Chapter 16

Chapter 16Chapter 16

Nonrenewable EnergyNonrenewable Energy

Questions for TodayQuestions for Today

What are the Two Types of Energy What are the Two Types of Energy Resources?Resources?

How much solar energy is used compared to How much solar energy is used compared to commercial energy?commercial energy?

Compare and Contrast the Commercial Compare and Contrast the Commercial Energy used by the world versus the US.Energy used by the world versus the US.

How much nonrenewable energy is used How much nonrenewable energy is used compared to renewable energy resources?compared to renewable energy resources?

What is Net Energy Use?What is Net Energy Use?

Core Case Study: Core Case Study: How Long Will the Oil Party Last? How Long Will the Oil Party Last?

Saudi Arabia could supply the world with oil Saudi Arabia could supply the world with oil for about 10 years.for about 10 years.

The Alaska’s North Slope could meet the The Alaska’s North Slope could meet the world oil demand for 6 months (U.S.: 3 world oil demand for 6 months (U.S.: 3 years).years).

Alaska’s Arctic National Wildlife Refuge Alaska’s Arctic National Wildlife Refuge would meet the world demand for 1-5 would meet the world demand for 1-5 months (U.S.: 7-25 months).months (U.S.: 7-25 months).

Core Case Study: Core Case Study: How Long Will the Oil Party Last? How Long Will the Oil Party Last?

We have three We have three options:options: Look for more oil.Look for more oil. Use or waste less oil.Use or waste less oil. Use something else.Use something else.

Figure 16-1Figure 16-1

TYPES OF ENERGY RESOURCESTYPES OF ENERGY RESOURCES

About 99% of the energy we use for heat About 99% of the energy we use for heat comes from the sun and the other 1% comes comes from the sun and the other 1% comes mostly from burning fossil fuels.mostly from burning fossil fuels. Solar energy indirectly supports wind power, Solar energy indirectly supports wind power,

hydropower, and biomass.hydropower, and biomass. Solar energy comes from the nuclear fusion of Solar energy comes from the nuclear fusion of

hydrogen atoms that make up the sun’s mass.hydrogen atoms that make up the sun’s mass. Life on earth is made possible by a gigantic Life on earth is made possible by a gigantic

nuclear fusion reactor that fortunately is nuclear fusion reactor that fortunately is safely located in space about 150 million safely located in space about 150 million kilometers away. kilometers away.


About 76% of the commercial energy we use About 76% of the commercial energy we use comes from nonrenewable fossil fuels (oil, comes from nonrenewable fossil fuels (oil, natural gas, and coal) with the remainder natural gas, and coal) with the remainder coming from renewable sources.coming from renewable sources. Commercial Energy sold in the marketplace Commercial Energy sold in the marketplace

makes up the remaining 1% of energy we use to makes up the remaining 1% of energy we use to supplement the earth’s direct input of solar supplement the earth’s direct input of solar energy. energy.


Nonrenewable energy resources and Nonrenewable energy resources and geothermal energy in the earth’s crust.geothermal energy in the earth’s crust.


Fig. 16-2, p. 357

Oil and natural gasOil and natural gasFloating oil drilling

platform Oil storage CoalCoalContour strip miningOil drilling

platform on legs

Geothermal Geothermal energyenergy

Hot water storageOil well

Pipeline Geothermal power plant

Gas well Valves Mined coal

Pump Area strip mining Drilling

tower

Pipeline

Impervious rock

Underground coal mineNatural gasWaterOil

Water is heated and brought up as dry

steam or wet steamWater

Coal seam Hot rock

Water penetrates

down through the rock

Magma


Commercial energy use by source for the Commercial energy use by source for the world (left) and the U.S. (right).world (left) and the U.S. (right).


Fig. 16-3a, p. 357

Nuclear power 6%

Hydropower, geothermal, solar, wind

7%Natural

gas 21%

REN

EWA

BLE 18%

Biomass 11%

Oil 33%

Coal 22%NO

NRENEWABLE 82%

World

Fig. 16-3b, p. 357

Hydropower geothermal, solar, wind

3%

Nuclear power 8

%R

EN

EW

AB

LE

8%

Coal 23%

Natural gas 23%

Oil 39%

Biomass 4%

NO

NR

ENEW

AB

LE 93%

United States


Net energy is the amount of high-quality Net energy is the amount of high-quality usable energy available from a resource after usable energy available from a resource after subtracting the energy needed to make it subtracting the energy needed to make it available.available. Net energy is like your net spendable income – Net energy is like your net spendable income –

your wages minus taxes and job-related your wages minus taxes and job-related expenses.expenses.

