fossil fuels - weebly
TRANSCRIPT
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Fossil Fuels
+Unit Outline
Energy Consumption
Formation of Fossil Fuels
Coal
Oil and Natural Gas
Synfuels and Other Potential Fossil Fuel Resources
U.S. Energy Strategy
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http://www.colbertnation.com/the-colbert-report-videos/261997/january-18-2010/coal-comfort---margaret-
palmer?xrs=share_copy
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+Energy Consumption
Dependency on foreign fuel:
1973 – OPEC decreased oil to US in response to Israel/Arab
conflicts economic recession
1979 – Iranian revol. decreased oil production; oil costs rose
1980’s – Cheap gas oil consumption increased
1990’s – Increase dependency on foreign oil, higher prices,
recession
2000’s – Over 50% of US oil is imported
+Energy Consumption
Strategic Petroleum Reserve
Emergency supply of oil
safeguard for US economy as a result of oil shortages
Energy Policy and Conservation Act –
Series of laws to help US decrease oil dependency
Nixon (1973), Ford, & Carter administration
OPEC – Organization of Petroleum Exporting
Countries
+Energy Consumption
Developed Countries
Greater (8x) per capita
consumption
20% world population
60% world energy
consumption
Ex. Agriculture – much
more energy intense in
developed countries
Stable energy
consumption????
Developing Countries
Less per capita
consumption
80% world population
40% world energy
consumption
Use firewood & charcoal
as energy source (BAD)
Greatest increase of
energy consumption
result of improved SOL
+Energy Consumption
Per capita energy consumption
+Energy Consumption
Energy consumption in the US
+Energy Consumption
Energy consumption in the US
+Energy Consumption
Energy consumption in the US
+Fossil Fuels
Fossil fuels – composed of partially
decayed remnants of organisms
Nonrenewable
Organic
+Coal
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+Coal
+Formation of Coal
Ancient swamp plants died, fell into swamp, & were covered
with water.
Slow decomposition because of watery, anaerobic
environment
Accumulation of dead plants
Sediment accumulated & covered dead plants
Heat and pressure from sediments transformed:
undecomposed plant matter into carbon-rich coal.
Sediments into sedimentary rock
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+Formation of Oil
Oil
Microscopic aquatic organisms died and settled in
sediments
Decomposition removed O2 in sediments
Subsequent anaerobic sediments halted more
decomposition
Remains covered in sediments
Heat & pressure changed remains into hydrocarbons
(OIL)
Natural Gas
Made of the simplest hydrocarbon = METHANE
Same formation process as oil, but higher temps.
+Location of Oil & Natural Gas
Found together
Less dense than sedimentary rock
Move upward through porous rock; found
beneath impermeable rock
In rocks less than 400 MYO.
+Oil & Natural Gas
+Importance of Coal
First became popular in the 18th century.
Powered the steam engine
Energy source for industrial revolution
Today:
Electricity production
Steel production
Key energy source in rapidly growing countries
+Types of Coal
lignite
subbituminous
bituminous
anthricite
+Types of Coal
Grade of coal depends upon heat & pressure levels during its formation.
High heat/pressure = more compact = higher energy content (heating value)
Lignite (lowest quality)
Soft coal, moist, little heat production
Used to fuel electric power plants
Subbituminous coal
Low heat value and sulfur content
Low S makes it desirable for power plants
Bituminous coal (most common; a.k.a. soft coal)
Contains S; high heat content
Anthracite (highest quality; a.k.a. hard coal)
Produces fewest pollutants and has highest heat capacity
+Coal Reserves
Coal is found in seams.
Enough reserves to last 200 years
+Coal
+Coal Mining
Surface
Extraction of resources near Earth’s surface
Removes soil subsoil, and overlying rock
Strip mining
series of parallel trenches are dug to remove
coal
Creates spoil bank – hill of loose rocks
Used for 60% of coal in US
Safer for miners; more complete removal of coal
Subsurface
Extraction of resources from deep underground
Used for 40% of coal in US
Less environmentally damaging
+Coal Mining
+Coal Mining
+Safety Problems of Coal
Cause 2000+ deaths / year
Mining accidents
Increased risk of cancer
Black lung disease
Coal dust coats lungs, restricting
exchange of oxygen between lungs and
blood
+Coal Mining Environmental Impacts
Abandoned mines left as open trenches or pits
Exposed highwalls
cliffs of excavated rocks
Loss of topsoil (buried &/or eroded)
Acid mine drainage
Caused by rainwater seeping through iron sulfide
minerals found in mine waste
Mountaintop removal
Dragline – large shovel that removes large chunks of
mountain top to reach coal below
+Coal Mining Environmental Impacts
Surface Mining Control and Reclamation Act, 1977
- Requires restoration of areas that have been SURFACE mined since 1977
- Requires permits and inspections of active mines and reclamation sites
- Prohibits mining in sensitive areas
- Requires that mines abandoned before 1977 must be restored using taxes on coal companies
- Mountaintop removal is EXCLUDED!!!
