1. ENVIRONMENTAL SCIENCE
CHAPTER 13: Energy

2. Three Big Ideas from This Chapter - #1
E resources should be evaluated on
potential supplies
how much net useful E they provide
environmental impact of using them

3. Three Big Ideas from This Chapter - #2
Using a mix of renewable energy:
Sunlight
Wind
flowing water
sustainable biofuels
geothermal energy
can drastically reduce pollution, greenhouse gas emissions, and biodiversity losses.

4. Three Big Ideas from This Chapter - #3
Making transition to more sustainable E future requires sharply reducing E waste,
using a mix of environmentally friendly renewable E resources,
and including harmful environmental costs of E resources in their market prices.

5. Evaluating Energy Resources
Energy from the sun
Indirect forms of renewable solar energy
Wind
Hydropower
Biomass
Commercial energy
Fossil fuels – non-renewable
Nuclear – non-renewable

6. comes from non-renewable fossil fuels.
75% world’s commercial E
comes from non-renewable fossil fuels.
Rest comes from
non-renewable nuclear fuel
renewable sources.

7. Net E = high-quality E available from resource minus amount of E needed to make it available.

8. Fig. 13-2, p. 298

11. Increasing heat and carbon content
Increasing moisture content
Peat
(not a coal)
Lignite
(brown coal)
Bituminous
(soft coal)
Anthracite
(hard 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
Figure 13.9: Stages in coal formation over millions of years. 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. 13-9, p. 305 11

12. Coal Is a Plentiful But Dirty Fuel
Used in electricity production
World’s most abundant fossil fuel
U.S. reserves should last ~ 250 years
Sulfur and particulate pollutants
Mercury and radioactive pollutants

13. Waste heat Cooling tower transfers waste heat to atmosphere
Coal bunker
Turbine
Generator
Cooling loop
Stack
Pulverizing mill
Condenser
Filter
Figure 13.10: Science: coal-burning power plant. Heat produced by burning pulverized coal in a furnace boils water to 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. 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?
Boiler
Toxic ash disposal
Fig , p. 306 13

14. Coal Is a Plentiful But Dirty Fuel
Heavy carbon dioxide emissions
Pollution control and environmental costs
China major builder of coal plants

15. Case Study: The Growing Problem of Coal Ash
Highly toxic
Often stored in ponds
Ponds can rupture
Groundwater contamination
EPA: in 2009 called for classifying coal ash as hazardous waste
Opposed by coal companies

16. Clean Coal Campaign
Coal industry
Rich and powerful
Fought against labeling CO2
a greenhouse gas
“Clean coal” touted by coal industry
Mining harms the environment
Burning creates CO2 & toxic chemicals
Plan to capture and store CO2

17. Converting Coal into Gaseous and Liquid Fuels
Synfuels
Coal gasification
Synthetic natural gas (SNG)
Coal liquefaction
Methanol or synthetic gasoline
Extracting & burning coal more cleanly

18. oil formation

19. The photo shows an oil refinery in U.S. state of Texas.
Lowest Boiling Point
Gases
Gasoline
Aviation fuel
Heating oil
Diesel
oil
Naphtha
Figure 13.3: Science: refining crude oil. Components of petroleum are removed at various levels, depending on their boiling points,
in a giant distillation column. The most volatile components with the lowest boiling points are removed at the top of the column.
The photo shows an oil refinery in U.S. state of Texas.
Grease
and wax
Heated
crude oil
Asphalt
Furnace
Highest Boiling Point 19

20. How Long Will Crude Oil Supplies Last?
Crude oil is the single largest source of commercial energy in world and U.S.
Proven oil reserves
Can be extracted profitably at today’s prices
with today’s technology
80% depleted between 2050 and 2100

21. Barrels of oil per year (billions)14 13 12 11 10
Projected U.S.
oil consumption 9 8
Barrels of oil per year (billions) 7 6 5 4
Figure 13.4: The amount of crude oil that might be found in the Arctic National Wildlife Refuge, 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 would take 10–20 years and lower gasoline prices at the pump by at most 6 cents per gallon. (Data from U.S. Department of Energy, U.S. Geological Survey, and Natural Resources Defense Council) 3 2
Arctic refuge oil
output over 50 years 1
2000
2010
2020
2030
2040
2050
Year
Fig. 13-4, p. 301 21

22. US Oil Production and Use
93% of energy from fossil fuels
39% from crude oil
Produces 9% of world’s crude oil
Uses 25% of world production
Has 2% of proven crude oil reserves

