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Chapter Seventeen: Magnetism
17.1 Properties of Magnets
17.2 Electromagnets
17.3 Electric Motors and Generators
17.4 Generating Electricity
Chapter 17.4 Learning Goals
Review the meaning of mechanical power and liken it to electrical power.
Compare and contrast renewable and nonrenewable sources of electrical energy.
Discuss methods of electrical energy conservation.
17.4 Generating ElectricityElectricity is made in a power plant.
Most power plants burn fossil fuels (natural resources like coal, oil, or natural gas) to produce heat.
17.4 Generating Electricity Next, this heat is used to boil water.
The steam from the boiling water turns a turbine.
The turbine turns a generator which produces electricity.
17.4 Electricity from fossil fuels
A nonrenewable resource is not replaced as it is used.
Because it takes so long for these resources to form, someday we will not have enough fossil fuels to produce the electricity we need.
The three major fossil fuels are coal, oil, and natural gas.
The United States gets about 19% of its electricity production from nuclear power plants.
17.4 Electricity from nuclear energy
The main advantage of using nuclear energy to produce electricity is that it doesn’t pollute the air like fossil fuel power plants do.
17.4 Electricity from nuclear energy
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.
17.4 Electricity from renewable resources
A renewable resource can be replaced naturally in a relatively short period of time.
The Sun and wind are renewable resources that can be used as energy sources.
17.4 Electricity from renewable resources
It is also possible to use: moving water (hydroelectric) hot spots near Earth’s surface
(geothermal) fuels made from once-living things
like wood or corn (called biomass) or tides to produce electricity.
17.4 Hydroelectric power
A hydroelectric (or hydropower) plant uses energy from falling water to generate electricity.
17.4 Geothermal and biomass
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.
17.4 Geothermal and biomass
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.
17.4 Wind and solar energyCalifornia 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.
17.4 Wind and solar energyThe Sun’s energy is often called solar energy.
A solar cell (also known as a photovoltaic cell) can convert solar energy to electricity.
17.4 Electrical power
Electrical power is measured in watts, just like mechanical power.
Electrical power is the rate at which electrical energy is changed into other forms of energy such as heat, sound, or light.
17.4 Electrical power
Utility companies charge customers for the number of kilowatt-hours (kWh) used each month.
A kilowatt-hour is a unit of energy. The number of kilowatt-hours used
equals the number of kilowatts multiplied by the number of hours the appliance was turned on.
17.4 Electrical powerThere are many simple things you can do to use less electricity.
When added up, these simple things can mean many dollars of savings each month.
Under the Sea Have you ever wondered
what it would be like to take a “walk” on the seafloor? Engineer Jim Varnum gets to go “down under” regularly, because he is a pilot of an extremely complex robot called Jason II. This robot dives deep into the ocean and is used to take pictures and collect data from the seafloor.
