APES First Unit Test Review
Intro concepts and Energy
Test Make Up
•
•
•
•
•
•
•
Commons
Nuclear
Fossil fuel
Biofuel
Solar
Geothermal
Hydro
3
10
3
2
3
2
1
• Science
2
• Wind
1
• Hydrogen
1
• General
3
What is the “Tragedy of the
Commons”?
• ARTICLE: published in 1968 by
Garrett Hardin.
• CONCEPT: a shared resource in
which any given user reaps the full
benefit of his/her personal use, while
the losses are distributed amongst
all users. Result? Tragedy all
around.
What is the “Tragedy of the
Commons”?
Belongs to a Class of Problems that have
no Technical Solutions
The Nuclear Arms Race
Human Population Growth
What is the “Tragedy of the
Commons”?
• CLASSIC EXAMPLE: cows on
shared pasture.
• What are other examples of commons?
•Air
•Water
•Scenery
Could we think of EARTH as a commons?????
Would education help?
One solution might be
education. If everyone
knew the best long-term
strategy, would they act
accordingly and “take 1
fish”?
Probably not.
More Conscious Farmers Get
Less:
1: Grass on Commons 4 2: F1 Cows Added
1:
2:
3:
4:
5:
100.00
12.00
3: F2 Cows Added 2
4: F3 Cows Added 3
5: F4 Cows Added 4
1
1
1
1
Farmer 1: 12 Cows
2
3
3
1:
2:
3:
4:
5:
6.00
3
4
4
4
0.00
5
4
Farmer 3: 4.5 Cows
2
1:
2:
3:
4:
5:
Farmer 2: 8 Cows
2
50.00
5
5
3
5
Farmer 4: 2 Cows
2
0.00
0.00
3.00
Graph 2: p1 (Untitled)
6.00
Time
9.00
12.00
7:51 PM Wed, May 12, 2004
Hardin’s Suggestion:
Mutual Coercion, Mutually Agreed Upon
• A regulation
accepted by the
majority of those
affected and
imposed upon all
involved.
• Examples?
– Speed limits
– Income tax
– Aesthetic standards
in a gated
community
Thomas Malthus:
Unlimited Growth
Unlimited Population Growth Based on the
Exponential Equation
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Hardin’s Suggestion:
Mutual Coercion, Mutually Agreed Upon
• Hardin admits there are drawbacks to
strict legislation, but believes:
– There is no perfect solution.
– Status quo is worse than a regulated
situation
– He writes: “Who enjoys taxes? We all
grumble about them. But we accept
compulsory taxes because we recognize
that voluntary taxes would favor the
conscienceless.” (Hardin, 338)
USA Energy Flow, 1999
Nuclear Energy
AN INTRODUCTION TO
FISSION &(a bit on)
FUSION
Introduction
• Nuclear reactions deal with
interactions between the nuclei of
atoms
• Both fission and fusion processes
deal with matter and energy
Matter and Energy
• We know that “matter and energy
cannot be created nor destroyed”
• We need to understand that Matter
and Energy are two forms of the
same thing
E = mc2
• Matter can be changed into Energy
• Einstein’s formula above tells us
how the change occurs
• In the equation above:
E = Energy
m = Mass
c = Speed of Light (Universal
Constant)
Energy
Mass
Light
Speed
E = mc2
• The equation may be read as
follows:
Energy (E) is equal to Mass (m)
multiplied
by the Speed of Light
(c) squared
• This tells us that a small amount of
mass can be converted into a very
large amount of energy because
the speed of light (c) is an
extremely large number
Fission
Used in Nuclear Power
Plants
• Fission may be defined as the process of
splitting an atomic nucleus into fission
fragments
• The fission fragments are generally in the form
of smaller atomic nuclei and neutrons
• Large amounts of energy are produced by the
fission process
Fission
• Fissile nuclei are generally heavy
atoms with large numbers of
nucleons
• The nuclei of such heavy atoms
are struck by neutrons initiating the
fission process
Fission
• A classic example of a fission
reaction is that of U-235:
U-235 + 1 Neutron
2 Neutrons + Kr-92 + Ba-142 +
Energy
• In this example, a stray neutron strikes
an atom of U-235. It absorbs the neutron
and becomes an unstable atom of U236. It then undergoes fission. Notice
that more neutrons are released in the
reaction. These neutrons can strike
other U-235 atoms to initiate their fission.
What is a Breeder Reactor?
A breeder reactor IS a fission reactor. It
is a much more efficient version of a
fission reactor because it "breeds"new fuel
while consuming the old fuel. This is
possible because the fission reactions
release lots of neutrons that can be used
to transform certain non-useful isotopes of
uranium(238) into useful isotopes (235.
