Chapter 19

• Since the industrial revolution

  Fossil fuels have replaced biomass as our dominant source of energy
• Fossil fuels


  High energy content makes them more efficient to burn, ship, and store
• Uses of fossil fuels

  • Transportation
  • Manufacturing
  • Heating
  • Cooking
  • Generating electricity
• The distribution of fossil fuel reserves varies from region to region
• Developed countries consume more fossil fuel than developing countries
• In the United States, coal, oil, and natural gas supply 82% of the total energy demand
• Formation of fossil fuels

  1. Organisms performing photosynthesis

  2. Organic matter converted by heat and pressure into a fossil fuel
• Coal


  Hard blackish substance formed from woody organic matter compressed into dense, solid, carbon structures
• Coal extraction


  1. Strip mining

  2. Subsurface mining

  3. Mountaintop removal
• Coal-fired power plants


  1. Coal combustion

  2. Convert water to steam

  3. Turn turbines to produce electricity
• Crude oil


  Unrefined oil extracted from the ground
• Natural gas


  Gas consisting primarily of methane (CH4) and other volatile hydrocarbons
• Formation of oil and natural gas


  Marine plankton that died, sank to sea bottom, became buried, and transformed by time, heat, and pressure
• Refining of crude oil


  Separation of molecules by size
• Refining


  Process that separates the molecules in crude oil by size
• Uses of natural gas and petroleum

  Natural gas: electricity generation, heat, cooking

  Petroleum: fuel for vehicles, household items
• Net energy


  Difference between energy returned and energy invested
• EROI (energy returned on investment)


  Ratio of energy returned to energy invested

  Ratios rise when extraction becomes easier or more efficient, and lower when resources become depleted and harder to extract
• EROI ratios for conventional oil and natural gas in the U.S. declined from 24:1 in the 1950s to 11:1 in recent years
• Extending reach for fossil fuels

  Drilling deeper oil and gas wells

  Tapping new resources like oil sands
• Oil sands


  Mixture of moist sand and clay containing 1–20% bitumen, a thick and heavy form of petroleum
• Fossil fuel extraction has direct impacts on landscapes and natural habitats
• Oil shale


  Sedimentary rock filled with organic matter that can be processed into shale oil
• Methane hydrate


  Solid consisting of molecules of methane embedded in a crystal lattice of water molecules, found in sediments in the Arctic and ocean floor
• Current estimate of oil reserves is 1.7 trillion barrels and the rate of production is 32 billion per year, lasting 53 years
• Natural gas reserves are estimated to last 54 more years, and coal's R/P ratio is about 110 years
• In 1956, Shell Oil geologist M. King Hubbard predicted that the U.S. would hit peak oil in 1970, which came true
• Reaching further for fossil fuels


  Mountaintop mining for coal

  Hydraulic fracturing for oil and gas

  Offshore drilling in deep waters

  Exploiting new "unconventional" fossil fuel sources
• These methods increase fuel production but reduce the EROI ratios of our fuels, intensify pollution, and worsen climate change
• Mountaintop removal mining


  Removes entire mountaintops to access the coal seams
• Hydraulic fracturing


  Pumps chemically treated water under high pressure into layers of rock to crack them
• Hydraulic fracturing has created many jobs but drawn down water resources and, in some cases, polluted water
• EROI for shale oil is low, ranging from 4:1 to 1.1:1
• Methane hydrate is abundant, but so far only Japan has attempted to extract it due to concerns about accidental releases of methane
• BP's Deepwater Horizon offshore oil drilling platform exploded and sank as emergency shutoff systems failed, leaking oil into the Gulf for three months
• The Deepwater Horizon spill caused a wide variety of impacts, ranging from birds becoming coated with oil to beach and ocean floor contamination
• Many nations lack adequate fossil fuel reserves to supply their own energy needs and rely on imports, giving seller nations more control over energy prices
• In 1973, OPEC resolved to stop selling oil to the United States, creating an energy crisis