Transcript Fossil Fuel Management

Fossil Fuels
Energy Production using Steam
http://ga.water.usgs.gov/edu/wupt-coalplant-diagram.html
Many power plant use steam to turn generators. Water is
heated by burning fossil fuels or through nuclear reaction,
and when the water boils, steam is produced. The steam
is then fed through the turbines, forcing them to rotate.
Fossil Fuels…
… include coal, oil (from petroleum/crude
oil), natural gas, tar sands, and oil shale.
… formed over a period of time from
compressed vegetation and other
organisms.
… are considered nonrenewable resources.
Why?
Coal
• Coal is the most abundant
and least expensive of the
fossil fuels.
• It is also the most popular,
accounting for almost 40 per
cent of the total worldwide
power generation.
www.freedigitalphotos.net
Coal is a rock consisting almost
entirely of organic material
www.freedigitalphotos.net
The great “coal” forests
• Today’s coal formed from
prehistoric vegetation that
accumulated thousands of
years ago when much of the
Earth's surface was covered in
swamps.
• As the plants and trees in
these swampy areas began to
die, their remains sank into the
swamp land, which eventually
formed a dense material called
peat.
• During this time there were
huge forests of mosses,
horsetails, and tree ferns
www.freedigitalphotos.net
Peat – an early step in coal
formation
www.flickr.com photo by: dModer101
A good place to look for peat
formation …
Peat only forms where there
are low oxygen conditions,
such as in this damp low
spot on a swamp or bog.
Bodies don’t decay in bogs
very well – as you can tell!
www.flickr.com by: LonePine
Bog Man
www.flickr.com by: saamiblog
The Coal Formation Process …
• The organic matter accumulates and forms a bed of
peat.
• The peat bed gets buried by other sediments and under
heat and pressure begins to transform to a low grade
coal known as lignite.
• More heat and pressure further change the lignite into
bituminous coal.
• Even more heat and pressure change the bituminous
coal into a nice hard shiny anthracite coal.
The Steps of Coal Formation…
www.uky.edu
U.S. Coal Deposits …
www.usgs.gov
Is coal being made now?
•
Coal formation is a continuing
process, however large deposits
of sediment are no longer
covering swamp lands as in the
past!
•
Today, in areas such as the Great
Dismal Swamp of North Carolina
and Virginia, the Okefenokee
Swamp of Georgia, and the
Everglades in Florida, plant life
decays and subsides, eventually
to be covered by silts and sands,
and other matter.
•
Perhaps many years from now,
those areas will contain large coal
beds.
The Florida Everglades
www.flickr.com by: Surrealplaces
Coal Mining …
2 main methods of
coal mining:
• Underground
• Surface
– strip mining
– mountaintop
removal (a new
type of mining)
http://simple.wikipedia.org/wiki/Non-renewable_resource
Coal mining has always been a
dirty, dangerous job.
http://hewit.unco.edu/dohist/mining/work/coal/photo1.htm
A coal seam exposed by mining
http://pl.wikipedia.org/wiki/Riese
Strip mining coal
Mountaintop Removal – a large scale
type of coal mining
www.flickr.com by : Mr. Stabile
What effect does this type of mining have on the environment?
Health and environmental impacts
of using coal as an energy source
• Surface mining requires the removal of massive amounts
of top soil, leading to erosion, loss of habitat and
pollution.
• Underground mining causes acid mine drainage, which
causes heavy metals to dissolve and seep into ground
and surface water.
• Coal mine workers also face serious health problems,
including black lung, a lung disease from prolonged
exposure to coal dust in mines.
• On the job hazards include: the mines may cave in,
accumulate poison gases, or suddenly flood – all of
which can injure or kill the miners
More Environmental Impacts of
Using Coal …
• Burning coal creates ground
level ozone, smog and acid
rain.
• Coal (and fuel oil) combustion
emit fly ash particles into the
atmosphere, which contribute
to air pollution problems.
Burning coal produces carbon
dioxide, nitrogen oxide,
sulfur dioxide and methane
gas, all of which could
contribute to global climate
change.
Burning Coal is also the
greatest producer of airborne
Mercury pollution.
hvo.wr.usgs.gov
Natural Gas…
A natural gas well
www.flickr.com by: United States Government Work
Natural gas …
•
Formed from the remains of tiny sea animals and plants that died thousands of years
ago. (Same process that formed petroleum.)
•
The gas became trapped in the rock layers much like a wet household sponge traps
water.
•
Raw natural gas is a mixture of different gases. Its main ingredient is methane. By itself,
methane is odorless, colorless, and tasteless. As a safety measure, natural gas
companies add a chemical odorant (it smells like rotten eggs) so escaping gas can be
detected.
www.seed.slb.com
Processing natural gas …
A natural-gas
processing plant
www.flickr.com by: A guy with A camera
•
After natural gas comes out of the ground, it goes to a processing plant
where it is cleaned of impurities (water, sulfur, dust) and separated into its
various components
•
Then it’s compressed and forced through pipelines under high pressure.
•
It’s often cooled to a liquid state before being transported. LNG – liquified
natural gas
Benefits of using natural gas …
• Cleaner fuel than petroleum or coal
• Has the highest energy content of the hydrocarbons used for fuel
• Our country has large reserves, mostly in the Gulf of Mexico,
Texas, Louisiana, Oklahoma, New Mexico, Wyoming, Kansas, and
Alaska.
