Energy Sources

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Energy Sources

• Chapter 10

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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.

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All Energy Sources
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2. What percent of fossil fuels are used?

• Fossil fuels supply 90 of worlds commercial
  energy.
• Oil 40
• Coal 24
• Natural Gas 25

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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.

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Resources and Reserves
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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.

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Recoverable Coal Reserves
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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

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Surface mining of coal

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

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Surface-Mine Reclamation
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Deep mining tunneling for coal
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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

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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.

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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.

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Crude Oil and Natural Gas Pool
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Oil rig ocean drilling for oil
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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.

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9. Uses of oil - Processing Crude Oil
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Oil products
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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.

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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.

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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.
• Liquefaction at -126o F
• (1/600 volume of gas)
• Least environmentally damaging fossil fuel.
• Almost no air pollution.
• Use is increasing (45 from 1985-2003).

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Renewable Sources of Energy

• Currently, alternative energy sources supply
  almost 10 of the worlds total energy.
• Suggested these sources could provide half of the
  worlds energy needs by 2050.
• Hydropower
• Wind Turbines
• Solar Cells
• Biomass Fuels
• Hydrogen Fuel

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Renewable Energy as a Share of Total Energy
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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.

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Hydroelectric Power

• Currently supplies 15 of worlds electricity.
• China possesses 10 of worlds 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

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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.

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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.

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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 worlds geothermal
  electricity.
• Can cause unpleasant odors and high mineral
  content leads to high maintenance.
• Corroded pipes and equipment.

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Geothermal Energy
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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.

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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.

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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.

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Three Major Use Categories

• Passive Heating - Suns energy is converted
  directly to heat and used at collection site.
• South-Facing Windows.
• Active Heating - Suns energy converted into
  heat, but transported elsewhere to be used.
• Domestic Water Heating
• Electrical Generation - Solar energy is
  transformed into electrical energy.
• Photovoltaic Science

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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.

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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.

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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

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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.

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Fuelwood

• In less-developed countries, fuelwood has been
  major energy source for centuries.
• Fuelwood is primary energy source for nearly half
  worlds 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.

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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.

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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.

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Simple Fuel Cell
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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.

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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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