Chapter 11: ENERGY
« The Law of Conservation of Energy tells us that we can’t get something for nothing, but we refuse to believe it. »
Isaac Asimov, American Science Writer
11.1 Energy Resources and Fossil Fuels
• How would a sunny day 2000 years ago relate to your life today?
Chances are when you traveled to school today you used some fuel or
product that was formed from plants or animals that lived alongside
the dinosaurs.
• Fuels we use to run cars, ships, planes and factories, as well as fuels to
produce electricity are natural resources called fossil fuels (remains of
ancient organisms).
• Fossil fuels are central to life in modern societies
• Two main problems with the supply of fossil fuels: supply is limited
and obtaining and using them has an impact on the environment
• In the 21st century, societies will continue to explore alternatives to
using fossil fuels and will focus on developing more efficient ways to
use these fuels.
Fuels for Different Uses
• Four main purposes: transportation, manufacturing,
heating and cooling buildings and generating electricity to
run machines and appliances
• Suitability of a fuel for each application depends on the
fuel’s energy content, cost, availability, safety and
byproducts of the fuel’s use. (ex: It’s hard to imagine a
plane running on coal; availability is there and it is
inexpensive but not feasible. Also, burning airplane fuel
at a campfire is not feasible, either.)
Electricity: Energy on Demand
• Energy in fuels is often converted into electrical
energy in order to power machines because
electricity is more convenient to use.
• Two disadvantages of electricity: difficult to
store and other energy sources have to be used
to generate it
How is Electricity Generated?
• Electric generators are simply devices used to convert
mechanical energy (motion) into electricity
• Enormous amounts of electrical energy can be transported
through a wire the diameter of a quarter; flow of electrons
(tiny charged particles that whirl around the nucleus of an
atom); to generate electricity, you just have to set the electrons
in motion (move an electrically conductive material – copper
wire – through a magnetic field); carried through a distribution
grid
• Most commercial electric generators convert the movement of
a turbine into electrical energy; most power plants boil water
to produce the stream that turns the turbine, in turn the
turbine spins a generator to produce electricity
Energy Use
• Everything requires energy to produce it; from
the food we eat to the clothing you wear;
furthermore, the price of nearly all those
products and services reflects the cost of that
energy
• Ex: plane ticket—you pay part of the fuel
• In 2000, airlines spent $5.4 billon on fuel
World Patterns
• There are dramatic differences in fuel use and
efficiency throughout the world.
• Developed societies use much more energy; striking
differences in energy between developed countries. Ex:
US and Canada use more than twice as much energy as
individuals in Japan or Switzerland
• Incomes in Japan and Switzerland are higher but they
use less energy; one reason for this lies in how energy
is generated and used in those countries
• Developing countries are rapidly increasing their
energy use
Energy Use in the United States
• US uses more energy per person than any other country
except for Canada and United Arab Emirates; in part because
US uses more than 25% of its energy resources to transport
goods and people (trucks and personal vehicles)
• In US and Canada: Availability and cost of fuels (lowest
gasoline taxes in the world) influence fuel use; little incentive
to conserve gasoline when the cost is low
• Japan and Switzerland are relatively small, compact countries;
primarily use their extensive rail systems; have minimal fossil
fuel resources so they supplement the majority of their
energy needs with hydroelectric or nuclear power
How Fossil-Fuel Deposits Form
• Fossil fuels are not distributed evenly; an
abundance in Alaska and Texas, very little in
Maine. Why?
• Why does eastern US produce so much coal?
