1. Chapter 15 Nonrenewable Energy

2. Case Study: A Brief History of Human Energy Use
Everything runs on energy
Industrial revolution began 275 years ago, relied on wood, which led to deforestation
Coal
Petroleum products
Natural gas
All of these are nonrenewable energy resources

3. Energy Use: World and United States
Figure 15.1: We get most of our energy by burning carbon-containing fossil fuels (see Figure 2-14, p. 46). This figure shows energy use by source throughout the world (left) and in the United States (right) in Note that oil is the most widely use form of commercial energy and that about 79% of the energy used in the world (85% of the energy used the United States) comes from burning nonrenewable fossil fuels. (These figures also include rough estimates of energy from biomass that is collected and used by individuals without being sold in the marketplace.) Question: Why do you think the world as a whole relies more on renewable energy than the United States does? (Data from U.S. Department of Energy, British Petroleum, Worldwatch Institute, and International Energy Agency)
Fig. 15-1, p. 370

4. 15-1 What is Net Energy and Why Is It Important?
Concept Net energy is the amount of high-quality energy available from an energy resource minus the amount of energy needed to make it available.

5. Basic Science: Net Energy Is the Only Energy That Really Counts (1)
First law of thermodynamics:
It takes high-quality energy to get high-quality energy
Pumping oil from ground, refining it, transporting it
Second law of thermodynamics
Some high-quality energy is wasted at every step

6. Basic Science: Net Energy Is the Only Energy That Really Counts (2)
Total amount of useful energy available from a resource minus the energy needed to make the energy available to consumers
Business net profit: total money taken in minus all expenses
Net energy ratio: ratio of energy produced to energy used to produce it
Conventional oil: high net energy ratio

7. Electric heating (coal-fired plant) 0.4
Space Heating
Passive solar
5.8
Natural gas
4.9
Oil
4.5
Active solar
1.9
Coal gasification
1.5
Electric heating (coal-fired plant)
Figure 15.3: Science.
Net energy ratios for various energy systems over their estimated lifetimes differ widely: the higher the net energy ratio, the greater the net energy available (Concept 15-1). Question: Based on these data, which two resources in each category should we be using? (Data from U.S. Department of Energy; U.S. Department of Agriculture; Colorado Energy Research Institute, Net Energy Analysis, 1976; and Howard T. Odum and Elisabeth C. Odum, Energy Basis for Man and Nature, 3rd ed., New York: McGraw-Hill, 1981)
0.4
Electric heating
(natural-gas-fired plant)
0.4
Electric heating (nuclear plant)
0.3
Fig. 15-3a, p. 373

8. High-Temperature Industrial Heat
28.2
Surface-mined coal
Underground-
mined coal
25.8
Natural gas
4.9
Oil
4.7
Figure 15.3: Science.
Net energy ratios for various energy systems over their estimated lifetimes differ widely: the higher the net energy ratio, the greater the net energy available (Concept 15-1). Question: Based on these data, which two resources in each category should we be using? (Data from U.S. Department of Energy; U.S. Department of Agriculture; Colorado Energy Research Institute, Net Energy Analysis, 1976; and Howard T. Odum and Elisabeth C. Odum, Energy Basis for Man and Nature, 3rd ed., New York: McGraw-Hill, 1981)
Coal gasification
1.5
Direct solar (concentrated)
0.9
Fig. 15-3b, p. 373

9. Transportation Natural gas 4.9 Gasoline (refined crude oil) 4.1
Biofuel (ethanol)
1.9
Coal liquefaction
Figure 15.3: Science.
Net energy ratios for various energy systems over their estimated lifetimes differ widely: the higher the net energy ratio, the greater the net energy available (Concept 15-1). Question: Based on these data, which two resources in each category should we be using? (Data from U.S. Department of Energy; U.S. Department of Agriculture; Colorado Energy Research Institute, Net Energy Analysis, 1976; and Howard T. Odum and Elisabeth C. Odum, Energy Basis for Man and Nature, 3rd ed., New York: McGraw-Hill, 1981)
1.4
Oil shale
1.2
Fig. 15-3c, p. 373

10. Energy Resources With Low/Negative Net Energy Yields Need Marketplace Help
Cannot compete in open markets with alternatives that have higher net energy yields
Need subsidies from taxpayers
Nuclear power as an example

11. Reducing Energy Waste Improves Net Energy Yields and Can Save Money
84% of all commercial energy used in the U.S. is wasted
43% after accounting for second law of thermodynamics
Drive efficient cars, not gas guzzlers
Make buildings energy efficient

12. 15-2 What Are the Advantages and Disadvantages of Oil?
Concept 15-2A Conventional oil is currently abundant, has a high net energy yield, and is relatively inexpensive, but using it causes air and water pollution and releases greenhouse gases to the atmosphere.
Concept 15-2B Heavy oils from tar sand and oil shale exist in potentially large supplies but have low net energy yields and higher environmental impacts than conventional oil has.

