MILLER/SPOOLMAN LIVING IN THE ENVIRONMENT

17 TH Chapter 15

Nonrenewable Energy

Case Study: A Brief History of Human Energy Use • Everything runs on energy • Industrial revolution began 275 years ago, relied on wood, which led to deforestation • Coal • Petroleum products • Natural gas • All of these are nonrenewable energy resources

Energy Use: World and United States

Fig. 15-1, p. 370

•

15-1 What is Net Energy and Why Is It Important?

Concept 15-1 Net energy is the amount of high quality energy available from an energy resource minus the amount of energy needed to make it available.

• Basic Science: Net Energy Is the Only Energy That Really Counts (1) First law of thermodynamics: • It takes high-quality energy to get high-quality energy • Pumping oil from ground, refining it, transporting it • Second law of thermodynamics • Some high-quality energy is wasted at every step

• Basic Science: Net Energy Is the Only Energy That Really Counts (2)

Net energy

• Total amount of useful energy available from a resource minus the energy needed to make the energy available to consumers • Business net profit: total money taken in minus all expenses • Net energy ratio: ratio of energy produced to energy used to produce it • Conventional oil: high net energy ratio

It Takes Energy to Pump Petroleum

Fig. 15-2, p. 372

Net Energy Ratios

Fig. 15-3, p. 373

Energy Resources With Low/Negative Net Energy Yields Need Marketplace Help • Cannot compete in open markets with alternatives that have higher net energy yields • Need subsidies from taxpayers • Nuclear power as an example

• Reducing Energy Waste Improves Net Energy Yields and Can Save Money 84% of all commercial energy used in the U.S. is wasted • 43% after accounting for second law of thermodynamics • Drive efficient cars, not gas guzzlers • Make buildings energy efficient

•

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 tar sand and oil shale exist in potentially large supplies but have low net energy yields and higher environmental impacts than conventional oil has.

We Depend Heavily on Oil (1) •

Petroleum

, or

crude oil:

conventional, or light oil • Fossil fuels: crude oil and natural gas • Peak production: time after which production from a well declines • Global peak production for all world oil

We Depend Heavily on Oil (2) • Oil extraction and refining • By boiling point temperature •

Petrochemicals

: • Products of oil distillation • Raw materials for industrial organic chemicals • Pesticides • Paints • Plastics

Science: Refining Crude Oil

Fig. 15-4, p. 375

How Long Might Supplies of Conventional Crude Oil Last? (1) • Rapid increase since 1950 • Largest consumers in 2009 • United States, 23% • China, 8% • Japan, 6%

How Long Might Supplies of Conventional Crude Oil Last? (2) •

Proven oil reserves

• Identified deposits that can be extracted profitably with current technology •

Unproven reserves

• Probable reserves: 50% chance of recovery • Possible reserves: 10-40% chance of recovery • Proven and unproven reserves will be 80% depleted sometime between 2050 and 2100

World Oil Consumption, 1950-2009

Figure 1, Supplement 2

History of the Age of Conventional Oil

Figure 9, Supplement 9

• OPEC Controls Most of the World’s Oil Supplies (1) 13 countries have at least 60% of the world’s crude oil reserves • Saudi Arabia: 20% • United States: 1.5% • Global oil production leveled off in 2005 • Oil production peaks and flow rates to consumers

• OPEC Controls Most of the World’s Oil Supplies (2) Three caveats when evaluating future oil supplies 1. Potential reserves are not proven reserves 2. Must use net energy yield to evaluate potential of any oil deposit 3. Must take into account high global use of oil

Crude Oil in the Arctic National Wildlife Refuge

Fig. 15-5, p. 376

• The United States Uses Much More Oil Than It Produces Produces 9% of the world’s oil and uses 23% of world’s oil • 1.5% of world’s proven oil reserves • Imports 52% of its oil • Should we look for more oil reserves?

• Extremely difficult • Expensive and financially risky

U.S. Energy Consumption by Fuel

Figure 6, Supplement 9

Proven and Unproven Reserves of Fossil Fuels in North America

Figure 18, Supplement 8

• Conventional Oil Has Advantages and Disadvantages Extraction, processing, and burning of nonrenewable oil and other fossil fuels • Advantages • Disadvantages

Trade-Offs: Conventional Oil

Fig. 15-6, p. 377

Bird Covered with Oil from an Oil Spill in Brazilian Waters

Fig. 15-7, p. 377

Case Study: Heavy Oil from Tar Sand •

Oil sand, tar sand

contains bitumen • Canada and Venezuela: oil sands have more oil than in Saudi Arabia • Extraction • Serious environmental impact before strip-mining • Low net energy yield: Is it cost effective?