• The answers lie 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; Coal in the
US was formed about 300 million to 250 million years
ago when vast swamplands covered the eastern US
• Ocean levels rose and fell repeatedly covering the area
with sediment; these layers compressed the plant
remains and then the heat and pressure within the
Earth’s crust caused coal to form
• Much younger coal deposits, in states such as
Wyoming, formed from ancient swamps between 100
million and 40 million years ago
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
• After being buried by sediment, they became
heated until they became energy rich carbon
molecules; eventually migrating into the porous
rock formations that now contain them
• US oil and natural gas is located in Alaska, Texas,
California and the Gulf of Mexico
Section 11.2: Coal
• Most of the world’s fossil fuel reserves are made
up of coal; Asia and North America are rich in
coal deposits
• Two major advantages of coal: relatively
inexpensive and needs little refining after it is
mined
• More than half of the electricity generated in the
US comes from coal fired power plants
Coal Mining and the Environment
• Environmental effects of coal mining vary;
underground mines can have minimal effect on the
environment; surface coal mining removes the top of
an entire mountain to get to the coal
• Waste rock from coal mines is not properly contained,
toxic chemicals can leach into nearby streams
• Research focus: finding better methods of locating the
most productive, clean burning coal deposits and
developing less damaging methods of mining coal
Air Pollution
• Quality of coal varies; higher grade coals (bituminous coal)
produce more heat, less pollution than a lower grade coal
(lignite)
• Sulfur (found in all grades of coal) can be a major source of
pollution when coal is burned
• Air pollution and acid precipitation that result from
burning high sulfur coal without adequate pollution
controls are serious problems in countries like China
• Clean burning technology used in the US has dramatically
reduced air pollution
Petroleum
• Oil that is pumped from the ground is also known
as crude oil, or petroleum
• Anything made from crude oil (fuels, chemicals,
plastics) is called a petroleum product
• Much of world’s energy needs are met by
petroleum products; 45% of the world’s
commercial energy
Locating Oil Deposits
• Oil is found in and around major geologic features that tend to
trap oil as it moves in the Earth’s crust: folds, faults, salt domes –
all bound by impermeable layers of rock that prevent oil from
escaping
• Most of the world’s oil reserves are found in the Middle East; there
are also large deposits in the US, Venezuela, North Sea, Siberia and
Nigeria
• Geologists use many different methods to locate the rock
formations that could contain oil, drill exploration wells to
determine the volume and availability of the oil deposit,
determine if oil can be extracted at a profitable rate, drill the wells
and then finally pump the oil.
• Once it is removed from the well, it is transported to a refinery to
be converted into fuels and other petroleum products.
The Environmental Effect of Using Oil
• When petroleum products are burned, they release
pollutants; carbon dioxide released into the air may
contribute to global warming
• Internal combustion engines in vehicles burn gasoline,
polluting the air; these pollutants contribute to the
formation of smog and cause health problems
• Catalytic converters and emissions regulations have
reduced air pollution in many areas
• Developing countries – cars are generally older, release
more sulfur into the atmosphere and thus contributes to
acid precipitation
The Environmental Effect of Using Oil…con’t
• Oil spills are another potential environmental problem;
in recent years, new measures have been taken to
prevent oil spills from tankers; double hulls (puncturing
the outer hull does not allow the oil to leak out) and
response times to clean up spills have improved.
• Oil spills are dramatic however, more oil pollution
comes from everyday sources, such as leaking cars
• Measures to reduce everyday contaminations in our
waterways is far behind that of the efforts made to
prevent oil spills
Natural Gas
• About 20% of the world’s nonrenewable energy comes
from natural gas; aka methane (CH4)
• Methane is a good example of how advances in
technology can make a fuel more common; used to be
burned off of an oil well, as technology improved,
transporting natural gas in pipelines and storing it in
compressed tanks became more practical
• Oil wells now recover natural gas; burning it produces
fewer pollutants than other fossil fuels, vehicles can
run on natural gas requiring fewer pollution controls
and electric power plants can also use natural gas.
Fossil Fuels and the Future
• Today, fossil fuels supply about 90% of the energy used in
developed countries
• By 2050, projections suggest the world’s energy demand
will double (increased populations and industry)
• Increase in demand for energy resources will more than
likely increase the cost of fossil fuels; alternative fuel
sources will become more attractive
• Planning now for future energy needs is important
because it takes many years for a new source of energy
to make a significant contribution to our energy supply.
