Monday, April 28, 2008

Hydroelectric Generation






Did you know that Hydroelectric generation is the predominant form of electric generation in Canada? It is, nearly two-thirds of Canada's power is generated each year by this process. Hydropower is both inexpensive and nonpolluting.

How it works: So just how do we get electricity from water?

"Actually, hydroelectric and coal-fired power plants produce electricity in a similar way. In both cases a power source is used to turn a propeller-like piece called a turbine, which then turns a metal shaft in an electric generator, which is the motor that produces electricity. A coal-fired power plant uses steam to turn the turbine blades; whereas a hydroelectric plant uses falling water to turn the turbine. The results are the same" (USGS).
"The theory is to build a dam on a large river that has a large drop in elevation. The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propeller, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. Power lines are connected to the generator that carry electricity to your home and mine. The water continues past the propeller through the tailrace into the river past the dam. By the way, it is not a good idea to be playing in the water right below a dam when water is released!" (USGS).
"A hydraulic turbine converts the energy of flowing water into mechanical energy. A hydroelectric generator converts this mechanical energy into electricity. The operation of a generator is based on the principles discovered by Faraday. He found that when a magnet is moved past a conductor, it causes electricity to flow. In a large generator, electromagnets are made by circulating direct current through loops of wire wound around stacks of magnetic steel laminations. These are called field poles, and are mounted on the perimeter of the rotor. The rotor is attached to the turbine shaft, and rotates at a fixed speed. When the rotor turns, it causes the field poles (the electromagnets) to move past the conductors mounted in the stator. This, in turn, causes electricity to flow and a voltage to develop at the generator output terminals." (USGS).
Pros:
- "sustainable and nonpolluting power source that can help decrease our dependence on fossil fuels and reduce the threat of global warming" (USC).
-cost effective
Cons:
By blocking rivers with massive dams, we have created a number of serious environmental and social problems:
-habitat destruction
-prevention of fish passage
-decrease in Salmon population
-displacement of local communities
-dam failures
Personally I think Canada has the right idea and hydropower is the way to go. I think many people would like it because it is cost effective. Look at how high oil prices are now, why not choose something that is inexpensive and will save us money in the future. I think the pros of hydropower outweigh the cons. "The major advantage of hydroelectric power is reduction of CO2 or elimination of same. In addition, no nuclear waste is generated. Lastly, hydroelectric power gives some considerable immunity to fuel cost increases" (The Local).
Enough about what I believe, I am curious to hear what you think. Just remember, "In our modern world, hydroelectric has a great deal to offer. It's efficient and environmentally sensitive. It is sustainable in rural and urban settings. It emits no greenhouse gases, wastes or air pollution. It is renewable, efficient, flexible, uses existing technology, is low maintenance and decreases pollutants from fossil fuel. These advantages need to be weighed against disadvantages, including high initial cost, impact on habitats, potential disturbance of water quality and forced migration of local populations." So weigh the pros and cons for yourself and let me know your reactions.
Work Cited:

2 comments:

Teddy said...

I think hydroelectric power is one of the many alternatives available to America as well. Canada has the natural advantage of having large streams and rivers in order to have such a power source. The one dam that comes to mind in America is Hoover. I am sure there are other dams, but I can't think of them now. America shouls be able to use many sources of energy to get its satisfaction. I'm sure Canada uses something else too; you said it doesn't cover all of its energy needs. BUt this could be a good lesson for us. Using the natural landscape to produce emission free energy is something to be explored. If we can have various sources of energy to power ourselves, like the Hoover dam, geothermal in the west, wind and soalr in the north, nuclear here and there, then we can continue on into a sustainable future.

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