23. Oil Sand and Oil Shale Oil sand (tar sand) Bitumen Kerogen Shale Oil
World reserves
Major environmental problems

24. Fig. 13-6, p. 303

26. Natural Gas Is a Useful and Clean-burning Fossil Fuel
Conventional natural gas
Unconventional natural gas

27. Liquefied natural gas (LNG)
Less CO2 emitted per unit of E than with crude oil, tar sand, shale oil
World supply of conventional natural gas: years
Unconventional natural gas
Coal-bed methane gas
Methane hydrate

29. What Are Advantages and Disadvantages of Nuclear Energy?
nuclear power fuel cycle:
low environmental impact
very low accident risk

30. What Are Advantages and Disadvantages of Nuclear Energy?
…but limited because of:
high costs
low net energy yield
long-lived radioactive wastes
vulnerability to sabotage
potential for spreading nuclear weapons
technology.

31. How Does a Nuclear Fission Reactor Work?
Light-water reactors
Boil water to produce steam to turn turbines to generate electricity
Radioactive uranium as fuel
Control rods, coolant, and containment vessels

32. storage of radioactive
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 13.14: Science: light-water-moderated and -cooled nuclear power plant with a pressurized water reactor. Some nuclear plants
withdraw water for cooling from a nearby source of water and return the heated water to that source, as shown here. Other
nuclear plants that do not have access to a source of cooling water transfer the waste heat 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).
A serious accident there in 1979 almost caused a meltdown of the plant’s reactor. Question: How does this plant differ from the coal-burning
plant in Figure 13-10?
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 , p. 310 32

33. Safety and Radioactive Wastes
On-site storage of radioactive wastes
Safety features of nuclear power plants
Nuclear fuel cycle
Reactor life cycle
Large amounts of very radioactive wastes

34. Fig , p. 311

35. Fig , p. 311

36. of spent fuel assemblies underwater or in dry casks
Decommissioning
of reactor
Fuel assemblies
Reactor
Enrichment
of UF6
Fuel fabrication
(conversion of enriched
UF6 to UO2 and fabrication
of fuel assemblies)
Temporary storage
of spent fuel assemblies
underwater or in dry casks
Uranium-235 as UF6 Plutonium-239 as PuO2
Conversion
of U3O8
to UF6
Spent fuel
reprocessing
Low-level radiation
with long half-life
Figure 13.16: Science: 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 whole nuclear fuel cycle,
costs are high, 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 material for nuclear
weapons (Concept 13-3). Also, an amount of energy equal to about 92% of the energy content of the nuclear fuel
is wasted in the nuclear fuel cycle. Question: Do you think the market price of nuclear-generated electricity should
include all the costs of the fuel cycle or should governments pay much of these costs as they do now? Explain.
Geologic disposal
of moderate and high-level
radioactive wastes
Mining uranium ore (U3O8 )
Open fuel cycle today
Recycling of nuclear fuel
Fig , p. 312 36

37. What Happened to Nuclear Power?
Optimism of 1950s is gone
Comparatively expensive source of power
No new plants in U.S. since 1978
Disposing of nuclear waste is difficult
Three Mile Island (1979)

38. Three Mile Island: Chernobyl March 28, 1979 near Harrisburg, Pa.
stuck valve in
cooling system.
$500 million cleanup of site thru 1993.
Chernobyl
26 April 1986
plume of highly radioactive smoke fallout.
50 to 200 thousand deaths.

39. Fukushima Daiichi nuclear disaster 11 March 2011
Reactors 1, 2 & 3 experienced full meltdown.
Measurements taken by the Japanese science ministry and education ministry in areas of northern Japan 30–50 km from the plant showed radioactive caesium levels high enough to cause concern.[17] Food grown in the area was banned from sale. Based on worldwide measurements of iodine-131 and caesium-137, it was suggested that the initial daily release of those isotopes from Fukushima are of the same order of magnitude as those from Chernobyl in 1986[18][19], and that the total release of radioactivity is about one-tenth that from the Chernobyl disaster[20]; Tokyo officials temporarily recommended that tap water should not be used to prepare food for infants.[21][22] Plutonium contamination has been detected in the soil at two sites in the plant,[23] although further analysis revealed that the detected densities are within limits from fallout generated from previous atmospheric nuclear weapons tests.[24] Two workers hospitalized with non-life threatening radiation burns on 25 March had been exposed to between 2 and 6 Sv of radiation at their ankles when standing in water in Unit 3.[25][26][27] Follow up examination at 11 April from National Institute of Radiological Sciences was without confirmation.[28]
Japanese officials initially assessed the accident as Level 4 on the International Nuclear Event Scale (INES) despite the views of other international agencies that it should be higher. The level was successively raised to 5 and eventually to 7, the maximum scale value.[29][30] The Japanese government and TEPCO have been criticized in the foreign press for poor communication with the public[31][32] and improvised cleanup efforts.[33] Foreign experts have said that a workforce in the hundreds or even thousands would take years or decades to clean up the area

