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Nonrenewable Energy
Chapter 15
Nonrenewable Resources
Things human use that have a limited supply; they cannot be regrown or replenished by man
Possible Solution– using less of a resource or reusing a resource, ex. refilling plastic laundry jugs, reusing plastic bags, etc.
Problems – • Requires a change in our lifestyle and some
people will resist.
Dealing with Nonrenewable Resources
Restoration
Definition – recycling our resources Examples – aluminum, glass, tin, steel,
plastics, etc.
Problems – recycling a resource often costs more than using the raw material; we don’t have the technology to recycle everything
Sustainability
Definition – prediction of how long specific resources will last; ex. we have a 200 year supply of coal in the U.S.
Problems – these are only predictions; they may not be accurate
Ownership costs – equipment, labor, safety (insurance), environmental costs (reclamation, pollution control, air monitors, water treatment, etc.), taxes
External costs – processing the resource, transporting the resource
Marginal costs – research: finding new sources of the resource and new ways to harvest it
Harvesting Nonrenewable Resources-COSTS
Direct – money received for resources; provides many jobs
Indirect – land can be reclaimed (brought back to original condition) and sold for profit.
Harvesting Nonrenewable Resources-BENEFITS
Original sources that are used to make electricity or heat
Primary Resources
Secondary Sources
Heat and electricity that we use for energy
Cogeneration
Production of two useful forms of energy, such as high-temperature heat or steam and electricity, from the same fuel source.
Ex. An industry using natural gas for manufacturing and using the waste heat to produce electricity.
Fossil Fuels Energy conversion – chemical to electrical, heat or
mechanical• Only about 30% efficient
Benefits – easy to use, currently abundant Costs – a nonrenewable resource, produces pollutants
that contribute to acid rain and the greenhouse effect
Oil- Supplies the most commercial energy in the world today. People in the U.S. use 23 barrels of petroleum per person or 6 billion barrels total each year!!!
Examples of Primary Sources
Saudi Arabia could supply the world with oil for about 10 years.
The Alaska’s North Slope could meet the world oil demand for 6 months. (U.S.: 3 yrs.)
Alaska’s Arctic National Wildlife Refuge (ANWR) would meet the world demand for 1-5 months. (U.S.: 7-24 months)
Core Case Study: How Long Will Supplies of Conventional Oil Last?
We have three options:• Look for more oil• Use or waste less oil• Use other energy sources
Core Case Study: How Long Will Supplies of Conventional Oil Last?
About 82% of global commercial energy comes from nonrenewable fossil fuels with the remainder coming from renewable sources.
SOURCE : DEPARTMENT OF ENERGY Annual Energy Review 2009
Fossil Fuels Supply Most of Our Commercial Energy
Commercial Energy Use by Source for the World and the United States
How Power Plants How Power Plants Produce ElectricityProduce Electricity
Natural Capital: Important Nonrenewable Energy Resources
Case Study: A Brief History of Human Energy Use
A Brief History of Human Energy Use
• Muscle power: early humans
• Discovery of fire
• Agriculture
• Use of wind and flowing water
• Machines powered by wood, then coal
• Internal combustion engine
• Nuclear energy
• Energy crisis
OIL / PETROLEUM
Only 35-50% can be economically recovered from a deposit.
We Depend Heavily on Oil
Crude oil (petroleum): thick liquid containing hydrocarbons that we extract from underground deposits and separate into products such as gasoline, heating oil and asphalt.
Science: Refining Crude Oil
An oil refinery uses distillation to separate crude oil into it’s components:• Based on boiling points,
components are removed at various layers in a giant distillation column.
• The components with the lowest boiling points are removed at the top.
Twelve OPEC countries have 60% of the world’s proven oil reserves and most of the world’s unproven reserves.• Organization of Petroleum Exporting Countries
OPEC Controls Most of the World’s Oil Supplies
Rising Oil Prices
Possible effects of steeply rising oil prices:• Higher food prices• Airfares higher• Reduce energy waste• Upgrade of public transportation• Smaller more fuel-efficient vehicles• Shift to non-carbon energy sources• Higher prices for products made with petrochemicals
Global oil production peaked around 2005 Sharp increases in oil prices could threaten the
economies of countries that have not shifted to new energy alternatives.
