Nonrenewable Energy Chapter 15

 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?

15-1 What Major Sources of Energy Do We Use?  Concept 15-1A About three-quarters of the world’s commercial energy comes from nonrenewable fossil fuels and the rest comes from nonrenewable nuclear fuel and renewable sources.  Concept 15-1B Net energy is the amount of high- quality usable energy available from a resource after the amount of energy needed to make it available is subtracted.

SOURCE : DEPARTMENT OF ENERGY Fossil Fuels Supply Most of Our Commercial Energy Back in 2000: Nat. Gas 24% Renew. 6% Coal 23% Nuclear 8% Oil 39%

 About 80% of global commercial energy comes from nonrenewable fossil fuels with the remainder coming from renewable sources. Fossil Fuels Supply Most of Our Commercial Energy

Commercial Energy Use by Source for the World and the United States

Natural Capital: Important Nonrenewable Energy Resources

Case Study: A Brief History of Human Energy Use  A Brief History of Human Energy Use – p 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

15-2 What Are the Advantages and Disadvantages of Oil?  Concept 15-2A Conventional oil is currently abundant, has a high net energy yield, and is relatively inexpensive, but using it causes air and water pollution and releases greenhouse gases to the atmosphere.  Concept 15-2B Heavy oils from oil sand and oil shale exist in potentially large supplies but have low net energy yields and higher environmental impacts than conventional oil has.

OIL / PETROLEUM

 Only 35-50% can be economically recovered from a deposit. We Depend Heavily on Oil  Crude oil (petroleum) is a 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.

FallingOil Prices

 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. used to import over 50% of the oil it uses. This number was down to 27% in 2014!! (lowest since 1985) The United States Uses Much More Oil Than It Produces

Trade-Offs: Conventional Oil, Advantages and Disadvantages  Burning oil for transportation accounts for 43% of global CO 2 emissions.  About 60% of U.S oil imports go through refineries in hurricane- prone regions of the Gulf Coast.

 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

15-3 What Are the Advantages and Disadvantages of Natural Gas?  Concept 15-3 Conventional natural gas is more plentiful than oil, has a high net energy yield and a fairly low cost, and has the lowest environmental impact of all fossil fuels.

NATURAL GAS

 Natural gas, consisting mostly of methane (CH 4 ), 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 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

Trade-Offs: Conventional Natural Gas  Natural gas is versatile and cleaner-burning fuel, but it releases the greenhouse gases carbon dioxide (when burned) and methane (from leaks) into the troposphere.  Some analysts see natural gas as the best fuel to help us make the transition to improved energy efficiency and greater use of renewable energy.

15-4 What Are the Advantages and Disadvantages of Coal?  Concept 15-4A Conventional coal is very plentiful and has a high net energy yield and low cost, but it has a very high environmental impact.  Concept 15-4B Gaseous and liquid fuels produced from coal could be plentiful, but they have lower net energy yields and higher environmental impacts than conventional coal has.

COAL

Coal Comes in Several Forms and Is Burned Mostly to Produce Electricity  Coal is a solid fossil fuel that is formed in several stages as the buried remains of land plants that lived 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

Stages in Coal Formation over Millions of Years

Science: Coal-Burning Power Plant

 World’s most abundant fossil fuel  Coal reserves in the United States, Russia, and China could last hundreds to over a thousand years. Coal Is a Plentiful but Dirty Fuel

 Environmental costs of burning coal: Single biggest air polluter in coal-burning countries CO 2 – one-fourth of the annual global emissions Sulfur released as SO 2 (acid rain) Large amount of soot Mercury (Hg) Radioactive materials  Environmentalists call for: Taxation on CO 2 production by power plants Cleaner coal-burning plants

Trade-Offs: Coal, Advantages and Disadvantages  Coal is the most abundant fossil fuel, but compared to oil and natural gas it is not as versatile, has a high environmental impact, and releases much more CO 2 into the troposphere.

15-5 What Are the Advantages and Disadvantages of Nuclear Energy?  Concept 15-5 Nuclear power has a low environmental impact and a very low accident risk, but high costs, a low net energy yield, long- lived radioactive wastes, vulnerability to sabotage, and the potential for spreading nuclear weapons technology have limited its use.

NUCLEAR FISSION The blue glow is known as Čerenkov radiation – when charged particles (electrons) passes through an insulator (water).

 Nuclear Fission is the splitting of atoms to release the energy they contain.  E = MC 2 E = energy M = mass C = speed of light 3.0x10 8 m / s 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 U 238 3% fissionable U 235 The concentration of U 235 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

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

 Duane Arnold Energy Center Located near Palo, Iowa - approximately nine miles NW of Cedar Rapids Generates about 592 million watts of electricity - enough power to supply the annual needs of more than 600,000 homes Our Very Own Nuclear Power Plant!

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

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, 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

Trade-Offs: Conventional Nuclear Fuel Cycle  In 1995, the World Bank said nuclear power is too costly and risky.  In 2006, it was found that several U.S. reactors were leaking radioactive tritium into groundwater.

Trade-Offs: Coal versus Nuclear to Produce Electricity  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 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?