Strip Mining for Tar Sands in Alberta

Fig. 15-8, p. 378

Will Heavy Oil from Oil Shales Be a Useful Resource?

• Oil shales contain kerogen • After distillation:

shale oil

• 72% of the world’s reserve is in arid areas of western United States • Locked up in rock • Lack of water needed for extraction and processing • Low net energy yield

Oil Shale Rock and the Shale Oil Extracted from It

Fig. 15-9, p. 379

Trade-Offs: Heavy Oils from Oil Shale and Oil Sand

Fig. 15-10, p. 379

•

15-3 What Are the Advantages and Disadvantages of Using 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 Is a Useful and Clean-Burning Fossil Fuel •

Natural gas:

mixture of gases • 50-90% is methane -- CH 4 • Conventional natural gas • Pipelines •

Liquefied petroleum gas (LPG)

•

Liquefied natural gas (LNG)

• Low net energy yield • Makes U.S. dependent upon unstable countries like Russia and Iran

Natural Gas Burned Off at Deep Sea Oil Well

Fig. 15-11, p. 380

Is Unconventional Natural Gas the Answer?

• Coal bed methane gas • In coal beds near the earth’s surface • In shale beds • High environmental impacts or extraction • Methane hydrate • Trapped in icy water • In permafrost environments • On ocean floor • Costs of extraction currently too high

Trade-Offs: Conventional Natural Gas

Fig. 15-12, p. 381

Methane Hydrate

Fig. 15-13, p. 381

•

15-4 What Are the Advantages and Disadvantages of Coal?

Concept 15-4A Conventional coal is 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 Is a Plentiful but Dirty Fuel (1) •

Coal

: solid fossil fuel • Burned in power plants; generates 42% of the world’s electricity • Inefficient • Three largest coal-burning countries • China • United States • Canada

Coal Is a Plentiful but Dirty Fuel (2) • World’s most abundant fossil fuel • U.S. has 28% of proven reserves • Environmental costs of burning coal • Severe air pollution • • Sulfur released as SO 2 Large amount of soot • • CO 2 Trace amounts of Hg and radioactive materials

Stages in Coal Formation over Millions of Years

Fig. 15-14, p. 382

Science: Coal-Burning Power Plant

Fig. 15-15, p. 382

Air Pollution from a Coal-Burning Industrial Plant in India

Fig. 15-16, p. 383

CO 2 Emissions Per Unit of Electrical Energy Produced for Energy Sources

Fig. 15-17, p. 383

World Coal and Natural Gas Consumption, 1950-2009

Figure 7, Supplement 9

Coal Consumption in China and the United States, 1980-2008

Figure 8, Supplement 9

Coal Deposits in the United States

Figure 19, Supplement 8

Trade-Offs: Coal

Fig. 15-18, p. 384

Case Study: The Problem of Coal Ash • Highly toxic • Arsenic, cadmium, chromium, lead, mercury • Ash left from burning and from emissions • Some used as fertilizer by farmers • Most is buried or put in ponds • Contaminates groundwater • Should be classified as hazardous waste

The Clean Coal and Anti-Coal Campaigns • Coal companies and energy companies fought • Classifying carbon dioxide as a pollutant • Classifying coal ash as hazardous waste • Air pollution standards for emissions • 2008 clean coal campaign • But no such thing as clean coal • “Coal is the single greatest threat to civilization and all life on the planet.” – James Hansen

• We Can Convert Coal into Gaseous and Liquid Fuels Conversion of solid coal to •

Synthetic natural gas (SNG)

by coal gasification • Methanol or synthetic gasoline by coal liquefaction • Synfuels • Are there benefits to using these synthetic fuels?

Trade-Offs: Synthetic Fuels

Fig. 15-19, p. 385

•

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 its use has been limited by a low net energy yield, high costs, fear of accidents, long-lived radioactive wastes, and the potential for spreading nuclear weapons technology.