Predicting Oil Production
• Oil production is still increasing, but much slower than in the past
• Many different factors must be considered when predicting oil
production: oil reserves that can be extracted profitably at current
prices; and oil deposits yet to be discovered; also, changes in
technology for future oil extractions
• Predictions of future oil productions are guided by the relative cost
of obtaining fuels influences the amount of fossil fuels that we
extract, ex: as available oil decreases, we may rely less on oil
reserves and focus more on using it selectively
• Cars and power plants can be powered using more alternative
energy sources
Future Oil Reserves
• No large oil reserves have been discovered in the
past decade; geologist feel the peak was in 2010
• Additional oil reserves are under the ocean but
extracting from there is much more expensive;
currently, oil platforms can be built to drill for oil
at depths greater than 1800 m, but much of the
oil in the ocean is inaccessible
• Deep ocean reserves may be tapped in the future
as oil drilling technology improves, however, it
will be much more expensive
11.3 Nuclear Energy
• In the 1950’s and 1960’s, nuclear power plants
were seen as the power source of the future
(clean and plentiful); predicted to provided
electricity “too cheap to meter”
• In 1970’s and 1980’s, almost 120 of the planned
nuclear power plants were canceled; 40 partially
constructed plants were abandoned
• 17% of world’s electricity comes from nuclear
power
Fission: Splitting Atoms
• Nuclear power plants get their power from nuclear energy (energy
within the nucleus of an atom); force that holds together the nucleus of
an atom are more than 1 million times stronger than the chemical bonds
between atoms
• Atoms of the element uranium are used as fuel in nuclear power plants
• Nuclei of uranium are bombarded with atomic particles (neutrons)
which cause the nuclei to split (nuclear fission) releasing a tremendous
amount of energy and more neutrons, which in turn collide with more
uranium nuclei
• If allowed to continue, the chain reaction will escalate quickly; ex: an
atomic bomb is an example of an uncontrolled fission reaction
• Nuclear power stations are designed so that the chain reaction produces
a controllable level of energy
How Nuclear Energy Works
• A nuclear reactor is surrounded by a thick pressure vessel that is filled with
a cooling fluid; designed to contain the fission products in case of an
accident; thick concrete walls also surround reactors
• Inside a reactor, metal fuel rods that contain solid uranium pellets are
bombarded with neutrons; the reactor core contains control rods (made
from boron or cadmium that absorb the neutrons to prevent uncontrolled
chain reactions); lowered between the fuel rods to slow the fission
reactions; when lowered completely, fission stops and reactor shuts down
• Heat released is used to generate electricity in the same way power plants
burn fossil fuels to generate electricity; nuclear power plants heat a closed
loop of water which heats another body of water, it produces steam that
drive the turbine
Advantages of Nuclear Energy
• Nuclear energy has many advantages: very concentrated and does
not produce air polluting gases
• Nuclear energy releases less radioactivity and does not add carbon
dioxide to the atmosphere
• One gram of uranium can supply the same amount of energy as about
7000 lbs. of coal
• Well designed reactors can run for years without having to be shut
down or refueled
• Nations who do not have access to fossil fuels to produce electricity
can use nuclear power instead (ex: France produces less than 1/5th of
the air pollutants per person than the US)
So Why Aren’t We Using more Nuclear Energy?
• Building and maintaining a safe reactor is very
expensive (last 20 reactors built in US cost more
that $3000 per kilowatt of electrical capacity); they
are very large and complex; and there is a fear of
nuclear accidents
• In contrast, wind power costs less than $1000 per
kilowatt; natural gas can cost less than $600 per
kilowatt
Storing Waste
• One of the most serious disadvantages of nuclear energy is that it
produces radioactive waste; fuel cycle of uranium produces fission
products than can remain dangerously radioactive for thousands of
years; uranium mining and fuel development produce radioactive
waste
• U.S. has no facility for the permanent disposal of its commercial
nuclear waste; each has its own temporary storage facility
• Storage sites must be located in areas that are geographically stable
for tens of thousands of years (a study of the Yucca Mountain in
southern Nevada is a possible site that has been under study for
about 2 decades)
• There is a relatively short supply of nuclear fuel
• Scientists are studying transmutation as a means of disposal
(recycling radioactive elements in nuclear fuel)
Safety Concerns
• Fission reaction creates radioactive products which are highly
dangerous; if it gets out of control, enormous amounts of heat
created will destroy reactors, spewing radioactive materials into the
air, ex: Chernobyl (1986 – engineers turned off most of the reactor’s
safety devices to conduct an unauthorized test), Ural Mountains
(1957)
• Many people died or were seriously injured; others contracted
cancers as a result of their exposure to the high levels of radiation:
areas of northern Europe and the Ukraine are still contaminated
from the Chernobyl accident
• U.S. suffered a serious nuclear accident in 1979 at the Three Mile
Island nuclear power plant; human error, blocked valves and broken
pumps lead to the accident; lead to over 300 safely improvements to
nuclear power plants.
