Chapter 11: Fossil Fuels
8/28/2012 1:12:00 AM
Fossil Fuels
 Energy Policy and Conservation Act: signed by President Ford in
1975 to help cope with oil dependence problems
 Strategic Petroleum Reserve: one of the provisions to protect
against the economic damage caused by interruptions in petroleum
supplies
o Emergency supply of up to 1 billion barrels of oil
 Stored in underground salt caverns along the coast of
the Gulf of Mexico
 The US has been very dependent on foreign oil
o Fought a war in Persian Gulf partially because of our oil
dependency
Energy Consumption
 Energy demands increased
o Have to meet these demands by increasing energy efficiency
Fossil Fuels
 Fossil Fuel: combustible deposits in Earth’s crust, composed of the
remnants of prehistoric organisms that existed millions of years ago
o Nonrenewable resources
 Limited supply of them
 The supply is depleted by use
How Fossil Fuels Formed
 Coal: a black combustible solid found in Earth’s crust, formed from
the remains of ancient plants that lived millions of years ago
o Really non-decomposed plant material
 Oil: a thick, yellow to black, flammable liquid hydrocarbon mixture
found in Earth’s crust
o Formed when microscopic aquatic organisms died and settled
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in the sediments
 The heat and pressure of the burial converted the
remains of the decomposed organisms into oil
Hydrocarbons: molecules containing carbon and hydrogen
o Oil is an example of a hydrocarbon
Natural gas: a mixture of gaseous hydrocarbons (primarily
methane) that occurs, often with oil deposits, in Earth’s crust
o Methane: the simplest hydrocarbon
o Formed in the same way as oil but at higher temperatures
 Typically greater than 100˚C
Chapter 11: Fossil Fuels
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Coal
-Coal exposed to high heat and pressure during its formation is drier, more
compact (harder), and has a higher heating value
The most common grades of coal:
 Lignite: a soft coal, brown or brown-black in color with a soft,
woody texture
o Moist
o Produces little heat compared with other types of coal
o Used to fuel electric power plants
o Found in the western states—largely in North Dakota
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Subbituminous coal: a grade of coal intermediate between lignite
and bituminous
o Has a relatively low heat value and sulfur content
o Found primarily in Alaska and a few western states
Bituminous coal: the most common type of coal
o AKA soft coal
o Harder than lignite and subbituminous coal
o Much bituminous coal contains sulfur
Anthracite: the highest grade of coal, with a dark black color
o AKA hard coal
o Burns most cleanly of all coals
 Produces the fewest pollutants per unit of heat released
o Not contaminated by large amounts of sulfur
 Coal is usually found in underground layers that vary in thickness
o Most, if not all major coal deposits have been identified
Coal Reserves
 Found primarily in the Northern Hemisphere
Coal Mining
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Two types of coal mines: surface and subsurface mines
o Type of mine chosen depends on surface shape and the
location
Surface mining: the extraction of mineral and energy resources
near Earth’s surface by first removing the soil, subsoil, and
overlying rock strata (i.e. the overburden)
o Done if the coal bed is within 30 m (100ft) of the surface
o Strip mining: a type of surface mining
o Spoil bank: a hill of loose rock
o Less expensive and safer for miners
o Allows a more complete removal of coal from the ground
 Subsurface mining: the extraction of mineral and energy
resources from deep underground deposits
o When the coal is deeper in the ground, it is mined
underground
o Does not disrupt the land as much
 More environmentally friendly
Safety Problems Associated with Coal
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Black lung disease: a condition in which the lungs are coated with
inhaled coal dust, and the exchange of oxygen between the lungs
and blood is severely restricted
Environmental Impacts of the Mining Process
 Surface Mining Control and Reclamation Act (SMCRA): an act
passed in 1977 that prevented surface coal minds from being
abandoned, left as large open pits or trenches
o Requires coal companies to restore areas that have been
surface mined
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o Prohibits coal mining in sensitive areas
