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

NONRENEWABLE
ENERGY
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
ENERGY SOURCES
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 kilowatt-hour (kW-h)
since it is larger.
EVALUATING ENERGY RESOURCES
U.S. has 4.6% of world population; 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
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Energy resources removed from the
earth’s crust include: oil, natural gas,
coal, and uranium
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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
Coal = ~ 400 years
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
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OIL
Deposits of crude oil often are trapped within the
earth's crust and can be extracted by drilling a well
Crude oil: complex liquid mixture of hydrocarbons, with
small amounts of S, O, N impurities
Formation of oil animation
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.
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Oil in U.S.
•2.3% of world
reserves
•65% for
transportation;
•increasing
dependence on
imports.
• Google Earth visuals
of oil consumption by
country
Low oil prices have stimulated economic growth,
they have discouraged / prevented improvements in
energy efficiency and alternative technologies
favoring renewable resources.
Current cost of crude oil
Oil
drilling
Deep water
drilling
Tar Sands and Keystone XL
Pipeline
OIL
Crude oil is transported to a refinery where
distillation produces petrochemicals
Animation
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
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 metres
NATURAL GAS
Experts predict increased use of natural gas during this century
Kansas city
owned cars run
on natural gas
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
Hydraulic Fracking Animation
Coal Fracking
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
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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
Lignite: A brownish-black coal of low quality ;Energy
content is lower 4000 BTU/lb.
Subbituminous: Black lignite, Energy content is 8,300
BTU/lb.
Bituminous: most common coal is dense and black
(Energy content about 10,500 Btu / lb.
Anthracite :A hard, black lustrous coal, often referred
to as hard coal, Energy content of about 14,000
Btu/lb.
Animation of how coal is formed
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MAIN COAL DEPOSITS
Bituminous
Subbituminous
Lignite
Anthracite
COAL
Coal gasification Synthetic
natural gas (SNG)
Coal liquefaction Liquid fuels
Disadvantage


High environmental impact (air
pollution-black lung disease)
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
installed at tops of factory exhaust pipes to trap
SO2 when coal is burned.
Two chief forms of sulfur is inorganic (FeS2 or
CaSO4) and organic (Sulfur bound to Carbon)
• Comparison of CO2 emitted by fossil fuels and nuclear
power.
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ACID MINE DRAINAGE
The impact of mine drainage on a
lake after receiving effluent
from an abandoned tailings
impoundment for over 50
years
Relatively fresh tailings in an
impoundment.
The same tailings impoundment
after 7 years of sulfide
oxidation.
MINE EFFLUENT
DISCHARGING FROM THE
BOTTOM OF A WASTE
ROCK PILE
1. Energy Resources
2. Oil
3. Natural Gas
4. Coal
5. Nuclear Energy
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NUCLEAR ENERGY
The process in a conventional
nuclear power plant:
1. A controlled nuclear fission chain
reaction
2. Heats water
3. Produce high-pressure steam
4. Cause turbines to turn
5. Generates electricity
Nuclear Energy
Controlled Fission
Chain Reaction:
•neutrons split the
nuclei of atoms such
as Uranium or
Plutonium
•release energy
(heat)
URANIUM
Controlled Nuclear Fission Reaction
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Radioactivity
• Radioactive decay continues until 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 of radiation:
• 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
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.
Half-time
emitted
Uranium-235
710 million yrs
alpha, gamma
Plutonium-239
24,000 yrs
alpha, gamma
During operation, nuclear power plants
produce radioactive wastes, including some
that remain dangerous for tens of thousands
of years.
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Effects of Radiation
• Genetic damages from mutations
in DNA.
• Genetic defects can become
apparent in the next generation or
future generations.
• Somatic damages to tissue, such as
burns, miscarriages & cancers.
Radioactive Waste
1. Low-level radiation
• Sources: nuclear power plants, hospitals &
universities
• 1940 – 1970 most was dumped into the ocean
• Today- bury in deep layers of land
2. High-level radiation
• Fuel rods from nuclear power plants
• 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
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“Nuke Us”Article – Forbes Magazine 1/25/12
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
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
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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
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TURKEY POINT NUCLEAR PLANT- HOMESTEAD, FL
Located on Biscayne Bay, 24 miles
south of Miami and just east of the
Homestead area
Two nuclear power units:
 the first unit began operation in 1972
 the second unit following in 1973
Generates about 1,400 million watts
of electricity -- enough power to
supply the annual needs of more
than 450,000 homes
Reactor manufacturer - Westinghouse
Turbine Generator Manufacturer Westinghouse
A safe, reliable and a low-cost
producer of electricity
www.fpl.com- Turkey Point
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.
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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.
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3 mile island
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
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Chernobyl
disaster
Chernobyl Radioactive
wolves
National
Geographic
returns to the
scene- 2006
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
increasingly
• U.S. currently ~7% of energy nuclear
• No new U.S. power plants ordered since 1978
• 40% of 105 commercial nuclear power expected to be
retired by 2015 and all by 2030
• North Korea is getting new plants from the US
• France 78% energy nuclear
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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
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