Mechanism of Hydroelectric Power
June 8, 2012 by ElectarL, PeterX, RyanW, SandraS
There are many ways to generate electricity in modern day. One of them is to use the gravitational force of falling water, which is also known as hydroelectricity. Hydroelectricity occurs in a dam, where the falling water is used to generate enough force to turn a turbine that is connected to an electricity generator. With this action, potential energy of water is transformed into mechanical energy and then into electrical energy. This is both an efficient and green way of generating electricity: it is not as hard as the geothermal electricity because people do not have to find a perfect area to generate it; and it is also not as polluting as the nuclear power plants are. Therefore, hydroelectricity is much greener than the nuclear power plants which generate electricity, and much easier to generate than the geothermal electricity. Now, how exactly does a dam actually work to generate electricity?
A dam is built where there is a natural source of water in a valley and it is used to hold the water and create pressure so that the water can produce more electrical power. The gravitational potential energy stored in the water is used to turn generators and create electricity. Electrical generators are turned by massive turbines, which are within tunnels in the dam wall—water flows through the tunnels with great pressure due to the great height, at which is kept in the dam. If there is a greater volume of water or there is a very large difference between the water level and where it flows out, then more power comes out of the water as it has greater potential energy. For example: Hydro power generation works well in mountainous countries as the water can be stored at very high pressures. The dam wall increases with width as you go down towards the base this is because the water pressure gets greater as depth increases. This difference in height of the water is called the head.
The generator contains two main parts: the rotor and the stator. The rotator is the part which rotates and the wire has a huge magnet inside of it; and the stator is the part which is covered in copper. The electrical current is created when the rotor spins around the copper wire on the stator. This is the charge which is then used as electricity.
Some countries that use hydroelectric power:
China is the largest producer of hydroelectricity depending on the Yangtze River., followed by Canada, Brazil, and the United States.
Egypt also uses hydroelectricity depending on the River Nile, which the longest river in the world (6695 km). The Nile River is often associated with Egypt; it actually touches Ethiopia, Zaire, Kenya, Uganda, Tanzania, Rwanda, Burundi and Sudan, as well as Egypt. President Gamal Abdel Nasser decided to make use of it and built High Dam in Aswan, Egypt in 1954 to produce hydroelectric power.
- Renewable energy source: hydroelectricity uses the energy of running water, without reducing its quantity, to produce electricity. Therefore, all hydroelectric developments, of small or large size, whether run of the river or of accumulated storage, fit the concept of renewable energy
- Hydroelectricity makes it feasible to utilize other renewable sources: the flexibility and storage capacity of hydroelectric power plants make them more efficient and economical in supporting the use of intermittent sources of renewable energy, such as solar energy or Aeolian energy
- A fundamental instrument for sustainable development: Hydroelectric enterprises that are developed and operated in a manner that is economically viable, environmentally sensible and socially responsible represent the best concept of sustainable development. That means development that today addresses people’s needs without compromising the capacity of future generations for addressing their own needs” (World Commission on the Environment and Development, 1987)
- Increases the stability and reliability of electricity systems: the operation of electricity systems depends on rapid and flexible generation sources to meet peak demands, maintain the system voltage levels, and quickly re-establish supply after a blackout. Energy generated by hydroelectric installations can be injected into the electricity system faster than that of any other energy source. The capacity of hydroelectric systems to reach maximum production from zero in a rapid and foreseeable manner makes them exceptionally appropriate for addressing alterations in the consumption and providing ancillary services to the electricity system, thus maintaining the balance between the electricity supply and demand
- Hydroelectricity helps fight climate changes: The hydroelectric life cycle produces very small amounts of greenhouse gases (GHG). In emitting less GHG than power plants driven by gas, coal or oil, hydroelectricity can help retard global warming. Although only 33% of the available hydroelectric potential has been developed, today hydroelectricity prevents the emission of GHG corresponding to the burning of 4.4 million barrels of petroleum per day worldwide
- Water can be stored, waiting to be used in peak times
- Hydropower plays a major role in reducing greenhouse gas emissions; hydroelectric power plants don’t release pollutants into the air. They very frequently substitute the generation from fossil fuels, thus reducing acid rain and smog. In addition to this, hydroelectric developments don’t generate toxic by-products
- Hydrology dependent (precipitation)
- In some cases, inundation of land and wildlife habitat
- In some cases, loss or modification of fish habitat
- Fish entrainment or passage restriction
- In some cases, changes in reservoir and stream water quality
- In some cases, displacement of local populations
- Building the dam is expensive and time taking
- The dam will change the habitat and landscape upstream, as much more land will be submersed
- The land below the dam is also affected as the flow of water is reduced .
- Silt can build up in the dam as the water slows down it does not have enough energy to carry the sand and silt which it was
In conclusion, Hydroelectricity is a very unique way of generating energy. It is one of the most used systems around the world. Also, it is a renewable energy source which is very helpful to our planet and it is something that will never end unlike natural gas and fossil fuels. Therefore, many of the countries and many more in the future will choose it over a lot of the other ways to generate electricity. All in all, it is a very cost efficient and green way to generate something that us human beings need in our daily lives!
Author: Attic Designs (2008), Used on June 3, 2012
Author: Think Quest (unknown), Used on June 3, 2012
Author: Unknown (2006), Used on June 3, 2012
Author: Unknown (2006), Used of June 3, 2012
Author: Unknown (unknown), Used of June 3, 2012
Author: BBC News (2006), Used on June 3, 2012
River Nile Facts
River Nile facts you always wanted to know.
Author: Attic Designs(2008, Used on June 3, 2012