41. Nuclear Power Is Vulnerable to Terrorist Acts
Insufficient security
On-site storage facilities
U.S.: 161 million people live within miles of an above-ground nuclear storage site

42. Dealing with Radioactive Wastes
High-level radioactive wastes
Long-term storage: 10,000–240,000 years
Deep burial
Detoxify wastes?

43. Case Study: Dealing with Radioactive Wastes in the United States
Yucca Mountain, Nevada
Concerns over groundwater contamination
Possible seismic activity
Transportation accidents & terrorism
2009: Obama ends Yucca funding

45. What Do We Do with Worn-Out Nuclear Power Plants?
Decommissioning old nuclear power plants
Dismantle power plant and store materials
Install physical barriers
Entomb entire plant
Chernobyl sarcophagus

46. What Is the Future for Nuclear Power?
Reduce dependence on foreign oil
Reduce global warming
Advanced light-water reactors
Nuclear fusion
How to develop relatively safe nuclear power with a high net energy yield?

47. Why Is Energy Efficiency an Important Energy Source?
The United States could save as much as 43% of all the energy it uses by improving the energy efficiency of industrial operations, motor vehicles, and buildings.

48. Improving Energy Efficiency
How much work we get from each unit of energy we use
Reducing energy waste
41% of all commercial energy in U.S. is wasted unnecessarily
Numerous economic and environmental advantages

49. Saving Energy and Money in Transportation
2/3 of U.S. oil consumption
Low fuel-efficiency standards for vehicles
Hidden costs: $12/gallon of gas
Raise gasoline taxes/cut payroll and income taxes
Tax breaks for fuel-efficient vehicles

50. Hybrid and Fuel-Cell Cars
Super-efficient and ultralight cars
Gasoline-electric hybrid car
Plug-in hybrid electric car
Hydrogen fuel cells
Accessible mass-transit systems as alternative

51. 50 45
Europe 40
Japan 35
China
Miles per gallon (mpg) (converted to U.S. test equivalents) 30
Canada 25
United States 20
2002
2004
2006
2008
Year 25
Cars 20
Cars, trucks, and SUVs
Trucks and SUVs 15
Average fuel economy (miles per gallon) 10
1975
1980
1985
1990
1995
2000
2005
Year
Figure 13.21: Average fuel economy of new vehicles sold in the United States, 1975–2008 (left) and fuel economy standards
in other countries, 2002–2008 (right). In 2009, President Obama called for an average of 15.1 kpl (35.5 mpg) for
new cars, vans, and SUVs in the United States by This is lower than China’s current fuel economy standard for new
vehicles and much lower than the 18.1 kpl (42.5 mpg) standard that China has set for (U.S. Environmental Protection
Agency and National Highway Traffic Safety Administration, International Council on Clean Transportation, 2008)
Stepped Art
Fig , p. 320 51

52. Conventional hybrid
Fuel tank
Battery
Internal combustion engine
Transmission
Electric motor
Plug-in hybrid
Fuel tank
Battery
Internal combustion engine
Transmission
Electric motor
Figure 13.22: Solutions: general features of a car powered by a hybrid gasoline–electric engine (left). A plug-in hybrid vehicle (right) would have a smaller internal
combustion engine and a second and more powerful battery that can be plugged into a standard 110-volt outlet and recharged. This allows it to run farther on
electricity alone. In effect, a conventional hybrid car is a car with a small internal combustion engine with a battery backup. A plug-in hybrid is an electric car with a
smaller internal combustion engine used only to recharge the battery pack.
Stepped Art
Fig , p. 321 52

53. Saving Energy and Money in New Buildings
Green architecture
Solar cells, fuel cells, eco-roofs, recycled materials
Super insulation
Straw bale houses

54. Renewable Energy Sustainability mostly depends on solar energy
Direct form: from the sun
Indirect forms
Wind
Moving water
Biomass
Geothermal