Suppose for every 10 units of energy in oil Suppose for every 10 units of energy in oil produced from the ground, we use or waste 8 produced from the ground, we use or waste 8 units of energy to find, extract, process, and units of energy to find, extract, process, and transport the oil to users. How much energy can transport the oil to users. How much energy can we use?we use?

HOW DO WE EXPRESS NET ENERGYHOW DO WE EXPRESS NET ENERGY

We can express net energy as a ratio.We can express net energy as a ratio. Energy gained/Energy used= Net Energy RatioEnergy gained/Energy used= Net Energy Ratio

The Higher the ration more Net Energy The Higher the ration more Net Energy Gained.Gained. Good thingGood thing

The Lower the ration the less energy gained.The Lower the ration the less energy gained. BadBad Worse if it’s less than 1. Why? Worse if it’s less than 1. Why?

Net Energy RatiosNet Energy Ratios

The higher the net energy ratio, the greater The higher the net energy ratio, the greater the net energy available. Ratios < 1 indicate the net energy available. Ratios < 1 indicate a net energy loss.a net energy loss.


Fig. 16-4, p. 358

Space HeatingSpace Heating

Passive solar 5.8Natural gas

Oil 4.5Active solar 1.9

Coal gasification 1.5Electric resistance heating (coal-fired plant) 0.4

0.4

Electric resistance heating (nuclear plant) 0.3

High-Temperature Industrial HeatHigh-Temperature Industrial Heat

28.2Surface-mined coalUnderground-mined coal 25.8

Natural gas 4.9Oil 4.7

Coal gasification 1.5Direct solar (highly concentrated by mirrors,

heliostats, or other devices)0.9

TransportationTransportation

Natural gas 4.9Gasoline (refined crude oil) 4.1

Biofuel (ethyl alcohol) 1.9Coal liquefaction 1.4

Oil shale 1.2

Electric resistance heating (natural-gas-fired plant)

4.9

STOPSTOP

Questions for Today:Questions for Today:

What is Crude Oil?What is Crude Oil? How is Oil found, extracted, and refined?How is Oil found, extracted, and refined? Who is in charge of the World’s Oil?Who is in charge of the World’s Oil? Who are the world’s Major Oil Consumers?Who are the world’s Major Oil Consumers? What are the trade-offs for using What are the trade-offs for using

Conventional Oil?Conventional Oil?

OILOIL

Crude oil (petroleum) is a thick liquid Crude oil (petroleum) is a thick liquid containing hydrocarbons that we extract from containing hydrocarbons that we extract from underground deposits and separate into underground deposits and separate into products such as gasoline, heating oil and products such as gasoline, heating oil and asphalt.asphalt. Also known as conventional oil and light oil.Also known as conventional oil and light oil. Only 35-50% can be economically recovered Only 35-50% can be economically recovered

from a deposit.from a deposit. As prices rise, about 10-25% more can be As prices rise, about 10-25% more can be

recovered from expensive secondary extraction recovered from expensive secondary extraction techniques.techniques.• This lowers the net energy yield.This lowers the net energy yield.

Steps to finding and extracting crude oilSteps to finding and extracting crude oil

1.1. Locate the Oil using satellite data, conduct Locate the Oil using satellite data, conduct ground and air surveys, drill rock cores, and ground and air surveys, drill rock cores, and seismic surveys.seismic surveys.

1.1. Oil is trapped in permeable rocks like limestone Oil is trapped in permeable rocks like limestone and sandstone like water in a sponge.and sandstone like water in a sponge.

2.2. To extract oil, a well is drilled into the To extract oil, a well is drilled into the deposit.deposit.

1.1. Drills can extend as far as 4 miles.Drills can extend as far as 4 miles.

2.2. Oil almost always squirts out due to pressure in Oil almost always squirts out due to pressure in the earth.the earth.

