Chapter 9 Nonrenewable Energy Resources

1
Chapter 9Nonrenewable Energy Resources
2
9-1 What is Net Energy and Why Is It Important?

• Concept 9-1 Net energy is the amount of
  high-quality energy available from an energy
  resource minus the amount of energy needed to
  make it available.

3
Fossil Fuels Supply Most of Our Commercial Energy

• Solar energy
• Indirect solar energy
• Wind
• Hydropower
• Biomass
• Commercial energy
• Nonrenewable energy resources, e.g. fossil fuels
• Renewable energy resources

4
Natural Capital Important Nonrenewable Energy
Resources
Fig. 9-1, p. 188
5
Oil and natural gas
Oil storage
Coal
Geothermal energy
Contour strip mining
Oil drilling platform
Hot water storage
Geothermal power plant
Oil well
Pipeline
Gas well
Mined coal
Pipeline
Area strip mining
Pump
Drilling tower
Underground coal mine
Impervious rock
Natural gas
Oil
Water
Water is heated and brought up as dry steam or
wet steam
Water
Coal seam
Hot rock
Water penetrates down through the rock
Magma
Fig. 9-1, p. 188
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Energy Use World and United States
Fig. 9-2, p. 189
7
Nuclear power 6
Nuclear power 8
Geothermal, solar, wind 1
Geothermal, solar, wind 1
Hydropower 3
Hydropower, 3
Natural gas 23
Natural gas 21
RENEWABLE 15
RENEWABLE 7
Coal 22
Biomass 11
Biomass 3
Coal 24
Oil 40
Oil 34
NONRENEWABLE 93
NONRENEWABLE 85
World
United States
Fig. 9-2, p. 189
8
Science Focus 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

9
Science Focus Net Energy Is the Only Energy That
Really Counts (2)

• Net energy
• 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

10
Net Energy Ratios
Fig. 9-A, p. 190
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Fig. 9-A (1), p. 190
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Fig. 9-A (2), p. 190
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Fig. 9-A (3), p. 190
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9-2 What Are the Advantages and Disadvantages of
Oil?

• Concept 9-2A 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 9-2B 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.

15
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

16
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

17
Science Refining Crude Oil
Fig. 9-3, p. 191
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Lowest Boiling Point
Gases
Gasoline
Aviation fuel
Heating oil
Diesel oil
Naphtha
Grease and wax
Heated crude oil
Asphalt
Furnace
Highest Boiling Point
Fig. 9-3, p. 191
19
Most of the Worlds Remaining Oil is Not Easily
Available (1)

• Proven oil reserves
• Identified deposits that can be extracted
  profitably with current technology
• 13 countries have at least 60 of the worlds
  crude oil reserves
• Saudi Arabia 20
• United States 1.5
• Oil production peaks and flow rates to consumers

20
Most of the Worlds Remaining Oil is Not Easily
Available (2)

• Produces 9 of the worlds oil and uses 23 of
  worlds oil
• 1.5 of worlds proven oil reserves
• Imports 52 of its oil
• Should we look for more oil reserves?
• Extremely difficult
• Expensive and financially risky

21
Crude Oil in the Arctic National Wildlife Refuge
Fig. 9-4, p. 191
22
14
13
12
11
10
Projected U.S. oil consumption
9
8
7
Barrels if oil per year (billions)
6
5
4
3
Arctic refuge oil output over 50 years
2
1
0
2000
2020
2030
2040
2050
2010
Fig. 9-4, p. 191
23
Using Conventional Oil Has Advantages and
Disadvantages

• Extraction, processing, and burning of
  nonrenewable oil and other fossil fuels
• Advantages
• Disadvantages

24
Trade-Offs Conventional Oil
Fig. 9-5, p. 192
25
Will Heavy Oils from Oil Sand and Oil Shale Save
Us? (1)

• Oil sand, or tar sand contains bitumen
• Canada and Venezuela oil sand have more oil than
  in Saudi Arabia
• Extraction
• Serious environmental impact before strip-mining
• Low net energy yield Is it cost effective?

26
Will Heavy Oils from Oil Sand and Oil Shale Save
Us? (2)

• Oil shales contain kerogen
• After distillation shale oil
• 72 of the worlds 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

27
Trade-Offs Heavy Oils from Oil Shale and Oil
Sand
Fig. 9-6, p. 193
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9-3 What Are the Advantages and Disadvantages of
Using Natural Gas?

• Concept 9-3 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.

29
Natural Gas Is a Useful and Clean-Burning Fossil
Fuel (1)

• 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

30
Natural Gas Is a Useful and Clean-Burning Fossil
Fuel (2)

• Coal bed methane gas
• In coal beds near the earths 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

31
Trade-Offs Conventional Natural Gas
Fig. 9-7, p. 194
32
9-4 What Are the Advantages and Disadvantages of
Coal?

• Concept 9-4A Conventional coal is plentiful and
  produces a high net energy yield at a low cost,
  but it has a very high environmental impact.
• Concept 9-4B Synthetic fuels produced from coal
  have lower net energy yields and higher
  environmental impacts than conventional coal.