55. Benefits of Shifting to Renewable Energy Resources
More decentralized, less vulnerable
Gradual shift from centralized macropower to decentralized micropower = $ shift!
Improve national security
Reduce trade deficits
Reduce air pollution

56. Using Solar Energy to Heat Buildings and Water
Passive solar heating system
Active solar heating system

57. Supplement 9, Fig. 5, p. S41

58. Figure 13.25: Solutions: passive and active solar heating for a home.
Vent allows
hot air to
escape in
summer
Summer
sun
Heavy
insulation
Winter
sun
Superwindow
Superwindow
Figure 13.25: Solutions: passive and active solar heating for a home.
Stone floor and wall for heat storage
PASSIVE
Fig , p. 325 58

59. Fig , p. 325

60. Solar Energy for High-Temperature Heat and Electricity
Solar thermal systems
Solar thermal plant
Solar cookers
Photovoltaic (solar) cells
Mike & David Hartkop

61. Solar Energy for High-Temperature
Trade-Offs
Solar Energy for High-Temperature
Heat and Electricity
Advantages
Disadvantages
Moderate environmental
impact
Low efficiency
Low net energy
High costs
No CO2 emissions
Environmental costs not
included in market price
Figure 13.27: Advantages and disadvantages of using solar energy to generate high-temperature heat and
electricity (Concept 13-5). Questions: Which single advantage and which single disadvantage do you
think are the most important? Why?
Fast construction
(1–2 years)
Needs backup or storage
system
Needs access to sun most of
the time
Costs reduced with
natural gas turbine
backup
May disturb desert areas
Fig , p. 326 61

63. Panels of solar cells Solar shingles
Single solar cell
Solar-cell roof
Boron-enriched
silicon
Junction
Phosphorus-
enriched silicon
Roof options
Figure 13.29: Solutions: Photovoltaic (PV) or solar cells can provide electricity for a house or building using solar cell
roof shingles, as shown in this house in Richmond Surrey, England. Solar-cell roof systems that look like a metal
roof are also available. In addition, new thin-film solar cells can be applied to windows and outside walls.
Panels of solar cells
Solar shingles
Fig , p. 328 63

64. Fig , p. 328

65. Producing Electricity from Flowing Water
Hydropower
Leading renewable energy source
Much unused capacity
Dams and reservoirs
Turbines generate electricity
Eventually fill with silt
Micro-hydro generators

66. Producing Electricity from Wind
Indirect form of solar energy
World’s second fastest-growing source of energy
Vast potential
Land
Offshore

70. Supplement 9, Fig. 8, p. S43

71. Energy from Burning Biomass
Wood
Agricultural waste
Plantations
Charcoal
Animal manure
Common in developing countries
Carbon dioxide increase in atmosphere

72. Converting Plant Matter to Liquid Biofuel
Biofuels
Ethanol and biodiesel
Crops can be grown in most countries
No net increase in carbon dioxide emissions
Available now
Sustainability

73. Energy by Tapping the Earth’s Internal Heat
Geothermal energy
Geothermal heat pumps
Hydrothermal reservoirs
Steam
Hot water
Deep geothermal energy

75. Supplement 9, Fig. 9, p. S43

76. Supplement 9, Fig. 10, p. S44

77. Can Hydrogen Replace Oil?
Hydrogen is environmentally friendly
Problems
Most hydrogen is in water
Net energy yield is negative
Fuel is expensive
Air pollution depends on production method
Storage

78. Science Focus: The Quest to Make Hydrogen Workable
Bacteria and Algae
Electricity from solar, wind, geothermal
Storage: liquid and solid
Preventing explosions

79. any disadvantages of a more decentralized power system?
Small solar-cell
power plants
Bioenergy power plants
Wind farm
Solar-cell
rooftop
systems
Commercial
Fuel cells
Rooftop solar-
cell arrays
Residential
Small wind
turbine
Smart electrical
and distribution
system
Figure 13.40: Solutions: decentralized power system in which electricity is produced by a large number of dispersed,
small-scale micropower systems. Some would produce power on site; others would feed the power they produce into
a modern electrical distribution system. Over the next few decades, many energy and financial analysts expect a shift to
this type of power system, largely based on locally available renewable energy resources. Question: Can you think of
any disadvantages of a more decentralized power system?
Microturbines
Industrial
Stepped Art
Fig , p. 339 79

80. Transition to a More Sustainable Energy Future
Gradual shift from centralized macropower to decentralized micropower
Greatly improved energy efficiency
Temporary use of natural gas
Decrease environmental impact of fossil fuels