Acid mine drainage: Pollution caused when sulfuric acid and
dangerous dissolved materials such as lead, arsenic, and cadmium,
wash from coal and metal mines into nearby lakes and streams
Dragline: a huge shovel with a 20-story-high arm
o used to take enormous chunks out of mountains
o eventually removes the entire mountaintop to reach the coal
located below
 SMCRA limits mountaintop removal
Environmental Impacts of Burning Coal
 We are releasing so much CO2 that we have disrupted the CO2
equilibrium
o Prevents heat from escaping the planet—global warming
 Increasing coastal erosion
o Burning coal contributes more air pollutants than burning oil
or natural gas
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Acid deposition: a type of air pollution in which acid falls from the
atmosphere to the surface as precipitation (acid precipitation) or as
dry acid particles
o Combustion of coal is partly responsible for acid deposition
Making Coal a Cleaner Fuel
 Scrubbers: desulfurization systems that clean power plants’
exhaust
o Remove 98% of the sulfur and 99% of the particulate matter
in smokestacks
 expensive
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Resource Recovery: the process of removing any material—sulfur
or metals, for example—from polluted emissions or solid waste and
selling it as a marketable product
o Increases the water-holding capacity of the soil
Clean Air Act Amendments of 1990: required the nation’s 111
dirtiest coal burning power plants to cut sulfur dioxide emissions
o Requires cut backs on nonrenewable resources
Clean coal technologies: new methods being developed for
burning coal that will not contaminate the atmosphere with sulfur
oxides and will significantly reduce nitrogen oxide production
Fluidized-bed combustion: a clean-coal technology in which
crushed coal is mixed with limestone to neutralize the acidic sulfur
compounds produced during combustion
o Takes place at a lower temperature than regular coal burning
o Fewer nitrogen oxides are produced
o Cheaper than desulfurization systems
Chapter 11: Fossil Fuels
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Oil and Natural Gas
 Became popular because it burns cleaner than coal
 Petroleum: a liquid composed of hundreds of hydrocarbon
compounds
o AKA crude oil
o Separated into different products based on their boiling points
 Petrochemicals: compounds in such diverse products as
fertilizers, plastics, paints, pesticides, medicines, and synthetic
fibers produced by oil
 Natural gas’ hydrocarbons:
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o Methane* MOSTLY METHANE
o Ethane
o Propane
o Butane
Liquefied petroleum gas: propane and butane that are separated
from the natural gas, stored in pressurized tanks as this liquid
Main uses of natural gas:
o Generation of electricity
 Transportation
Commercial cooling
Cogeneration: a process in which natural gas is used
to produce both electricity and steam
 When transporting natural gas over long distances, it must be
compressed to form liquefied natural gas (LNG), then carried on
refrigerated ships
o Then it must return to its gaseous state at regasification
plants before being piped to where it will be used
Exploration for Oil and Natural Gas
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Structural traps: underground geologic structures that tend to
trap any oil or natural gas if it is present
o Strata: layers (in this case when referring to rocks)
Salt domes: underground columns of salt
o Form when extensive salt deposits form at Earth’s surface
 After evaporation of water
 Ex. If a lake dries up, a salt deposit would remain
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Three-dimensional seismology- new technology that maps oil fields
3D
o Enables geologists to have a higher success rate when drilling
Reserves of Oil and Natural Gas
 Distribution of oil and natural gas deposits is uneven
 Coal bed methane: a form of natural gas associated with coal
deposits
 Continental shelves: the relatively flat underwater areas that
surround continents
o In deepwater areas—adjacent to the continental shelves
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o Most likely where large oil deposits exist under
o Environmentalists and coastal industries oppose oil and
natural gas
 Because of the threat a major oil spill would pose to
marine and coastal environments
How Long Will Oil and Natural Gas Supplies Last?
