Energy Sources

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					Energy Sources
  Chapter 10




                 1
                 Energy Sources

•   Non-Renewable Energy - Energy sources
    used faster than can be replenished.
         Coal - Oil - Natural Gas

•   Renewable Energy - Continuously present as
    a feature of the environment (solar energy),
    or is continually replenished.
         Some forms are referred to as perpetual

          energy.


                                                    2
All Energy Sources




                     3
     2. What percent of fossil fuels are used?

•   Fossil fuels supply 90% of world’s
    commercial energy.
     – Oil                 40%
     – Coal                24%
     – Natural Gas         25%




                                                 4
        3. What is the difference between
            Resources and Reserves
•   Resource - Naturally occurring substance of
    use to humans that can potentially be
    extracted using current technology.
•   Reserve - Amount of a known deposit that
    can be economically extracted using current
    technology, under certain economic
    conditions.
        Reserve levels change as technology
         advances, new discoveries are made,
         and profit margins change.

                                                  5
Resources and Reserves




                         6
             4. How is coal formed?

•   Coal
    – 300 mya plant material began collecting
      underwater, initiating decay, forming a
      spongy mass of organic material (peat).
        Due to geological changes, some of
         these swamps were covered by seas,
         and covered with sediment.
            Pressure and heat over time
             transformed peat into coal.

                                                7
Recoverable Coal Reserves




                            8
              5. Types of extraction
•   Two main extraction methods:
    – Surface Mining (Strip Mining)

        Removing overburden on top of a vein.

           Efficient but destructive.

    – Underground Mining

        Minimizes surface disturbance, but costly

         and dangerous.
           Black Lung Disease



                                                 9
               Surface mining of coal




•   Strip mine
•   Eco problem – over burden
     – Laws in 1990’s now require ground replacement

                                                       10
Surface-Mine Reclamation




                           11
Deep mining – tunneling for coal




                                   12
                 Problems with Coal

•   Bulky - causes some transport problems.
•   Black Lung Disease: Mining creates dust pollution.
•   Mining accidents: collapse of tunnels,
    malfunctioning machinery
•   Ecosystem damage/reclamation efforts
•   Burning releases pollutants (C and S).
    – Millions of tons of material released into

      atmosphere annually.
        Acid Rain: Sulfur leads to acid mine drainage

         and acid deposition.
        Global warming: Increased carbon dioxide
                                                         13
                 Coal Use Issues
•   Coal is most abundant fossil fuel.
    – Primarily used for generating electricity.

        Three Categories:

           Lignite

              High moisture content - Least
               desirable.
           Bituminous

              Most abundant - Most widely used.

           Anthracite

              Highest energy content - Hard to
               obtain.                           14
               7. Oil and Natural Gas

•   Accumulations of dead marine organisms on
    the ocean floor were covered by sediments.
     – Muddy rock gradually formed rock (shale)
       containing dispersed oil.
         Sandstone formed on top of shale, thus
          oil pools began to form.
            Natural gas often forms on top of oil.

                Organic matter changed to lighter,
                 more volatile hydrocarbons than
                 those in oil.
                                                      15
Crude Oil and Natural Gas Pool




                                 16
Oil rig & ocean drilling for oil




                                   17
                    Oil extraction
•   Primary Recovery – oil rig drilling
    – Only removes 1/3 of a deposit.

•   Secondary Recovery
    – Force water or gas into wells.

        As oil prices increase, more expensive

         and aggressive secondary recovery
         methods will need to be used.



                                                  18
9. Uses of oil - Processing Crude Oil




                                        19
Oil products




               20
                   Oil Use Issues
•   Processing
    – As it comes from the ground, oil is not in a

      form suitable for use, and must be refined.
         Multiple products can be produced from a

          single barrel of crude oil.
•   Oil Spills
    – Accidental spills only account for about 1/3

      of oil pollution resulting from shipping.
         60% comes from routine shipping

          operations.
                                                     21
                Advantages of oil use
•   More concentrated than coal, burns cleaner,
    and is easily transported through pipelines.
     – Ideal for automobile use.

     – Difficult to extract.

     – Causes less environmental damage than

       coal mining.




                                                   22
                 Natural Gas Use
•   Drilling requirements similar to oil.
•   Hard to transport - flamed off at oil fields.
•   As demand increases, new transportation
    methods will be developed and implemented.
                            o
     – Liquefaction at -126 F

         (1/600 volume of gas)

•   Least environmentally damaging fossil fuel.
     – Almost no air pollution.

•   Use is increasing (45% from 1985-2003).
                                                    23
          Renewable Sources of Energy

•   Currently, alternative energy sources supply
    almost 10% of the world’s total energy.
     – Suggested these sources could provide

       half of the world’s energy needs by 2050.
         Hydropower

         Wind Turbines

         Solar Cells

         Biomass Fuels

         Hydrogen Fuel

                                                   24
Renewable Energy as a Share of Total Energy




                                              25
                Hydroelectric Power

•   Hydroelectric power is created when flowing
    water is captured and turned into electricity.
    – Damming a river and storing water in a

      reservoir is the most common method.
        Pumped Storage Plants - Use two

         reservoirs separated by a significant
         elevation difference.



                                                     26
                Hydroelectric Power

•   Currently supplies 15% of world’s electricity.
     – China possesses 10% of world’s potential.

