1. 17.1: Energy Resources & Fossil Fuels Preview
Fuels for Different Uses
Coal
Electricity-Power on Demand
Coal Mining /Environment
Air Pollution
How Is Electricity Generated?
Petroleum
Locating Oil Deposits
Energy Use: World, US
The Environmental Effects of Using Oil
How Fossil-Fuel Deposits Form
Natural Gas
Coal Formation
Fossil Fuels and the Future
Oil & Natural Gas Formation
Predicting Oil Prediction
Future Oil Reserves

2. List 5 different fuels and their characteristics.
Bellringer
List 5 different fuels and their characteristics.

3. Bellringer List 5 different fuels and their characteristics
Bellringer List 5 different fuels and their characteristics. Types of Fuels: 3 Main Types of Fuels are: 1.) Solid fuels: Ex) wood, coal, charcoal 2.) Liquid fuels: Ex) kerosene, petroleum, diesel 3.) Gaseous fuels: Ex) CNG (compressed natural gas), LPG (liquefied petroleum gas), biogas, hydrogen

4. Objectives List 5 factors that influence the value of the fuel.
Explain how fuels are used to generate electricity in an electric power plant.
Identify patterns of energy consumption and production in the world and in the US.
Explain how fossil fuels form and how they are used.
Compare the advantages and disadvantages of fossil-fuel use.
List 3 factors that influence predictions of fossil fuel production.

5. Energy Resources and Fossil Fuels
A fossil fuel
a nonrenewable energy resource
formed from the remains of organisms that lived long ago.
examples include oil, coal, and natural gas.
Used to run cars, ships, planes, and factories and to produce electricity.
Oil pipeline map viewer

6. Energy Resources and Fossil Fuels
Fossil fuels are central to life in modern societies, but there are two main problems with fossil fuels.
The supply of fossil fuels is limited.
Obtaining and using them has environmental consequences.
In the 21st century, societies will continue to explore alternatives to fossil fuels but will also focus on developing more-efficient ways to use these fuels.

7. Fuels for Different Uses
Fuel is used for four main purposes:
Transportation
Manufacturing
Heating and cooling buildings
Generating electricity to run machines and appliances

8. Electricity-Power Advantages:
More convenient to use
Transported quickly across great distances.
A good source of power for computers, light switches, etc.
Generated from fossil fuels.

9. Electricity-Power Disadvantages:
It is difficult to store
Other energy sources have to be used to generate it.

10. How is Electricity Generated

11. Electric generator
device that converts chemical energy (burning) to mechanical energy into electrical energy.

12. Electric generator
The water is heated using
a coal-fired or gas-fired plant, or
is heated from the fission of uranium in nuclear plants.
Steam is formed turns the turbine
A turbine: a wheel that changes the force of a moving gas or a liquid into energy that can do work.
produces electrical energy by moving an electrically conductive material within a magnetic field.

13. How Fossil-Fuel Deposits Form
Deposits are not distributed evenly.
abundance of oil in Texas and Alaska,
very little in Maine.
The eastern US produces more coal
The reason for this difference lies in the geologic history of the areas.

14. Oil and Gas Deposits in the United States

15. Coal Formation Formed from remains of plants
lived in swamps hundreds of millions of years ago.
As ocean levels rose and fell, swamps were covered with sediment.
Layers of sediment compressed the plant remains,
Heat and pressure within the Earth’s crust caused coal to form.
Most formed about 300 to 250 million years ago (mya)
In western states, formed between 100 & 40 mya

16. Oil and Natural Gas Formation
result from the decay of tiny marine organisms that accumulated on the bottom of the ocean millions of years ago.
Buried by sediments
Heated until they became complex energy-rich hydrocarbons
migrated into the porous rock formations that now contain them.
(12:09)
(15:00)

18. Coal Makes up most of world’s fossil-fuel reserves
Relatively inexpensive
Needs little refining after being mined.
Asia and North America are particularly rich in coal deposits.