13. We Depend Heavily on Oil (1)
Petroleum, or crude oil: conventional, or light oil
Fossil fuels: crude oil and natural gas
Peak production: time after which production from a well declines
Global peak production for all world oil

14. We Depend Heavily on Oil (2)
Oil extraction and refining
By boiling point temperature
Petrochemicals:
Products of oil distillation
Raw materials for industrial organic chemicals
Pesticides
Paints
Plastics

15. Science: Refining Crude Oil
Figure 15.4: Science.
When crude oil is refined, many of its components are removed at various levels, depending on their boiling points, of a giant distillation column (left) that can be as tall as a nine-story building. The most volatile components with the lowest boiling points are removed at the top of the column. The photo above shows an oil refinery in the U.S. state of Texas.
Fig. 15-4, p. 375

16. Lowest Boiling Point Gases Gasoline Aviation fuel Heating oil
Diesel oil
Naphtha
Figure 15.4: Science.
When crude oil is refined, many of its components are removed at various levels, depending on their boiling points, of a giant distillation column (left) that can be as tall as a nine-story building. The most volatile components with the lowest boiling points are removed at the top of the column. The photo above shows an oil refinery in the U.S. state of Texas.
Grease and wax
Heated crude oil
Asphalt
Furnace
Highest Boiling Point
Fig. 15-4a, p. 375

17. How Long Might Supplies of Conventional Crude Oil Last? (1)
Rapid increase since 1950
Largest consumers in 2009
United States, 23%
China, 8%
Japan, 6%

18. How Long Might Supplies of Conventional Crude Oil Last? (2)
Proven oil reserves
Identified deposits that can be extracted profitably with current technology
Unproven reserves
Probable reserves: 50% chance of recovery
Possible reserves: 10-40% chance of recovery
Proven and unproven reserves will be 80% depleted sometime between 2050 and 2100

19. World Oil Consumption, 1950-2009
Figure 1, Supplement 2

20. History of the Age of Conventional Oil
Figure 9, Supplement 9

21. OPEC Controls Most of the World’s Oil Supplies (1)
13 countries have at least 60% of the world’s crude oil reserves
Saudi Arabia: 20%
United States: 1.5%
Global oil production leveled off in 2005
Oil production peaks and flow rates to consumers

22. OPEC Controls Most of the World’s Oil Supplies (2)
Three caveats when evaluating future oil supplies
Potential reserves are not proven reserves
Must use net energy yield to evaluate potential of any oil deposit
Must take into account high global use of oil

23. Crude Oil in the Arctic National Wildlife Refuge
Figure 15.5: The amount of crude oil that might be found in the Arctic National Wildlife Refuge (right), if developed and extracted over 50 years, is only a tiny fraction of projected U.S. oil consumption. In 2008, the DOE projected that developing this oil supply would take 10–20 years and would lower gasoline prices at the pump by 6 cents per gallon at most. (Data from U.S. Department of Energy, U.S. Geological Survey, and Natural Resources Defense Council)
Fig. 15-5, p. 376

24. The United States Uses Much More Oil Than It Produces
Produces 9% of the world’s oil and uses 23% of world’s oil
1.5% of world’s proven oil reserves
Imports 52% of its oil
Should we look for more oil reserves?
Extremely difficult
Expensive and financially risky

25. U.S. Energy Consumption by Fuel
Figure 6, Supplement 9

26. Proven and Unproven Reserves of Fossil Fuels in North America
Figure 18, Supplement 8

27. Conventional Oil Has Advantages and Disadvantages
Extraction, processing, and burning of nonrenewable oil and other fossil fuels
Advantages
Disadvantages

28. Trade-Offs: Conventional Oil
Figure 15.6: Using crude oil as an energy resource has advantages and disadvantages (Concept 15-2a). Questions: Which single advantage and which single disadvantage do you think are the most important? Why?
Fig. 15-6, p. 377

29. Bird Covered with Oil from an Oil Spill in Brazilian Waters
Figure 15.7: This bird was covered with oil from an oil spill in Brazilian waters. If volunteers had not removed the oil, it would have destroyed this bird’s natural buoyancy and heat insulation, causing it to drown or die from exposure because of a loss of body heat.
Fig. 15-7, p. 377

30. Case Study: Heavy Oil from Tar Sand
Oil sand, tar sand contains bitumen
Canada and Venezuela: oil sands have more oil than in Saudi Arabia
Extraction
Serious environmental impact before strip-mining
Low net energy yield: Is it cost effective?