The Future of Nuclear Power
• One possible future energy source is nuclear fusion; occurs when lightweight
atomic nuclei combine to form a heavier nucleus and release tremendous
amounts of energy
• Nuclear fusion is the process that powers the stars, including our sun;
potentially safer than fission because it creates less dangerous radioactive
byproducts
• Technically difficult to achieve even though the potential for great amounts of
energy; needs extremely high temperatures to combine the atomic nuclei
(100,000,000 degrees C), must have the ability to maintain those high
temperatures and must be able to properly confine it.
• Achieving all 3 simultaneously is extremely difficult; building a nuclear fusion
plant may take decades to achieve or it may never happen at all.
11.4 Renewable Energy
• When we think about renewable energy (energy coming from sources
that are constantly being formed), many people think about high tech,
solar powered cars, but life on Earth has always been powered by the sun
• Other renewable energy sources include: wind, water and Earth’s inner
heat
• Many governments have plans to increase their use of renewable energy
sources. Ex: European Union planned to produce 12% of their energy
from renewable by 2010; thus, reducing the environmental impact of
nonrenewable sources
• However, all energy sources, including renewable, have an affect on the
environment
Solar Energy—Power from the Sun
• Energy from the sun; medium sized star that radiates
energy from a nuclear fusion reaction in its core
• Only a small fraction of that energy ever reaches the Earth;
enough to power the wind, planet growth and water cycle,
therefore almost all energy comes from directly or
indirectly from the sun
• We use direct solar energy everyday. Ex: sun shining in a
room, heats it up
• Solar cells – are devices that change the sun’s energy into
electricity; these are not efficient enough for large jobs and
are very expensive to make
Passive Solar Heating
• Simplest form of solar energy; heating something directly
• Passive solar heating – used in homes made of materials that help
insulate the inside in conjunction with high efficiency windows that
maximize the ‘greenhouse effect;’ in the Northern Hemisphere, south
facing windows receive the most solar energy (must be well insulated
with thick walls and floors, receive solar heat by day, slowly release heat
by night
• Passive solar heated homes: must have overhang to shade the sun in
summer months when sun is high in the sky and allow heat to enter in
winter months when sun is low in the sky, also must be in an area which
receives a reliable amount of sunlight (may not need any other type of
heating if these conditions exist)
• Any home could reduce their energy bills by using these passive solar
features
Active Solar Heating
• Solar water heating – solar collectors capture the sun’s energy
and transfer it to a mixture which flows through the collectors
and is pumped through a heat exchanger which directly heats
water for use in homes or pools
• More than 1 million homes in the US use active solar energy
to heat water
• 8% of energy used in the US is used to heat water; therefore,
active solar technology could save a lot of energy
Photovoltaic Cells
• Solar cells, called photovoltaic cells, convert the sun’s energy into electricity
• Invented 120 years ago, now used to power everything from calculators to
space stations
• They have no moving parts, they run on nonpolluting power from the sun;
energy is stored in batteries
• Produces only a very small electrical current so to use on a large scale would
require several 100’s of acres of solar panels and extended periods of
sunshine
• Since 1985, energy production has doubled every 4 years; becoming
increasingly efficient and less expensive
• Great potential for use in developing countries; currently, in the developing
world, solar cells provide energy for more than 1 million households
Wind Power—Cheap and Abundant
• Energy from the sun warms the Earth’s surface unevenly,
causing air masses to flow in the atmosphere
• Energy in the wind can be harnessed by windmills which
are attached to electrical generators; new wind turbines
are cost effective and can be erected in three months
• Wind generated electricity is relatively inexpensive,
efficient and is the fastest growing energy source in the
world (quadrupled between 1995 and 2000)
Wind Farms
• Large arrays of wind turbines are called wind farms
• In California, large wind farms supply electricity to 280,000
homes; small wind farms (20 or fewer turbines) are
becoming common and take up little space
• Strong wind is not consistent enough in most areas to make
it feasible
• Windmills are very large structures and their blades can
interfere with communications (cell phones)
• Some small farms are putting in wind farms and then sell
the electricity they generate to the local utility companies
An Underdeveloped Resource
• The windiest spots on Earth could generate more than
ten times the energy used worldwide
• All the large energy companies are developing ways to
use more wind power
• Problem: transporting the energy from rural areas
where it is generated to urban centers
• Wind energy in the future may be used to produce
hydrogen from water to be trucked or piped to cities
for use as a fuel.
