Chapter 11 Fossil Fuels

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Chapter 11Fossil Fuels
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Overview

• Energy Sources and Consumption
• How Fossil Fuels are Formed
• Coal
• Coal Reserves and Mining
• Environmental Impacts
• Oil and Natural Gas
• Exploration for Reserves of Oil and Natural Gas
• Environmental Impacts
• Arctic National Wildlife Refuge
• Synfuels
• US Energy Strategy

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Energy Sources and Consumption

• Energy sources used to be local
• Now they are worldwide
• Fossil fuels (55.5 imported)
• Nuclear energy
• Electricity
• Energy consumption is different between
  developing and developed nations
• 20 of worlds population use 60 of the worlds
  energy sources (developed uses 8xs more than
  developing)

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• Per capita energy consumption of selected
  developed and developing countries

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• Energy consumption in the US
• Industries (production) use the most
• Heating, cooling, and illuminating building is 1/3

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Fossil Fuels

• Combustible deposits in the Earths crust
• Composed of the remnants (fossils) of prehistoric
  organisms that existed millions of years ago
• Includes coal, oil (petroleum) and natural gas
• Non-renewable resource
• Fossil fuels are created too slowly to replace
  the reserves we use
• We will have to transition to other sustainable
  fuels in the future

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How Are Fossil Fuels Formed?

• 300 million years ago
• Climate was mild
• Vast swamps covered much of the land
• Dead plant material decayed slowly in the swamp
  environment

Plants include giant ferns, horsetails, and club
mosses
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How Are Fossil Fuels Formed

• Over time, layers of sediment accumulated over
  the dead plant material
• Coal
• Heat, pressure and time turned the plant material
  into carbon-rich rock (coal)
• Oil
• Sediment deposited over microscopic plants
• Heat pressure and time turned them into
  hydrocarbons (oil)
• Natural Gas
• Formed the same way as oil, but at temperatures
  higher than 100 C

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Coal

• Occurs in different grades
• Based on variations in heat and pressure during
  burial
• Lignite
• Subbitumimous
• Bituminous
• Anthracite
• Most, if not all, coal deposits have been
  identified
• Primarily in northern hemisphere

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Coal Types and Quality

• Lignite poor quality, dark brown, 30 carbon,
  11.41 (per 2000 lbs to mine), heat value 6000
  btu/lb
• Subbituminous Poor quality but better, dull
  black, 40 carbon, 7.12, heat value 9000 btu/lb
• Bituminous also called soft coal, high sulfur ,
  50-70 carbon, 24.15 to mine, 13000 btu/lb
• Antracite- black, high quality, low sulfur,90
  carbon, 40.90 to mine, 14,000 btu/lb (fig 10.1)

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Coal

• US has 25 of worlds coal supplies
• Known coal deposits could last 200 years
• At present rate of consumption

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2 Types of Coal Mining

• Surface mining (right)
• Chosen if coal is within 30m of surface
• mineral and energy resources are extracted near
  Earths surface by first removing the soil,
  subsoil, and overlying rock strata
• Subsurface mining
• Extraction of mineral and energy resources from
  deep underground deposits

Surface mine near Wyoming
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Environmental Impacts of Mining Coal

• Surface Mining Control and Reclamation Act (1977)
• Requires filling (reclaiming) of surface mines
  after mining
• Expensive!
• Reduces Acid Mine Drainage
• Requires permits and inspections of active coal
  mining sights
• Prohibits coal mining in sensitive areas
• Mountaintop Removal
• Fills valleys and streams with debris
• Most land destructive tecnique

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Environmental Impacts of Burning Coal

• Releases large quantities of CO2 into atmosphere
• Greenhouse gas
• Releases other pollutants into atmosphere
• Mercury
• Sulfur oxides
• Nitrogen oxides
• Can cause acid precipitation

Dead trees enveloped in acid fog on Mt. Mitchell,
North Carolina
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Making Coal Cleaner

• Scrubbers
• Fluidized Bed Combustion (below)

1. Coal and limestone suspended
2. Coal burns and limestone neutralizes most of
   sulfur dioxide
3. Heat converts water to steam
4. This powers industrial processes

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Oil and Natural Gas

• Oil and gas provide 60 of worlds energy
• They provide 63 of USs energy, 23 provided by
  coal

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Petroleum Refining

• Numerous hydrocarbons present in crude oil
  (petroleum) are separated
• Based on boiling point
• Natural gas contains far fewer hydrocarbons than
  crude oil
• Methane, ethane, propane and butane

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Oil and Natural Gas Exploration

• Oil and natural gas migrate upwards until they
  hit impermeable rock
• Usually located in structural traps

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Oil Reserves

• Uneven distribution globally
• More than half is located in the Middle East
  which includes Iran, Iraq, Kuwait, Oman, Qatar,
  Saudi Arabia, Syria, Yemen, and the United Arab
  Emirates

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Natural Gas Reserves

• Uneven distribution globally
• More than half is located in Russia and Iran
  (app. 48 of worlds deposits)

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How long will Supplies Last?

• Difficult to determine and estimates vary
• Depends on

• How many more deposits will be located
• What technology might be available to extract
  deeper resources
• Changes in global consumption rates
• Experts indicate there may be shortages in 21st
  century

Long lines at gas station as a result of the OPEC
oil embargo in 1973
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Environmental Impacts of Oil and Natural Gas

• Combustion
• Increase carbon dioxide and pollutant emissions
  (nitrogen oxides/photochemical smog)
• Natural gas is far cleaner burning than oil
• Production
• Disturbance to land and habitat
• Transport
• Spills- especially in aquatic systems
• Ex Alaskan Oil Spill (1989)

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1989 Alaskan Oil Spill
Water currents caused the oil to spread hundreds
of miles
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1989 Alaskan Oil Spill

• Exxon Valdez hit a reef and spilled 260,000
  barrels of crude oil into sound
• Largest oil spill in US history
• Led to Oil Pollution Act of 1990

Worker attempting to cleanup rocky shoreline of
Eleanor Island
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Case in Point - Arctic National Wildlife Refuge
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Synfuel and Other Fossil Fuel Resources

• Synfuel
• A liquid or gaseous fuel that is synthesized from
  coal and other naturally occurring sources
• Used in place of oil or natural gas
• Include
• Tar sands
• Oil shales
• Gas hydrates
• Liquefied coal
• Coal gas (right)

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US Energy Strategy

• Objective 1 Increase Energy Efficiency and
  Conservation
• Requires many unpopular decisions
• Examples
• Decrease speed limit to conserve fuel
• Eliminate government subsidies
• Objective 2 Secure Future Fossil Fuel Energy
  Supplies
• 2 oppositions environmental and economic

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US Energy Strategy

• Objective 3 Develop Alternative Energy Sources
• Who should pay for this? Gas taxes?
• Objective 4 Meet the First Three Objectives
  Without Further Damage to the Environment

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National Energy Policy (2005)