31. Strip Mining for Tar Sands in Alberta
Figure 15.8: Producing heavy oil from Canada’s Alberta tar sands project involves strip-mining areas large enough to be seen from outer space, draining wetlands, and diverting rivers. It also produces huge amounts of air and water pollution and has been called the world’s most environmentally destructive project. For oil from the sands to be profitable, oil must sell for $70–90 a barrel.
Fig. 15-8, p. 378

32. Will Heavy Oil from Oil Shales Be a Useful Resource?
Oil shales contain kerogen
After distillation: shale oil
72% of the world’s reserve is in arid areas of western United States
Locked up in rock
Lack of water needed for extraction and processing
Low net energy yield

33. Oil Shale Rock and the Shale Oil Extracted from It
Figure 15.9: Shale oil (right) can be extracted from oil shale rock (left). However, producing shale oil requires large amounts of water and has a low net energy yield and a very high environmental impact.
Fig. 15-9, p. 379

34. Trade-Offs: Heavy Oils from Oil Shale and Oil Sand
Figure 15.10: Using heavy oil from tar sands and oil shales as an energy resource has advantages and disadvantages (Concept 15-2b). Questions: Which single advantage and which single disadvantage do you think are the most important? Why?
Fig , p. 379

35. 15-3 What Are the Advantages and Disadvantages of Using Natural Gas?
Concept Conventional natural gas is more plentiful than oil, has a high net energy yield and a fairly low cost, and has the lowest environmental impact of all fossil fuels.

36. Natural Gas Is a Useful and Clean-Burning Fossil Fuel
Natural gas: mixture of gases
50-90% is methane -- CH4
Conventional natural gas
Pipelines
Liquefied petroleum gas (LPG)
Liquefied natural gas (LNG)
Low net energy yield
Makes U.S. dependent upon unstable countries like Russia and Iran

37. Natural Gas Burned Off at Deep Sea Oil Well
Figure 15.11: Natural gas found above a deep sea oil well deposit or in a remote land area is usually burned off (flared) because no pipeline is available to collect and transmit the gas to users. This practice wastes this energy resource and adds climate-changing CO2, soot, and other air pollutants to the atmosphere. Question: Can you think of an alternative to burning off this gas?
Fig , p. 380

38. Is Unconventional Natural Gas the Answer?
Coal bed methane gas
In coal beds near the earth’s surface
In shale beds
High environmental impacts or extraction
Methane hydrate
Trapped in icy water
In permafrost environments
On ocean floor
Costs of extraction currently too high

39. Trade-Offs: Conventional Natural Gas
Figure 15.12: Using conventional natural gas as an energy resource has advantages and disadvantages (Concept 15-3). Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Do you think that the advantages of using conventional natural gas outweigh its disadvantages?
Fig , p. 381

40. 15-4 What Are the Advantages and Disadvantages of Coal?
Concept 15-4A Conventional coal is plentiful and has a high net energy yield and low cost, but it has a very high environmental impact.
Concept 15-4B Gaseous and liquid fuels produced from coal could be plentiful, but they have lower net energy yields and higher environmental impacts than conventional coal has.

41. Coal Is a Plentiful but Dirty Fuel (1)
Coal: solid fossil fuel
Burned in power plants; generates 42% of the world’s electricity
Inefficient
Three largest coal-burning countries
China
United States
Canada

42. Coal Is a Plentiful but Dirty Fuel (2)
World’s most abundant fossil fuel
U.S. has 28% of proven reserves
Environmental costs of burning coal
Severe air pollution
Sulfur released as SO2
Large amount of soot
CO2
Trace amounts of Hg and radioactive materials

43. Stages in Coal Formation over Millions of Years
Figure 15.14: Over millions of years, several different types of coal have formed. Peat is a soil material made of moist, partially decomposed organic matter and is not classified as a coal, although it too is used as a fuel. The different major types of coal vary in the amounts of heat, carbon dioxide, and sulfur dioxide released per unit of mass when they are burned.
Fig , p. 382

