Op ch14 lecture_earth3, solar energy

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Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces thatnaturally circulate air.
Solar technologies , Mineral resources , Igneous rock .definition of a mineral , Alfred Wegener Earth's lithosphere,plate tectonics, Abraham Ortelius , The continents drift, the Earths interior, drrobisawesome, ESE 11, Bronx Community college

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Op ch14 lecture_earth3, solar energy

  1. 1. Chapter 14 Squeezing Power from a Stone: Energy Resources LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  2. 2. Squeezing Power from a Stone: Energy Resources Prepared by Ronald Parker Earlham College Department of Geosciences Richmond, Indiana
  3. 3. Energy Resources Energy is the capacity to do work.  An energy resource is matter that can…  Produce heat.  Power muscles.  Generate electricity  Move machinery.  In usable form, an energy resource is called a fuel.  Energy stored in chemical bonds fuels biotic life.  Many energy resources are geological materials.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  4. 4. Energy Human energy consumption has grown steadily.  Early humans had modest energy requirements.  Food.  Fuel for fires.   We consume 110x as much. Food for livestock.  Agriculture.  Transportation.  Mining.  Manufacturing.  Industry.   Industrial societies depend mostly on fossil fuels. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  5. 5. Sources of Energy  There are 5 fundamental sources of energy. Nuclear fusion in the Sun.  The pull of gravity.  Nuclear fission reactions.  Energy in the interior of the Earth.  Energy stored in chemical bonds.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  6. 6. Sources of Energy  Energy directly from the Sun’s nuclear fusion reactor. Heat and light radiate outward from the Sun.  A tiny portion of the solar output strikes Earth.  Direct solar energy can be used by humans.  Conversion into electricity by photovoltaic cells. Conversion into heat.  Controlled fusion is currently beyond human technology. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  7. 7. Sources of Energy  Energy directly from gravity. Gravitational pull of the Moon on the Earth causes tides.  Tidal flow can be harnessed to drive turbines.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  8. 8. Sources of Energy  Energy involving both solar energy and gravity. Solar radiation heats air and evaporates water.  Gravity…  Causes cooler air to sink and condense water vapor. Pulls condensed water back to Earth, where it flows downhill.  Energy can be extracted from flowing wind and water. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  9. 9. Sources of Energy  Energy via photosynthesis.  Chlorophyll stores solar energy in H-C bonds. Water and carbon dioxide react to form sugar and oxygen. 6CO2 + 12H2O + light > C6H12O6 + 6O2 + 6H2O  H-C bonds release stored energy when broken (oxidized). Organic respiration (breakdown of food by organisms). Rapid thermal oxidation (combustion). Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  10. 10. Sources of Energy  Energy from chemical reactions. Energy stored in chemical bonds drives reactions.  When bonds are broken, this energy may be used.  Exothermic reactions produce heat. Some also produce light and usable energy. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  11. 11. Sources of Energy  Energy from fossil fuels. Oil, natural gas, and coal derive from living organisms.  These materials store energy in preserved H-C bonds.  Created by photosynthesis; solar energy from the past. Thus, oil, gas, and coal represent “fossilized sunshine.” Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  12. 12. Sources of Energy  Energy from nuclear fission. Certain radioactive atoms can be fragmented.  This process, called fission, yields tremendous energy.  Fission energy is used to run nuclear power plants.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  13. 13. Sources of Energy  Energy from Earth’s internal heat.  Earth’s internal (geothermal) energy has 2 sources. Residual heat from planet formation. Heat from radioactivity. Geothermal energy drives tectonic plates.  Heat lost through the crust can be harnessed.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  14. 14. Oil and Gas Industrial society depends on oil and natural gas.  Oil and gas are hydrocarbons.  Complex organic molecules.  Made of hydrogen and carbon.  From once-living creatures.   Many hydrocarbon types. Found as complex mixtures.  Pure compounds are separated by refining.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  15. 15. Oil and Gas  Hydrocarbon properties due to size and structure. Viscosity – Tendency to flow.  Volatility – Tendency to evaporate.   Short-chain hydrocarbons (1 to 4 carbon atoms). Low viscosity and high volatility.  Vapors at room temperature.  Examples: Methane, propane.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  16. 16. Oil and Gas  Moderate-chain hydrocarbons (5 to 40 C atoms). Medium viscosity and volatility; liquids at room temp.  