• Used for making plastics, detergents, drugs
• But, if we continue to use natural gas at the same rate as we use it
today, the United States will run out in about 50 years (more can
be recovered for higher cost).
Other sources of natural gas
• Landfills - Landfill gas is
considered a renewable
source of natural gas
since it comes from
decaying garbage.
– Landfill gas is 50 percent
methane
• Biomass - a fuel source
derived from plant and
animal wastes which
generates natural gas
There are more than 350 commercial
landfill gas recovery operations in
the U.S. which generate electricity
on-site, supply industrial gas-fired
boilers, or produce substitute natural
gas fuels such as CNG.
www.flickr.com by: Wisconsin Department of
Natural Resources
Some landfills are currently capturing the
gas produced by decaying garbage.
A well is drilled into the waste mass in order to install a well.
The landfill gas is then pumped to a gas treatment and
processing facility to separate out the methane from
carbon dioxide and other non-methane compounds.
www.flickr.com by: Wisconsin Department of Natural Resources
Study Reveals Huge U.S. Oil
Shale Field …
WASHINGTON — The United States has an oil reserve at least three
times that of Saudi Arabia locked in oil-shale deposits beneath
federal land in Colorado, Utah and Wyoming, according to a study
released yesterday.
Headline from The Seattle Times, September 1, 2005
As the head of Shell's Unconventional Resources unit, Steve Mutt,
explained that as far back as the native Americans, people have
been trying to exploit this resource, which is essentially immature
petroleum. The Indians called it fire rock and inexperienced
homesteaders tried to use it for their fireplaces with disastrous
consequences.
An oil-shale rock burns on its own
once it has been lit by a blowtorch.
www.flickr.com by: asia blues
Oil shale doesn’t contain oil or
(usually) shale
• The organic material is kerogen (not oil), and the "shale"
is usually a relatively hard rock, called marl.
• Properly processed, kerogen can be converted into a
substance somewhat similar to petroleum.
• The kerogen must be heated to a high temperature.
This causes the organic material to be converted into a
liquid. The liquid is then further processed to produce an
medium grade oil which is said to be better than the
lowest grade of oil.
Here’s the down side…….
• The report also says oil-shale mining,
above-ground processing and disposing of
spent shale cause significant adverse
environmental impacts.
• Shell Oil is working on a process that
would heat the oil shale in place, which
could have less effect on the environment.
A new oil shale method uses in-ground heaters to
“preheat” the oil shale so it is easier to remove the oil.
www.flickr.com by: SkyTruth
Instead of stripmining the rock
and then
processing it, this
new method
superheats huge
underground
areas for several
years,
This method
gradually forces
the oil out of the
stone and then
pumps it to the
surface
Tar sands (also called oil sands or
bituminous sands)
• These sands contain clay,
water, sand, and bitumen
• Bitumen contains 83.2%
carbon
• This can be processed to
make synthetic crude oil or
be refined into petroleum
products.
www.flickr.com by: The Co-operative
• This may prove to be a viable
alternative to oil imported from
the Middle East.
Environmental impacts of using
shale or tar sands
• Takes lots of energy to
remove and process.
• Uses large amounts of
water which is then
polluted by the process.
• Generate huge amounts
of waste that must be
“put back” somewhere
(unless the in-ground
heating method is used).
www.flickr.com by: coopfs
Environmental Impact of Tar Sands
Alberta Tar Sands
The term “tar sands” refers to thick oil called bitumen that is mixed in with
sand, clay, and water. Intensive energy is required to process the sands into
crude oil. Tar Sands oil is the world’s most harmful type of oil for the
atmosphere, emitting high volumes of greenhouse gases during
development, which contribute to global warming, as well as other
pollutants. Tar Sands projects are the largest contributor to greenhouse
gas emissions growth in Canada. By 2015, the Tar Sands are expected
to emit more greenhouse gases than the nation of Denmark (pop. 5.4
million).
Summary of Fossil Fuels …
• Petroleum
• Coal
• Natural Gas
• Oil Shale
• Tar Sands
How much longer will we have access to these fuels?
How expensive will they get as demand exceeds supply?
What are some alternative energy sources?
Nuclear Energy Produces
Electricity…
Nuclear Energy
Two
ways that nuclear energy can be
produced are fusion and fission.
Fusion
–
the combining of atomic nuclei – such as
in the stars (and sun!) – generates energy
http://www.aa.washington.edu
Nuclear Energy
Fission – the breaking apart of atomic
nuclei
hyperphysics.phy-astr.gsu.edu/hbase/nucene/im...
Nuclear energy
Two advantages of
nuclear energy:
It
produces huge
amounts of energy from
small amounts of nuclear
fuel (uranium and
plutonium).
Earth
contains enough
nuclear fuel to meet all
present and future needs.
www.pollutionissues.com
Nuclear Energy
Nuclear energy produces wastes in the form
of heat and spent (used) fuel – which
can remain radioactive for thousands of
years.
• Disposing of this radioactive spent fuel is a
major problem.
• One proposed disposal site is Yucca
Mountain in Nevada.
Nuclear Energy
Four reasons why nuclear
power is not as widely used
as it could be…
– High cost
– Peoples’ fear of exposure to
radiation
– The threat of a meltdown
(nuclear explosion)
– The fear that nuclear weapons
could be developed using this
technology
Stable, highly centralized
governmental control is
necessary for the safe
operation of nuclear
power.
www.answers.com
Sources
Wikimedia commons
Freedigitalphotos.net
Flickr.com
USGS.gov
Uky.edu
aa.washington.edu