Introduction
The water of the oceans and water bodies on land are evaporated by the energy of the sun’s heat and gets transported as clouds to different parts of the earth. The clouds travelling over land and falling as rain on earth produces flows in the rivers which returns back to the sea. The water of rivers and streams, while flowing down from places of higher elevations to those with lower elevations, loose their potential energy and gain kinetic energy. The energy is quite high in many rivers which have caused them to etch their own path on the earth’s surface through millions of years of continuous erosion. In almost every river, the energy still continues to deepen the channels and migrate by cutting the banks, though the extent of morphological changes vary from river to river. Much of the energy of a river’s flowing water gets dissipated due to friction encountered with its banks or through loss of energy through internal turbulence. Nevertheless, the energy of water always gets replenished by the solar energy which is responsible for the eternal circulation of the Hydrologic Cycle.
Hydropower engineering tries to tap this vast amount of energy available in the flowing water on the earth’s surface and convert that to electricity. There is another form of water energy that is used for hydropower development: the variation of the ocean water with time due to the moon’s pull, which is termed as the tide. Hence, hydropower engineering deals with mostly two forms of energy and suggest methods for converting the energy of water into electric energy. In nature, a flowing stream of water dissipates throughout the length of the watercourse and is of little use for power generation. To make the flowing water do work usefully for some purpose like power generation (it has been used to drive water wheels to grind grains at many hilly regions for years), it is necessary to create a head at a point of the stream and to convey the water through the head to the turbines which will transform the energy of the water into mechanical energy to be further converted to electrical energy by generators. The necessary head can be created in different ways of which two have been practically accepted.
These are:
1. Building a dam across a stream to hold back water and release it through a channel, conduit or a tunnel (Figure 1)
Figure 1. Creation of head by constructing a dam
2. Divert a part of the stream by creating a low-head diversion structure like barrage. (Figure 2)
FIGURE 2. Power generation through stream flow diversion (a) Power house as a part of diversion structure (b) Power house on diversion channel
A series of integrated power developments along the same watercourse form what may be called a multistage hydroelectric system in which each portion of the river with a power plant of its own is referred to as a stage (Figure 3). The head created by a dam put across a lowland river usually ranges from 30 to 40m. In mountainous terrain, it may run over 200m.
FIGURE 3 . (a) Single-stage hydro-power development scheme (b) Cascade or Multi-stage hydro-system
The following sections briefly discuss the issues related to the fundamentals of hydropower project development.
1. What is hydropower engineering? | ![]() |
2. How does hydropower work? | ![]() |
3. What are the advantages of hydropower? | ![]() |
4. What are the challenges of hydropower engineering? | ![]() |
5. What is the future of hydropower engineering? | ![]() |