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Reclaimed highwall in West Virginia
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+Coal Burning Environmental Impacts
Increases CO2 (greenhouse gas) conc. in atmosphere
Disrupts equilibrium of CO2 in biosphere GLOBAL WARMING
Coal releases more CO2 per unit energy produced than other FF
Increased Hg pollution
Rapidly moves to land & water
Bioaccumulation of Hg
Causes health problems
Lower quality coals release sulfur and nitrogen dioxides
causes acid deposition
Decreases pH (5.6 2.1)
Results in lake & stream acidification and decline of aquatic
species & forests
+“Clean Coal”
Scrubbers
Removes sulfur by cleaning power plant’s exhaust
Water & lime cause pollutants in exhaust to precipitate
Remove 98% S and 99% particulate matter
Expensive
Sludge is disposal problem
Resource recovery
Selling of parts of
pollutant as a marketable
product
+“Clean Coal”
Clean Air Act Amendments (1990)
Required US’s 111 dirtiest coal burning power plants
to cut SO2 emissions
200 other power plants made more SO2 cuts by 2000
Net decrease of 10,000,000 metric tons of SO2
Also cut NO emissions
Provides incentives for clean coal technologies
+“Clean Coal”
Clean Coal Technologies
Methods of burning coal that decrease emissions
Types:
Fluidized-bed combustion
Crushed coal & limestone mix calcium sulfate removal of S
Lower temp less NO
Comperable cost to scrubbers
Coal gasification
Coal liquification
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+Oil and Natural Gas
Benefits
Easier to transport
Burn cleaner
World commercial energy sources for electrical power:
+Oil and Natural Gas
Petroleum (crude oil)
Consists of MANY hydrocarbons
Compounds separated into
different products
Gases
Gasoline
Heating oil
Diesel oil
Asphalt
Petrochemicals – in fertilizers,
plastics, paints, pesticides,
medicines, & synthetic fibers
+Oil and Natural Gas
Natural Gas – contains a few hydrocarbons
– Methane – heating in homes/businesses & electricity
– Ethane
– Propane
– Butane
Uses– Electricity
– Transportation – much less emissions than gasoline/diesel
– Cooling
– Cogeneration
– Natural gas produces electricity & steam for heating
Expensive to transport – must be compressed to liquid
Liquid petroleum gas – used in rural areas
+Exploration of Oil and Natural Gas
+Exploration of Oil and Natural Gas
Structural traps – underground structures trapping oil/NG
Strata – layers of rock
Salt domes
underground columns of salt formed from evaporation of
water
Rise above rock layers
Test holes to examine rock samples
Explosions – measure sound echoes
3-D seismology – maps oil fields
Horizontal drilling – follows geologic contours
+Oil Reserves
Uneven distribution of oil/NG
Coal bed methane – NG
associated with coal deposits
Continental shelves
Flat, underwater area surrounding
continents
Large oil deposits (ex. Gulf of
Mexico)
+Natural Gas Reserves
Reserves of Natural Gas
+Oil & Natural Gas Supplies
Supplies depend upon rate of consumption.
Economic factors influence availability and consumption.
Peak production between 2010 and 2020? 2050 and 2100?
Role of technology?
+Global Oil Demand & Supply
U.S. imports more than 50% of its oil; predicted to import
100% by 2015.
Persian Gulf nations have 65% of world’s oil reserves.
North America &
Western Europe
Consumption Production
Persian Gulf
region
50.6% 28.9%
5.9% 26.7%
+Environmental Impacts of Oil
and Natural Gas
Production – Land disturbance
Transport – Oil spills
Combustion = burning of fossil fuels
Natural gas is much cleaner than oil
Pollution
Increased CO2 emissions
1 gallon gas = 20 lb CO2 in atmosphere
Acid deposition
Produces half of NOx in atmosphere
Photochemical Smog
+Environmental Impacts of Oil
and Natural Gas
1989, Exxon Valdez oil spill
10.9 mill. gallons spilled off the coast of Alaska
Killed 30,000+ birds and 3500-5500 otters; disrupted
food web
Oil Pollution Act, 1990 – establishes liability for
damages to natural resources resulting from a
catastrophic oil spill; includes trust fund
1991, Persian Gulf War – 250 mill. gallons were
dumped into Persian Gulf & wells were set on fire
2002, Prestige – Thousands of tons of oil spilled off
the coast of Spain
+Environmental Impacts of Oil
and Natural Gas Largest Oil Spill in the US: Alaska, 1989
http://www.npr.org/templates/story/story.php?storyId=48308288
+Environmental Impacts of Oil
and Natural Gas Largest Oil Spill in the US: Alaska, 1989
+Oil and Natural Gas
Case-in-Point: The Arctic National Wildlife Refuge
+Synfuels and Other Potential
Fossil Fuel Resources Synthetic fuel – fuels that are similar
to chemical comp. of oil/NG
• Tar sands (oil sands)
• Oil shales
• Gas hydrates
• Coal liquefaction
• Coal gasification
Problems: produce CO2, use a lot
of water, & disturb large areas of
land
+Tar Sands
Underground sand deposits saturated
with thick oil.
+Tar Sands
+Oil Shales
Sedimentary rocks containing hydrocarbons.
+Gas Hydrates
Reserves of ice-encrusted natural gas in
deep, underground rock
+Coal Liquefaction
Liquid fuel similar to oil but made from coal.
+Coal Liquefaction
+Coal Gasification
Production of combustible gas from coal, air,
and steam.
+The U.S. Energy Strategy
Obj. 1: Increase energy efficiency and conservation
+The U.S. Energy Strategy
Obj. 1: Increase energy efficiency and conservation
Obj. 2: Secure future fossil fuel energy supplies
Obj. 3: Develop alternative energy sources
Obj 4: Meet above objectives without further damage to
environment