Extracting OilExtracting Oil

After a period of time, the pressure lessens After a period of time, the pressure lessens and it require more energy to pump out the and it require more energy to pump out the oil.oil. When the pressure disappears and production When the pressure disappears and production

starts declining, we have passed the half way starts declining, we have passed the half way point or point or peak production peak production of a well.of a well.• Lowers net energy ratioLowers net energy ratio• What left over is called,What left over is called, Heavy Crude Oil Heavy Crude Oil

Usual wells have a lifetime of a decadeUsual wells have a lifetime of a decade

OILOIL Refining crude oil:Refining crude oil:

Based on boiling Based on boiling points, components points, components are removed at are removed at various layers in a various layers in a giant distillation giant distillation column.column.

The most volatile The most volatile components with components with the lowest boiling the lowest boiling points are removed points are removed at the top.at the top.


Fig. 16-5, p. 359

Gases

Gasoline

Aviation fuel

Heating oil

Diesel oil

Naptha

Grease and wax

Asphalt

Heated crude oil

Furnace

Oil refiningOil refining

Refining oil decreases its net energy yield.Refining oil decreases its net energy yield. Accounts for about 8% of all US energy consumption.Accounts for about 8% of all US energy consumption.

Most of the products we used today are connected Most of the products we used today are connected to oil.to oil. Products of oil distillation are called petrochemicalsProducts of oil distillation are called petrochemicals

• PLASTICPLASTIC• PaintsPaints• MedicineMedicine

Production of a typical desktop computer consumes 10 Production of a typical desktop computer consumes 10 times its weight in fossil fuels, mostly oil. times its weight in fossil fuels, mostly oil.

Who controls the Oil?Who controls the Oil?

OPECOPEC Organization of Petroleum CountriesOrganization of Petroleum Countries

• 12 Countries make up OPEC12 Countries make up OPEC AngolaAngola AlgeriaAlgeria IndonesiaIndonesia IranIran IraqIraq KuwaitKuwait LibyaLibya NigeriaNigeria QatarQatar Saudi ArabiaSaudi Arabia UAEUAE VenezuelaVenezuela

Who controls the Oil?Who controls the Oil?

OPEC controls 78% of the world’s crude oil.OPEC controls 78% of the world’s crude oil. Saudi Arabia and Venezuela controls 70% of that Saudi Arabia and Venezuela controls 70% of that

oil.oil. Saudi Arabia has the world’s largest Oil Reserves Saudi Arabia has the world’s largest Oil Reserves

(25%)(25%) Canada is Second with 15 %Canada is Second with 15 % Iraq has 11%Iraq has 11% UAE 9.3%UAE 9.3% Kuwait 9.2%Kuwait 9.2% Iran 8.6%Iran 8.6%

Who needs the most Oil?Who needs the most Oil?

Top three oil CONSUMERSTop three oil CONSUMERS US, China, and JapanUS, China, and Japan

• US imports 60% of it’s OilUS imports 60% of it’s Oil• China Imports 33%China Imports 33%• Japan imports 95%!Japan imports 95%!

After Global Oil Production Peaks, oil prices After Global Oil Production Peaks, oil prices will rise and could threaten the lifestyles and will rise and could threaten the lifestyles and economies of oil-addicted countries that have economies of oil-addicted countries that have not switched to alternative fuel sources.not switched to alternative fuel sources.

OILOIL

Inflation-adjusted price of oil, 1950-2006.Inflation-adjusted price of oil, 1950-2006.Figure 16-6Figure 16-6

Fig. 16-6, p. 361

Oil

pri

ce p

er b

arre

l ($)

(2006 dollars)

Year

Case Study: U.S. Oil SuppliesCase Study: U.S. Oil Supplies

The U.S. – the world’s largest oil user – has The U.S. – the world’s largest oil user – has only 2.9% of the world’s proven oil reserves.only 2.9% of the world’s proven oil reserves.

U.S oil production peaked in 1974 (halfway U.S oil production peaked in 1974 (halfway production point).production point).

About 60% of U.S oil imports goes through About 60% of U.S oil imports goes through refineries in hurricane-prone regions of the refineries in hurricane-prone regions of the Gulf Coast.Gulf Coast.