19. Coal

20. Coal-fired power plants generate over ½ the electricity in US

21. Coal Mining and the Environment
Effects vary.
Underground mining
minimal effect on the environment at the surface,
Strip Mining (surface coal-mining)
sommetimes remove the top of an entire mountain
A lot of research focuses on locating the most productive, clean-burning coal deposits and finding less damaging methods of mining coal.

22. Air Pollution
The quality of coal varies. Higher-grade coals, such as bituminous coal, produce more heat and less pollution than lower-grade coal, such as lignite.
Sulfur, found in all grades of coal, can be a major source of pollution when coal is burned.
The air pollution and acid precipitation that result from burning high-sulfur coal without adequate pollution controls are serious problems in countries such as China.
However, clean-burning coal technology has dramatically reduced air pollution in countries such as the United States.

23. US Oil Usage by Sector (gallons per year)

24. Petroleum (crude oil) a liquid mixture of complex
hydrocarbon compounds
used widely as a fuel source.
a petroleum product
Anything that is made from crude oil, such as fuels, chemicals, and plastics,
88% is burned or used as fuel
3% manufacturing
accounts for 45% of the world’s commercial energy use.

25. Locating Oil Deposits Most of the world’s oil reserves Middle East.
United States,
Venezuela,
the North Sea,
Siberia, and
Nigeria.

26. Natural Gas or methane (CH4),
About 20% of the world’s nonrenewable energy
produces fewer pollutants than other fossil fuels
Vehicles that run on NG require fewer pollution controls.
Electric power plants can also use this clean-burning fuel.
Existing gasoline-powered vehicles may be converted to run on CNG or LNG (compressed/liquid natural gas), and can be dedicated (running only on natural gas) or bi-fuel (running on either gasoline or natural gas). However, an increasing number of vehicles worldwide are being manufactured to run on CNG.

27. Methane Hydrates
Gas hydrates occur when sufficient methane is produced by organic matter degradation in the sea floor under low temperature and high pressure conditions. 
Information:
Methane Hydrate Lab video:

29. Math Practice

30. Quick check 17.1
Describe 5 factors that influence the value of a fuel.
Describe how fossil fuels are used to produce electricity, and explain how an electric generator works.
Describe how coal, oil and natural gas form, how these fuels are used and how using each fuel affects the environment.
What is the relationship between natural gas and petroleum.
What do you think account for the dramatic increase in the worldwide production of oil
after 1950?

31. Quick Check Answers
1. Cost, availability, safety, energy content, and the byproducts of the fuel’s use.
2. Fossil fuels are burned to produce heat, which is used to heat water. The water turns into steam, and the steam turns a turbine. The turbine turns an electrically conductive material within a magnetic field inside the electric generator, which produces electrical energy.
3. Coal forms when plant remains are covered with layers of sediment and then placed under high temperature and pressure for millions of years.
Coal is used for electricity generation and heating. (next slide…)

32. Quick Check 17.1 (cont’d)
3. (cont’d) Environmental Effects: removal of mountain tops during excavation, pollution of streams from mine debris, air pollution, and acid rain.
Oil and natural gas form when marine organisms are buried by sediment. As the remains decay, the are changed into oil and gas. Oil is used to produce fuels, chemicals, and plastics. When oil is burned it produces pollution, causing; smog, health problems, acid rain, and global warming. Leaking cars and accidental spills pollute waterways. Natural gas is used as fuel in electric power plants, cars, and for heating and cooking. Natural gas produces air pollution when burned.

33. Quick Check 17.1 (cont’d)
4. Natural gas and petroleum are both formed when trapped underground.
5. Improved exploration and extraction technology; demand for oil as a fuel for cars, trucks and diesel locomotives.

