 km long. The most southern mountain stream comes into the Indus approximately 30 km from the nearest WAPDA Grid. The Project goes by the principle that we pull the transmission line with us as we go slowly up north building one power plant after the other on the different rivers, accumulating the price for electricity plus the transmission.