OILOIL

Burning oil for Burning oil for transportation transportation accounts for 43% accounts for 43% of global COof global CO22

emissions.emissions.


Fig. 16-7, p. 363

Trade-OffsConventional Oil

Advantages Disadvantages

Ample supply for 42–93 years Need to find

substitutes within 50 years

Low cost (with huge subsidies)

Artificially low price encourages waste and discourages search for alternatives

High net energy yield

Easily transported within and between countries

Air pollution when burnedLow land use

Releases CO2 when burned

Technology is well developed

Efficient distribution system Moderate water

pollution

STOPSTOP

Questions for TodayQuestions for Today

What is Natural Gas?What is Natural Gas? What are the Tradeoffs for using Natural What are the Tradeoffs for using Natural

Gas?Gas? What are the Four Types of Coal?What are the Four Types of Coal? What are the Tradeoffs for using Coal?What are the Tradeoffs for using Coal?

NATURAL GASNATURAL GAS

Natural gas a mixture of gases, of which 50% Natural gas a mixture of gases, of which 50% - 90% are methane.- 90% are methane. Two TypesTwo Types

• ConventionalConventional – found above crude oil reservoirs – found above crude oil reservoirs• UnconventionalUnconventional - Coal beds and bubbles of methane - Coal beds and bubbles of methane

trapped in ice crystals deep under the arctic trapped in ice crystals deep under the arctic permafrost and beneath deep-ocean sediments permafrost and beneath deep-ocean sediments

When a natural gas-field is tapped, gasses are When a natural gas-field is tapped, gasses are liquefied and removed as liquefied petroleum gas liquefied and removed as liquefied petroleum gas (LPG).(LPG).• Lower temperature and increase pressure of the Lower temperature and increase pressure of the

containercontainer

Economics of Natural GasEconomics of Natural Gas

Only 20% is imported to the US.Only 20% is imported to the US. 60% for Oil.60% for Oil.

Burns cleaner than oil and coal.Burns cleaner than oil and coal. Able to run medium sized turbines for Able to run medium sized turbines for

electricityelectricity Twice the energy efficiency of Coal Plants and Twice the energy efficiency of Coal Plants and

Nuclear Plants.Nuclear Plants.


Russia and Iran have almost half of the Russia and Iran have almost half of the world’s reserves of conventional gas, and world’s reserves of conventional gas, and global reserves should last 62-125 years.global reserves should last 62-125 years.

Natural gas is versatile and clean-burning Natural gas is versatile and clean-burning fuel, but it releases the greenhouse gases fuel, but it releases the greenhouse gases carbon dioxide (when burned) and methane carbon dioxide (when burned) and methane (from leaks) into the troposphere.(from leaks) into the troposphere.


Some analysts see Some analysts see natural gas as the natural gas as the best fuel to help us best fuel to help us make the transition to make the transition to improved energy improved energy efficiency and greater efficiency and greater use of renewable use of renewable energy.energy.


Fig. 16-11, p. 368

Trade-Offs

Conventional Natural Gas


Ample supplies (125 years) Nonrenewable resource

High net energy yieldReleases CO2 when burnedLow cost (with huge

subsidies)

Methane (a greenhouse gas) can leak from pipelines

Lower CO2 emissions than other fossil fuels

Difficult to transfer from one country to another

Moderate environmental impact Shipped across ocean as

highly explosive LNG

Easily transported by pipeline

Sometimes burned off and wasted at wells because of low price

Low land use

Good fuel for fuel cells and gas turbines

Requires pipelines

Less air pollution than other fossil fuels

COALCOAL

Coal is a solid fossil fuel that is formed in Coal is a solid fossil fuel that is formed in several stages as the buried remains of land several stages as the buried remains of land plants that lived 300-400 million years ago.plants that lived 300-400 million years ago. Coal is burned in power plants to generate 62% Coal is burned in power plants to generate 62%

of the world’s Electricityof the world’s Electricity It is also burned to make ¾ of the world’s steel.It is also burned to make ¾ of the world’s steel.

