Hydro-Electric Energy

Hydro-Electric Energy: Flowing water is used to push turbines which generate electricity. Several steps can be taken to maximize the power provided by hydro-electric plants like storing water by using a dam to increase the height the water will fall and thus giving the water a higher potential energy, thus increasing the flow of water (speed) by diverting part of the waterway to other paths or using the natural drop of the waterway to power the Hydro-Electric plant. The flow to a lower level, causes electric generation; therefore, the higher mass flow rate (ammount of water per time period * speed), the more energy generation that can occur.




Dam - Most hydropower plants rely on a dam that holds back water, creating a large reservoir. Often, this reservoir is used as a recreational lake, such as Lake Roosevelt at the Grand Coulee Dam in Washington State.

Intake - Gates on the dam open and gravity pulls the water through the penstock, a pipeline that leads to the turbine. Water builds up pressure as it flows through this pipe.

Turbine - The water strikes and turns the large blades of a turbine, which is attached to a generator above it by way of a shaft. The most common type of turbine for hydropower plants is the Francis Turbine, which looks like a big disc with curved blades. A turbine can weigh as much as 172 tons and turn at a rate of 90 revolutions per minute (rpm), according to the Foundation for Water & Energy Education (FWEE).

Generators - As the turbine blades turn, so do a series of magnets inside the generator. Giant magnets rotate past copper coils, producing alternating current (AC) by moving electrons. (You'll learn more about how the generator works later.)

Transformer - The transformer inside the powerhouse takes the AC and converts it to higher-voltage current.

Power lines - Out of every power plant come four wires: the three phases of power being produced simultaneously plus a neutral or ground common to all three. (Read How Power Distribution Grids Work to learn more about power line transmission.)

Outflow - Used water is carried through pipelines, called tailraces, and re-enters the river downstream.