34. 17.2: Nuclear Energy Preview
Fission: Splitting Atoms
How Nuclear Energy Works
The Advantages of Nuclear Energy
Why Aren’t We Using More Nuclear Energy?
Storing Waste
Safety Concerns
The future of Nuclear Power

35. Section 2: Nuclear Energy
Preview, continued
Safety Concerns
The Future of Nuclear Power

36. Bellringer

37. Objectives Describe nuclear fission.
Describe how a nuclear power plant works.
List three advantages and three disadvantages of nuclear energy.
Fission: Splitting Atoms

38. Nuclear Energy
In the 1950s and 1960s, nuclear power plants were seen as the power source of the future because the fuel they use is clean and plentiful.
In the 1970s and 1980s, however, many planned nuclear power plants were cancelled and others under construction were abandoned.
Today, nuclear power accounts for 17% of the world’s electricity.

39. Fission: Splitting Atoms
The nuclei of uranium atoms
are bombarded with atomic particles called neutrons.
These collisions cause the nuclei to split into two or more fragments
Releases
a tremendous amount of energy and
more neutrons, which in turn collide with more uranium nuclei.

40. Fission: Splitting Atoms
Nuclear power plants
energy released by a fission or fusion reaction.
binding energy of the atomic nucleus.
The forces that hold together a nucleus of an atom are more than 1 million times stronger than the chemical bonds between atoms.
Fuel: uranium atoms

41. Fission: Splitting Atoms

42. How Nuclear Energy Works
The heat released is used to generate electricity in the same way that power plants burn fossil fuels to generate electricity.
The energy released from the fission reactions heats a closed loop of water that heats another body of water.
As the water boils, it produces steam that drives a turbine, which is used to generate electricity.

43. How Nuclear Energy Works

44. The Advantages of Nuclear Energy
a very concentrated energy source.
do not produce air-polluting gases.
release less radioactivity than coal-fired power plants do, when operated properly.
Countries will limited fossil-fuel resources rely heavily on nuclear plants to supply electricity.

45. Why Aren’t We Using More Nuclear Energy?
Building and maintaining a safe reactor is very expensive.
This makes nuclear plants no longer competitive with other energy sources in many countries.
The actual cost of new nuclear power plants is uncertain, so it is difficult to predict whether investors will build new plants in the United States.

46. Storing Waste The greatest disadvantage
difficulty in finding a safe place to store nuclear waste.
can remain dangerously radioactive for thousands of years.

47. Safety Concerns
In a poorly designed nuclear plant, the fission process can potentially get out of control.
The Chernobyl reactor was destroyed in 1986 when an unauthorized test caused explosions and blasted radioactive materials into the air.
Hundreds of people in the Ukraine died from radioactive exposure from this explosion.
Even today, parts of northern Europe and the Ukraine remain contaminated from this disaster.

48. Safety Concerns
The most serious nuclear accident in the United States occurred in 1979 at the Three Mile Island nuclear power plant in Pennsylvania.
Human error, along with blocked valves and broken pumps, was responsible for this accident.
Fortunately, only a small amount of radioactive gas escaped.
Since that accident, the U.S. Nuclear Regulatory Commission has required more than 300 safety improvements to nuclear plants.

49. The Future of Nuclear Power
One possible future energy source is nuclear fusion.
Nuclear fusion
the combination of the nuclei of small atoms to form a larger nucleus.
releases tremendous amounts of energy.
potentially a safer energy source than nuclear fission is because it creates less dangerous radioactive byproducts.

50. Nuclear Fusion

51. Fission: Splitting Atoms

52. The Future of Nuclear Power
Although the potential for nuclear fusion is great, so is the technical difficulty of achieving that potential.
For fusion to occur, three things must occur simultaneously:
Atomic nuclei must be heated to extremely high temperatures (about 100,000,000ºC or 180,000,000ºF).
The nuclei must be maintained at very high conditions.
The nuclei must be properly confined.
The technical problems are so complex that building a nuclear fusion plant may take decades or may never happen.