4 types of “Coal”:4 types of “Coal”: PeatPeat Lignite (Brown Coal)Lignite (Brown Coal) Bituminous (Soft Coal)Bituminous (Soft Coal) Anthracite (Hard Coal) – 98% CarbonAnthracite (Hard Coal) – 98% Carbon


Fig. 16-12, p. 368

Highly desirable fuel because of its high heat content and low sulfur content;supplies are limited in most areas

Extensively usedas a fuel becauseof its high heat content and large supplies; normally has ahigh sulfur content

Low heat content;low sulfur content; limited supplies in most areas

Partially decayed plant matter in swamps and bogs; low heatcontent

Increasing heat and carbon content

Increasing moisture content

Peat(not a coal)

Lignite(brown coal)

Bituminous(soft coal)

Anthracite(hard coal)

Heat

Pressure

Heat

Pressure

Heat

Pressure

Stepped Art

COALCOAL

Coal reserves in the United States, Russia, Coal reserves in the United States, Russia, and China could last hundreds to over a and China could last hundreds to over a thousand years.thousand years. The U.S. has 27% of the world’s proven coal The U.S. has 27% of the world’s proven coal

reserves, followed by Russia (17%), and China reserves, followed by Russia (17%), and China (13%).(13%).

In 2005, China and the U.S. accounted for 53% In 2005, China and the U.S. accounted for 53% of the global coal consumption.of the global coal consumption.

COALCOAL

Coal is the most Coal is the most abundant fossil fuel, abundant fossil fuel, but compared to oil but compared to oil and natural gas it is and natural gas it is not as versatile, has not as versatile, has a high environmental a high environmental impact, and releases impact, and releases much more COmuch more CO22 into into

the troposphere.the troposphere.


Fig. 16-14, p. 370

Trade-Offs

Coal


Ample supplies (225–900 years)

Severe land disturbance, air pollution, and water pollutionHigh net

energy yield

High land use (including mining)

Low cost(with huge subsidies)

Severe threat to human healthWell-developed

mining and combustion technology High CO2

emissions when burnedAir pollution

can be reduced with improved technology (but adds to cost)

Releases radioactive particles and toxic mercury into air

COALCOAL

Coal can be converted into synthetic natural Coal can be converted into synthetic natural gas (SNG or syngas) and liquid fuels (such gas (SNG or syngas) and liquid fuels (such as methanol or synthetic gasoline) that burn as methanol or synthetic gasoline) that burn cleaner than coal.cleaner than coal. Costs are high.Costs are high. Burning them adds more COBurning them adds more CO22 to the troposphere to the troposphere

than burning coal.than burning coal.

COALCOAL

Since Since COCO22 is not is not

regulated as an air regulated as an air pollutantpollutant and costs are and costs are high, U.S. coal-high, U.S. coal-burning plants are burning plants are unlikely to invest in unlikely to invest in coal gasification.coal gasification.


Fig. 16-15, p. 371

Trade-Offs

Synthetic Fuels


Large potential supply

Low to moderate net energy yield

Higher cost than coal

Vehicle fuelRequires mining 50% more coal

High environmental impact

Moderate cost (with large government subsidies)

Increased surface mining of coal

High water useLower air pollution when burned than coal

Higher CO2 emissions than coal

Questions for Today:Questions for Today:

What is Nuclear Energy?What is Nuclear Energy? What are parts on Nuclear Reactor and What are parts on Nuclear Reactor and

Nuclear Power Plant?Nuclear Power Plant? What are some Tradeoffs for using Nuclear What are some Tradeoffs for using Nuclear

Energy?Energy? What is a Dirty Bomb?What is a Dirty Bomb? What are some suggested ways to deal with What are some suggested ways to deal with

Nuclear Waste?Nuclear Waste?

NUCLEAR ENERGYNUCLEAR ENERGY

When isotopes of uranium and plutonium When isotopes of uranium and plutonium undergo controlled nuclear fission, the undergo controlled nuclear fission, the resulting heat produces steam that spins resulting heat produces steam that spins turbines to generate electricity.turbines to generate electricity. Nuclear Energy is nonrenewable and very clean, Nuclear Energy is nonrenewable and very clean,

air pollution-wise, fuel source.air pollution-wise, fuel source.• Emits 1/6Emits 1/6thth as much CO as much CO22 as coal plants. as coal plants.