The U.S. – the world’s largest oil user – has only 2.4% of the world’s proven oil reserves.
The U.S. uses 24% of worldwide crude oil. The U.S. imports 60% of the oil it uses.
The United States Uses Much More Oil Than It Produces
Case Study: Oil and the U.S. Arctic National Wildlife Refuge
The Arctic National Wildlife Refuge (ANWR)• Not open to oil and gas development• Fragile tundra biome
Decrease dependence on foreign oil??• “Drill baby, drill!”
OIL
PROs Relatively Cheap Easily transported –
pipelines, oil tankers Versatile
CONs CO2 emissions
H2O pollution from tanker spills
Habitat destruction from pipeline construction and oil spills
Heavy and tarlike oils from oil sand and shale oil could supplement conventional oil, but there are environmental problems.• High sulfur content• Extracting and processing produces toxic sludge• Uses and contaminates larges volumes of water• Requires large inputs of energy which reduces net energy
Will Heavy Oil from Oil Sand or Shale Oil Be Viable Options?
Canada has 75% of the world’s oil sand. The Western U.S. has 72% of the
world’s shale oil.
Trade-Offs: Heavy Oils from Oil Shale and Oil Sand
NATURAL GAS
Natural gas, consisting mostly of methane (CH4), is often found above reservoirs of crude oil.• Coal beds, bubbles of methane trapped under the
arctic permafrost and beneath deep-ocean sediments, and landfills are unconventional sources of natural gas.
Natural Gas Is a Useful and Clean-Burning Fossil Fuel
Russia, Iran, and Qatar have about 3/4 of the world’s reserves of conventional gas, and global reserves should last 62-125 years.
Natural Gas Is a Useful and Clean-Burning Fossil Fuel
Fuel burning in a combustion chamber produces hot gases that pass directly through the turbine, which spins a generator to produce electricity. Then these hot gases are used to turn water to steam, which pushes a second turbine producing more electricity.
Natural Gas Is a Useful and Clean-Burning Fossil Fuel
Produces electricity X 2
Natural gas is transported through dense networks of pipelines
Liquefied petroleum gas (LPG)• Pressurized tanks used in rural areas
Liquefied natural gas (LNG)• Gas is cooled and pressurized in
order to ship across the ocean
Natural Gas Is a Useful and Clean-Burning Fossil Fuel
Natural Gas
Natural Gas: Fracking
COAL
Coal Comes in Several Forms and Is Burned Mostly to Produce Electricity
Coal: solid fossil fuel that is formed in several stages as the buried remains of land plants that lived 300-400 million years ago.
Burned in 2100 power plants, generates 40% of the world’s electricity (49% in the U.S.)• Inefficient process that burns coal to boil water which
produces steam that turns a turbine
Coal
Most abundant fossil fuel! 4 types:
• Lignite• Low energy, low sulfur
• Sub-bituminous• Intermediate energy, low sulfur
• Bituminous• Intermediate energy, high sulfur
• Anthracite• Hard coal: high energy, low sulfur, small
quantities
Stages in Coal Formation over Millions of Years
Science: Coal-Burning Power Plant
Coal
Major use: electricity Our current supply will last 150 – 200
years Largest reserves: US, Russia, China
Coal Is a Plentiful but Dirty Fuel
Environmental costs of burning coal:• Single biggest air polluter in coal-burning countries
• CO2 – one-fourth of the annual global emissions
• Sulfur released as SO2 (acid rain)
• Large amount of soot• Mercury (Hg)• Radioactive materials
Environmentalists call for:• Taxation on CO2 production by power plants
• Cleaner coal-burning plants
NUCLEAR POWER
The blue glow is known as Čerenkov radiation – when charged particles (electrons) passes through an insulator (water).
Nukes
A Little Chemistry Review:•Nucleus = protons + neutrons
– Protons: positive, = to atomic #
– Neutrons: no charge, same mass as proton
– Atomic mass = protons + neutrons
•Electrons– Orbit nucleus, negative charge, = to protons
•Isotope: different neutrons– Same number, same protons
•Ion = charged particle
Nukes
Fission!• Breaking down into 2 smaller atoms
Fusion• Combining atoms (the sun!)