53. Quick Check 17.2

54. Renewable Energy
Chapter 18

55. Section 1: Renewable Energy Today
Preview
Bellringer
Objectives
Renewable Energy
Solar Energy-Power from the Sun
Passive Solar Heating
Active Solar Heating
Photovoltaic Cells

56. Section 1: Renewable Energy Today
Preview, continued
Wind Power
Wind Farms
An Underdeveloped Resource
Biomass-Power from Living Things
Methane
Alcohol
Hydroelectricity-Power from Moving Water

57. Section 1: Renewable Energy Today
Preview, continued
The Benefits of Hydroelectric Energy
Disadvantages of Hydroelectric Energy
Modern Trends
Geothermal Energy-Power from the Earth
Geothermal Heat Pumps: Energy for Homes

58. Bellringer

59. Objectives
List six forms of renewable energy, and compare their advantages and disadvantages.
Describe the difference between passive solar heating, active solar heating, and photovoltaic energy.
Describe the current state of wind energy technology.
Explain the differences in biomass fuel use between developed and developing nations.
Describe how hydroelectric energy, geothermal energy, and geothermal heat pumps work.

60. Renewable Energy
Renewable energy is energy from sources that are constantly being formed.
Types of renewable energy includes:
solar energy
wind energy
the power of moving water
Earth’s heat
Remember, all sources of energy, including renewable sources, affect the environment.

61. Solar Energy-Power from the Sun
Nearly all renewable energy comes directly or indirectly from the sun.
Direct solar energy is used every day, like when the sun shines on a window and heats the room.
Solar energy can also be used indirectly to generate electricity in solar cells.

62. Passive Solar Heating
Passive solar heating is the use of sunlight to heat buildings directly.
In the Northern Hemisphere, south facing windows receive the most solar energy.
Therefore, passive solar buildings have large windows that face south.
An average household could reduce its energy bills by using any of the passive solar features shown on the next slide.

63. Passive Solar Heating

64. Active Solar Heating
Active solar heating is the gathering of solar energy by collectors that are used to heat water or heat a building.
More than 1 million homes in the United States use active solar energy to heat water.
Solar collectors, usually mounted on a roof, capture the sun’s energy.

65. Active Solar Heating

66. Active Solar Heating
A liquid is heated by the sun as it flows through solar collectors.
The hot liquid is then pumped through heat exchangers, which heats water for the building.
About 8% of the energy used in the United States is used to heat water; therefore, active solar technology could save a lot of energy.

67. Photovoltaic Cells
Photovoltaic cells are solar cells that convert the sun’s energy into electricity.
Solar cells have no moving parts, and they run on nonpolluting power from the sun.
However, they produce a very small electrical current. Meeting the electricity needs of a small city would require covering hundreds of acres with solar panels.

68. Photovoltaic Cells
Sunlight falls on a semiconductor, causing it to release electrons. The electrons flow through a circuit that is complete when another semiconductor in the solar cell absorbs electrons and passes them on to the first semiconductor.

69. Photovoltaic Cells
Solar cells require extended periods of sunshine to produce electricity. This energy is stored in batteries, which supplies electricity when the sun is not shining.
Currently, solar cells provide energy for more than 1 million households in developing countries, where energy consumption is minimal and electricity distribution networks are limited.

70. Wind Power
Energy from the sun warms the Earth’s surface unevenly, which causes air masses to flow in the atmosphere.
We experience the movement of these air masses as wind.
Wind power, which converts the movement of wind into electric energy, is the fastest growing energy source in the world.

71. Wind Farms Wind turbines are used to capture the energy from the wind.
Large arrays of wind turbines are called wind farms. Large wind farms supply electricity to thousands of homes.
In windy rural areas, small wind farms with 20 or fewer turbines are also becoming common.
Because wind turbines take up little space, some farmers can add wind turbines to their land and still use the land for other purposes.

