Visualizing Environmental Science
Nonrenewable Energy
Resources
Chapter 17
Chapter 7
[chapter opener image]
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Energy Consumption
• Human society depends on energy
– Grow, store, cook food; warm/cool homes; extract/process natural
resources, manufacture items; transportation
• Per capita consumption of energy is much higher in developed
than developing countries
− In U.S., 31% of total energy is
for industry
− 41% consumed by buildings
(homes and offices)
− 28% transportation
− In developing countries,
industrial energy use is lower,
and household use higher
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Energy Consumption
• Human society depends on energy
– Global energy
consumption increases
almost every year (biggest
increases in India and
China)
– World’s energy
requirements will increase
as populations become
larger
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Coal
• Most abundant fossil fuel
– Mostly found in Northern
Hemisphere
• U.S., Russia, China, Australia,
India, Germany, South Africa
have largest deposits
• U.S. has 25% of world’s coal
deposits
– 100+ years’ reserve
– Used to produce electricity
and steel
– Consumption has surged in
recent years
• China and India
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Coal
• Coal mining
– Surface mining
• Within 30 m of the surface
• First removes soil, subsoil, and overlying
rock strata
• Usually safer for miners, less expensive
• Disrupts the land extensively
• 60% of U.S. coal is obtained this way
– Subsurface mining (deep
underground)
• Approximately 40% of coal mined in the
U.S.
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Coal
• Environmental impacts of coal mining
– Substantial effects on the environment
• Topsoil loss (from erosion or removal during mining)
prevents restoration of site
• Landslides occur due to loss of soil-stabilizing
vegetation
• Acid and toxic mineral drainage leaches from minerals
exposed in mine waste
– Acid mine drainage—sulfuric acid and dangerous dissolved
materials, such as lead, arsenic, and cadmium, wash from coal
and metal mines into nearby lakes and streams
• Streams become polluted with silt runoff and acid mine
drainage
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Coal
• Environmental impacts of coal mining
– Mountaintop removal
• One of most destructive mining methods
• Has leveled 15–25% of mountains in southern West Virginia
• Valleys and streams between mountains are obliterated; filled
in with tailings and debris
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Coal
• Environmental impacts of coal burning
– Contributes more air pollutants than oil or natural
gas
– Coal-burning electric power plants produce 1/3 of
all airborne mercury emissions
– When coal is burned it produces sulfur and
nitrogen oxides, which react with water in the
atmosphere and produce acid deposition
– Releases more CO2 into the atmosphere (per unit
of heat produced) than other fossil fuels
© 2014 John Wiley & Sons, Inc. All rights reserved.
Coal
• Making coal cleaner
– Scrubbers and other technologies can be used to
remove sulfur and particulates from emissions
• In scrubbers, chemicals react with exhaust from burning coal
and precipitate out the polluting emissions
• Fluidized-bed combustion
– Crushed coal is mixed with limestone to neutralize acidic
compounds
– Produces fewer nitrogen oxides and removes sulfur
– Produces more heat per unit, so reduces CO2 emissions
– Clean Air Act—1990
• Provides incentives for utility companies to convert to clean
coal technologies
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Oil and Natural Gas
• Provide 56% of world’s energy
• In U.S., supplies approximately 62% energy
– Coal 21%
– Nuclear power 9%
– Renewables 7%
(hydropower, wind,
solar)
– Liquid biofuels 1%
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Oil and Natural Gas
• Petroleum, or crude oil
– Refining separates crude oil
into different products based
on boiling points
• Gases, jet fuel, heating oil,
diesel, asphalt
– Petrochemicals
• Oil is used to produce
fertilizers, plastics, paints,
pesticides, medicines, synthetic
fibers
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Oil and Natural Gas
• Natural gas
• Methane is used primarily for
heating residential and
commercial buildings, and
generating electricity
• Ethane
• Propane
• Butane
– Liquefied petroleum gas
• Propane and butane are
separated and stored in
pressurized tanks as a liquid
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Natural Gas Uses
• Electricity generation
• Transportation
– Environmental advantages over gasoline/diesel
• Cooling and Heating
• Plastics and fertilizer production
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Oil and Natural Gases
• Main disadvantage
– Deposits are located far from where gas is needed
– Costs four times more to transport through
pipelines than crude oil
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Reserves of Oil and Natural Gases
• On every continent, but uneven distribution
• More than half of oil reserves in Persian Gulf
– Venezuela, Mexico, Russia, Kazakhstan, Libya, U.S.
