HYDROELECTRICITY

‚Äč



Hydroelectricity is generated by harnessing the power of running water. There are many communities that don't have a waterfall, so they build dams across the river to store water in a place called a reservoir.The water then goes through a place called a penstock to a turbine with ridges around it. Lastly the water turns the turbine which is connected to the generater.

Most Hydroelectric stations uses a natural drop of water (river, rapids) or a damn is built across a river, in order to raise the water level and provide a drop that is necessary to create a driving force. The higer water levels then flow into a place called a penstock, where it is then carried down a turbine. The turbine is connected to a generator. When the water flows down the penstock, the water pressure increases. This water pressure is what causes the turbine and the generator to work. As the generator spins the magnets flow of electrons are made. This is the process that creats hydroelectricity.

This is a diagram of this process:

external image Hydroelectric_dam.gif
This is a diagram of a generator used to create hydroelectricity:
external image 230px-Water_turbine.jpg

There are many pros and cons to using Hydroelectricity.

POSSITIVE:
  • Large generating stations makes cheap electricity
  • You can use reservoirs for controling floods,drinking water, irrigation,and recreation
  • Small-scale hydrelectrucity plants using local rivers, can be practicale for some communities.

NEGATIVE:
  • The environment is impacted a lot when dams are made
  • the environment is effected when there are flooding large areas of land, disruption or destruction of wildlife and fish habitat and migration routes, and displacement of Aboriganals and other communities.
  • It is quite expensive to build a hyroelectricity staion.

EFFICIENCY:

Hydroelectricity is the most common form of electricity in the Canadian provinces of Newfoundland, Quebec, and British Columbia. This form of electricity is 80%-90% efficient. Compared to nuclear enery, it is better because it is both more efficient and better for the environment. Although hydroelectricity can harm the environment a bit, but other forms of energy creates more environmental hazards.


BIBLIOGRAPHY:

http://www.hydro.com.au/education/discovery/student/efficiency.htm
http://www.opg.com/power/hydro/howitworks.asp
Science Text Book.