Chapter 15: Nonrenewable Energy

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

Net Energy Ratios Fig. 15-3, p. 373

What are the pros and cons of using natural gas as a “bridge fuel”? Explain at least three of each. How is much of the natural gas in the U.S. being extracted today? What is that?

Fracking Video—From Industry Video

Summaries (Index Cards)

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.

Science: Refining “Sweet” Crude Oil Fig. 15-4, p. 375

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

OPEC Controls Most of the World’s Oil Supplies (1) In accordance with its Statute, the mission of the Organization of the Petroleum Exporting Countries (OPEC) is to coordinate and unify the petroleum policies of its Member Countries and ensure the stabilization of oil markets in order to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers and a fair return on capital for those investing in the petroleum industry. 12 countries have at least 60% of the world’s crude oil reserves: Saudi Arabia: 20% United States: 1.5%

Crude Oil in the Arctic National Wildlife Refuge (ANWR) Fig. 15-5, p. 376

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

BP Oil Spill in Gulf of Mexico, 2010

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 , p. 379

Define bitumen. Why is the Keystone XL pipeline an issue? (And what is the issue?) What are the pros/cons of constructing the Keystone XL pipeline? How do oil sands compare to “sweet”/light crude oil in terms of greenhouse gas emissions? Why the difference? Carbon pollution in U.S., as %: Electric power plants Vehicle emissions Other If Keystone XL were approved, what would be net result for global carbon emissions? President Obama’s stance?

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.

Using articles from last night on fracking, argue that we must continue to extract natural gas using this method (and why), and assure environmentalists that their three main concerns with fracking (what are they?) can be addressed.

Trade-Offs: Conventional Natural Gas Fig , 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, though percentage of plants using coal has reduced dramatically: 2005: 50% 2012: 34% 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 Some released as acid rain Large amount of soot CO 2 Trace amounts of Hg and radioactive materials

Stages in Coal Formation over Millions of Years Fig , p. 382

Types of Coal Different types of coal resulted from differences in the pressure and temperature that prevailed during formation. The softest coal (about 50% carbon), which also has the lowest energy output, is called lignite. Lignite has the highest water content (about 50%) and relatively low amounts of smog-causing sulfur. With increasing temperature and pressure, lignite is transformed into bituminous coal (about 85% carbon and 3% water). Anthracite (almost 100% carbon) is the hardest coal and also produces the greatest energy when burned. Less than 1% of the coal found in the United States is anthracite. Most of the coal found in the United States is bituminous. Unfortunately, bituminous coal has the highest sulfur content of all the coal types. When the coal is burned, the pollutant sulfur dioxide is released into the atmosphere.

Science: Coal-Burning Power Plant Fig , p. 382

Coal Deposits in the United States Figure 19, Supplement 8

Trade-Offs: Coal Fig , 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

Questions: What is coal ash, and why is it such a concern?

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

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.

Nuclear Energy Institute

Bottom Line: Energy Institute (U.K.)

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

Nuclear Accidents/Near-Accidents Chernobyl; Three Mile Island; Fukushima Quick research, from reliable sources: When and where? What happened? Short-term effects? Long-term effects? Did this accident/near accident result in significant changes in the nuclear industry?

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

Fig a, p. 387 Small amounts of radioactive gases Uranium fuel input (reactor core) Containment shell Waste heat Control rods Heat exchanger SteamTurbine Generator Hot coolant Useful electrical energy about 25% Hot water output Coolant Moderator Cool water input Waste heat ShieldingPressure vessel Coolant passage WaterCondenser Periodic removal and storage of radioactive wastes and spent fuel assemblies Periodic removal and storage of radioactive liquid wastes Water source (river, lake, ocean)

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

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 , p. 389

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Trade-Offs: Coal versus Nuclear to Produce Electricity Fig , 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 , 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.Dismantle the plant and safely store the radioactive materials 2.Enclose the plant behind a physical barrier with full-time security until a storage facility has been built 3.Enclose the plant in a tomb Monitor this for thousands of years

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.