Nonrenewable Energy Resources 9 Nonrenewable Energy Resources

Changes in Energy Sources

Fossil Fuels During the Carboniferous period, (286-362 million years ago) conditions were conducive to the formation of large deposits of coal from abundant plant growth. Oil and natural gas formed primarily from one-celled marine organisms.

Crude Oil and Natural Gas Deposits

Fossil fuels supply 80% of world’s commercial energy.

Net Energy Is the Only Energy That Really Counts It takes energy to get energy Second law of thermodynamics Some high-quality energy is wasted at every step Net energy yield Total amount of high-quality energy available from an energy resource minus the energy needed to find, extract, process, and get that energy to consumers Energy return on investment (EROI)

9-2 What Are the Advantages and Disadvantages of Oil? We depend heavily on oil Crude oil (petroleum): conventional or light crude oil Oil extraction Peak production Refining: separating oil into separate components Petrochemicals: distillation products

Lowest Boiling Point Gases Gasoline Aviation fuel Heating oil Diesel oil Naphtha Figure 9-4 Crude oil is refined in a giant distillation column that can be as tall as a nine-story building. Its components are removed at various levels, depending on their boiling points. The most volatile components with the lowest boiling points are removed at the top of the column. Grease and wax Heated crude oil Asphalt Furnace Highest Boiling Point Fig. 9-4

Are We Running Out of Conventional Oil? Proven oil reserves Identified deposits that can be extracted profitably with current technology Organization of Petroleum Exporting Countries (OPEC) countries Have 72 percent of the world’s crude oil reserves Venezuela (18 percent) Saudi Arabia (16 percent)

Oil companies say: >550 years Scientists : 53 years

Are We Running Out of Conventional Oil? U.S. produces nine percent of the world’s oil Uses 21 percent of the world’s oil U.S. has two percent of the world’s proven oil reserves 2012: Imported 39 percent of its oil

Barrels of oil per year (billions) Projected U. S. oil consumption Barrels of oil per year (billions) Figure 9-5 The amount of conventional light crude oil that might be found in the Arctic National Wildlife Refuge, if developed and extracted over 50 years, is a tiny fraction of the projected U.S. demand for oil. (Compiled by the authors using data from U.S. Department of Energy and U.S. Geological Survey.) Arctic refuge oil output over 50 years Year Fig. 9-5

Trade-Offs Conventional Oil Advantages Disadvantages Ample supply for several decades Water pollution from oil spills and leaks Environmental costs not included in market price Net energy yield is medium but decreasing Releases CO2 and other air pollutants when burned Low land disruption Figure 9-6 Using crude oil as an energy resource has advantages and disadvantages. Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Efficient distribution system Vulnerable to international supply interruptions Fig. 9-6

Science Focus: Removing Oil and Natural Gas by Drilling Sideways and Fracking Newer extraction technologies Horizontal drilling Hydraulic fracturing (fracking) Potentially serious environmental problems associated with these extraction methods

Hydraulic Fracturing Or “Fracking”

The chemicals used in hydraulic fracturing shows that of the 750 compounds in hydraulic fracturing products ,more than 650 of these products contained chemicals that are known human carcinogens. For example: benzene (causes cancer, bone marrow failure) lead (damages the nervous system and causes brain disorders) ethylene glycol (antifreeze, causes death) methanol (highly toxic) boric acid (kidney damage, death) 2-butoxyethanol (causes hemolysis) Gamma-emitting isotopes (radioactive; can cause cancer)

Air emissions and pollution Groundwater contamination Radioactive contamination Earthquakes Greenhouse gas emissions

Heavy Oils from Tar Sand and Oil Shale Tar sand (oil sand) contains bitumen Heavy oil potentially available in Canada’s tar sand Seven times Saudi Arabia’s total conventional oil reserves Heavy oil production from tar sands Inefficient, dirty and environmentally harmful

