V. Energy Resources Consumption
(10–15%)
V. Energy Resources and Consumption
A. Energy Concepts (Energy forms; power; units; conversions;
Laws of Thermodynamics)
B. Energy Consumption
1. History (Industrial Revolution; exponential growth;
energy crisis)
2. Present global energy use
3. Future energy needs
C. Fossil Fuel Resources and Use (Formation of coal, oil, and
natural gas; extraction/purification methods; world reserves
and global demand; synfuels; environmental
advantages/disadvantages of sources)
D. Nuclear Energy (Nuclear fission process; nuclear fuel;
electricity production; nuclear reactor types;
environmental advantages/disadvantages; safety issues;
radiation and human health; radioactive wastes; nuclear
fusion)
E. Hydroelectric Power (Dams; flood control; salmon; silting;
other impacts)
F. Energy Conservation (Energy efficiency; CAFE standards;
hybrid electric vehicles; mass transit)
G. Renewable Energy (Solar energy; solar electricity;
hydrogen fuel cells; biomass; wind energy; small-scale
hydroelectric; ocean waves and tidal energy; geothermal;
environmental advantages/disadvantages)
Energy Concepts (Energy forms; power; units;
conversions; Laws of Thermodynamics)
• Potential Energy
• Position – dam
• Stored – chemical
– Ex. Fossil fuels
– Endothermic – stores
energy (photosynthesis)
– Exothermic – releases
energy (fire)
• Kinetic Energy
• Movement
• Heat – molecules in
motion (thermo)
– Ex. Heat water to steam,
steam moves a turbine
Energy Units and Conversions
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BTU – measure of heat (1lb. Of water 1oF)
Calorie – measure of heat (1 g of water 1oC)
Kilocalorie – 1000g 1oC
Horsepower – energy (ability to move)
Joule – energy (1 Newton 1 meter)
Metric Prefixes
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Tera (T) – 1012 (trillion); terabyte
Giga (G) – 109 (billion); gigabytes
Mega (M) – 106 (million); megawatts; mHz
Kilo (K) – 103 (thousand); kilogram, kilometer,
kilowatt; kHz
Thermodynamics
• 1st Law – energy can be transformed but cannot be
created or destroyed (energy conservation)
• 2nd Law – some energy is lost as heat. Entropy
increases in a closed system
– Entropy – the amount of disorder
– Food chains, energy pyramids
Energy Consumption
• History – switch from biomass (wood) to coal during
the Industrial Revolution (6,000 BTU/lb. vs 14,000
BTU/lb.
• Coal replaced by oil in 1950’s
• Coal and natural gas being used more in latter half of
20th century – (cost, depletion of stocks)
• 1960’s US began to import oil
– Larger homes
– Shift from agriculture to industry
– More/bigger appliances (TV, refrigerators, dishwashers)
Energy Consumption
• Industry – mining, refining, farming, construction,
manufacturing; research/development of technology
• Transportation –
– Infrastructure – roads, rail, airports, docks, pipelines,
warehouses
• Residential – homes, apartments, schools, hospitals,
parks
• Commercial – stores
• More people = more energy (cell phones, cars, etc.)
Energy Consumption
• Most energy is produced from non-renewable sources
(FF, nuke)
• Fossil fuels
– Coal
– Oil (petroleum)
– Natural gas
• Energy conversion – chemical to electrical, heat to
mechanical (about 30% efficient)
• Advantages – easy to use, currently abundant
• Disadvantages – nonrenewable, produces pollutants
(acid rain and the greenhouse effect)
FF - Coal
• Dirtiest, most abundant
– Sulfur (acid rain) and C (CO2)
• Coal reserves in the United States, Russia, and China
could last hundreds to over a thousand years.
– US has 27% of the world’s proven coal reserves
– Russia (17%)
– China (13%)
– In 2005, China and the U.S. accounted for 53% of
the global coal consumption.
50% US reserves
2% US reserves
• Coal is formed in several stages as the buried
remains of land plants that lived 300-400 million
years ago.
Cogeneration
• Production of two useful forms of energy from
the same fuel. Heat from burning the fuel can
produce steam for electricity and to warm the
building
Coal
• Advantages:
– Abundant in the US
(cheap)
– May be able to ‘clean up’
• Scrubbers
• Electrostatic
precipitators
• Disadvantages
– Acid rain (SO2)
– CO2 emissions (climate change)
– Fly/coal ash – may contain As,
Pb, Co, Hg
Oil
• Crude oil (petroleum)
• Extracted from underground deposits
• Separated into: gasoline, heating oil and asphalt
– Only 35-50% can be recovered economically
– As the price of oil increases it will become more
economical to remove it
– Increased to remove it, cost lowers the net energy
yield
• Transportation
• U.S. uses 23 barrels per capita/year
Oil
• OPEC have 78% of the world’s proven oil
reserves and most of the world’s unproven
reserves.