• About half of natural gas reserves are in Russia
and Iran
• Large oil deposits under continental shelves and
adjacent deep-water areas
• Hydraulic fracturing (fracking) techniques have
changed estimates of natural gas resources
– Expensive, environmentally disruptive
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Oil and Natural Gases
• How long will supplies last?
– Cannot predict
• Technological breakthroughs and new reserves
discovered
• Most optimistic predictions - global oil production will
peak around 2035
• Natural gas is more plentiful, production will continue
to rise for perhaps 10 more years after that
© 2014 John Wiley & Sons, Inc. All rights reserved.
Environmental Impacts of Oil and
Natural Gas
• Oil
–
–
–
–
CO2 production contributes to global warming
Acid deposition
Photochemical smog
Nitrogen oxides (almost no sulfur oxides)
• Natural gas
–
–
–
–
Relatively clean
No sulfur
Releases far less CO2 and hydrocarbons
Almost no particulates compared to oil and coal
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Major Oil Spills in the U.S.
• Deepwater Horizon
drilling platform
explosion—2010
– 11 workers died
– 4 million barrels of
crude oil spilled from
the damaged well at the
ocean floor in the Gulf
of Mexico
– Fisheries disrupted,
wildlife killed, extensive
ecological damage
occurred
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Major Oil Spills in the U.S.
• Exxon Valdez supertanker—1989
– 260,000 barrels/10.9 million gallons of
crude oil
• Prince William Sound, along coast of Alaska
– 300,000 birds and 3500–5500 sea otters
died
– Orca and harbor seal populations
declined
– Salmon migration was disrupted
– Fishing season was halted
– After ‘completing’ the cleanup, shores
were still contaminated and continued
damage to birds, fishes, and mammals
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Major Oil Spills in the U.S.
• Oil Pollution Act of 1990
– Liability for damages to natural resources resulting
from oil spills, including a trust fund to pay for
damages when responsible party cannot
– Requires double hulls on tankers entering U.S.
waters by 2015
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Earth’s Largest Oil Spill
• Persian Gulf War—1991
–
–
–
–
6 million barrels deliberately dumped into Persian Gulf
Oil wells set on fire
Lakes of oil spilled into the desert around wells
May take a century or more for area to recover
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Case Study
• The Arctic National Wildlife Refuge (ANWR)—
1980
– “America’s Serengeti”
• Biologically rich-home to many species
• Fragile ecosystem
– Environment vs. economy conflict
• Proposed opening of area to oil exploration
• Supporters—economic considerations are main reason
for drilling; make U.S. less dependent on foreign oil
• Detractors—money spent on exploration would be
better spent on developing alternative, renewable fuel
sources, and energy conservation
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Case Study
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Nuclear Energy
• Atoms are composed of
–
–
–
–
Protons (+)
Neutrons (0)
Electrons (–)
Protons and neutrons are
in the nucleus, and electrons
orbit the nucleus
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Nuclear Energy
• Two different types of nuclear reactions
– Fission
• Splitting of nucleus into two smaller fragments,
accompanied by the release of large amounts of energy
– E.g., a neutron crashes into a nucleus of uranium
• Used in nuclear power plants
– Fusion
• Two small atoms are combined to form a large atom of
a different element
– E.g., process that powers the sun and other stars
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Nuclear Energy
• Fission process in U-235 atoms
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Nuclear Energy
• Fission of U-235 releases an
enormous amount of heat,
which is used to convert
water into steam
• Steam then drives a turbine,
generating electricity
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Nuclear Energy and Fossil Fuels
• Nuclear power production
steadily increasing
– Concerns for climate change
– Increasing demand for energy
• Decreases demand on foreign oil
– Expensive to build
• Nuclear energy generates
radioactive waste
– Spent fuel, coolant fluids and
gases
– Special measures for safe
storage and disposal
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Nuclear Energy
• Three Mile Island, Pennsylvania, USA 1979
– Most serious commercial reactor accident in U.S.
