Hydroelectric Power

Hydroelectric power works by storing a lot of water behind a dam. The water is put through the dam and it pushes a turbine (a big fan thingy) and that turns a generator. The generator generates electircity and the water leaves the dam to join its natural stream that its suppolsed to be in, instead of being in a big dam or reservour. In the U.S. only about 12 percent of our energy comes from hydropower. Over the entire world hydroelectric power supplies 20% of all energy and that number is riseing! In Canada they use 70% hydropower. They are the world leaders in hydroelectric power, next being Austria at 67%. One of the advantavges to hydroelectric power is that it takes no fuel to run. Fossil fuels aren't used to produce hydroelectric power (unless you count the construction of the dam and repairs, but it makes up for that eventually). Also the dams are automated so that they dont require many people around to function. The dams also create reservours that can be used for recreation and that becomes a tourist thing, which leads to $$. Some of the disadvantages include: the need for irrigation is often greater than the need for power, and that can cause problems. Also The dams can disrupt the aquatic life and mess with things like the salmon's rush up stream to get to breeding grounds, but there is a lot of research going into more animal-friendly dams. Also the water that leaves the dam has little sediment in it, which can lead to the defertalization of areas, as well as the destruction of deltas and the like. the water that leaves the dam is also colder than how it was before the dam was built and that can endanger species.

my info and my pictures came from this site http://ga.water.usgs.gov/ I also used http://www.answers.com/topic/hydroelectricity