hydroelectric power- hidroelektrik santrali

               hydroelectric power

Hydroelectric power or hydroelectricity is electrical power which is generated through the energy of falling water. This method of energy generation is viewed as very environmentally friendly by many people, since no waste occurs during energy generation. However,hydroelectric power can have a profound impact on the surrounding environment, leading some people to question the promotion of hydroelectric power as a method of  clean energy generation.

Advantages of Hydroelectric Power

1. Using this type of energy to generate electricity is not dependent upon the price of uranium, oil, or other types of fuel. This makes electricity costs lower and more stable, one of its most significant advantages.

2. The pollution created by hydroelectric energy generation is quite minimal. There is some pollution involved in initially constructing the power stations, but this is true of all power plants. It also does not produce radioactive waste or involve the environmental impact of fuel being transported to it.

3. It doesn't require many employees to run a hydroelectric station. According to wikipedia.org, most plants of this type are largely automated. This is another one of the advantages which help keep the cost of hydroelectricity low.

4. Hydroelectric power stations can be set up in almost any size, depending upon the river or stream used to operate them; big enough to power a single home, factory, small town, or large city.

5. Another of its advantages is that hydroelectric is a renewable form of energy, like wind and solar; it does not rely upon finite resources like natural gas or coal to generate power.

6. Hydroelectric stations can operate for many years after they are built. Wikipedia.org states that a number of operational hydro stations were constructed fifty to one-hundred years ago; in contrast to this, IAEA.org indicates that the "design life" of nuclear power plants is generally thirty to forty years.

7. Small hydro electricity generation systems sometimes offer more economic advantages for home owners than solar power, and tend to last longer than solar panels do.

The above-mentioned factors make hydroelectric a form of energy generation which offers advantages with regard to cost, pollution, flexibility of installation, and conservation of resources.

Hydro comes from the Greek word for water. Hydro-electricity, or hydro-power, is usually generated by turbines in a dam in a river. The dam means that a great body of water builds up in the river valley behind the dam. This is released through the turbines when electricity is needed. 

Smaller than dams are barrages across the mouths of rivers which capture water from high tides and release it to generate electricity. Smaller still are turbines in river and tidal streams which do the same thing.

Disdvantages of Hydroelectric Power

• Dams are extremely expensive to build and must be built to a very high standard.
• The high cost of dam construction means that they must operate for many decades to become profitable.
• The flooding of large areas of land means that the natural environment is destroyed.
• People living in villages and towns that are in the valley to be flooded, must move out. This means that they lose their farms and businesses. In some countries, people are forcibly removed so that hydro-power schemes can go ahead.
• The building of large dams can cause serious geological damage. For example, the building of the Hoover Dam in the USA triggered a number of earth quakes and has depressed the earth's surface at its location.
• Although modern planning and design of dams is good, in the past old dams have been known to be breached (the dam gives under the weight of water in the lake). This has led to deaths and flooding.
• Dams built blocking the progress of a river in one country usually means that the water supply from the same river in the following country is out of their control. This can lead to serious problems between neighboring countries.
• Building a large dam alters the natural water table level. For example, the building of the Aswan Dam in Egypt has altered the level of the water table. This is slowly leading to damage of many of its ancient monuments as salts and destructive minerals are deposited in the stone work from 'rising damp' caused by the changing water table level.
• Hydro power dams can damage the surrounding environment and alter the quality of the water by creating low dissolved oxygen levels, which impacts fish and the surrounding ecosystems. They also take up a great deal of space and can impose on animal, plant, and even human environments.
• Fish populations can be impacted if fish cannot migrate upstream past impoundment dams to spawning grounds or if they cannot migrate downstream to the ocean. Upstream fish passage can be aided using fish ladders or elevators, or by trapping and hauling the fish upstream by truck. Downstream fish passage is aided by diverting fish from turbine intakes using screens or racks or even underwater lights and sounds, and by maintaining a minimum spill flow past the turbine.
• Hydro power can impact water quality and flow. Hydro power plants can cause low dissolved oxygen levels in the water, a problem that is harmful to riparian (riverbank) habitats and is addressed using various aeration techniques, which oxygenate the water. Maintaining minimum flows of water downstream of a hydro power installation is also critical for the survival of riparian habitats.
• Hydro power plants can be impacted by drought. When water is not available, the hydro power plants can't produce electricity.
• New hydro power facilities impact the local environment and may compete with other uses for the land. Those alternative uses may be more highly valued than electricity generation. Humans, flora, and fauna may lose their natural habitat. Local cultures and historical sites may be flooded. Some older hydro power facilities may have historic value, so renovations of these facilities must also be sensitive to such preservation concerns and to impacts on plant and animal life.
• By 2020, it is projected that the percentage of power obtained from hydro power dams will decrease to around four percent because no new plants are in the works, and because more money is being invested in other alternative energy sources such as solar power and wind power.