Transcript fossil fuel - Harrison High School

Renewable and
Non-Renewable Resources
Environmental Science
Chapter 17
Energy Resources and Fossil
Fuels
•
A fossil fuel is a nonrenewable
energy resource formed from the
remains of organisms that lived
long ago; examples include oil,
coal, and natural gas.
•
Most of the energy we use
comes from fossil fuels.
•
We use fossil fuels to run cars,
ships, planes, and factories and
to produce electricity.
Energy Use in the United States
Chapter 17
Energy Resources and Fossil
Fuels
• Fossil fuels are central to life in modern
societies, but there are two main
problems with fossil fuels.
• The supply of fossil fuels is limited.
• Obtaining and using them has environmental
consequences.
Fossil Fuels
How Fossil-Fuel Deposits
Form
• Fossil fuel deposits are not distributed evenly.
• There is an abundance of oil in Texas and
Alaska, but very little in Maine.
• The eastern United States produces more coal
than other areas.
• The reason for this difference lies in the
geologic history of the areas.
Coal Formation
• Coal forms from the remains of plants that lived
in swamps hundreds of millions of years ago.
• As ocean levels rose and fell, swamps were
repeatedly covered with sediment.
• Layers of sediment compressed the plant
remains, and heat and pressure within the
Earth’s crust caused coal to form.
• Much of the coal in the United States formed
about 300 to 250 million years ago.
Ranks of Coal
• Lignite: A brownish-black coal of low quality (i.e., low heat
content per unit) with high inherent moisture and volatile
matter. Energy content is lower 4000 BTU/lb.
• Subbituminous: Black lignite, is dull black and generally
contains 20 to 30 percent moisture Energy content is 8,300
BTU/lb.
• Bituminous: most common coal is dense and black (often
with well-defined bands of bright and dull material). Its
moisture content usually is less than 20 percent. Energy
content about 10,500 Btu / lb.
• Anthracite :A hard, black lustrous coal, often referred to as
hard coal, containing a high percentage of fixed carbon and
a low percentage of volatile matter. Energy content of
about 14,000 Btu/lb.
www.uvawise.edu/philosophy/Hist%20295/ Powerpoint%5CCoal.ppt
How a Coal Power Plant
Works?
Oil and Natural Gas Formation
• Oil and natural gas result from the decay of tiny
marine organisms that accumulated on the
bottom of the ocean millions of years ago.
• These remains were buried by sediments and
then heated until they became complex energyrich carbon molecules.
• Over time these molecules migrated into the
porous rock formations that now contain them.
Nuclear Energy
• In the 1950s and 1960s, nuclear power plants
were seen as the power source of the future
because the fuel they use is clean and plentiful.
• In the 1970s and 1980s, however, many
planned nuclear power plants were cancelled
and others under construction were abandoned.
• Today, nuclear power
accounts for 17% of the
world’s electricity.
Fission: Splitting Atoms
• Nuclear power plants get their power from
nuclear energy.
• Nuclear energy is the binding energy of the
atomic nucleus energy released by a fission
or fusion reaction
• The forces that hold together a nucleus of an
atom are more than 1 million times stronger
than the chemical bonds between atoms.
• In nuclear power plants, the element uranium
is used as the fuel.
Fission: Splitting Atoms
• The nuclei of uranium atoms are bombarded with atomic
particles called neutrons. These collisions cause the
nuclei to split in a process called nuclear fission.
• Nuclear fission releases a tremendous amount of energy
and more neutrons, which in turn collide with more
uranium nuclei.
Nuclear Reactors in the U.S.
How a nuclear reactor works
• http://classic.hippocampus.org/course_loc
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Why use nuclear power?
Please list the pros and cons of nuclear
power on the index card.
Pros
Cons
Nuclear Disasters
• Chernobyl
• April 28, 1986
• A failure of the cooling
system caused a
complete meltdown of the
reactor core
• 56 died from radiation
released from accident
• 4,000 est. will die of
cancers from radiation
• http://video.pbs.org/vi
deo/1862529183
You decide
• Write an argument using the facts as your
support as to whether or not you support
the building or new nuclear power plants
to provide us with clean energy.
Renewable Energy
• Renewable energy is energy from sources that
are constantly being formed.
• Types of renewable energy includes:
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solar energy
wind energy
the power of moving water
Earth’s heat.
• Remember, all sources of energy, including
renewable sources, affect the environment.
Solar Energy—Power from the
Sun
• Nearly all renewable energy comes
directly or indirectly from the sun.
• Direct solar energy is used every day, like
when the sun shines on a window and
heats a room.
• Solar energy can also be used indirectly to
generate electricity in solar cells.
Passive solar heating
• Passive solar heating is the use of sunlight to
heat buildings directly.
– Large windows that face the sun can be used to heat
a home
• Active solar heating is the gathering of solar
energy by collectors that are used to heat water
or heat a building.
– A liquid is heated by the sun as it flows through solar
collectors.
– The hot liquid is then pumped through heat
exchangers, which heats water for the building.
Photovoltaic Cells
• Photovoltaic cells are solar
cells that convert the sun’s
energy into electricity.
• Solar cells have no moving parts,
and they run on nonpolluting
power from the sun.
• However, they produce a very
small electrical current. Meeting
the electricity needs of a small
city would require covering
hundreds of acres with solar
panels.
Wind Power
• Energy from the sun warms
the Earth’s surface unevenly,
which causes air masses to
flow (wind)
• Wind power, which converts
the movement of wind into
electric energy, is the fastest
growing energy source in the
world.
Wind Farms
• Windmills spin a turbine, which is used to
capture the energy from the wind.
• Large arrays of wind turbines are called wind
farms. Large wind farms supply electricity to
thousands of homes.
– In windy rural areas, small wind farms with 20 or
fewer turbines are also becoming common.
• Because wind turbines take up little space,
some farmers can add wind turbines to their
land and still use the land for other purposes.
Biomass—Power from Living
Things
• Biomass fuel consists of plant material,
manure, or any other organic matter that is
used as an energy source.
• Fossil fuels can be thought of as biomass
energy sources, although they are
nonrenewable.
• Renewable biomass fuels, such as wood and
dung, are major sources of energy in
developing countries.
Methane
• When bacteria decompose organic wastes,
one byproduct is methane gas.
– Methane can be burned to generate heat or
electricity.
• In China, more than 6 million households use
biogas digesters to ferment manure and
produce gas for heating and cooking.
• Some landfills in the United States generate
electricity by using the methane from the
decomposition of trash.
Alcohol
• Liquid fuels can also be derived from biomass.
• For example, ethanol can be made by
fermenting fruit or agricultural waste.
• Cars and trucks can run on ethanol or gasohol,
a blend of gasoline and ethanol. Gasohol
produces less air pollution than fossil fuels.
• Some states require the use of gasohol in
vehicles as a way to reduce air pollution.
Hydroelectricity—Power from
Moving Water
• Hydroelectric energy is
electrical energy
produced by falling water.
• Hydroelectric energy
accounts for 20% of the
world’s electricity.
• The water in a reservoir is
released to turn a turbine
in a dam, which
generates electricity.
Geothermal Energy—Power
from the Earth
• Geothermal energy is the
energy produced by heat
within the Earth.
• Although geothermal energy
is considered a renewable
resource, the water that is
used must be managed
carefully so that it is not
depleted.
Geothermal Energy
• Geothermal power plants
generate electricity using the
following steps
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Steam rises through a well
Steam drives turbines, which
generate electricity
Leftover liquid is pumped back
into the hot rock
• The leftover liquid, water, is
returned to Earth’s crust
because it can be reheated by
geothermal energy and used
again.