– Partial meltdown of reactor core
– Most radioactive material was kept in
containment building, did not escape
– No substantial environmental or human damage
– New regulations were put in place
• More frequent inspections
• Risk assessments
• Improved emergency and evacuation plans
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Nuclear Energy
• Chernobyl, Ukraine 1986
– 1-2 explosions ripped apart reactor and released
large amounts of radioactive material into
environment
– Increases in birth defects, leukemia, thyroid cancer,
abnormal immune systems
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Nuclear Energy
• Fukushima Daiichi, Japan
– Tsunami following an underwater 9.0 earthquake in
March 2011, disrupted normal and backup reactor
cooling systems
– Three of six reactors had meltdowns
– Overheating led to hydrogen gas buildup and
explosion in one reactor
– Contamination from accident extensive to both ocean
and local land areas
– Neighboring areas permanently evacuated
– High radiation levels will limit seafood catches locally
for decades
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Nuclear Energy
© 2014 John Wiley & Sons, Inc. All rights reserved.
Nuclear Energy
• Link between nuclear energy and nuclear
weapons
– Fission is the process involved in both
– Countries with nuclear power plants have access
to material for nuclear weapons
• Spent fuel is reprocessed into plutonium
• Leaders worried about terrorist groups and some
nations (Iran, North Korea)
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Radioactive Wastes
• Low-level
– Glassware, tools, paper, clothing, etc.
– Produced by power plants, nuclear medical facilities, university
research labs
– Stored in four sites in the U.S.
• High-level
– Produced during nuclear fission in reactors
• Fuel rods and assemblies, coolants, air and gases from reactor,
reprocessing of spent fuel
– Among the most dangerous human-made hazardous wastes
• Difficult to store; toxic and produce considerable amounts of heat
– Secure storage must be guaranteed for thousands of years
• Commercial nuclear power plants store spent fuel on-site,
but none are designed for long-term storage
• Currently no long-term centralized storage in U.S.
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Radioactive Wastes
• Recommended storage
– Stable rock formations deep in the ground
• In 1987 the U.S. Department of Energy
announced plans to build the first high-level
waste repository on a barren desert ridge under
Yucca Mountain, Nevada.
• President Obama cut off funding for the project
in 2009 after 20 years of research and $100
billion in exploratory drilling and development.
• No countries have successfully selected or
developed long-term storage facilities for highlevel nuclear waste as of 2012
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EnviroDiscovery
• A nuclear waste nightmare
– Over past three decades Soviet (now Russian)
practices have violated international standards
• Billions of gallons of radioactive waste pumped directly
underground
• Wastes dumped into the ocean, more than double of
the waste of 12 nuclear nations combined
• Potential health and environmental hazards unknown
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Decommissioning Nuclear
Power Plants
• Nuclear power plants do not last forever
– Critical components become brittle or corroded and eventually
the plants must be shut down and decommissioned
• Three options for decommissioning
– Storage
• Utility company guards facility for 50–100 years while radioactive
materials decay, making it safer to dismantle later
– Entombment
• Permanently encase plant in concrete
• Tomb would have to remain viable for 1000+ years—not viable option
– Immediate dismantling
• Robotics make it feasible to dismantle ‘hot’ sections of plant
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