72. Wind Farms
The cost of wind power has been steadily falling as wind turbines have become more efficient.

73. An Underdeveloped Resource
Scientists estimate that the windiest spots on Earth could generate more than ten times the energy used worldwide.
In the future, the electricity may be used on the wind farm to produce hydrogen from water.
Today, all of the large energy companies are developing plans to use more wind power.

74. Biomass-Power from Living Things
Biomass fuel consists of plant material, manure, or any other organic matter that is used as an energy source.
Fossil fuels can be thought of as biomass energy sources, although they are nonrenewable.
Renewable biomass fuels, such as wood and dung, are major sources of energy in developing countries.
More than half of all wood cut in the world is used as fuel for heating and cooking.

75. Biomass-Power from Living Things

76. Biomass-Power from Living Things
Although materials like wood are a renewable resource, if trees are cut down faster than they grow, the resulting habitat loss, deforestation, and soil erosion can be severe.
In addition, harmful air pollution may result from burning wood and dung.

77. Methane
When bacteria decompose organic wastes, one byproduct is methane gas.
Methane can be burned to generate heat or electricity.
In China, more than 6 million households use biogas digesters to ferment manure and produce gas for heating and cooking.
Some landfills in the United States generate electricity by using the methane from the decomposition of trash.

78. Alcohol Liquid fuels can also be derived from biomass.
For example, ethanol, an alcohol, can be made by fermenting fruit or agricultural waste. In the United States, corn is a major source of ethanol.
Cars and trucks can run on ethanol or gasohol, a blend of gasoline and ethanol. Gasohol produces less air pollution than fossil fuels.
Some states require the use of gasohol in vehicles as a way to reduce air pollution.

79. Hydroelectricity-Power from Moving Water
Hydroelectric energy is electrical energy produced by falling water.
Hydroelectric energy accounts for 20% of the world’s electricity.
Large hydroelectric power plants have a dam that is built across a river to hold back a reservoir of water.
The water in the reservoir is released to turn a turbine, which generates electricity.

80. Hydroelectricity-Power from Moving Water

81. The Benefits of Hydroelectric Energy
Hydroelectric dams are expensive to build, but relatively inexpensive to operate.
Unlike fossil fuel plants, hydroelectric dams do not release air pollutants that cause acid precipitation.
Hydroelectric dams also tend to last much longer than fossil fuel-powered plants.
Dams also provide other benefits such as flood control and water for drinking, agriculture, industry, and recreation.

82. Disadvantages of Hydroelectric Energy
A dam changes a river’s flow, which can have far-reaching consequences.
A reservoir floods large areas of habitat above the dam. Water flow below the dam is reduced, which disrupts ecosystems downstream.
For example, many salmon fisheries of the northwestern United States have been destroyed by dams that prevent salmon from swimming upriver to spawn.

83. Disadvantages of Hydroelectric Energy
When the land behind a dam is flooded, people are often displaced. If a dam bursts, people living in areas below the dam can be killed.
River sediments build up behind the dam instead of enriching land farther down the river, making farmland below the dam less productive.
Recent research has also shown that the decay of plant matter trapped in reservoirs can release large amounts of greenhouse gases-sometimes more than a fossil-fuel powered plant.

84. Modern Trends
While in developing countries the construction of large dams continues, in the United States, the era of large dam construction is probably over.
One modern trend is micro-hydropower, which is electricity produced in a small stream without having to build a big dam. The turbine may even float in the water, not blocking the river at all.
Micro-hydropower is much cheaper than large hydroelectric dam projects, and it permits energy to be generated from small streams in remote areas.

85. Geothermal Energy-Power from the Earth
In some areas, deposits of water in the Earth’s crust are heated by geothermal energy.
Geothermal energy is the energy produced by heat within the Earth.
The United States is the world’s largest producer of geothermal energy.
Although geothermal energy is considered a renewable resource, the water that is used must be managed carefully so that it is not depleted.

