It is seen that the construction of power production stations of most of renewable sources of energy are quite costly. Hydro electric power station installations are also very costly.
For hydroelectric power, the initial costs of building are high and the period of construction of dams is long due to the time taken to relocate all the living things originally placed in the site. It also is quite difficult to channelize required amount of water into the dam. But, in the long run it is seen that the cost of production of power is quite cheap, hen calculated on an overall long term basis.
Once the basic structures are built the process becomes quite simple because, water is free and is also a renewable resource.
When compared to the cost of production of other power production is very low, it is almost half when compared to that of power production using coal. Also there are no techno- barriers in hydro power production, because all technologies are quite established.
When the construction of hydroelectric power plant is properly handled a lot of water can be conserved and used up for irrigation and other household uses. This makes the construction of dams multipurpose. It is used as a flood control mechanism also and a reservoir for the associated wetland flora and fauna.
For the multiplication of fishes a ladder system can be provided, thereby making the water stored restore the natural environment of the fishes and other organisms. Thus with one establishment cost many purposes can be solved, along with the conservation of the ecosystem.
The clean energy generated every year offers a valuable alternate for the very polluting and carbon and sulphur di oxide emitting other non renewable sources of energy, and reducing the amount of acid rains.
The viability of hydro electricity can be understood from the fact that more and more countries are increasing the production of electicity from water. 82% of power generated in the US is from hydroelectricity, Japan produces 84% of its energy from water followed by more than 80% in France and 73% in Germany. China, which primarily depends on its large coal deposits, has also started to turn its attention towards hydropower.
Generally the pay back period of hydropower is after 5-8 years, this period onwards the returns are very stable and the maintenance becomes simple. Having a power project in hilly terrains also reduces the cost of construction because, here we can use adjoining hills as a natural barrier for water and construct a structure to control the flow of water alone.
This kind of structure is helpful to restore the agricultural landscape of the area, it broadens the recreational quality and also makes the environment more healthy and picturesque.
Every system, natural or man made has advantages and disadvantages of its own. Depending on the extent of disadvantage the system is exploited further or discarded. Though hydro power has a number of advantages, it also has some disadvantages. Some of the problems faced during the generation of hydroelectricity are given below:
ALTERATION OF SURROUNDING- Generation of hydroelectricity demands a vast area of land to construct dams and the hydro electric power station. To store water in dams, large area has to be evacuated first and then water is let in. This is not an easy job, because such vast barren land is not available in most parts of the world. They are occupied by human beings, plants and animals. All these have to displaced to construct a dam, and trees have to be felled. This causes a large damage to all the flora and fauna of the area, bringing about a destruction of the ecological balance of the place. The food chains of many organisms, micro and macro are also disturbed. This causes serious trouble to these organisms, sometimes causing the extinction of certain species altogether.
CHANGE IN PHYSICAL CHARACTER OF WATER- in the process of generation of hydro power water is used to rotate large turbines, in the process the water is also circulated along with the turbine. During such circulation a number of physical changes occur to the water such as
The rise of temperature of water- the temperature of water increases thus bringing about loss of water due to vaporisation. Decrease in oxygen content- large amount of water is present dissolved in the water. This oxygen is used by the aquatic organisms for their breathing process. Due to rotation the oxygen reduces bringing about reduction of biological oxygen demand for the aquatic organisms. This in turn reduces the number of flora and fauna present in the water. Rotation of water also changes the phosphorus and nitrogen content of water. The carbon content responsible for the temperature maintenance of water increases; this may increase the temperature of the water.
DAMAGE TO AQUATIC LIFE – When dams are constructed in the path of water the life of many plant and animal life in the water is damaged. This is evident in the case of salmon fish. Salmon fish generally migrate upstream to spawn, but due to dam construction they are hindered from travelling upstream. This reduces the population of salmon fish, which in turn affects the population of other animals feeding on salmon fish.
METHANE PRODUCTION – New researches have found that when water is stagnant for long periods of time the plant present in them start decomposing. This decomposition process releases methane, which is a green house gas and has the property of increasing the temperature of Earth.