Section 11.5: Renewable Energy Today -- Biomass,
Hydroelectric and Geothermal
Biomass—Power from Living Things
• Biomass is the organic matter in plants or plant products
• A biomass fuel is any plant material, manure or any other organic matter
that is used as an energy source
• This form of energy is primarily from the burning of wood; wood is the
major source of energy for much of the world, especially in developing
countries; more than ½ of all wood cut in the world is used as fuel for
heating and cooking
• If trees are cut down faster than they are growing, the results are
deforestation, soil erosion and habitat loss
• In the U.S., more people are using wood to heat their homes in order to
conserve fossil fuels; however, it produces carbon dioxide and other
noxious gases
Methane
• One of the by-products of organic waste being broken
down by bacteria is methane gas
• Methane gas can be burned to generate heat or electricity;
In China, more than 6 million households use methane gas
for heating and cooking
• In developed countries, methane was once thought of as a
waste; today, used for energy
• In 2002, Britain’s first dung-fired power station started
producing electricity (methane from cow manure); US uses
methane gas from decomposition of trash to generate
electricity
Alcohol
• Liquid fuels can be derived from certain types of
biomass, ex: Ethanol (another alcohol) comes from
corn, fruit or agriculture waste; in US, corn is a major
source of ethanol
• Cars and trucks can run on either one with a little
modification; called gasohol
• Gasohol is a blend between gasoline and alcohol (10%
alcohol/90% gasoline); used in some parts of the U.S.;
Brazil relies on it more than any other country
• They burn cleaner than gasoline or diesel
Hydroelectricity—Power from Moving Water
• Energy from the sun causes water to evaporate, condense and
then fall back to Earth as rain; rainwater flows across the land.
• Electricity is generated by the energy of that moving water; it is
a clean and renewable source of energy
• Hydroelectric energy is produced from moving water and
accounts for about 20% of the world’s electricity; Canada, US,
Brazil, China, Russia and Norway are leaders in the world of
hydroelectricity.