44. Increasing moisture content Increasing heat and carbon content
Peat
(not a coal)
Lignite
(brown coal)
Bituminous
(soft coal)
Anthracite
(hard coal)
Heat
Pressure
Partially decayed plant matter in swamps and bogs; low heat content
Low heat content; low sulfur content; limited supplies in most areas
Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content
Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas
Stepped Art
Fig , p. 382

45. Science: Coal-Burning Power Plant
Figure 15.15: Science.
This power plant burns pulverized coal to boil water and produce steam that spins a turbine to produce electricity. The steam is cooled, condensed, and returned to the boiler for reuse. Waste heat can be transferred to the atmosphere or to a nearby source of water. The largest coal-burning power plant in the United States, located in Indiana, burns three 100-car trainloads of coal per day. There are about 600 coal-burning power plants in the United States. The photo shows a coal-burning power plant in Soto de Ribera, Spain. Question: Does the electricity that you use come from a coal-burning power plant?
Fig , p. 382

46. Air Pollution from a Coal-Burning Industrial Plant in India
Figure 15.16: This coal-burning industrial plant in India produces large amounts of air pollution because it has inadequate air pollution controls.
Fig , p. 383

47. CO2 Emissions Per Unit of Electrical Energy Produced for Energy Sources
Figure 15.17: CO2 emissions, expressed as percentages of emissions released by burning coal directly, vary with different energy resources. Question: Which produces more CO2 emissions per kilogram, burning coal to heat a house or heating with electricity generated by coal? (Data from U.S. Department of Energy)
Fig , p. 383

48. World Coal and Natural Gas Consumption, 1950-2009
Figure 7, Supplement 9

49. Coal Consumption in China and the United States, 1980-2008
Figure 8, Supplement 9

50. Coal Deposits in the United States
Figure 19, Supplement 8

51. Trade-Offs: Coal
Figure 15.18: Using coal as an energy resource has advantages and disadvantages (Concept 15-4a). Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Do you think that the advantages of using coal as an energy resource outweigh its disadvantages?
Fig , p. 384

52. Case Study: The Problem of Coal Ash
Highly toxic
Arsenic, cadmium, chromium, lead, mercury
Ash left from burning and from emissions
Some used as fertilizer by farmers
Most is buried or put in ponds
Contaminates groundwater
Should be classified as hazardous waste

53. The Clean Coal and Anti-Coal Campaigns
Coal companies and energy companies fought
Classifying carbon dioxide as a pollutant
Classifying coal ash as hazardous waste
Air pollution standards for emissions
2008 clean coal campaign
But no such thing as clean coal
“Coal is the single greatest threat to civilization and all life on the planet.” – James Hansen

54. We Can Convert Coal into Gaseous and Liquid Fuels
Conversion of solid coal to
Synthetic natural gas (SNG) by coal gasification
Methanol or synthetic gasoline by coal liquefaction
Synfuels
Are there benefits to using these synthetic fuels?

55. Trade-Offs: Synthetic Fuels
Figure 15.19: The use of synthetic natural gas (SNG) and liquid synfuels produced from coal has advantages and disadvantages (Concept 15-4b). Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Do you think that the advantages of using synfuels produced from coal as an energy source outweigh the disadvantages?
Fig , p. 385

56. 15-5 What Are the Advantages and Disadvantages of Nuclear Energy?
Concept Nuclear power has a low environmental impact and a very low accident risk, but its use has been limited by a low net energy yield, high costs, fear of accidents, long-lived radioactive wastes, and the potential for spreading nuclear weapons technology.

57. How Does a Nuclear Fission Reactor Work? (1)
Controlled nuclear fission reaction in a reactor
Light-water reactors
Very inefficient
Fueled by uranium ore and packed as pellets in fuel rods and fuel assemblies
Control rods absorb neutrons

58. How Does a Nuclear Fission Reactor Work? (2)
Water is the usual coolant
Containment shell around the core for protection
Water-filled pools or dry casks for storage of radioactive spent fuel rod assemblies 58

59. Water-Cooled Nuclear Power Plant
Figure 15.20: Science.
This water-cooled nuclear power plant, with a pressurized water reactor, pumps water under high pressure into its core where nuclear fission takes place. It produces huge quantities of heat that is used to convert the water to steam, which spins a turbine that generates electricity. Some nuclear plants withdraw the water they use from a nearby source such as a river and return the heated water to that source, as shown here. Other nuclear plants transfer the waste heat from the intensely hot water to the atmosphere by using one or more gigantic cooling towers, as shown in the inset photo of the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania (USA). There, a serious accident in 1979 almost caused a meltdown of the plant’s reactor. Question: How do you think the heated water returned to a body of water affects that aquatic ecosystem?
Fig , p. 387