• Very little Particulate matter, i.e. smoke.Very little Particulate matter, i.e. smoke.

PARTS OF A NUCLEAR REACTORPARTS OF A NUCLEAR REACTOR

Most Nuclear Reactors in the World are Most Nuclear Reactors in the World are Light Light Water Reactors.Water Reactors.

Core – Core – Most important part of the reactorMost important part of the reactor Contains 35,000 – 70,000 long, thin fuel rods, Contains 35,000 – 70,000 long, thin fuel rods,

packed with radioactive fuel pellets.packed with radioactive fuel pellets.• Each pellet is 1/3 the size of a cigarette buttEach pellet is 1/3 the size of a cigarette butt• Each pellet contains the energy equivalent to 0.9 Each pellet contains the energy equivalent to 0.9

metric ton of coal or 4 barrels of crude oil.metric ton of coal or 4 barrels of crude oil.


ModeratorModerator – Neutron absorbing material that – Neutron absorbing material that slows down the neutrons emitted by the slows down the neutrons emitted by the fission process to keep the chain reaction fission process to keep the chain reaction going.going. Moderators are usually water, but can be solid Moderators are usually water, but can be solid

graphite, or heavy water.graphite, or heavy water. Control Rods – Control Rods – Rods that are moved in and out Rods that are moved in and out

of the reactor core to absorb neutrons.of the reactor core to absorb neutrons.


CoolantsCoolants – Water, usually, that help cool the – Water, usually, that help cool the reactor’s core to prevent meltdowns and reactor’s core to prevent meltdowns and produce steam for turbines.produce steam for turbines.

Containment VesselsContainment Vessels – Strong, thick steel – Strong, thick steel reinforced concrete walls to prevent nuclear reinforced concrete walls to prevent nuclear material from entering the environment.material from entering the environment.

Fig. 16-16, p. 372

Small amounts of radioactive gases

Uranium fuel input (reactor core)

Control rodsContainment shell

Heat exchanger

Steam Turbine Generator

Waste heat

Electric power

Hot coolant

Useful energy 25%–30%Hot

water outputPumpPump

Coolant Pump Pump

Moderator

Cool water input

Waste heat

Shielding Pressure vessel

Coolant passage

Water CondenserPeriodic removal and storage of radioactive wastes and spent fuel assemblies

Periodic removal and storage of radioactive liquid wastes

Water source (river, lake, ocean)


After three or four After three or four years in a reactor, years in a reactor, spent fuel rods are spent fuel rods are removed and stored removed and stored in a deep pool of in a deep pool of water contained in a water contained in a steel-lined concrete steel-lined concrete container.container.



After spent fuel rods are cooled considerably, After spent fuel rods are cooled considerably, they are sometimes moved to dry-storage they are sometimes moved to dry-storage containers made of steel or concrete.containers made of steel or concrete.


Fig. 16-18, p. 373

Decommissioning of reactorFuel assemblies

ReactorEnrichment of UF6 Fuel fabricationFuel fabrication

(conversion of enriched UF(conversion of enriched UF66

to UOto UO22 and fabrication of and fabrication of

fuel assemblies)fuel assemblies) Temporary storage of Temporary storage of spent fuel assemblies spent fuel assemblies underwater or in dry underwater or in dry caskscasks

Conversion of U3O8 to UF6

Uranium-235 as UFUranium-235 as UF66

Plutonium-239 as PuOPlutonium-239 as PuO22

Spent fuel Spent fuel reprocessingreprocessing

Low-level radiation Low-level radiation with long half-lifewith long half-life

Geologic disposal of moderate &

high-level radioactive

wastesOpen fuel cycle today

“Closed” end fuel cycle

Case Study: The Chernobyl Nuclear Case Study: The Chernobyl Nuclear Power Plant AccidentPower Plant Accident

The world’s worst nuclear power plant The world’s worst nuclear power plant accident occurred in 1986 in Ukraine.accident occurred in 1986 in Ukraine.

The disaster was caused by poor reactor The disaster was caused by poor reactor design and human error.design and human error.

By 2005, 56 people had died from radiation By 2005, 56 people had died from radiation released.released. 4,000 more are expected from thyroid cancer and 4,000 more are expected from thyroid cancer and

leukemia.leukemia.

