Chapter 17 17.4 Generating Electricity. Generating Electricity Lots of heat energy is generated from coal, gas, and oil Lots of heat energy is generated.

Chapter 17Chapter 17

17.4 Generating Electricity17.4 Generating Electricity

Generating ElectricityGenerating Electricity

Lots of heat energy is generated from coal, gas, and oilLots of heat energy is generated from coal, gas, and oil

Most of the heat energy is “lost” as unusable energyMost of the heat energy is “lost” as unusable energy

Generating ElectricityGenerating Electricity

Nonrenewable resourcesNonrenewable resources: not replaced as it is used : not replaced as it is used (ex: coal, oil, natural gas)(ex: coal, oil, natural gas)

Renewable resourcesRenewable resources: a natural resource that can be : a natural resource that can be replaced (ex: falling water, Sun, wind)replaced (ex: falling water, Sun, wind)

Electricity from Fossil FuelsElectricity from Fossil Fuels Three major fossil fuels: Three major fossil fuels:

coal, oil, natural gascoal, oil, natural gas

Because it takes so long for these Because it takes so long for these resources to form, someday we will not resources to form, someday we will not have enough have enough fossil fuelsfossil fuels to produce the to produce the electricity we need.electricity we need.

Electricity from Nuclear EnergyElectricity from Nuclear Energy Nuclear energy does not pollute the air like fossil fuel Nuclear energy does not pollute the air like fossil fuel

power plants do.power plants do.

Electricity from Nuclear EnergyElectricity from Nuclear Energy

Storage of nuclear waste has Storage of nuclear waste has always been a major always been a major disadvantage of nuclear power disadvantage of nuclear power plants.plants.

Uranium fuel from the reactor Uranium fuel from the reactor stays dangerously radioactive stays dangerously radioactive for a long time.for a long time.

Renewable: Wind EnergyRenewable: Wind Energy

California was the first U.S. state to build large California was the first U.S. state to build large wind wind farmsfarms..

Wind farms can disturb natural habitats, and can perhaps Wind farms can disturb natural habitats, and can perhaps scar a large area of scenery.scar a large area of scenery.

Renewable: Solar EnergyRenewable: Solar Energy

A solar cell (also known A solar cell (also known as a as a photovoltaic cell)photovoltaic cell) can convert solar energy can convert solar energy to electricity.to electricity.

The Sun’s energy is often The Sun’s energy is often called called solar energysolar energy. .

Renewable: Hydroelectric PowerRenewable: Hydroelectric Power

A A hydroelectrichydroelectric (or hydropower) plant uses energy from (or hydropower) plant uses energy from falling water to generate electricity.falling water to generate electricity.

Hoover Dam

Renewable: Geothermal EnergyRenewable: Geothermal Energy

Geothermal power plantsGeothermal power plants use Earth’s internal heat energy, use Earth’s internal heat energy, in the form of water or steam, to produce electricity.in the form of water or steam, to produce electricity.

A A geothermal heat pump systemgeothermal heat pump system takes advantage of the takes advantage of the relatively constant temperature of Earth’s shallow ground.relatively constant temperature of Earth’s shallow ground.

Renewable: Biomass EnergyRenewable: Biomass Energy

BiomassBiomass is organic material from plants or animals. is organic material from plants or animals. In waste-to-energy plants, renewable solid waste is In waste-to-energy plants, renewable solid waste is

burned to produce electricity, which also creates some burned to produce electricity, which also creates some air pollution.air pollution.

Quick Check!Quick Check!

1.1. List 3 fossil fuels.List 3 fossil fuels.2.2. Are fossil fuels nonrenewable or Are fossil fuels nonrenewable or

renewable? EXPLAIN.renewable? EXPLAIN.3.3. List 3 renewable resources.List 3 renewable resources.

Electrical PowerElectrical Power

Electrical powerElectrical power is is measured in watts, just like measured in watts, just like mechanical power.mechanical power.

Electrical powerElectrical power: the : the raterate at which electrical energy at which electrical energy is changed into other forms of energy such as heat, is changed into other forms of energy such as heat, sound, or light.sound, or light.

Power = current x voltagePower = current x voltage

PP = = II VV

Electrical PowerElectrical Power Utility companies charge customers for the number of Utility companies charge customers for the number of

kilowatt-hourskilowatt-hours (kWh) used each month. (kWh) used each month. A kilowatt-hour is a unit of A kilowatt-hour is a unit of energyenergy, not power, not power

# of kilowatt-hours = # of kilowatts x hours# of kilowatt-hours = # of kilowatts x hours

Electrical Power ExampleElectrical Power Examplea.a. A toaster uses 12 amps of current when plugged into a A toaster uses 12 amps of current when plugged into a

120 volt outlet. What is the power rating of the toaster in 120 volt outlet. What is the power rating of the toaster in watts?watts?

b.b. What is the power rating in kilowatts?What is the power rating in kilowatts?

c.c. How many kilowatt-hours does the toaster use if you use How many kilowatt-hours does the toaster use if you use it for 2.5 hours a month?it for 2.5 hours a month?

d.d. The utility company charges $0.15 per kilowatt-hour. The utility company charges $0.15 per kilowatt-hour. What does it cost you to use the toaster for that month?What does it cost you to use the toaster for that month?