Download 17.4 Generating Electricity

Chapter 17
17.4 Generating Electricity
Generating Electricity

Lots of heat energy is generated from coal, gas, and oil

Most of the heat energy is “lost” as unusable energy
Generating Electricity
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Nonrenewable resources: not replaced as it is used
(ex: coal, oil, natural gas)
Renewable resources: a natural resource that can be
replaced (ex: falling water, Sun, wind)
Electricity from Fossil Fuels


Three major fossil fuels:
coal, oil, natural gas
Because it takes so long for these
resources to form, someday we
will not have enough fossil fuels to
produce the electricity we need.
Electricity from Nuclear Energy

Nuclear energy does not pollute the air like fossil fuel
power plants do.
Electricity from Nuclear Energy
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
Storage of nuclear waste has
always been a major
disadvantage of nuclear power
plants.
Uranium fuel from the reactor
stays dangerously radioactive
for a long time.
Renewable: Wind Energy


California was the first U.S. state to build large wind farms.
Wind farms can disturb natural habitats, and can perhaps
scar a large area of scenery.
Renewable: Solar Energy


A solar cell (also known
as a photovoltaic cell)
can convert solar energy
to electricity.
The Sun’s energy is often
called solar energy.
Renewable: Hydroelectric Power
Hoover Dam

A hydroelectric (or hydropower) plant uses energy from
falling water to generate electricity.
Renewable: Geothermal Energy


Geothermal power plants use Earth’s internal heat energy,
in the form of water or steam, to produce electricity.
A geothermal heat pump system takes advantage of the
relatively constant temperature of Earth’s shallow ground.
Renewable: Biomass Energy

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Biomass is organic material from plants or animals.
In waste-to-energy plants, renewable solid waste is
burned to produce electricity, which also creates some air
pollution.
Quick Check!
1.
2.
3.
List 3 fossil fuels.
Are fossil fuels nonrenewable or
renewable? EXPLAIN.
List 3 renewable resources.
Electrical Power

Electrical power: the rate at which electrical energy
is changed into other forms of energy such as heat,
sound, or light.

Electrical power is
measured in watts, just like
mechanical power.
Power = current x voltage
P=IV
Electrical Power

Utility companies charge customers for the number of
kilowatt-hours (kWh) used each month.

A kilowatt-hour is a unit of energy, not power
# of kilowatt-hours = # of kilowatts x hours
Electrical Power Example
a. A toaster uses 12 amps of current when plugged into a
120 volt outlet. What is the power rating of the toaster in
watts?
b. What is the power rating in kilowatts?
c.
How many kilowatt-hours does the toaster use if you use
it for 2.5 hours a month?
d. The utility company charges $0.15 per kilowatt-hour.
What does it cost you to use the toaster for that month?