• How Does a Nuclear Fission Reactor Work? (1) Controlled nuclear fission reaction in a reactor • Light-water reactors • Very inefficient • Fueled by uranium ore and packed as pellets in fuel rods and fuel assemblies • Control rods absorb neutrons

• How Does a Nuclear Fission Reactor Work? (2) Water is the usual coolant • Containment shell around the core for protection • Water-filled pools or dry casks for storage of radioactive spent fuel rod assemblies

Water-Cooled Nuclear Power Plant

Fig. 15-20, p. 387

Fission of Uranium-235

Fig. 2-9b, p. 43

What Is the Nuclear Fuel Cycle?

1. Mine the uranium 2. Process the uranium to make the fuel 3. Use it in the reactor 4. Safely store the radioactive waste 5. Decommission the reactor

Science: The Nuclear Fuel Cycle

Fig. 15-21, p. 388

What Happened to Nuclear Power?

• Slowest-growing energy source and expected to decline more • Why?

• • • Economics Poor management Low net yield of energy of the nuclear fuel cycle • • Safety concerns Need for greater government subsidies • Concerns of transporting uranium

Global Energy Capacity of Nuclear Power Plants

Figure 10, Supplement 9

Nuclear Power Plants in the United States

Figure 21, Supplement 8

Case Study: Chernobyl: The World’s Worst Nuclear Power Plant Accident • Chernobyl • April 26, 1986 • In Chernobyl, Ukraine • Series of explosions caused 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 • Effects on human health, water supply, and agriculture

• Nuclear Power Has Advantages and Disadvantages Advantages • Disadvantages

Trade-Offs: Conventional Nuclear Fuel Cycle

Fig. 15-22, p. 389

Trade-Offs: Coal versus Nuclear to Produce Electricity

Fig. 15-23, p. 389

• Storing Spent Radioactive Fuel Rods Presents Risks Rods must be replaced every 3-4 years • Cooled in water-filled pools • Placed in dry casks • Must be stored for thousands of years • Vulnerable to terrorist attack

Dealing with Spent Fuel Rods

Fig. 15-24, p. 390

Dealing with Radioactive Wastes Produced by Nuclear Power Is a Difficult Problem • High-level radioactive wastes • Must be stored safely for 10,000–240,000 years • Where to store it • Deep burial: safest and cheapest option • Would any method of burial last long enough?

• There is still no facility • Shooting it into space is too dangerous

Case Study: High-Level Radioactive Wastes in the United States • 1985: plans in the U.S. to build a repository for high level radioactive wastes in the Yucca Mountain desert region (Nevada) • Problems • Cost: $96 billion • Large number of shipments to the site: protection from attack?

• Rock fractures • Earthquake zone • Decrease national security

What Do We Do with Worn-Out Nuclear Power Plants?

• Decommission or retire the power plant • Some options 1.

2.

3.

Dismantle the plant and safely store the radioactive materials Enclose the plant behind a physical barrier with full-time security until a storage facility has been built • Enclose the plant in a tomb Monitor this for thousands of years

Can Nuclear Power Lessen Dependence on Imported Oil & Reduce Global Warming?

• Nuclear power plants: no CO 2 emission • Nuclear fuel cycle: emits CO 2 • Opposing views on nuclear power • Nuclear power advocates • 2007: Oxford Research Group • Need high rate of building new plants, plus a storage facility for radioactive wastes

Are New Generation Nuclear Reactors the Answer?

• Advanced light-water reactors (ALWR) • Built-in passive safety features • Thorium-based reactors • Cheaper and safer • But much research and development needed

Solutions: New Generation Nuclear Reactors

Fig. 15-25, p. 393

Will Nuclear Fusion Save Us?

• “

Nuclear fusion

• Fuse lighter elements into heavier elements • No risk of meltdown or large radioactivity release • Still in the laboratory phase after 50 years of research and $34 billion dollars • 2006: U.S., China, Russia, Japan, South Korea, and European Union • Will build a large-scale experimental nuclear fusion reactor by 2018

Nuclear Fusion

Fig. 2-9c, p. 43

• Experts Disagree about the Future of Nuclear Power Proponents of nuclear power • Fund more research and development • Pilot-plant testing of potentially cheaper and safer reactors • Test breeder fission and nuclear fusion • Opponents of nuclear power • Fund rapid development of energy efficient and renewable energy resources

Three Big Ideas 1. A key factor to consider in evaluating the usefulness of any energy resource is its net energy yield.

2. Conventional oil, natural gas, and coal are plentiful and have moderate to high net energy yields, but using any fossil fuel, especially coal, has a high environmental impact.

Three Big Ideas 3. 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, and the potential for spreading nuclear weapons technology have limited its use.