60. Useful electrical energy
Small amounts of radioactive gases
Uranium fuel input (reactor core)
Control rods
Containment shell
Waste heat
Heat exchanger
Steam
Turbine
Generator
Hot coolant
Useful electrical energy
about 25%
Hot water output
Pump
Pump
Coolant
Pump
Pump
Waste heat
Figure 15.20: Science.
This water-cooled nuclear power plant, with a pressurized water reactor, pumps water under high pressure into its core where nuclear fission takes place. It produces huge quantities of heat that is used to convert the water to steam, which spins a turbine that generates electricity. Some nuclear plants withdraw the water they use from a nearby source such as a river and return the heated water to that source, as shown here. Other nuclear plants transfer the waste heat from the intensely hot water to the atmosphere by using one or more gigantic cooling towers, as shown in the inset photo of the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania (USA). There, a serious accident in 1979 almost caused a meltdown of the plant’s reactor. Question: How do you think the heated water returned to a body of water affects that aquatic ecosystem?
Cool water input
Moderator
Shielding
Pressure vessel
Coolant passage
Water
Condenser
Periodic removal and storage of radioactive wastes and spent
fuel assemblies
Periodic removal and storage
of radioactive
liquid wastes
Water source
(river, lake, ocean)
Fig a, p. 387

61. Fission of Uranium-235
Figure 2.9: There are three types of nuclear changes: natural radioactive decay (top), nuclear fission (middle), and nuclear fusion (bottom).
Fig. 2-9b, p. 43

62. Nuclear fission Uranium-235 Energy Fission fragment n n Neutron n n
Figure 2.9: There are three types of nuclear changes: natural radioactive decay (top), nuclear fission (middle), and nuclear fusion (bottom).
Radioactive isotope Radioactive decay occurs when nuclei of unstable isotopes
spontaneously emit fast-moving chunks of matter (alpha particles or beta particles), high-energy radiation (gamma rays), or both at a fixed rate. A particular radioactive isotope may emit any one or a combination of the three items shown in the diagram.
Fig. 2-9b, p. 43

63. What Is the Nuclear Fuel Cycle?
Mine the uranium
Process the uranium to make the fuel
Use it in the reactor
Safely store the radioactive waste
Decommission the reactor

64. Science: The Nuclear Fuel Cycle
Figure 15.21: Science.
Using nuclear power to produce electricity involves a sequence of steps and technologies that together are called the nuclear fuel cycle. As long as a reactor is operating safely, the power plant itself has a fairly low environmental impact and a very low risk of an accident. But considering the entire nuclear fuel cycle, the financial costs are high and the environmental impact and other risks increase. Radioactive wastes must be stored safely for thousands of years, several points in the cycle are vulnerable to terrorist attack, and the technology used in the cycle can also be used to produce uranium in a form that can be used in nuclear weapons (Concept 15-5). All in all, an amount of energy equal to about 92% of the energy content of the nuclear fuel is wasted in the nuclear fuel cycle. As a result, electricity produced by this fuel cycle has such a low net energy yield that it cannot compete in the open marketplace with energy alternatives that have higher net energy yields, unless it is supported by huge government subsidies. Question: Do you think the market price of nuclear-generated electricity should include all the costs of the nuclear fuel cycle or should governments (taxpayers) continue to subsidize nuclear power? Explain.
Fig , p. 388

65. What Happened to Nuclear Power?
Slowest-growing energy source and expected to decline more
Why?
Economics
Poor management
Low net yield of energy of the nuclear fuel cycle
Safety concerns
Need for greater government subsidies
Concerns of transporting uranium

66. Global Energy Capacity of Nuclear Power Plants
Figure 10, Supplement 9

67. Nuclear Power Plants in the United States
Figure 21, Supplement 8

68. Case Study: Chernobyl: The World’s Worst Nuclear Power Plant Accident
April 26, 1986
In Chernobyl, Ukraine
Series of explosions caused the roof of a reactor building to blow off
Partial meltdown and fire for 10 days
Huge radioactive cloud spread over many countries and eventually the world
350,000 people left their homes
Effects on human health, water supply, and agriculture

