Transcript Energy and Waste Chapters 15, 16, and 22 Living in the

Nonrenewable Energy
Resources
Chapter 17
Advanced Placement Environmental Science
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
Energy Sources
Modern society requires large quantities of energy that
are generated from the earth’s natural resources.
Primary Energy Resources: The fossil fuels(oil, gas, and
coal), nuclear energy, falling water, geothermal, and
solar energy.
Secondary Energy Resources: Those sources which are
derived from primary resources such as electricity, fuels
from coal, (synthetic natural gas and synthetic gasoline),
as well as alcohol fuels.
Thermodynamics
The laws of thermodynamics tell us two
things about converting heat energy from
steam to work:
1) The conversion of heat to work cannot be
100 % efficient because a portion of the heat
is wasted.
2) The efficiency of converting heat to work
increases as the heat temperature increases.
Energy Units and Use
BTU (British Thermal Unit) - amount of energy
required to raise the temperature of 1 lb. of water
by 1 ºF.
cal (calorie) - the amount of energy required to
raise the temperature of 1 g of water by 1 ºC.
Commonly, kilocalorie (kcal) is used.

1 Btu = 252 cal = 0.252 kcal

1 Btu = 1055 J (joule) = 1.055 kJ

1 cal = 4.184 J
Energy Units and Use
Two other units that are often seen are the horsepower
and the watt. These are not units of energy, but are
units of power.


