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Alternative Energy Source: Hyrdoelectric Energy

Updated on January 21, 2012
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Alternative Resources

There are a lot of different energy sources that can be used to the power the world besides fossil fuels. There is solar, wind, tidal and wave, bio-fuel, ethanol, and geothermic, just to name a few. One of the possible ways to get energy is hydroelectric power.

But what is hydroelectric power? How does it work? Can it be used in place of fossil fuel? What are the pros and cons of hydroelectric power? Is it the most efficient energy source available?

Well . . .

Let's find out! This hub will discuss what hydroelectric power is, how it works, and the pros and cons.

What is Hydroelectric Power and How Does it Work?

Hydroelectric power is electricity generated by water and turbines. It is a big, concrete structure built across a river that the water flows in to, spinning a turbine, producing power. That is the short of it.

But the process is a little bit more complicated than that.

Usually, a dam is constructed across a river and a little (or big, like the size of Switzerland) body of water called a reservoir is created behind the dam. The reservoir is at a higher elevation that the river below it, so that gravity pushes the water through the dam. The water travels down through an intake, which is located towards the bottom of the dam, into a tunnel called the penstock. Near the end of the penstock is a turbine that is connected to a generator. As the water turns the turbine, the generator turns and creates electricity to be sent out onto the grid.

A dam can also be created without the need for a reservoir when it is created across a river and the river is still allowed to flow to keep the water levels from rising too high. However, it is the same that the water behind the dam must be at a higher elevation than the water below it. An example of this would the low-impact lock-dam located in a few small towns in Upstate New York, which an areal view is shown below.

Most of the time, hydroelectric power is just used to supplement other energy sources during times when the demand for electricity is high. It depends on the type of dam and other varying factors, but that is usually the case. To keep a reservoir dam's efficiency, a pumping system can be set in place. This system will pump water back into the reservoir during times when the electricity demand is low, such as two in the morning. This fills up the reservoir to prepare it for when the demand for electricity is high. But the reservoirs that have this pumping system are relatively small in comparison to dams like the Hoover Dam.

The dam is located to the left in the picture.  The structure to the right is a lock.  There are at least four "low-impact dams" along this one particular river.  To find out more about these types of dams, click the link of this picture.
The dam is located to the left in the picture. The structure to the right is a lock. There are at least four "low-impact dams" along this one particular river. To find out more about these types of dams, click the link of this picture. | Source

Pros and Cons of Hydroelectric Power

It's the same with solar, wind, tidal and wave energy. There is no "perfect" solution for energy. It is the same with hydroelectric power.

Pros

  • A dam can store water. During times of drought, the dam will most likely still have water to flow through it (unless the drought is really bad).
  • It can control flooding and the reservoir can provide a place for recreation.
  • Cheap repair and maintenance to simple designs.
  • Once the dam is built, the power is clean and efficient.
  • When there is a problem, dams can be shut down instantly.
  • Dams are pretty sturdy and can take a while to break down.


Cons

  • Dams are expensive to build! And it is possible that they can produce less energy than anticipated.
  • Reservoirs can flood entire areas, causing destruction to towns that must be abandoned and harming the ecosystem (including changes that happen with the change of seasons).
  • Preventing flooding can really choke up rivers with silt and that silt will not make it down to oceans and estuaries.
  • Greenhouse gases are visible with some studies. The decaying plants downstream of dams are causing this rise, and it is not a small rise.
  • Dams can break in a flash flood.


Is hydroelectric power a viable resource? Probably not by itself. The cons are pretty hefty, causing a lot of environmental impact, which removes points from the "environmentally friendly" category. There is room for further development when it comes to hydroelectric power, so as a supplement energy, it can be used. Overall, it's safe to say the hydroelectric power will not completely bring us off our dependency on fossil fuels. The question that remains, then, is "What will make fossil fuels obsolete?"

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    • Cammiebar profile image
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      Cammiebar 5 years ago from Upstate New York

      Thanks for reading! I just wish I could make it a little more entertaining. All the best!

    • vespawoolf profile image

      vespawoolf 5 years ago from Peru, South America

      This is a nice hub...educational and interesting. Thank you! Voted up.