69. Trade-Offs: Conventional Nuclear Fuel Cycle
Figure 15.22: Using the nuclear power fuel cycle (Figure 15-21) to produce electricity has advantages and disadvantages (Concept 15-5). Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Do you think that the advantages of using the conventional nuclear power fuel cycle to produce electricity outweigh its disadvantages? Explain.
Fig , p. 389

70. Trade-Offs: Coal versus Nuclear to Produce Electricity
Figure 15.23: The risks of using nuclear power, compared with the risks of using coal-burning plants to produce electricity. A 1,000-megawatt nuclear plant is refueled once a year, whereas a coal plant of the same size requires 80 rail cars of coal a day. Question: If you had to choose, would you rather live near a coal-fired power plant or a nuclear power plant? Explain.
Fig , p. 389

71. Storing Spent Radioactive Fuel Rods Presents Risks
Rods must be replaced every 3-4 years
Cooled in water-filled pools
Placed in dry casks
Must be stored for thousands of years
Vulnerable to terrorist attack

72. Dealing with Spent Fuel Rods
Figure 15.24: Science.
After 3 or 4 years in a reactor, spent fuel rods are removed and stored in a deep pool of water contained in a steel-lined concrete basin (left) for cooling. After about 5 years of cooling, the fuel rods can be stored upright on concrete pads (right) in sealed dry-storage casks made of heat-resistant metal alloys and concrete. Questions: Would you be willing to live within a block or two of these casks or have them transported through the area where you live in the event that they were transferred to a long-term storage site? Explain. What are the alternatives?
Fig , p. 390

73. Dealing with Radioactive Wastes Produced by Nuclear Power Is a Difficult Problem
High-level radioactive wastes
Must be stored safely for 10,000–240,000 years
Where to store it
Deep burial: safest and cheapest option
Would any method of burial last long enough?
There is still no facility
Shooting it into space is too dangerous

74. Case Study: High-Level Radioactive Wastes in the United States
1985: plans in the U.S. to build a repository for high-level radioactive wastes in the Yucca Mountain desert region (Nevada)
Problems
Cost: $96 billion
Large number of shipments to the site: protection from attack?
Rock fractures
Earthquake zone
Decrease national security

75. What Do We Do with Worn-Out Nuclear Power Plants?
Decommission or retire the power plant
Some options
Dismantle the plant and safely store the radioactive materials
Enclose the plant behind a physical barrier with full-time security until a storage facility has been built
Enclose the plant in a tomb
Monitor this for thousands of years

76. Can Nuclear Power Lessen Dependence on Imported Oil & Reduce Global Warming?
Nuclear power plants: no CO2 emission
Nuclear fuel cycle: emits CO2
Opposing views on nuclear power
Nuclear power advocates
2007: Oxford Research Group
Need high rate of building new plants, plus a storage facility for radioactive wastes

77. Are New Generation Nuclear Reactors the Answer?
Advanced light-water reactors (ALWR)
Built-in passive safety features
Thorium-based reactors
Cheaper and safer
But much research and development needed

78. Solutions: New Generation Nuclear Reactors
Figure 15.25: Some critics of nuclear power say that any new generation of nuclear power plants should meet all of these five criteria. So far, no existing or proposed reactors even come close to doing so.
Fig , p. 393

79. Will Nuclear Fusion Save Us?
Fuse lighter elements into heavier elements
No risk of meltdown or large radioactivity release
Still in the laboratory phase after 50 years of research and $34 billion dollars
2006: U.S., China, Russia, Japan, South Korea, and European Union
Will build a large-scale experimental nuclear fusion reactor by 2018

80. Nuclear Fusion
Figure 2.9: There are three types of nuclear changes: natural radioactive decay (top), nuclear fission (middle), and nuclear fusion (bottom).
Fig. 2-9c, p. 43

81. Experts Disagree about the Future of Nuclear Power
Proponents of nuclear power
Fund more research and development
Pilot-plant testing of potentially cheaper and safer reactors
Test breeder fission and nuclear fusion
Opponents of nuclear power
Fund rapid development of energy efficient and renewable energy resources

82. Three Big Ideas
A key factor to consider in evaluating the usefulness of any energy resource is its net energy yield.
Conventional oil, natural gas, and coal are plentiful and have moderate to high net energy yields, but using any fossil fuel, especially coal, has a high environmental impact.

83. Three Big Ideas
Nuclear power has a low environmental impact and a very low accident risk, but high costs, a low net energy yield, long-lived radioactive wastes, and the potential for spreading nuclear weapons technology have limited its use.