86. Geothermal Energy-Power from the Earth
Geothermal power plants generate electricity using the following steps
Steam rises through a well
Steam drives turbines, which generate electricity
Leftover liquid is pumped back into the hot rock
The leftover liquid, water, is returned to Earth’s crust because it can be reheated by geothermal energy and used again.

87. Geothermal Energy-Power from the Earth

88. Geothermal Heat Pumps: Energy for Homes
More than 600,000 homes in the United States are heated and cooled using geothermal heat pumps.
A geothermal heat pump uses stable underground temperatures to warm and cool homes because the temperature of the ground is nearly constant year-round.
A heat pump is simply a loop of piping that circulates a fluid underground.

89. Geothermal Heat Pumps: Energy for Homes

90. Geothermal Heat Pumps: Energy for Homes
In the summer, the ground is cooler than air and the fluid cools the home.
In the winter, the ground is warmer than air, and the fluid warms the home.

91. Section 2: Alternative Energy and Conservation
Preview
Bellringer
Objectives
Alternative Energy
Tidal Power
Ocean Thermal Energy Conservation
Hydrogen—A Future Fuel Source?
The Challenge of Hydrogen Fuel

92. Section 2: Alternative Energy and Conservation
Preview, continued
Fuel Cells
Energy Efficiency
Efficient Transportation
Hybrid Cars
Cogeneration
Energy Conservation

93. Section 2: Alternative Energy and Conservation
Preview, continued
Cities and Towns Saving Energy
Conservation Around the Home
Conservation in Daily Life

94. Bellringer

95. Objectives Describe three alternative energy technologies.
Identify two ways that hydrogen could be used a fuel source in the future.
Explain the difference between energy efficiency and energy conservation.
Describe two forms of energy-efficient transportation.
Identify three ways that you can conserve energy in your daily life.

96. Alternative Energy
To achieve a future where energy use is sustainable, we must make the most of the energy sources we already have and develop new sources of energy.
Alternative energy describes energy that does not come from fossil fuels and that is still in development.

97. Alternative Energy
For an alternative energy source to become a viable option for the future, the source must be proven to be cost effective.
Also, the environmental effects of using the energy source must be acceptable.

98. Tidal Power A tidal power plant works much like a hydroelectric dam.
As the tide rises, water enters a bay behind a dam. The gate then closes at high tide.
At low tide, the gate opens and the water in the bay rushes through, spinning a turbine that generates electricity.

99. Tidal Power

100. Tidal Power
Although tidal energy is renewable and nonpolluting, it will not become a major energy source in the future.
The cost of building and maintaining tidal power plants is high, and there are few suitable locations.

101. Ocean Thermal Energy Conservation
In the tropics, the temperature difference between the surface of the ocean and the deep ocean waters can be as much as 24ºC (43ºF).
Ocean thermal energy conservation (OTEC) is the use of temperature differences in ocean water to produce electricity.

102. Ocean Thermal Energy Conservation
An OTEC plant produces energy using the following steps
Warm surface water is boiled in a vacuum chamber.
This produces a steam that drives a turbine to generate electricity.
Cold deep-ocean water will condense the steam.
The steam turns into water that can be used again.

103. Ocean Thermal Energy Conservation

104. Ocean Thermal Energy Conservation
The United States and Japan have experimented with OTEC power, but so far, no project has been able to generate cost effective electricity.
OTEC plants are inefficient because about one-third of the electricity the plant produces is used to pump cold water up from the deep ocean.
The environmental effects of pumping large amounts of cold water to the surface are also unknown.

105. Hydrogen-A Future Fuel Source?
Hydrogen, the most abundant element in the universe, can be burned as a fuel.
Hydrogen does not contain carbon, so it does not release pollutants associated with burning fossil fuels and biomass.
When hydrogen is burned in the atmosphere, it combines with oxygen to produce water vapor, a harmless byproduct, and small amounts of nitrogen oxides.