• Alternative fuels?
Case Study: U.S. Oil Supplies
• U.S. – the world’s largest oil user – has only
2.9% of the world’s proven oil reserves.
• U.S oil production peaked in 1974
• About 60% of U.S oil imports goes through
refineries in hurricane-prone regions of the
Gulf Coast.
Oils from Tar Sand and Oil Shale
• Petroleum from tar sand
– High sulfur
– Extracting and processing produces:
• Toxic sludge
• Lots of contaminated water
• Requires large inputs of natural gas which reduces net
energy yield.
• Oil shales - kerogen (solid combustible mixture
of hydrocarbons) that can be processed
Natural Gas
• Mostly methane - often found above crude oil
– Gases are tapped and liquefied, removed as
liquefied petroleum gas (LPG).
• Remains of tiny algae and animals decomposed
in anaerobic conditions (pressure, heat + time)
Natural Gas
• Russia and Iran have almost half of the world’s
reserves of conventional gas, and global
reserves should last 62-125 years.
• Natural gas is versatile and clean-burning fuel
• It produces CO2 and CH4 (from leaks) into the
troposphere (Greenhouse gases)
Methane Hydrates
• Methane pockets trapped in permafrost
(tundra) or deep in the oceans
• 350-3500 year supply (?)
• Disadvantage – cost to remove, release of CH4
during removal
Elements in the Earth
• Oxygen - most abundant element in crust
• Nitrogen - most abundant element in the
atmosphere
• Iron - most abundant element in the core
• Aluminum - element extracted from bauxite
• Nuclear fission (U, Pu)
• Energy conversion – nuclear to heat to
mechanical to electrical
• Advantages: very efficient, no air pollution
• Disadvantages: radiation, thermal pollution,
not cheap to build/operate reactors, nonrenewable fuel
Energy Produced
• One gram of U235 delivers as much energy as 3.5
metric tons of coal!!!
• 20% of homes in the U.S. is supplied with nuke
• Reactors can run for years without refueling or
being shut down and need little maintenance.
Types of Reactors
Thermal
• Uses moderators to
slow neutrons which
increases probability of
collisions
• Can use more U238 in
the fuel
• Moderator is also
coolant
• Most reactors
Fast reactors
• No moderator, faster
neutrons
• U235 has to be more
concentrated but other
atoms are fissile
• Less radioactive waste
• More expensive to build
and operate
• Less common
Thermal Reactors
• Use different moderators and/or coolants
– Pressurized – water (under pressure) cools the
core; second system of water converted to steam
to run the turbine
– Boiling water – one system
– Graphite – uses graphite as moderator (allows use
of more U238); Chernobyl
Disadvantages
• Radioactive Waste - no permanent long-term
disposal site for commercial nuclear waste.
• Relatively short supply of U235 (only enough left
for 100~200 years)
• Nuclear Power Plants are expensive to build.
• Minor maintenance problems can be very
expensive to fix.
Nuclear Waste
• Fission products (cesium, strontium, I2) emit
radiation (cancer, birth defects)
• Radiation – radioactive elements are unstable
and give off pieces (particles and waves)
– Half-life – length of time it takes for half of the
radioactive element to become stable
Half-Life
• Every radioactive element has a half-life
• Fraction of a second to billions of years
– 4.5 billion for U238
• The longer the half-life, the less
intense the radiation.
• Nuclear wastes are stored for 10
half-lives (harmless)
Types of Waste
• High-level waste
• Most dangerous
• Spent fuel
• Liquid and solid waste from production of fuel (Pu)
• Low-level waste
– Hospitals, research institutions, and decommissioned
power plants
• After three or four years, spent fuel rods are
stored/cooled in a steel-lined concrete
container
• After cooling they are temporarily stored on
site
• In the past • Stored in underground tanks that leaked into the
soil, contaminating groundwater
• Dumped at sea into deep water
• Incinerated
• How to store radioactive wastes long-term:
– Bury it deep underground, or in the Antarctic or deep
ocean.
– Shoot it into space.