1 watt (W) = 3.412 BTU/hour
1 horsepower (hp) = 746 W
Watt-hour - Another unit of energy used only to
describe electrical energy. Usually we use kilowatthour (kW-h) since it is larger.
quad (Q) - used for describing very large quantities of
energy. 1 Q = 1015 Btu
Evaluating Energy Resources
U.S. has 4.6% of world population and
uses 24% of the world’s energy.
84% from nonrenewable fossil fuels (oil,
coal, & natural gas).
7% from nuclear power.
9% from renewable sources (hydropower,
geothermal, solar, biomass).
Changes in U.S. Energy Use
Energy resources removed from the
Earth’s crust include: oil, natural gas,
coal, and uranium.
Fossil Fuels
Fossil fuels originated from the decay of
living organisms millions of years ago, and
account for about 80% of the energy
generated in the U.S.
The fossil fuels used in energy generation
are:
Natural gas, which is 70 - 80% methane (CH4)
Liquid hydrocarbons obtained from the
distillation of petroleum
Coal - a solid mixture of large molecules with a
H/C ratio of about 1
Problems with Fossil Fuels
Fossil fuels are nonrenewable resources.
At projected consumption rates, natural gas
and petroleum will be depleted before the end
of the 21st century.
Impurities in fossil fuels are a major source
of pollution.
Burning fossil fuels produce large amounts
of CO2, which contributes to global
warming.
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Oil
Deposits of crude oil often are trapped within
the earth's crust and can be extracted by drilling
a well.
Fossil fuel, produced by the decomposition of
deeply buried organic matter from plants and
animals.
Crude oil: complex liquid mixture of
hydrocarbons, with small amounts of S, O, N
impurities.
 How Oil Drilling Works by Craig C. Freudenrich, Ph.D. – read
the entire article on science.howstuffworks.com.
Sources of Oil
•Organization of Petroleum Exporting Countries
(OPEC) – 13 countries have 67% world reserves:
• Algeria, Ecuador, Gabon, Indonesia, Iran,
Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi
Arabia, United Arab Emirates, & Venezuela
•Other important producers:
• Alaska, Siberia, & Mexico.
Oil in U.S.
•2.3% of world
reserves.
•Uses nearly 30%
of world
reserves.
•65% for
transportation.
•Increasing
dependence on
imports.
Low oil prices have stimulated economic growth, they
have discouraged/prevented improvements in energy
efficiency and alternative technologies favoring
renewable resources.
• Burning any fossil fuel releases carbon dioxide into the
atmosphere and thus promotes global warming.
• Comparison of CO2 emitted by fossil fuels and nuclear
power.
Oil
Crude oil is transported to a refinery
where distillation produces
petrochemicals.
How Oil Refining Works
by Craig C. Freudenrich, Ph.D.
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Natural Gas - Fossil Fuel
• Mixture
• 50–90% Methane (CH4)
• Ethane (C2H6)
• Propane (C3H8)
• Butane (C4H10)
• Hydrogen sulfide (H2S)
Sources of Natural Gas
•Russia & Kazakhstan - almost 40% of
world's supply.
•Iran (15%), Qatar (5%), Saudi Arabia
(4%), Algeria (4%), United States (3%),
Nigeria (3%), Venezuela (3%).
•90–95% of natural gas in U.S. domestic
(~411,000 km = 255,000 miles of
pipeline).
billion cubic meters
Natural Gas
Experts predict increased use of natural gas
during this century.
Natural Gas
When a natural gas field is tapped, propane
and butane are liquefied and removed as
liquefied petroleum gas (LPG).
The rest of the gas (mostly methane) is dried,
cleaned, and pumped into pressurized
pipelines for distribution.
Liquefied natural gas (LNG) can be shipped
in refrigerated tanker ships.
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Coal: Supply and Demand
Coal exists in many forms therefore a chemical
formula cannot be written for it.
Coalification: After plants died they
underwent chemical decay to form a product
known as peat.
Over many years, thick peat layers formed.
Peat is converted to coal by geological events such
as land subsidence which subject the peat to great
pressures and temperatures.
Ranks of Coal
 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.
 Bituminous: Most common coal and 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.
 Subbituminous: Black lignite and is dull black and generally
contains 20 to 30 percent moisture Energy content is 8,300
BTU/lb.
 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 than 4,000 BTU/lb.
PEAT
LIGNITE
BITUMINOUS
ANTHRACITE
Main Coal Deposits
Bituminous
Subbituminous
Lignite
Anthracite
garnero101.asu.edu/glg101/Lectures/L37.ppt
Advantages and Disadvantages
Pros
•Most abundant fossil fuel.
•Major U.S. reserves.
•300 years at current consumption rates.
•High net energy yield.
Cons
•Dirtiest fuel, highest carbon dioxide.
•Major environmental degradation.
•Major threat to health.
© Brooks/Cole Publishing Company / ITP
Sulfur in Coal
When coal is burned, sulfur is released
primarily as sulfur dioxide (SO2 - serious
pollutant).
Coal Cleaning - Methods of removing sulfur
from coal include cleaning, solvent refining,
gasification, and liquefaction. Scrubbers are
used to trap SO2 when coal is burned.
Two chief forms of sulfur are inorganic (FeS2
or CaSO4) and organic (Sulfur bound to
Carbon).
Coal
Coal gasification  Synthetic
natural gas (SNG)
Coal liquefaction  Liquid fuels
Disadvantage
Costly
High Environmental Impact
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Nuclear Energy
