Earth Science Hydroelectric Energy

1. HYDROELECTRIC ENERGY

2. Hydroelectric energy is produced
by the force of moving and
flowing water. It is harnessed
from water resources that have
tendencies to flow or to fall from a
certain height. This energy
depends on the water cycle for
replenishing resources and the
kinetic energy from the flow or fall
of water. Hydroelectric energy is
widely used as an alternative
source of energy worldwide.

3. Hydroelectric energy is not a newly-discovered source of energy. Ancient Romans have used
it to turn turbines that helped them grind grains. In the 1800s, flowing water provided the
same function to water mills. Water mills that functioned as grain and lumber cutters were
powered by moderately flowing water.
Harnessing Hydroelectric Energy
Ideal sources of hydroelectric energy are large, fast-flowing rivers, and waterfalls. The two
main factors considered in selecting a good source of hydroelectric energy are the flow of
water (rate and volume) and the height difference between the water source and outflow.
1 - Reservoirs, such as dams, are built on rivers that have a high potential energy (flow and
height). Reservoirs increase water height and enable the water to be controlled.
2 - The water from the reservoirs is channeled to the turbines in hydroelectric plants. The
release of water is controlled through the intake or inlet gates. When the inlet gates are
opened, the water flows through it into the penstock until it reaches the turbines. The
penstock is a large shaft that connects the reservoir and the power generating units (turbines
and generators).
3 - The energy from the flowing water turns the turbines that are connected to electric
generators.

4. 4 - The turbines produce energy that spins electromagnets on the generators. The movement
of the electromagnets produces current.
5 - The current is transferred to transformers through the long-distance power lines or
transmission cables that store or distribute electricity.
6 - Water flows out of the turbines to rivers or to other nearby water resources