106. Hydrogen-A Future Fuel Source?
Hydrogen gas (H2) can be produced by using electricity to split molecules of water (H2O).
Hydrogen fuel can be made from any material that contains a lot of hydrogen.
In the future, we may also be able to grow plants to produce hydrogen cost effectively.

107. The Challenge of Hydrogen Fuel
One difficulty of using hydrogen as a fuel today is that hydrogen takes a lot of energy to produce.
If this energy came from burning fossil fuels, generating hydrogen would be expensive and polluting.

108. The Challenge of Hydrogen Fuel
One alternative is to use electricity from solar cells or wind power to split water molecules to produce hydrogen.
Hydrogen could then be stored in pressurized tanks and transported in gas pipelines.
Or hydrogen might not be stored at all-it might be used as it is produced, in fuel cells.

109. Fuel Cells
A fuel cell is a device that produces electricity chemically by combining hydrogen fuel with oxygen from the air.
When hydrogen and oxygen are combined, electrical energy is produced and water is the only byproduct.
Fuel cells can be fueled by anything that contains plenty of hydrogen, including natural gas, alcohol, or even gasoline.

110. Fuel Cells

111. energy efficiency (in %) = energy out/energy in  100
There are two main ways to reduce energy use:
lifestyle changes
increases in energy efficiency
Energy efficiency is the percentage of energy put into a system that does useful work.
Energy efficiency can be determined by this equation:
energy efficiency (in %) = energy out/energy in  100

112. Energy Efficiency
Most of our devices are fairly inefficient. More than 40 percent of all commercial energy used in the United States is wasted.
Increasing efficiency may involve sacrifices or investments in new technology.

113. Efficient Transportation
Developing efficient engines to power vehicles and increasing the use of public transportation systems would help increase energy efficiency of American life.
The internal combustion engines that power most vehicles do so inefficiently and produce air pollution.
In the next 50 years, the design of these engines may change radically to meet the need for more efficient transportation.

114. Hybrid Cars Hybrid cars are examples of energy-efficient vehicles.
Hybrid cars use small, efficient gasoline engines most of the time, but they also use electric motors when extra power is needed, such as while accelerating.
Hybrid cars do not cost much more than conventional vehicles, they cost less to refuel, and they produce less harmful emissions.

115. Hybrid Cars

116. Hybrid Cars Hybrid cars feature many efficient technologies.
They convert some energy of braking into electricity and store this energy in the battery.
The gasoline engine is sometimes shut off to save fuel, such as when the car is stopped at a red light.
They are aerodynamic in design and need less energy to accelerate.

117. Cogeneration
Cogeneration is the production of two useful forms of energy from the same fuel source.
For example, the waste heat from an industrial furnace can power a steam turbine that produces electricity.
Small cogeneration systems have been used for years to supply heat and electricity to multiple buildings at specific sites.

118. Energy Conservation
Energy conservation is the process of saving energy by reducing energy use and waste.
This can occur in many ways, including using energy-efficient devices and wasting less energy.
Between 1975 and 1985, conservation made more energy available in the United States than all alternative energy sources combined did.

119. Cities and Towns Saving Energy
The town of Osage, Iowa, numbers 3,600 people.
This town saved more than $1 million each year in energy because they found ways to conserve energy.
In addition to saving energy, the town has greatly improved its economy through energy conservation.
Businesses have relocated to the area to take advantage of low energy costs. Unemployment rates have also declined.

120. Conservation Around the Home
The average household in the U.S. spends more than $1,200 on energy bills each year.
Unfortunately, much of the energy from homes is lost through poorly insulated windows, doors, walls, and the roof.
There are dozens of ways to reduce energy use around the home.

121. Conservation in Daily Life
There are many simple lifestyle changes that can help save energy.
Using less of any resource usually translates into saving energy.

122. Conservation Around the Home

123. Quick LAB

124. Graphic Organizer

125. Math Practice