How Hydropower Works:
Mechanical energy is derived by directing, harnessing, or channeling moving water. The amount of available energy in moving water is determined by its flow or fall. Swiftly flowing water in a big river carries a great deal of energy in its flow, so with water descending rapidly from a very high point.
In either instance, the water flows through a pipe, or penstock, then pushes against and turns blades in a turbine to spin a generator to produce electricity. In a run-of-the-river system, the force of the current applies the needed pressure, while in a storage system, water is accumulated in reservoirs created by dams, then released when the demand for electricity is high. Meanwhile, the reservoirs or lakes are used for boating and fishing, and often the rivers beyond the dams provide opportunities for whitewater rafting and kayaking.
Advantages and Disadvantages of Hydropower Energy:
Some people regard hydropower as the ideal fuel for electricity generation because, unlike the non-renewable fuels used to generate electricity, it is almost free, there are no waste products, and hydropower does not pollute the water or the air.
However, it is criticised because it does change the environment by affecting natural habitats. Aquatic animals must swim upstream to their spawning grounds to reproduce, but the series of dams gets in their way.
Different approaches to fixing this problem have been used, including the construction of “fish ladders” which help the salmon “step up” the dam to the spawning grounds upstream.