– Change it into harmless or less harmful isotopes.
Yucca Mountain
• Federal Government
• Located 100 miles from Las Vegas
• Store radioactive sources at least 10,000 years;
peak radiation after 400,000 years
• Storage in one place (the middle of the desert)
is safer than scattered around the country in
temporary facilities.
• Remote, sparse population
• Hard rock formations
• Yucca Mountain is the most studied geological
formation ever
Cons About Yucca Mountain
• Peak radiation - after 10,000 years
• Water corrode containers and leak radiation
• Transportation to Yucca Mountain will take 24
years
• Waste will travel through 45 states
• Accidents, terrorists
• Harry Reid (D Nv); Senate Majority Leader has
blocked Yucca Mountain project, Obama
stopped funding
Accidents:
• Chernobyl - former Soviet Union – worst in
history
– Hundreds died from radiation exposure.
– Thousands contracted cancers from high levels
of radiation exposure.
• Fukushima, Japan – tsunami
• Three Mile Island – Pa.
– Small radioactive gas leak
http://youtu.be/kLId9kso2oE - fukushima
http://youtu.be/RXZ9MhSJfVU - chernobyl
Case Study: Chernobyl
• 1986, Ukraine
• Poor reactor design
and human error
• 2005, 56 people had
died from radiation
– 4,000 more expected
from cancer
Fukushima - 2011
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Earthquake created a tsunami
Flooding caused pumps to fail
Back-up pumps (battery) failed later
Hydrogen gases built up inside the reactor buildings
causing them to explode
What Happened to Nuclear Power?
• Multi billion-dollar construction costs.
• Higher operation costs and more malfunctions
than expected.
• Public concerns
– Safety
– Terrorism
• Nuclear power plants will not lessen dependence
on imported oil and will not reduce CO2 emissions
as much as other alternatives.
• Wind turbines, solar cells, geothermal energy, and
hydrogen contributes much less to CO2 emissions.
Alternative Solutions
• Today’s inefficient reactors burn only 3% of Uranium.
The other 97% is waste.
• A new “fast” reactor promises to burn 99.9% of fuel
creating a residue that will be harmless in only 300
years
• Solution will take at least 10 years and $2 billion
dollars in federal funds
Hydroelectric
• 98% of usable rivers are already dammed
• Hydroelectric power
• Irrigation, flood control
Water
• Energy conversion – kinetic to electrical or heat
• Benefits – already have the technology to do this,
pollution free, dams are also useful as water
sources and flood controls; world’s largest source
of electrical power
• Costs – there are environmental costs to building
new dams, there are not rivers located
everywhere
Solar - Types
• Photovoltaic cells - convert sunlight to electricity - 10%
efficiency
• Thermal systems - sun’s heat is used to heat bodies of
water enough to produce steam for electricity
• Energy conversion – radiant/heat to electrical, heat or
mechanical
• Benefits – pollution-free, unlimited source
• Costs – not useful in cloudy areas or at night, we do
not have the technology needed to use very efficiently
Photovoltaic Cells
Solar Energy
• Renewable energy resources are hindered by a
lack of government support compared to
nonrenewable fossil fuels and nuclear power.
– Direct solar
– Moving water
– Wind
– Geothermal
Solar
• Advantages:
• Free
• Net energy is moderate
(active) to high (passive)
• No pollution
• Relatively low cost to
build/maintain
• Disadvantages:
• 60% sunlight
• Remove blocks
(buildings/trees)
• Need storage
• High costs to build/
maintain (active)
• Unattractive
Passive Solar Heating
• Absorbs and stores heat
without pumps to
distribute the heat.
Wind
• Energy conversion – solar, mechanical, electric
• Benefits – no pollution, source is free (after
construction), maintenance is moderate and
renewable
• Costs – can only be used in places with lots of
wind
• Much of the world’s potential for wind power
remains untapped
• Capturing only 20% of the wind energy at the
world’s best energy sites could meet all the
world’s energy demands
Geothermal
• Only energy source that doesn’t come from the
sun
• Conversion – thermal to mechanical to
electrical and heat
• Benefits – pollution-free
• Disadvantages – not available everywhere, we
don’t have all the technology needed to use it,
takes up a lot of room, initial costs are high,
pumping costs are high
Tidal Power
• Energy conversion –
kinetic to electrical
• Advantages – no
pollution, free, cheap
renewable
• Disadvantages – cost to build/maintain
Renewable Energy
• European Union - 22% of electricity from renewable by
2010.