o Depends on whether world consumption of oil and natural gas
increases, remains the same, or decreases
o Economic factors affect their availability and consumption
o Natural gas is more plentiful than oil
Global Demand and Supply
 The world’s major oil producers are not its major oil consumers
 Oil is mainly imported from foreign countries
o This is much more expensive
Environmental Impacts of Oil and Natural Gas
 The problems that result from burning the fuels
o CO2
o Global Warming
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o Acid deposition
 Production of nitrogen oxides
 Smog
The problems that result in obtaining them (transportation, etc)
o Spills
The Largest Oil Spill in the US
o 1989-Exxon Valdes spilled 260,000 barrels (10.9 million gal)
crude oil into Prince William Sound along the Alaskan
coast
12,000 workers took part in the cleanup
left behind contaminated shore lines
 Cost: may exceed $10 billion (still paying)
o Oil Pollution Act: legislation that established liability for
damages to natural resources resulting from a catastrophic oil
spill
 Passed in 1990
 Includes a trust fund that pays to clean up spills when
the responsible party
 Money for this is provided by a tax on oil
 Only good thing that came from the Exxon Spill
The Largest Global Oil Spill
o 1991 during the Persian Gulf War
o 6 million barrels (250 million gallons) of crude oil
o Deliberately dumped into the Persian Gulf
o May take a century or more for the area to completely
recover
The Arctic National Wildlife Refuge
 Environment-versus-economy conflict since 1980
o Environment: want to protect rare and fragile natural
environments
o Economy: prioritize the development of some of the last
major U.S. oil supplies
 The refuge
o “America’s Serengeti”
 Home to many species—animal and plant
 In Alaska
Support for and Opposition to Oil Exploration in the Refuge
o Supporters look at the economic considerations for their
reason to drill for oil in the refuge
 Development of domestic oil would improve the balance
of trade
 Make us less dependent on foreign countries for
oil
o Conservationists think oil exploration poses permanent
threats to the balance of nature
 The money spent drilling for oil would be better spent
on research of alternative, renewable energy sources
Chapter 11: Fossil Fuels
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Synfuels and Other Potential Fossil Fuel Resources
Synfuels (synthetic fuels): a liquid or gaseous fuel that is synthesized
from coal and other naturally occurring sources and used in place of oil or
natural gas
 Tar sands: underground sand deposits permeated with a thick,
asphalt-like oil called bitumen
o AKA oil sands
 Oil shales: sedimentary rocks containing a mixture of
hydrocarbons known collectively as kerogen
o Oil shale’s are crushed and heated to yield their oil
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 Kerogen must be refined after it is mined
o Not cost efficient because mining and refinement require a
great amount of energy
Gas hydrates: reserves of ice-encrusted natural gas located deep
underground in porous rock
o AKA methane hydrates
o Massive deposits have been found in the arctic tundra
o Expensive
 Most deposits are too small to be removed economically
Coal liquefaction: a process in which a nonalcohol liquid fuel
similar to oil can be produced from coal
o Liquid fuel is cleaned before burning
o Less polluting than solid coal
Coal gas: a gaseous product of coal
Coal gasification: production of the combustible gas methane
from coal by reacting it with air and steam
o Coal gas is a plus over solid coal
 Coal gas burns almost as cleanly as natural gas
Scrubbers are not needed because sulfur is being
removed during coal gasification
 More expensive, though
Environmental Impacts of Synfuels
o Combustion releases enormous quantities of CO2 and other
pollutants
 Still contributing to global warming and air pollution
o Coal gas requires large amount of water during production
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Limited use in arid areas
 Less water—water shortages
o Large areas of land would have to be surface mined to
recover the fuel in the tar sands and oil shades
o **OBVIOUSLY STILL FLAWED**
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The U.S. Energy Strategy
 The supply of fuels is limited
 The production, transport, and use of fossil fuels pollute the
environment
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Our heavy dependence on foreign oil makes us economically
vulnerable and unstable
Objectives:
o Increase Energy Efficiency and Conservation
o Secure Future Fossil Fuel Energy Supplies
o Develop Alternative Energy Sources
o Meet the First Three Objectives without Further Damage to
the Environment