• Made possible by large dams which channel a river’s energy;
hydroelectric power plants use the energy of the moving water
to turn a turbine which generates electricity (Hoover Dam,
Itaipu Dam in Paraguay)
The Benefits of Hydroelectric Energy
• Even though they are expensive to build, they are
relatively inexpensive to operate
• They release no air pollutants and tend to last much
longer than fossil fuel powered plants
• Nearly ¼ of the world’s electricity is generated from
this nonpolluting, renewable source
• Dams also provide other benefits: flood control,
drinking water, water for agriculture, industry and
recreation
Disadvantages of Hydroelectric Energy
• Dams change the flow of a river
• Consequences: reservoir floods large areas of habitat
above the dam, the river below the dam is reduced
(disrupting ecosystems downstream), salmon in the
western US cannot swim back upstream to spawn because
of the dams, people have been displaced from their homes
(about 50 million), dam failure (bursting) kills many people
living in areas below the dam
• Also, the land below a dam is affected. Farmland becomes
less productive, decay of plant matter trapped in reservoirs
can release large amounts of greenhouse gases
Modern Trends
• In US, era of building large dams is over
• In developing countries (Brazil, India, China),
construction of large dams continues
• Modern trend is micro-hydropower, electricity
produced in a small stream without building a dam;
turbine floats in the water, not blocking the river at all
• Micro-hydropower is less expensive and permits
energy to be generated from small streams in remote
areas
Geothermal Energy—Power from the Earth
• Heat generated from the Earth’s interior can be used to convert
water into the steam used to power a turbine that drives
electrical generators; water can then be returned to the Earth’s
crust to be heat and reused
• US is the world’s largest producer of geothermal energy; largest
geothermal power plant is The Geysers in California which
powers electricity for 1.7 million households
• Other countries that use geothermal energy are the Philippines,
Iceland, Japan, Mexico, Italy and New Zealand
• Overuse of this energy can deplete it’s availability; another
disadvantage is that it can only be tapped in a few places;
availability is limited
Geothermal Heat Pumps: Energy for Homes
• More than 600,000 homes in the US are heated and
cooled using geothermal heat pumps
• Underground temperatures are nearly constant yearround; geothermal heat pumps use the stable
underground temperatures to warm and cool home;
loops of piping circulate a fluid underground.
• In summer, ground is cooler than the air, fluid is used
to cool a home; in winter, the ground is warmer than
the air, fluid is used to warm a home.
Section 11.6: Alternative Energy
• Our goal is to achieve a future where energy use is sustainable, to
do this we must: 1) make the most of the energy resources we
already have, and 2) develop new sources of energy
• Alternative energy describes energy sources that are still in
development, ex: geothermal power was once considered an
alternative energy
• In order for it to be considered viable, it must prove to be cost
effective and the environmental effects of using the energy
source must be acceptable
• The government must invest in the energy source in order to do
the research needed
Tidal Power
• Tides are the movement of water in the oceans and seas caused
by gravitational attraction between the sun, Earth and the moon;
happen twice each day; marked by rising and falling of sea level
• Tide power was used in Britain and France a 1000 years ago to
power their mills; today, it is used to generate electricity in
countries such as France, Russia and Canada
• Tidal power plants work like a hydroelectric dam; when tide rises,
water flows behind a dam; when tide falls, water trapped behind
the dam releases, turns a turbine which generates electricity
• Will not become a major source of energy in the future because
the cost of building and maintaining a facility is high and there
are only a few suitable locations
Ocean Thermal Energy Conversion
• Differences in temperatures between surface water and deep ocean water
in the tropics can be as much as 24 degrees C (43 degrees F)
• Off the shores of Hawaii there is an experimental power station, uses this
temperature difference to generate electricity
• OTEC -- warm surface water is used to boil sea water (water boils at low
temperatures when it is at low pressure in a vacuum chamber), boiling
water turns to steam, which spins a turbine, which runs an electric
generator, cold water from the deep ocean cools the steam, turning the
steam into water which can be used again
• Problem: 1/3 of the energy generated at the plant is used to pump cold
water up from deep in the ocean; not cost effective and inefficient
• The environmental effects of pumping large amounts of cold water to the
surface are unknown
Hydrogen—A Future Fuel Source?
• Most plentiful substance on Earth and can be
burned as a fuel; could be the fuel of the future
• Water is 2 parts hydrogen, one part oxygen; when
split from oxygen, hydrogen is a clean-burning gas
that has great promise as a fuel for the future; it is a
nonpolluting fuel because it does not contain
carbon
• Most internal-combustion engines can run on
hydrogen gas without any major modifications
The Challenge of Hydrogen Fuel
• Why is hydrogen the fuel of the future and not the fuel of
today?
• Drawbacks: takes a lot of energy to produce it; separating
it from oxygen requires energy; it is not concentrated
enough and would require large amounts at any one time
so it would need to be either compressed to a very high
pressure or chilled to extremely low temps
• Could possibly be stored in pressurized tanks and
transported in gas pipelines or not be stored at all, it might
be used as it is produced in fuel cells
Fuel Cells
• Could possibly be the engines of the future; like a battery,
fuel cells produce electricity chemically (combining
hydrogen with oxygen); produces electricity and water as a
byproduct.