NUCLEAR NUCLEAR ENERGYENERGY

In 1995, the World In 1995, the World Bank said nuclear Bank said nuclear power is too costly power is too costly and risky.and risky.

In 2006, it was found In 2006, it was found that several U.S. that several U.S. reactors were leaking reactors were leaking radioactive tritium into radioactive tritium into groundwater.groundwater.


Fig. 16-19, p. 376

Trade-Offs

Conventional Nuclear Fuel Cycle


Large fuel supply Cannot compete economically without huge government subsidies

Low environmental impact (without accidents) Low net energy yield

High environmental impact (with major accidents)

Emits 1/6 as much CO2 as coal

Catastrophic accidents can happen (Chernobyl)

Moderate land disruption and water pollution (without accidents)

No widely acceptable solution for long-term storage of radioactive wastes and decommissioning worn-out plants

Moderate land use

Low risk of accidents because of multiple safety systems (except for 15 Chernobyl-type reactors)

Subject to terrorist attacks

Spreads knowledge and technology for building nuclear weapons

NUCLEAR NUCLEAR ENERGYENERGY

A 1,000 megawatt A 1,000 megawatt nuclear plant is nuclear plant is refueled once a refueled once a year, whereas a year, whereas a coal plant coal plant requires 80 rail requires 80 rail cars a day.cars a day.


Fig. 16-20, p. 376

Coal vs. Nuclear

Trade-Offs

Coal Nuclear

Ample supply Ample supply of uranium

High net energy yield Low net energy yield

Very high air pollutionLow air pollution (mostly from fuel reprocessing)

High CO2 emissions Low CO2 emissions (mostly from fuel reprocessing)

High land disruption from surface mining Much lower land disruption

from surface mining

Low cost (with huge subsidies) High cost (even with huge subsidies)

High land use Moderate land use


Terrorists could attack nuclear power plants, Terrorists could attack nuclear power plants, especially poorly protected pools and casks especially poorly protected pools and casks that store spent nuclear fuel rods.that store spent nuclear fuel rods.

Terrorists could wrap explosives around small Terrorists could wrap explosives around small amounts of radioactive materials that are amounts of radioactive materials that are fairly easy to get, detonate such “Dirty” fairly easy to get, detonate such “Dirty” bombs, and contaminate large areas for bombs, and contaminate large areas for decades.decades.


When a nuclear reactor reaches the end of When a nuclear reactor reaches the end of its useful life, its highly radioactive materials its useful life, its highly radioactive materials must be kept from reaching the environment must be kept from reaching the environment for thousands of years.for thousands of years.

At least 228 large commercial reactors At least 228 large commercial reactors worldwide (20 in the U.S.) are scheduled for worldwide (20 in the U.S.) are scheduled for retirement by 2012.retirement by 2012. Many reactors are applying to extent their 40-Many reactors are applying to extent their 40-

year license to 60 years.year license to 60 years. Aging reactors are subject to embrittlement and Aging reactors are subject to embrittlement and

corrosion.corrosion.


Building more nuclear power plants will not Building more nuclear power plants will not lessen dependence on imported oil and will lessen dependence on imported oil and will not reduce COnot reduce CO22 emissions as much as other emissions as much as other

alternatives.alternatives. The nuclear fuel cycle contributes to COThe nuclear fuel cycle contributes to CO22

emissions.emissions. Wind turbines, solar cells, geothermal energy, Wind turbines, solar cells, geothermal energy,

and hydrogen contributes much less to COand hydrogen contributes much less to CO22

emissions.emissions.

NUCLEAR ENERGYNUCLEAR ENERGY Scientists disagree about the best methods Scientists disagree about the best methods

for long-term storage of high-level radioactive for long-term storage of high-level radioactive waste:waste: Bury it deep underground.Bury it deep underground. Shoot it into space.Shoot it into space. Bury it in the Antarctic ice sheet.Bury it in the Antarctic ice sheet. Bury it in the deep-ocean floor that is geologically Bury it in the deep-ocean floor that is geologically

stable.stable. Change it into harmless or less harmful isotopes.Change it into harmless or less harmful isotopes.

Documents

Chapter 16