The Many Forms of Water Power - Water Power - page 10

Modern hydroelectric plants are centered around dams
built across rivers. The dam creates a body of water called a
reservoir . Water from the reservoir passes through a gate
and travels through a tube called a penstock. The water
lows downward through the penstock and then reaches the
turbine. The spinning turbine powers the generator, while
the water passes through another tube to return to the river.
The electricity created by the generator then goes through a
device called a transformer, which makes the electricity easier to
send through power lines to homes and businesses.
Today, the United States has about 2,000 hydroelectric plants,
which provide about 6 percent of the country's electricity needs.

How a Hydropower Plant Works

Powerhouse Powerhouse

Reservoir

Dam

Generator Generator

Power lines Power lines

Penstock Penstock

Tu rbine Tu rbine

Gate Gate

In a hydropower plant, the movement of water causes a turbine to spin, which powers a
generator that creates electricity.