Bioenergy: Refueling the Future

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Hydroelectricity

Hydroelectricity is a method that creates electricity using moving water. It is similar to wind power, because it uses a turbine to create electricity. Also like wind power, hydroelectricity is another form of solar energy.

The sun's heat causes water to evaporate. When this water vapor turns into rain or snow and flows downhill into rivers or streams, its energy can be captured using hydroelectric power. [11.1]

[11.2]

How does it work?

There are three methods.

1) Hydroelectric dam

[11.3]

A large body of water is dammed.
A small tunnel under the dam lets water flow through to the other side.
The water current moves the blades on the turbine.
The rotating turbines power the generator.
The generator creates electricity. [11.3]

2) Run of the River

[11.4]

Water enters the forebay to be filtered.
The penstock carries the water down to the powerhouse.
In the powerhouse, the water passes through the turbines.
Turbines generate electricity.
Water returns to the stream. [11.4]

This is the most favored method, because is does not require damming a river and does not harm the local wildlife.

3) Hydro Pump storage

[11.5]

During a hot summer day, the demand for electricity will be at its peak. At times like this, the hydropower plant will let the water flow down through the turbines to generate more electricity for the high demand.

2.	When customer demand for energy is low, during the middle of a hot summer night for example, water is pumped up to a water reservoir or upper lake for the water to be used again. [11.5]