Energy Efficiency Fuels used for electricity generation in the
United States. Coal is the fuel most commonly used for electricity
generation. [Data from U.S. Department of Energy, Energy
Information Administration, 2009.] However most coal burning power
plants are only about 35% efficient.
Slide 3
Process of Energy Use The efficiency of the transfer of energy
from a fuel to electricity is approximately 35%. Another 30% is
lost during electricity transmission from the generator to the
user.
Slide 4
Electricity Generation
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The use of Coal as a fuel rose in the late 1800s. Coal is
widely used around the world because: a. coal is plentiful b.
resources are relatively easy to exploit c. coal is easily
transported d. coal needs little refining e. Coal has a high energy
density The drop in the use of coal as a fuel in the 1940s was
caused by a rise in the use of natural gas. In 2000, natural gas
provided about as much energy as coal. However the use of coal is
continuing to rise world wide due to the increased use of coal in
developing countries such as China and India.
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AdvantagesDisadvantages Energy-denseContains impurities
PlentifulRelease impurities into air when burned Easy to exploit by
surface miningTrace metals like mercury, lead, and arsenic are
found in coal Technological demands are smallCombustion leads to
increased levels of sulfur dioxide and other air pollutants into
the atmosphere. Economic costs are lowAsh is left behind Easy to
handle and transportCarbon is released into the atmosphere which
contributes to climate change Needs little refining Advantages and
Disadvantages of Coal Coal is 60-80% carbon. When it is burned,
most of that carbon is converted into CO 2. Coal produces far more
CO 2 per unit energy released than either oil or natural gas.
Slide 7
Coal Coal- a solid fuel formed primarily from the remains of
trees, ferns, and other plant materials that were preserved 280-360
million years ago. Four types of coal ranked from lesser to greater
age, exposure to pressure, and energy content. These four types
are: lignite, sub-bituminous, bituminous, and anthracite. The
largest coal reserves are in the United States, Russia, China, and
India.
Slide 8
The use of petroleum as a fuel rose dramatically in the mid
1900s due to: a.its relative ease of extraction b.its relative ease
of transportation c.its use as a transportation fuel d. its
relatively inexpensive cost However, a vast majority of U.S. oil is
being imported The United States imports about 30% of our energy
needs.
Slide 9
A mixture of hydro- carbons, water, and sulfur that formed from
the remains of ocean-dwelling phytoplankton that died 50-150
million years ago and occurs in under- ground deposits. The fluid
nature of oil and gasoline make this ideal for mobile combustion,
such as vehicles. Countries with the most petroleum are Saudi
Arabia, Russia, Iran, China, Canada, and Mexico. Petroleum
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AdvantagesDisadvantages Convenient to transport and useReleases
carbon dioxide into atmosphere Relatively energy-densePossibility
of leaks when extracted and transported Cleaner-burning than
coalSignificant imports create dependency on foreign countries
Releases sulfur, mercury, lead, and arsenic into the atmosphere
when burned Advantages and Disadvantages of Petroleum
Slide 11
Natural gas- exists as a component of petroleum in the ground
as well as in gaseous deposits separate from petroleum. methane
Contains 80 to 95 percent methane and 5 to 20 percent ethane,
propane, and butane. Natural Gas
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AdvantagesDisadvantages Contains fewer impurities and therefore
emits almost no sulfur dioxide or particulates When unburned,
methane escapes into the atmosphere Clean Coal - Emits only 60% as
much carbon dioxide as coal Exploration of natural gas: Fracking
contaminates groundwater with carcinogenic (cancer-causing)
chemicals Land experiences degradation due to drilling techniques
and pipelines are built through environmentally sensitive areas
Advantages and Disadvantages of Natural Gas
Slide 13
Slide 14
Oil sands Oil sands - slow-flowing, viscous deposits of bitumen
mixed with sand, water, and clay. Bitumen Bitumen (tar or pitch)- a
degraded type of petroleum that forms when a petroleum migrates
close to the surface, where bacteria metabolize some of the light
hydrocarbons and others evaporate. Other Fossil Fuels
Slide 15
Hubbert curve Hubbert curve - a graph that shows the point at
which world oil production would reach a maximum and the point at
which we would run out of oil. The Hubbert Curve
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less than 40 years If current global use continues, we will run
out of conventional oil in less than 40 years. at least 200 years
Coal supplies will last for at least 200 years, and probably much
longer. The Future of Fossil Fuel Use