•   Reservoir construction causes significant
    environmental and social damage.
     – Loss of farmland.

     – Community relocation.

     – Reduction of nutrient-rich silt leading to

       loss of wetlands.
         Three Gorges Dam on Yangtze River

                                                     27
28
      Environmental Effects of Hydroelectric

•   Flooding of vast areas of land behind dams.
•   Prevention of fish migrations.
•   Trapping of silt.
     – Stops flow of nutrients downstream.

     – Fills in reservoir.

•   Mercury Accumulation
•   Decaying vegetation produces greenhouse
    gases.

                                                  29
                     Tidal Power

•   Daily rise and fall of ocean levels relative to
    coastlines (tides) are a result of gravitational
    forces and the revolution of the earth.
     – As water flows from a higher level to a

       lower level, it can be used to spin an
       electricity - generating turbine.
         Since tidal changes are greatest near

          the poles, and accentuated in narrow
          bays and estuaries, suitable sites are
          limited.
                                                       30
                  Geothermal
•   In some areas, molten material is close
    enough to surface to heat underground water
    and form steam - drilled and captured.
     – Only practical in limited areas.

     – California produces 40% of world’s

       geothermal electricity.
     – Can cause unpleasant odors and high

       mineral content leads to high maintenance.
         Corroded pipes and equipment.



                                                31
Geothermal Energy




                    32
                          Wind
•   As warm air becomes less dense and rises,
    cooler, denser, air flows in to take its place.
•   U.S. Department of Energy has stated the
    Great Plains could supply 48 states with 75%
    of their electricity.
     – Cost becoming very competitive with

       various fossil fuel sources.
         Currently 3-6 cents per kilowatt hour.




                                                  33
                     Wind

•   Potential Problems
    – Steady,dependable wind source is critical.

        Wide open areas are most desirable.

    – Can be hazardous to birds.

    – Produce noise and visual pollution.

    – Vibrations can cause structural damage.




                                                   34
                       Solar

•   Daily energy from the sun is six hundred
    times greater than energy produced each
    day by all other energy sources combined.
     – Major problem as an energy source is its

       intermittent nature.




                                                  35
           Three Major Use Categories

•   Passive Heating - Sun’s energy is converted
    directly to heat and used at collection site.
     – South-Facing Windows.

•   Active Heating - Sun’s energy converted into
    heat, but transported elsewhere to be used.
     – Domestic Water Heating

•   Electrical Generation - Solar energy is
    transformed into electrical energy.
     – Photovoltaic Science

                                                    36
37
                 Photovoltaic Cells

•   Solid-state semiconductors that allow direct
    conversion of sunlight to electricity.
     – Developed in 1954 by Bell Laboratories

       essentially as a novelty.
         Amount of PV power installed worldwide

          has increased from 100 megawatts in
          1992 to 1,200 megawatts in 2002.
            Film technology has made it possible

             to build solar cells into roof tiles,
             skylights, and building facades.
                                                     38
                 Photovoltaic Cells

•   Photovoltaics will be the most practical
    choice for generation of electricity in rural
    areas and less developed countries.
     – In place of generators that require fuel and

       centralized power plants that require
       distribution lines.




                                                      39
               Biomass Conversion

•   Biomass is still the predominant form of
    energy used by people in less-developed
    countries.
     – Account for 14% of world energy use.

•   Three Distinct Sources:
     – Municipal and Industrial Wastes

     – Agricultural Crop Residue

     – Energy Plantations



                                               40
              Biomass Conversion

•   Releasing chemical energy stored in biomass.
     – Burned directly for heat.

     – Burned to produce electricity.

     – Converted to alcohol or used to generate
       methane.
•   Costs depends on type of technology used,
    size of the power plant, and the cost of
    biomass supply.
     – Currently as low as 9 cents per kilowatt
       hour.
                                               41
                    Fuelwood

•   In less-developed countries, fuelwood has
    been major energy source for centuries.
•   Fuelwood is primary energy source for nearly
    half world’s population.
•   Due to intense population growth, an
    estimated 1.3 billion people cannot get
    enough feulwood, or are using it faster than
    rate of regeneration.
•   Source of air pollution and fly ash.
                                                   42
                   Solid Waste

•   Using municipal waste as a source of energy:
    – Reduces landfill volume.

        Not economically profitable.

           Must be sorted.

           Requires large, sustainable volume.

    – Produces air pollution.

        Chlorine-containing organic compounds.




                                                   43
                Hydrogen Economy

•   Hydrogen is abundant and generates heat
    and pure water when it reacts with air.
     – Hydrogen Fuel Cells

         Proton Exchange Membrane Fuel Cell

            Self-Sustaining

            Low Operating Temperature

            No Pollution

               Successor to internal combustion
                engine.

                                                   44
Simple Fuel Cell




                   45
               Energy Conservation

•   Conservation is not a way of generating
    electricity, but a way of reducing need for
    additional energy production/consumption
    and saving money for the consumer.
     – Lighting and air conditioning account for

       25% of U.S. electricity consumption.
         Widespread use of energy-efficient

          lighting could significantly reduce energy
          consumption.

                                                       46
               Energy Conservation

•   Energy-inefficient machines can be produced
    very cheaply.
     – Long-term vs. short-term costs.

•   Electrical utilities will lead energy
    conservation charge.
     – Conservation is cheaper than building more

       power plants to meet increased demands.



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