Plutonium is generally a product of breeder
reactors. However, plutonium 239 (1/2 life
of 24,000 years)is also rather hazardous
and dangerous for reasons associated with
proliferation of nuclear weapons, so
breeder reactors have not been very popular
in the U.S. They are widely used in other
countries though
Pressurized Water Reactor
From: Joseph Gonyeau, P.E., Virtual Nuclear Tourist
http://www.nucleartourist.com/
Fusion
• Fusion is a nuclear reaction
whereby two light atomic nuclei
fuse or combine to form a single
larger, heavier nucleus
• The fusion process generates
tremendous amounts of energy;
refer back to Einstein’s equation
• Fusion reactions do not occur
naturally on our planet but are the
principal type of reaction found in
stars
So Nuclear Energy is:
•
•
•
•
Clean energy during production
Seems to be unlimited
Technology is mostly in place
Then why is it not used more???
Three Mile Island
•
•
•
•
Middletown, PA 1979
nuclear portion of plant had a pump malfunction.
This caused pressure to build
valve was opened to release pressure and was
stuck open, allowing coolant to leak out.
• Reactor core overheated, started meltdown, but
did not breach containment building.
• HUGE SCARE..’cause this could have been…
Chernobyl
The Chernobyl disaster was a nuclear reactor
accident that occurred on 26 April 1986 at the
Chernobyl Nuclear Power Plant in Ukraine
(then part of the Soviet Union). It is
considered to be the worst nuclear power
plant disaster in history and the only level 7
event on the International Nuclear Event
Scale. It resulted in a severe release of
radioactivity following a massive power
excursion that destroyed the reactor. Most
deaths from the accident were caused by
radiation poisoning.
Chernobyl Pictures
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Fears of Nuclear Power Plants
• Possible meltdowns caused by human
error such as Chernobyl
• Storage of Waste leaking dangerous
radiation
• Use of “waste” product for nuclear
bombs
USA Reaction to these Fears
• Strong laws governing building and
regulating nuclear power plants have
increased cost beyond profitability
• No new reactors have been ordered since 1978 and
all ordered after 1973 were cancelled.
fossil-fuel power plant
• is a power plant that burns fossil fuels
such as coal natural gas or
petroleum(oil) to produce electricity
• Net energy is the amount of energy
gained from using the fuel minus what it
takes to get it.
Coal = 22% Oil = 33% Natural gas = 21%
Crude Oil
• Location (world): Middle East (OPEC 78%)
• Location (US): Gulf of Mexico, Gulf Coast(3% of
world reserves)
• Availability projections (US reserves): 10-48
years.
• Availability projections (world): 42-93years
• Advantages: Abundant, convenient, cheap
• Disadvantages: Dependant on foreign oil,running
out, emissions, pollution, at current rate, we will run
out in 53 years!
Crude Oil
• Conventional oil/light oil: what we use; pumped
from ground
• Heavy crude oil: Oil that is difficult to pump out;
currently not recovered
• Oil sand (tar sand): mixture of clay, sand, water and
bitumen. Could be used, but has high sulfur content
• Shale oil: can be extracted from oil shale rock. Low
quality oil
Natural Gas
•
•
•
•
Location (world): Russia (31%), Middle East(36%)
Location (US): (3%) Gulf coast, above crude oil
Availability projections (US reserves): 55-80years
Availability projections (world): 62-125 (and upto 200 years
with unconventional)
• Advantages: Can be transported easily, lower pollution than
other fossil fuels, high energy yield
• Disadvantages: running out, greenhouse gas
released, explosive (especially in liquid form)
Natural Gas
• LPG: liquefied petroleum gas (LP). For
rural areas where natural gas lines
aren’t run. Propane and Butane mixed
• LNG: liquefied natural gas. For
shipping across oceans
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COAL
Location (world): China, Russia
Location (US): (25% of world supply) Eastern areas of US: Montana,
Utah, Arizona and southern areas of midwest
Availability projections (US reserves): 300 years at current rates (64
years with 4% increase)
Availability projections (world):400+ years if new reserves are found
and current rate of usage
Advantages: most abundant fossil fuel, high energy, US has large supply
Disadvantages: health concerns, high pollution when burned (CO2, high
in sulfur, releases mercury
COAL
• Coal can be converted into synthetic
natural gas (SNG), but the process
releases more CO2 than burning coal
does.