33
Coal Is a Plentiful but Dirty Fuel (1)

• Coal solid fossil fuel
• Burned in power plants generates 42 of the
  worlds electricity
• Inefficient
• Three largest coal-burning countries
• China
• United States
• Canada

34
Coal Is a Plentiful but Dirty Fuel (2)

• Worlds 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

35
Stages in Coal Formation over Millions of Years
Fig. 9-8, p. 195
36
Increasing heat and carbon content
Increasing moisture content
Anthracite (hard coal)
Lignite (brown coal)
Peat (not a coal)
Bituminous (soft coal)
Heat
Heat
Heat
Pressure
Pressure
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
Fig. 9-8, p. 195
37
Science Coal-Burning Power Plant
Fig. 9-9, p. 195
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Waste heat
Cooling tower transfers waste heat to atmosphere
Coal bunker
Turbine
Generator
Cooling loop
Stack
Filter
Pulverizing mill
Condenser
Boiler
Toxic ash disposal
Fig. 9-9, p. 195
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Waste heat
Cooling tower transfers waste heat to atmosphere
Generator
Stack
Filter
Stepped Art
Fig. 9-9, p. 195
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CO2 Emissions Per Unit of Electrical Energy
Produced for Energy Sources
Fig. 9-10, p. 196
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Trade-Offs Coal
Fig. 9-11, p. 196
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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

43
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?

44
Trade-Offs Synthetic Fuels
Fig. 9-12, p. 197
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9-5 What Are the Advantages and Disadvantages of
Nuclear Energy?

• Concept 9-5 Nuclear power has a low
  environmental impact and a low accident risk, but
  high costs, public fear of accidents, long-lived
  radioactive wastes, and the potential for
  spreading nuclear weapons technology have limited
  its use.

46
How Does a Nuclear Fission Reactor Work? (1)

• Controlled nuclear fission reaction in a reactor
• Light-water reactors
• Very inefficient
• Chain reaction with radioactive isotopes
• Fueled by uranium ore and packed as pellets in
  fuel rods and fuel assemblies
• Control rods absorb neutrons

47
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

48
Fission of Uranium-235
Fig. 9-13, p. 197
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Uranium-235
Fission fragment
Energy
n
n
Neutron
n
n
Energy
Energy
n
n
Uranium-235
Fission fragment
Energy
Fig. 9-13, p. 197
50
Water-Cooled Nuclear Power Plant
Fig. 9-14, p. 198
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Small amounts of radioactive gases
Uranium fuel input (reactor core)
Control rods
Containment shell
Waste heat
Heat exchanger
Generator
Turbine
Steam
Hot coolant
Useful electrical energy 2530
Hot water output
Pump
Pump
Coolant
Pump
Pump
Waste heat
Moderator
Cool water input
Coolant passage
Shielding
Pressure vessel
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. 9-14, p. 198
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Small amounts of radioactive gases
Uranium fuel input (reactor core)
Control rods
Containment shell
Waste heat
Heat exchanger
Hot coolant
Useful electrical energy 2530
Pump
Pump
Coolant
Pump
Pump
Waste heat
Moderator
Coolant passage
Shielding
Pressure vessel
Periodic removal and storage of radioactive
wastes and spent fuel assemblies
Periodic removal and storage of radioactive
liquid wastes
Water source (river, lake, ocean)
Stepped Art
Fig. 9-14, p. 198
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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

54
Science The Nuclear Fuel Cycle
Fig. 9-15, p. 199
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Decommissioning of reactor
Fuel assemblies
Reactor
Enrichment of UF6
Fuel fabrication
(conversion of enriched UF6 to UO to UO2 and
fabrication of fuel assemblies)
Temporary storage of spent fuel assemblies
underwater or in dry casks
Conversion of U3O8 to UF6
Uranium-235 as UF6 Plutonium-239 as PuO2
Spent fuel reprocessing
Low-level radiation with long half-life
Geologic disposal of moderate- and high-level
radioactive wastes
Open fuel cycle today Recycling of nuclear fuel
Fig. 9-15, p. 195
56
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

57
Trade-Offs Conventional Nuclear Fuel Cycle
Fig. 9-16, p. 200
58
Case Study Chernobyl The Worlds Worst Nuclear
Power Plant Accident

• Chernobyl
• 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

59
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

60
Dealing with Radioactive Wastes Produced by
Nuclear Power Is a Difficult Problem

• High-level radioactive wastes
• Must be stored safely for 10,000240,000 years
• Where to store it
• Deep burial safest and cheapest option
• Would any method of burial last long enough?
• There is still no facility

61
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

62
What Should 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

63
Can Nuclear Power Lessen Dependence on Imported
Oil Reduce Climate Change?

• 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

64
Are New Generation Nuclear Reactors the Answer?

• Smaller
• Safer?
• Do not eliminate problems of conventional nuclear
  reactors

65
Will Nuclear Fusion Save Us?

• Nuclear fusion
• 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

66
Nuclear Fusion
Fig. 9-17, p. 202
67
Reaction conditions
Fuel
Products
Neutron
Proton
Helium-4 nucleus
Hydrogen-2 (deuterium nucleus)
100 million C
Energy
Hydrogen-3 (tritium nucleus)
Neutron
Nuclear fusion occurs when two isotopes of light
elements, such as hydrogen, are forced together
at extremely high temperatures until they fuse to
form a heavier nucleus and release a
tremendous amount of energy.
Fig. 9-17, p. 202
68
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

69
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 of these fossil fuels has a
  high environmental impact.

70
Three Big Ideas

• 3. Nuclear power has a low environmental impact
  and a very low accident risk, but high costs, a
  low net energy yield, but high costs, public fear
  of accidents, long-lived radioactive wastes, and
  the potential for spreading nuclear weapons
  technology have limited its use.