In a conventional nuclear power
plant:
a controlled nuclear fission chain
reaction
heats water
produces high-pressure steam
that turns turbines
generates electricity.
Nuclear Energy
Controlled Fission
Chain Reaction
Neutrons split the
nuclei of atoms such
as of Uranium or
Plutonium
Release energy
(heat)
Controlled Nuclear Fission Reaction
Radioactivity
• Radioactive decay continues until the the
original isotope is changed into a stable
isotope that is not radioactive.
• Radioactivity: Nuclear changes in which
unstable (radioactive) isotopes emit
particles & energy.
Radioactivity
• Types
• Alpha particles consist of 2 protons and 2 neutrons,
and therefore are positively charged
• Beta particles are negatively charged (electrons)
• Gamma rays have no mass or charge, but are a form
of electromagnetic radiation (similar to X-rays)
• Sources of natural radiation
•
•
•
•
•
Soil
Rocks
Air
Water
Cosmic rays
Relative
Doses
from
Radiation
Sources
Half-Life
The time needed for one-half of the nuclei in a
radioisotope to decay and emit their radiation to
form a different isotope.
Uranium 235
Plutonium 239
Half-time
710 million yrs
24.000 yrs
emitted
alpha, gamma
alpha, gamma
During operation, nuclear power plants
produce radioactive wastes, including some
that remain dangerous for tens of thousands
of years.
Diagram of Radioactive Decay
Effects of Radiation
• Genetic Damages: from mutations
that alter genes.
• Genetic defects can become
apparent in the next generation.
• Somatic Damages: to tissue, such
as burns, miscarriages, and cancers.
Radioactive Waste
1.
Low-level radiation (Gives off low amount of
radiation.)
• Sources: nuclear power plants, hospitals, and
universities.
• 1940 -1970 most was dumped into the ocean.
• Today deposited into landfills.
2.
High-level radiation (Gives off large amount of
radiation.)
• Fuel rods from nuclear power plants.
• Half-time of Plutonium 239 is 24,000 years.
• No agreement about a safe method of storage.
Radioactive Waste
1. Bury it deep underground.
• Problems: i.e., earthquake, groundwater…
2. Shoot it into space or into the sun.
• Problems: costs, accident would affect large area.
3. Bury it under the Antarctic ice sheet.
• Problems: long-term stability of ice is not known,
global warming.
4. Most likely plan for the US.
• Bury it into Yucca Mountain in desert of Nevada.
• Cost of over $ 50 billion.
• 160 miles from Las Vegas.
• Transportation across the country via train & truck.
Yucca Mountain
www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt
Plutonium Breeding
238U is the most plentiful isotope of
Uranium.
Non-fissionable - useless as fuel.
Reactors can be designed to convert
238U into a fissionable isotope of
plutonium, 239Pu.
Conversion of 238U to 239Pu
Under
appropriate
operating
conditions, the
neutrons given
off by fission
reactions can
"breed" more
fuel, from
otherwise nonfissionable
isotopes, than
they consume.
www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt
Reprocess Nuclear Fuel
During the operation of a nuclear
reactor the uranium runs out.
Accumulating fission products
hinder the proper function of a
nuclear reactor.
Fuel needs to be (partly) renewed
every year.
Plutonium in Spent Fuel
Spent nuclear fuel contains many
newly formed plutonium atoms.
Miss out on the opportunity to split.
Plutonium in nuclear waste can be
separated from fission products and
uranium.
Cleaned Plutonium can be used in a
different Nuclear Reactor.
Nuclear Energy
Concerns about the safety, cost,
and liability have slowed the
growth of the nuclear power
industry.
Accidents at Chernobyl and
Three Mile Island showed that a
partial or complete meltdown is
possible.
Nuclear Power Plants in U.S.
Three Mile Island
• March 29, 1979, a reactor near Harrisburg, PA, lost
coolant water because of mechanical and human
errors and suffered a partial meltdown.
• 50,000 people evacuated & another 50,000 fled area.
• Unknown amounts of radioactive materials released.
• Partial cleanup & damages cost $1.2 billion.
• Released radiation increased cancer rates.
Chernobyl
• April 26, 1986, reactor explosion (Ukraine) flung
radioactive debris into atmosphere.
• Health ministry reported 3,576 deaths.
• Green Peace estimates32,000 deaths.
• About 400,000 people were forced to leave their
homes.
• ~160,000 sq km (62,00 sq mi) contaminated.
• > Half million people exposed to dangerous levels of
radioactivity.
• Cost of incident > $358 billion.
Nuclear Energy
Nuclear plants must be decommissioned
after 15-40 years.
New reactor designs are still proposed.
Experimental breeder nuclear fission
reactors have proven too costly to build
and operate.
Attempts to produce electricity by nuclear
fusion have been unsuccessful.
Use of Nuclear Energy
• U.S. phasing out.
• Some countries (France, Japan) investing is
increasing.
• U.S. currently ~7% of energy is nuclear.
• No new U.S. power plants ordered since 1978.
• 40% of 105 commercial nuclear power plants
expected to be retired by 2015 and all by 2030.
• North Korea is getting new plants from the US.
• France has 78% of energy from nuclear.
Phasing Out Nuclear Power
•Multi-billion-$$ construction costs
•High operation costs
•Frequent malfunctions
•False assurances and cover–ups
•Overproduction of energy in some areas
•Poor management
•Lack of public acceptance
Energy &
Mineral resources
Energy