Examples: Hexane, octane, nonane.   Long-chain hydrocarbons (> 40 C atoms). High viscosity and low volatility; solids at room temp.  Examples: Tar.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  17. 17. Oil and Gas Genesis  Oil and gas hail from plankton and marine algae. Dead plankton and algae sink in quiet water.  This organic material accumulates with fine mud.  Under anoxic conditions, organic matter is preserved.  Lithification forms a black shale petroleum source rock.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  18. 18. Oil and Gas Genesis  Burial to depths of 2 to 4 km heats the black shale. Heating breaks the organics down into waxy kerogen.  Kerogen-rich source rocks are called oil shales.  Continued heating breaks down kerogen.  Oil and gas form in specific T ranges.  Oil and gas – 90o to 160oC.  Gas only – 160o to 250oC.  Graphite – >250oC.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  19. 19. Oil and Gas Genesis The “oil window” T range is quite narrow.  Oil window depth dictated by geothermal gradient.  25oC/km – 3.5 to 6.5 km depth.  15oC/km – Below 11 km depth.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  20. 20. Hydrocarbon Systems Oil and gas preservation is geologically rare.  A known supply of oil is called an oil reserve.  Oil reserves are geographically limited.  Most oil is in super-giant fields in the Persian Gulf.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  21. 21. Hydrocarbon Systems  Creation of an oil reserve is dependent on 4 features. A source rock.  A migration pathway.  A reservoir rock.  A trap.   These features must develop in a specific order. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  22. 22. Hydrocarbon Systems  Source rocks and hydrocarbon generation. Organic-rich black shale is the source of oil and gas.  The organic matter is transformed within the oil window.  The source rock does not store oil or gas.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  23. 23. Hydrocarbon Systems  Reservoir rocks and hydrocarbon migration. Recoverable oil and gas are found in reservoir rocks.  Reservoir rocks can store and transmit fluids.  Porosity – Open space in the rock that stores fluid. Permeability – Ease of fluid movement through pore space. Low – Small well yields. High – Large well yields. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  24. 24. Hydrocarbon Systems  Reservoir rocks and hydrocarbon migration. Oil and gas must migrate from source to reservoir.  Migration is facilitated by density/buoyancy differences.  Oil floats on water; gas floats on oil. Migration is promoted by fractures in rock.  Reservoirs can leak to form an oil seep at the surface.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  25. 25. Hydrocarbon Systems  Traps and seals. An oil or gas reserve requires trapping in the reservoir.  Trap – A geological configuration that holds oil and gas.  Seal – A low-permeability rock layer above a reservoir.  Trap geometry is often crucial for fluid collection.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  26. 26. Hydrocarbon Systems  Traps and seals.  Anticline trap – A structural arch traps oil. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  27. 27. Hydrocarbon Systems  Traps and seals.  Salt-dome trap – Plastic flow in salt faults and folds rock, forming traps. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  28. 28. Hydrocarbon Systems  Traps and seals.  Fault trap – Displacement juxtaposes rocks with varying permeability. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  29. 29. Hydrocarbon Systems  Traps and seals.  Stratigraphic trap – Subtle depositional features create traps. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  30. 30. Birth of the Oil Industry Oil from seeps has been used for millennia.  The 1st oil well was drilled in Titusville, Pa., in 1859.  Eased petroleum recovery.  Initiated an oil boom.   Within years, 1,000s of oil wells had been drilled. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  31. 31. Oil Exploration  The modern search for oil: Early exploration involved searching for rare oil seeps.  Investors realized systematic exploration was needed.  Petroleum exploration became a subdiscipline of geology.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  32. 32. Oil Exploration Complex, dangerous, and exciting; many steps.  Geologists map sedimentary rocks.  Guide searches for source rocks, reservoirs, and traps.  Rock sequences compiled from outcrops and drill cores.   Cross-sections show rock geometry, aid search. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  33. 33. Oil Exploration  Seismic reflection profiles subsurface layers. Sound is “bounced off’ subsurface layers.  Permits geologists to look for traps without drilling.  Seismic imaging is conducted on land and at sea.  Seismic studies are sophisticated and expensive.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  34. 34. Oil Exploration  Expensive drilling required to tap a potential trap.  A diamond rotary bit pulverizes rock. High-density drilling mud cools the bit and lifts cuttings. The heavy mud reduces blowouts. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  35. 35. Oil Exploration As the bit advances, the open borehole deepens.  Drill pipe is added by a drill derrick.  Some derricks are mounted on offshore platforms.  Platforms can drill many holes in many directions.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  36. 36. Oil Production When a reservoir is encountered, drilling ceases.  Steel casing prevents collapse of the hole.  After casing, the well is pumped.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  37. 37. Oil Production  Primary recovery. Uses reservoir pressure and pumping to extract oil.  Inefficient; only able to recover about 30% of the oil.   Secondary recovery.  Fluids (steam, CO2) are injected to heat and push oil.  Hydrofracturing – Artificially increases permeability. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  38. 38. Oil Production  Crude oil must be refined. Crude oil is distilled into separate compounds.  Lighter molecules rise to the top of distillation columns.  Heavier molecules remain at the bottom.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  39. 39. Alternative Hydrocarbons  Tar sands – Deposits of residual petroleum in sand. Heavy oil, or bitumen, is residue of a former oil field.  Lighter hydrocarbons are removed by bacterial digestion.  The remaining hydrocarbon is too viscous to be pumped.  Tar sands must be mined and processed.  Extensive deposits in Alberta and in Venezuela.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  40. 40. Alternative Hydrocarbons  Oil shale – Shale containing abundant kerogen. An oil source rock that has not been in the oil window.  Burning transforms the kerogen into liquid hydrocarbon.  Large supplies occur in…  Estonia. Scotland. China. Russia. Western United States. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  41. 41. Alternative Hydrocarbons  Natural gas – Volatile, short-chain hydrocarbons. Methane, ethane, propane, butane, and others.  Gas floats on top of oil in a reservoir.  Below the oil window, hydrocarbons are turned into gas.  Natural gas is more abundant than oil; a cleaner fuel.  Utilization requires expensive, high-pressure pipelines.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  42. 42. Alternative Hydrocarbons  Gas hydrate – Methane (CH4) in a cage of water ice.  CH4 is from bacterial decomposition of organic matter. Methane hydrate forms in water depths exceeding 300 m.  Stores more carbon than all other reservoirs combined.  Recovery is not currently feasible.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  43. 43. Coal Black, brittle, carbonaceous sedimentary rock.  Remains of organic matter from vegetation.  Important global energy source; CO2 emitter.   Only found in rocks younger than 420 Ma. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  44. 44. Coal  Coal-forming eras.  Carboniferous (354 – 286 Ma). Warm climate. Broad epicontinental seas. Tropical deltaic wetlands.  Cretaceous (144 – 65 Ma). Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  45. 45. Coal Formation  Vegetation accumulates in an O2-free setting.  Absence of oxygen prevents organic matter decay. Marine deltas.  Tropical coastal wetlands.   Sea level rise and fall buries wetland deposits. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  46. 46. Coal Formation Coal formation requires heat and pressure.  Compaction and decay turns plant debris into peat.  Approximately 50% carbon.  Readily cut out of a wetland deposit.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  47. 47. Coal Formation Peat is buried several km in a subsiding basin.  Burial compaction squeezes out water.  At depth, heat alters the plant material.  H, N, and S are expelled as gases; C content increases.  At 70% carbon, this solid material becomes coal.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  48. 48. Coal Rank  Classification based on the carbon content. Peat Lignite Bituminous Anthracite 50% C 70% C 85% C 95% C Anthracite forms by metamorphism in an orogenic belt.  Higher-rank coal yields more energy when burned.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  49. 49. Coal Rank Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  50. 50. Coal Mining  Coal is part of a specific sedimentary sequence. Shallow marine, coastal, fluvial, and deltaic environments.  Tropical to subtropical.   To be mined, coal must be… Within reach.  Thick enough (1 – 3 m).  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  51. 51. Coal Mining Huge coal reserves have been discovered.  Mining type depends on the depth of the coal seam.  Within 100 m, coal is strip mined.  For deeper coal seams, underground mining is required.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  52. 52. Coal Mining  Strip mining – Landscape destroyed to reach coal.  A large drag line bucket is used to scrape off overburden. Spoil is stockpiled nearby for later use during reclamation.  Exposed coal is removed and the excavation is reclaimed. Excavation is backfilled with spoil and soil, then planted. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  53. 