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.
2
All Energy Sources
3
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.
4
Resources and Reserves
5
Fossil Fuel Formation
•
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.
6
Recoverable Coal Reserves
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.
8
Crude Oil and Natural Gas Pool
9
Issues Related to Fossil Fuel Use
•
Fossil fuels supply 90% of world’s
commercial energy.
– Oil
40%
– Coal
24%
– Natural Gas
25%
10
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
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obtain.
Coal Use Issues
•
Two main extraction methods:
– Surface Mining (Strip Mining)
 Removes soil on top of a vein.
 Efficient but destructive.
– Underground Mining
 Minimizes surface disturbance, but costly
and dangerous.
 Black Lung Disease
12
Fig. 10.8
13
Fig. 10.7
14
Coal Use Issues
•
•
•
Bulky - causes some transport problems.
Mining creates dust pollution.
Burning releases pollutants (C and S).
– Millions of tons of material released into
atmosphere annually.
 Sulfur leads to acid mine drainage and
acid deposition.
 Increased amounts of atmospheric
carbon dioxide implicated in global
warming.
15
Surface-Mine Reclamation
16
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.
17
Oil Use
•
•
Primary Recovery
– 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
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.
19
Fig. 10.10
20
Fig. 10.12
21
Processing Crude Oil
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
– (LPG’s) 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
Fig. 10.6
24
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
25
Renewable Energy as a Share of Total Energy
26
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.
27
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.
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Fig. 10.14
29
30
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.
31
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.
 Areas near the poles, and in narrow
bays and estuaries are ideal but limited.
32
Fig. 10.16
33
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.
34
Geothermal Energy
35
•
•
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
compared to 38 cents (1980’s) due to
technological advances.
36
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.
37
Darrieus Rotor
38
Solar
•
Daily energy from the sun is six hundred
times greater than energy produced each
day by all other energy sources combined.
– Weather dependent.
39
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
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41
42
Fig. 10.19
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Fig. 10.20
44
Photovoltaic Cells
•
Solid-state semiconductors that allow direct
conversion of sunlight to electricity.
– Developed in 1954 by Bell Laboratories.
 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 other building materials.
45
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.
– Prices have decreased.
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47
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
48
Fig. 10.22
49
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.
50
Fig. 10.23
51
Fuel wood
•
•
•
•
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 fuel wood, or are using it faster than
rate of regeneration.
Source of air pollution and fly ash.
52
Fig. 10.24
53
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.
 CFCs
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55
Fig. 10.25
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Table 10.2
57
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.
58
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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Fig. 10.26
60
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
62
Fig. 10.28
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Table 10.3
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