• China - 10% of its total energy from renewable by 2020.
• California got about 12% of its electricity (2004) from
wind; plans to increase this to 50% by 2030.
• Denmark - 20% of electricity from wind and plans to
increase this to 50% by 2030.
• Brazil - 20% of its gasoline from sugarcane residue.
• In 2004, the world’s renewable-energy industries
provided 1.7 million jobs.
Biomass
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Any organic matter (wood, crop wastes, trash, etc.)
Currently about 5% of U.S. energy
Energy conversion – chemical to electrical or heat
Benefits – cheap, less toxic pollutants, uses wastes
Disadvantages – more technology needed to make it
efficient, not useful in everywhere, some pollution
Alternative Fuels
• Biodiesel – vegetable oils and alcohols; expensive
• Biogas – by-product of decaying vegetation; need
technology
• Hydrogen – free, renewable; expensive and more
technology is needed
Converting Plants and Plant
Wastes to Liquid Biofuels
• Motor vehicles can run on ethanol, biodiesel,
and methanol produced from plants and plant
wastes.
• The major advantages of biofuels are:
– Crops used for production can be grown almost
anywhere.
– There is no net increase in CO2 emissions.
– Widely available and easy to store and transport.
Ethanol/Methanol – not as efficient (Miles per
gallon) needs more technology; uses grains (corn)
• Propane – most usable form of alternative fuel;
not as efficient (mpg)
• Syngas – man-made gas made of hydrogen and
carbon monoxide; needs more technology
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Case Study: Producing Ethanol
• Crops (sugarcane, corn, and switchgrass) and
wastes (agricultural, forestry and municipal) can
be converted to ethanol.
• 10-23% pure ethanol makes gasohol which can
be run in conventional motors.
• 85% ethanol (E85) must be burned in flex-fuel
cars.
• Processing all corn grown in the U.S. into ethanol
would cover only about 55 days of current
driving.
Case Study: Biodiesel and Methanol
• Growing crops for biodiesel could cause
deforestation.
• Methanol is made mostly from natural gas but
can also be produced at a higher cost from
CO2 from the atmosphere which could help
slow global warming.
– Can also be converted to other hydrocarbons to
produce chemicals that are now made from
petroleum and natural gas.
Improve Energy Efficiency
• General features of a
car powered by a
hybrid-electric engine.
• “Gas sipping” cars
account for less than
1% of all new car sales
in the U.S.
Fuel-Cell Vehicles
• Fuel-efficient vehicles powered by a fuel cell that
runs on hydrogen gas are being developed.
• Combines hydrogen gas (H2) and oxygen gas (O2)
fuel to produce electricity and water vapor
(2H2+O2  2H2O).
• Emits no air pollution or CO2 if the hydrogen is
produced from renewable-energy sources.
Conservation
• Passive solar heating/cooling in commercial
buildings
• Insulation, plugging leaks, and using energyefficient heating and cooling systems,
appliances, and lighting.
Reducing Waste
• Four widely used devices waste large amounts of
energy:
– Incandescent light bulb: 95% is lost as heat.
– Internal combustion engine: 94% of the energy in its
fuel is wasted.
– Nuclear power plant: 92% of energy is wasted through
nuclear fuel and energy needed for waste
management.
– Coal-burning power plant: 66% of the energy released
by burning coal is lost.
Saving Energy in Existing Buildings
• About one-third of the heated air in typical U.S.
homes and buildings escapes through closed
windows and holes and cracks.
Resources & Their Uses
• Limestone – abundant locally, formed from
layers of seashells and corals under pressure as
they were covered; concrete
• Lead – batteries, radiation shielding
• Clay – books, magazines, bricks, and linoleum
• Gold – money and for jewelry, medicine (teeth,
lasers, cauterizing agents) and in electronics
Nonrenewable Resources
• Sustainability - prediction of how long resources
will last
– Ex. Coal, oil
• Conservation - using less of a resource or
reusing a resource
• Restoration – recycling resources
– Ex. – aluminum, paper, plastic, glass
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CAFÉ - Corporate Average Fuel Economy Act –
1975; mpg stickers required on cars/trucks
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Public Utility Regulatory Policies Act (PURPA)–
1978; higher utility rates for increased
electricity use
National Appliance Energy Act – 1987; energy
efficiency stickers on all appliances
• Clean Air Act Amendments – 1990; cities and
emissions
• Energy Policy Act – 1992; find renewable energy
resources
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