• Fuel cells can be fueled by anything (hydrogen, natural gas,
alcohol, gasoline)
• Fuel cells have been used by space shuttles for years
• By 2010, they felt many portable devices (phones, video
games) would be powered by fuel cells; fueled with alcohol
which would end the problem of charging or changing
batteries
Energy Efficiency
• Two main ways to reduce energy use: lifestyle changes (walking,
biking, using mass transit) and increases in energy efficiency
(percentage of energy put into a system that does useful work)
• Can be determined by using this simple equation:
energy efficiency (in %) = energy in/energy out x 100
• Most of our devices are inefficient; more than 40% of all commercial
energy used in the US is wasted; mostly from inefficient fuel wasting
vehicles, furnaces, appliances and leaky, poorly insulated buildings
• We could save enormous amounts of energy by using fuel cells
instead of internal combustion engines in cars and by changing from
using incandescent to fluorescent light bulbs
11.7 Conservation
• Efficient Transportation
• Development of efficient engines to power vehicles and use
of public transportation would greatly increase energy
efficiency
• Internal combustion engines used to power vehicles use fuel
inefficiently and produce air pollution; the current engine
design has not changed much since 1900, but will radically
change in the next 50 years
• Little demand for fuel efficient cars in the US due to the
gasoline prices being so low compared to that of other
countries
Hybrid Cars
• Hybrid cars are examples of energy efficient vehicles currently in
use; use a small, efficient gasoline engine most of the time, but
they also use an electric motor when extra power is needed (ex:
while accelerating)
• Feature many other efficient technologies: convert some of the
energy of braking into electricity and store this energy in the
battery, when sitting at a red light, the gasoline engine may shut
off; designed to be aerodynamic; made of lightweight materials
so less energy is needed when accelerating
• Benefits: cost is about the same as conventional vehicles; cost
less to refuel, produce less harmful emissions
Cogeneration
• Cogeneration is the production of two useful forms of
energy from the same fuel source, ex: waste heat from
an industrial furnace can be used to power a steam
turbine that produces electricity; that industry can use
that electricity or sell it to a utility company
• For many years, small cogeneration systems have
supplied heat and electricity to multiple buildings on a
specific site; small units suitable for single buildings are
now available in the US
Energy Conservation
• Energy conservation means saving energy; the average
American uses twice as much energy as an average
European
• Use of energy efficient devices and wasting less energy
are examples of conserving energy; ex: riding a bike
instead of driving, modifying structures, systems and
vehicles to use less energy and not waste as much
• Between 1975 and 1985, conservation made more energy
available in the US than all alternative energy sources
combined
Cities and Towns Saving Energy
• Osage, Iowa (3600 people) adopted an energy
conservation program, which saved $1 million
each year.
• In homes: plugged the leaks around windows
and doors, where much heat escapes; replaced
inefficient furnaces; insulated hot water heaters
• Many businesses have relocated there in order to
take advantage of low energy costs and
unemployment rates have declined
Conservation Around the Home
• Average household in the US spends more than $1200 on
energy bills each year; much of that is wasted through
poorly insulated windows, doors, walls and roof
• Ways to increase energy efficiency: add to the insulation of
a home; replace old windows (can reduce energy bill by
15%); sealing leaks around doors and windows with caulk or
weather stripping
• There are dozens of ways to reduce energy use around the
home besides the ones mentioned above (see handout)
Conservation in Daily Life
• The best way to combat the “deficit” is by taking
conservation measures – doesn’t mean making do with less,
just using it wisely, ex: turn down thermostat in the winter
and putting on a sweater; use a fan in summer rather then
an air conditioner
• Other examples: washing clothes in cold water uses only
25% of the energy needed to wash clothes in warm water;
driving fuel efficient vehicles; choose energy star appliances;
recycle and choose recycled products whenever possible; set
computers to “sleep” mode when they are not in use;
carpool/public transportation