53. Coal Mining  Underground mining – Coal removed by tunneling. For coal deeper than 100 m, shafts are advanced to seam.  Tunnels excavated along the seam remove the coal.  Coal mining is specialized, expensive, and dangerous.  Tunnels can collapse. Methane gas. Asphyxiation. Explosions. Black lung disease. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  54. 54. Coal  Coal can yield energy without direct combustion. Coalbed methane – Natural gas trapped in buried coal.  Coal gasification – Coal is changed to a combustible gas.  Old coal gas plants in many cities are now waste sites. Modern coal gasification is much less polluting. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  55. 55. Coalbed Fires  Runaway coal combustion underground. Coal can be ignited in place by lightning, spontaneous combustion, gas explosions, or deliberate ignition.  Difficult to extinguish, these fires may burn for decades.  Produce hazards like toxic fumes and ground collapse.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  56. 56. Nuclear Power  Energy from breaking apart atomic nuclei. Neutrons strike the fuel and start fission.  Fission splits a large nucleus into smaller fragments.  Nuclear reactors are contained in a domed building.  Reactors are loaded with uranium oxide fuel rods.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  57. 57. Nuclear Power  A high-speed neutron initiates fission creating… Nuclear fragments.  A large yield of energy.  More high-speed neutrons.  Neutrons fuel a sustained nuclear chain reaction.  Control rods absorb neutrons, slowing fission.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  58. 58. Nuclear Power  Fission produces enormous amounts of energy. High-pressure steam is created in a closed reactor loop.  Heat is transferred to an external water loop.  Steam in the external loop is used to spin electrical turbines.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  59. 59. Nuclear Power Nuclear power is a major source of electricity.  Nuclear power emits zero greenhouse gases.  Nuclear power use likely to increase in the future.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  60. 60. Nuclear Power  The geology of uranium. Uranium – 235 (235U) is the most common nuclear fuel.  Uranium has 2 major isotopes.     U – 99.3% (not fissionable). 235 U – 0.7% (fissionable). 238 U must be enriched 2 to 3 times to be fissionable. 235 Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  61. 61. Nuclear Power  The geology of uranium.  Uranium occurs naturally in all rocks; amount varies. Uranium dissolved from minerals is transported by water. Dissolved uranium solidifies in mineral veins and fractures.  Radiation detectors are used to find uranium. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  62. 62. Nuclear Problems Nuclear power is expensive.  Loss of reactor control may start core “meltdown.”  Molten reactor materials could bore through containment.  A steam explosion could then spread radioactivity.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  63. 63. Nuclear Problems Plant safety is a major concern.  Extensive efforts applied to thwart terrorism.  Nuclear accidents are rare but have occurred.  1986 – Chernobyl (Ukraine) spread radioactivity globally.  1979 – Three Mile Island (Pennsylvania, U.S.).  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  64. 64. Nuclear Problems  Generates highly radioactive wastes. Extremely toxic, wastes are poisonous for 1,000s of years.  High-level waste storage is a major societal issue.   Wastes also generated by processing uranium ore. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  65. 65. Other Energy Sources  There are a number of other energy options. Geothermal energy.  Hydroelectric power.  Wind energy.  Solar power.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  66. 66. Geothermal Energy  Energy from Earth's internal heat. Geothermal gradient: Earth becomes hotter with depth.  Geothermal gradients vary (15oC/km to 50oC/km).  High geothermal gradients: hotter at shallower depths.   No wastes; no greenhouse gases or air pollution. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  67. 67. Geothermal Energy  Geothermal energy is utilized in 2 ways. Hot water is pumped and used to heat buildings.  Steam is used to drive electric turbines.   Geothermal is a dominant energy source in some areas (e.g., Iceland, New Zealand). Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  68. 68. Hydroelectric Power Flowing water turns potential energy into kinetic energy.  This energy works by eroding and moving sediment.  Hydroelectric power dams arrest the flow of water.  Water is directed past turbines to create electricity.  Some dams generate electricity via tidal flux.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  69. 69. Hydroelectric Power  Positive aspects. Reduces the risk of floods.  Impounds water for drinking, irrigation, and recreation.  Provides renewable energy without creating wastes.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  70. 70. Hydroelectric Power  Negative aspects : Dams destroy valued landscapes and alter ecosystems.  