• Low quality coal is often burnt with high
emissions: mercury, sulfur, CO2
• Different types of coal: Lignite,
Bituminous,Anthracite, Peat
Coal Types
Peat
(not a coal)
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Bituminous
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Lignite
(brown coal) (soft coal)
Heat
Heat
Pressure
Partially
decayed plant
matter in
swamps and
bogs; low heat
content
Pressure
Low heat
content; low
sulfur content;
limited supplies
in most areas
Anthracite
(hard
coal)
Heat
Pressure
Extensively used as
a fuel because of its
high heat content
and large
supplies;normally
has a high sulfur
content
Highly desirable
fuel because of its
high heat content
and low sulfur
content;supplies
are limited in most
areas
U.S. Energy Consumption by Source, 1
Renewable Energy Sources
•
•
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•
•
•
•
•
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Wind
Solar photovoltaics
Solar thermal power
Passive solar air and water heating
Hydropower
Biomass
Ocean energy
Geothermal
Waste to Energy
How Wind Turbines Work
Overview – Like a windmill, the wind turns the blades
of the wind turbines. This generates electricity which
is then stored for later use.
More in detail – At the top of a wind turbine is a
rotor. This rotor is made up of 2 or 3 blades. These
blades turn when the wind blows. The entire top
swivels to face the changing direction of the wind.
Wind is stronger at higher altitudes, so the wind
turbines are built at least 30 meters above the
ground. As the rotor spins, it powers a generator,
which makes electricity that can be stored.
Controller – The controller
turns the turbine on and
off depending on the wind
speed. For example, it
turns on when the wind is
blowing 8 mph or faster. It
turns it off when the wind
is blowing 65 mph or
faster, because the
machine would overheat.
Nacelle – Holder of
important parts of the
turbine including the
generator.
Rotor – This is the hub
(tip) and the blades.
Wind Vane – This detects
the direction of the wind
and communicates this
information to the yaw
drive.
Yaw Drive – This ensures
that the rotor is always
facing the wind.
Additional:
Produced
domestically
Doesn’t
augment
greenhouse
effect
Doesn’t cause
acid rain
Renewable
energy source
One of the
cheapest
renewable
energy sources
– 4 to 6 cents
per kilowatthour
They benefit
rural farms in
the Midwest
(where the
wind is
greatest) by
helping the
rural economy
Additional:
Higher initial
cost (compared
to fossil fuel)
Located in
areas at a
distance from
cities where
electricity is in
highest
demand
Photovoltaics
Using the sun
to generate
electricity
Photovoltaic (PV) systems convert
sunlight directly into electricity, and are
potentially one of the most useful of the
renewable energy technologies.
The heart of a photovoltaic system is a solid-state
device called a solar cell.
Groups of solar cells can be packaged into
modules, panels and arrays to provide useful
output voltages and currents to provide a
specific power output.
PV applications
include lighting for
remote signs like
this outdoor board
along a U.S.
highway.
Many utility companies in the U.S. are turning to large
PV systems to help meet peak power demand and
reduce the need for building new power plants.
Maybe no uses are
as dramatic and
important as the
portable PV panels
and small
refrigerators carried
around Africa on the
backs of camels.
Solar Thermal Power Uses the same technology
but uses the sun’s energy to hear water to
generate electricity that would flow to the grid
Geothermal Energy can be
spectacular!
Photos of US Geological Survey
Geysirs and
volcanoes show the earth heat
Geothermal Energy
Definition:
Geothermal Energy is energy stored in the form of
heat beneath the
surface of the
solid earth
Graph from Geothermal Education Office, California
High-Enthalpy
Geothermal Energy world-wide
Graph from Geothermal Education Office, California
-Conversion from potential energy of
water to electric energy is at 80 – 90%
efficiency
-Hydroelectric projects in the United
States have rated capacities from
950 – 6480 MW
-The use of Water Power is much
greater in some other countries.
Norway obtains 99% of its electricity
from water power. Nepal, Brazil, and
New Zealand are close seconds.
Water generated - Hydroelectric
Shasta Dam In California
-About 50% of the United States potential for hydroelectric energy has been
tapped. However, further advances are unlikely.
-The Wild and Scenic River Act and the Endangered Species Act have
inhibited development of some sites
-Silt collection in hydroelectric Dam storage volumes over time causes
maintenance issues, as well as environmental concerns
-The loss of free flowing streams and land due to flooding behind the dam
disturbs the life of species: eg – Salmon
- Possibility of dam failure
-Solar Power – uses the sun energy to either boil water or directly converts
solar energy to electrical energy
-Ocean Thermal Energy Conversion – uses temperature differences
between different depths of ocean water to drive a heat engine. Working
fluid is ammonia which is gas at room temperature.
-Biomass Energy: Municipal Solid Waste – burning wastes to drive heat
engines
-Geothermal Energy – based on naturally occurring heat in the Earth in the
Earth due to radioactive decay
-Tidal Energy – uses the gravitational pull of the moon on our oceans to
drive turbines