Radioactivity• Spontaneous decay of unstable
nuclei
How Does a Nuclear Fission Reactor Work?
Isotopes of uranium and plutonium undergo controlled nuclear fission, the resulting heat produces steam that spins turbines to generate electricity.• The uranium oxide consists of about:
• 97% non-fissionable U238
• 3% fissionable U235
• The concentration of U235 is increased through an enrichment process (normally only 0.7%).• Uranium enrichment is a difficult process
An uncontrolled nuclear fission reaction is used in/for atomic weapons.
How Does a Nuclear Fission Reactor Work?
The nuclear fission reaction takes place in a reactor Fueled by uranium dioxide and packed as pellets in
fuel rods and fuel assemblies• Each eraser-sized pellet contains the energy of a TON of coal
Control rods absorb neutrons• Moved up/down to control the
speed of the reaction Water is the usual coolant Containment shell around the core for protection
Nukes
Nuclear Power Plant
Nuclear Power Plant:Light-Water-Reactor
Nuclear power plants are highly inefficient• Lose as much as 83% of its energy as waste heat
After three or four years in a reactor, spent fuel rods are removed and stored in a deep pool of water contained in a steel-lined concrete container.
After spent fuel rods have cooled considerably, they are sometimes moved to dry-storage containers made of steel or concrete.• Typically stored on-site
How Does a Nuclear Fission Reactor Work?
What Is the Nuclear Fuel Cycle?
Mine the uranium Process the uranium to make the fuel Use it in the reactor Safely store the radioactive waste Decommission the reactor
• Safely shut it down and seal it up
What Happened to Nuclear Power?
After more than 50 years of development and enormous government subsidies, nuclear power has not lived up to its promise of “almost limitless energy at a very small cost per kWh” because:• Multi billion-dollar construction costs• Higher operation costs and more
malfunctions than expected• Poor management• Public concerns about safety and
strict government safety regulations• Low net yield of energy
Nuclear Power: Explained
Case Study: Worst Commercial Nuclear Power Plant Accident in the U.S.
The accident occurred at the Three Mile Island Unit 2 (TMI-2) nuclear power plant near Middletown, PA on March 28, 1979.• Human and mechanical errors lead to part of one of
the reactor cores melting (meltdown).• Unknown amounts of radioactivity escaped• People fled the area
Case Study: Worst Nuclear Power Plant Accident in the World
The world’s worst nuclear power plant accident occurred on April 26, 1986 near Chernobyl, Ukraine.• Poor reactor design and human error led to a series of
explosions causing the roof of a reactor building to blow off• Partial meltdown and fire for 10 days• Huge radioactive cloud spread over many countries and
eventually the world • 350,000 people left their homes
A 1,000 MW nuclear plant is refueled once a year, whereas a coal plant requires 80 rail cars a day.
When a nuclear reactor reaches the end of its useful life, its high-level radioactive wastes must be stored safely for 10,000 – 240,000 years• Deep burial: safest and cheapest option• Change it into harmless or less harmful isotopes?
At least 228 large commercial reactors worldwide (20 in the U.S.) are scheduled for retirement by 2012.• Many reactors are applying to extent their 40-year
license to 60 years
What Do We Do with Worn-Out Nuclear Power Plants?
Dealing with Radioactive Wastes Produced by
Nuclear Power Plants Is a Difficult Problem
Case Study: Experts Disagree about What to Do with
Radioactive Wastes in the U.S.
1985: plans in the U.S. to build a repository for high-level radioactive wastes in the Yucca Mountain desert region (Nevada)
Problems• Cost: $58–100 billion• Large number of shipments to the site
• protection from attack?
• Rock fractures• Earthquake zone• Decrease national security
Nuclear fusion is a nuclear change in which two isotopes are forced together.• No risk of meltdown or radioactive releases• May also be used to breakdown toxic material• Still in laboratory stages after 50 years of research
and $34 billion dollars• So far, more energy is put in
than we get out
Will Nuclear Fusion Save Us?