Reservoirs accumulate the sediment load of the river.  Sediments added to reservoirs require expensive dredging. Erosion is accelerated downstream of dams. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  71. 71. Wind Energy  High-tech wind farms are sprouting worldwide. Wind drives a large turbine to produce electricity.  Wind-derived electricity is renewable and carbon-free.   Drawbacks. Wind farms have negative aesthetic impacts.  Turbine blades are noisy and kill birds.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  72. 72. Solar Power By far the most abundant source of energy to the surface.  Solar energy dwarfs that of hydrocarbon resources.  But solar energy is hard to utilize because it is…  Diffuse. Highly variable on a seasonal and daily basis. Difficult to convert into more usable forms of energy. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  73. 73. Solar Power  There are two ways to use solar energy directly. Solar collectors concentrate sulight for heating. Photovoltaic (PV) cells convert light directly into electricity.  Both are useful for small buildings; not large cities. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  74. 74. Biomass  Biomass – Energy from plant and animal matter. Early humans used biomass (wood, charcoal, dung).  To be useful today, biomass must be grown quickly.  Ethanol – Alcohol derived from corn.  Burned as a motor fuel. Produced in large quantities. Unproven as a gasoline replacement. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  75. 75. Hydrogen Fuel Cells Produce electricity via chemical reactions.  Hydrogen reacts with oxygen in an electrolyte bath.     Generates electricity, heat, and H2O. The reaction is environmentally benign. Fuel cells are useful as engines for motor vehicles.  Technological issues must be addressed 1st. Safely storing compressed hydrogen. Producing hydrogen efficiently. Distributing hydrogen. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  76. 76. Energy Problems Global energy use increased dramatically.  Use reflects rapid expansion of industrialization.  Oil, the dominant energy source, is dwindling.  Many countries import oil to meet demands.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  77. 77. Energy Problems  The 1970s energy crisis. In 1973, the Organization of Petroleum-Exporting Countries (OPEC) began to limit the volume of exports.  The price of oil skyrocketed, resulting in fuel shortages.  Gas stations witnessed long lines for the 1st time.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  78. 78. Energy Problems  The 1970s energy crisis.  The result was a new understanding of energy by all. Regulations lowered speed limits and raised mileage stds. Goods tended to be smaller and more energy-efficient. A new consumer ethos was born. Reducing home energy usage. Carpooling. Public transportation. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  79. 79. Energy Problems  The oil crunch - Renewable vs. nonrenewable.  Renewable – Can be replaced within months to years. Biomass, solar, wind, geothermal, hydroelectric.  Nonrenewable – Replacement requires hundreds to millions of years. Oil, natural gas, coal, uranium ores. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  80. 80. Energy Problems  The oil crunch. We consume nonrenewable resources too rapidly.  We face running out of nonrenewable resources.  For each resource, the question is “When?”  The answer, for oil, may be “Soon.”  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  81. 81. Energy Problems  The oil crunch. Oil extinction will occur by 2050 to 2150.  Future historians will see the “Oil Age” as a 200-year era.  We are now close to the peak of global oil production.  Humanity faces many changes as oil runs out.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  82. 82. Energy Problems The oil crunch: What can humanity do?  There are many sources of energy that we can use.  Tar sands and oil shales.  Coal.  Natural gas.  Coalbed methane.  Uranium.  Renewables.  Each energy source has associated difficulties.  Society faces difficult choices.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  83. 83. Environmental Issues  Energy production creates environmental insults. Oil drilling and production scars the landscape.  Spills from oil storage tanks, pipelines, and ships...  Contaminate surface water and ground water. May devastate large areas of coastline.  Coal mining creates pits, spoil piles, and acid mine runoff. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  84. 84. Environmental Issues  Air pollution results from fossil fuel combustion. Unburned hydrocarbons add to photochemical smog.  Sulfur dioxide (SO2) from coal yields acid rain.   CO2 addition fuels global warming and climate change. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources
  85. 85. This concludes the Chapter 14 Squeezing Power from a Stone: Energy Resources LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 14: Squeezing Power from a Stone: Energy Resources

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