17THMILLER/SPOOLMAN

LIVING IN THE ENVIRONMENT

Chapter 15Nonrenewable Energy

Energy Use: World and United States

Fig. 15-1, p. 370

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

• 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

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

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

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

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

Natural Gas Is a Useful and Clean-Burning Fossil Fuel

• Natural gas: mixture of gases• 50-90% is methane -- CH4

• Conventional natural gas• Sits above oil

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

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 SO2

• Large amount of soot• CO2

• Trace amounts of Hg and radioactive materials

Air Pollution from a Coal-Burning Industrial Plant in India

Fig. 15-16, p. 383

CO2 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

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

How Does a Nuclear Fission Reactor Work? (1)

• Controlled nuclear fission reaction in a reactor• 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

Fission of Uranium-235

Fig. 2-9b, p. 43

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

Trade-Offs: Conventional Nuclear Fuel Cycle

Fig. 15-22, 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

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

• Decommission or retire the power plant

• Some options1. Dismantle the plant and safely store the radioactive materials2. Enclose the plant behind a physical barrier with full-time

security until a storage facility has been built3. 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 CO2 emission

• Nuclear fuel cycle: emits CO2

• Need high rate of building new plants, plus a storage facility for radioactive wastes

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

• 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.

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.