Heavy Oils from Oil Shale and Tar Sand Trade-Offs Heavy Oils from Oil Shale and Tar Sand Advantages Disadvantages Large potential supplies Low net energy yield Easily transported within and between countries Releases CO2 and other air pollutants when produced and burned Figure 9-7 Using heavy oil from tar sand and oil shale as energy resources has advantages and disadvantages (Concept 9-2). Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Efficient distribution system in place Severe land disruption and high water use Fig. 9-7

9-3 What Are the Advantages and Disadvantages of Using Natural Gas? Natural gas is a useful and clean-burning fossil fuel Natural gas: mixture of gases 50 to 90 percent is methane (CH4) Conventional natural gas Pipelines for distribution Liquefied petroleum gas (LPG) Liquefied natural gas (LNG) Low net energy yield Liquefaction at -126o F (1/600 volume of gas)

Natural Gas Is a Useful and Clean-Burning Fossil Fuel 2011: world’s three largest natural gas producers United States (20 percent) Russia (19 percent) Canada (5 percent) Unconventional natural gas Coal bed methane gas Methane hydrate

Conventional Natural Gas Trade-Offs Conventional Natural Gas Advantages Disadvantages Ample supplies Low net energy yield for LNG Versatile fuel Production and delivery may emit more CO2 and CH4 per unit of energy produced than coal Medium net energy yield Figure 9-8 Using conventional natural gas as an energy resource has advantages and disadvantages. Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Do you think that the advantages of using conventional natural gas outweigh its disadvantages? Fracking uses and pollutes large volumes of water Emits less CO2 and other air pollutants than other fossil fuels when burned Potential groundwater pollution from fracking Fig. 9-8

9-4 What Are the Advantages and Disadvantages of Coal? Coal is a plentiful but dirty fuel Coal: solid fossil fuel Burned in power plants; generates 45 percent of the world’s electricity Three largest coal-burning countries China United States India

Increasing moisture content Increasing heat and carbon content Peat (not a coal) Lignite (brown coal) Bituminous (soft coal) Anthracite (hard coal) Heat Pressure Partially decayed plant matter in swamps and bogs; low heat content Low heat content; low sulfur content; limited supplies in most areas Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas Figure 9-9 Over millions of years, several different types of coal have formed. Peat is a soil material made of moist, partially decomposed organic matter and is not classified as a coal, although it is used as a fuel. These different types of coal vary in the amounts of heat, carbon dioxide, and sulfur dioxide released per unit of mass when they are burned. Stepped Art Fig. 9-9

Cooling tower transfers waste heat to atmosphere Coal bunker Turbine Generator Cooling loop Stack Pulverizing mill Condenser Filter Figure 9-10 This power plant burns pulverized coal to boil water and produce steam that spins a turbine to produce electricity. The steam is cooled, condensed, and returned to the boiler for reuse. Waste heat can be transferred to the atmosphere or to a nearby source of water. The largest coal-burning power plant in the United States, located in Indiana, burns three 100-car trainloads of coal per day. Question: Does the electricity that you use come from a coal-burning power plant? Boiler Ash disposal Fig. 9-10

Coal Is a Plentiful but Dirty Fuel World’s most abundant fossil fuel U.S. has 28 percent of proven reserves Dirtiest of all fossil fuels to burn Severe air pollution Large amount of soot Large amounts of CO2 Ash that contains highly toxic and indestructible chemicals

Trade-Offs Coal Advantages Disadvantages Severe land disturbance and water pollution Ample supplies in many countries Fine particle and toxic mercury emissions threaten human health Medium to high net energy yield Figure 9-12 Using coal as an energy resource has advantages and disadvantages. Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Do you think that the advantages of using coal as an energy resource outweigh its disadvantages? Low cost when environmental costs are not included Emits large amounts of CO2 and other air pollutants when produced and burned Fig. 9-12

9-5 What Are the Advantages and Disadvantages of Nuclear Energy? How does a nuclear fission reactor work? Controlled nuclear fission reaction in a reactor Multiple fissions within a critical mass of nuclear fuel form a chain reaction Enormous amount of energy released that can be used to produce electricity

Nuclear Chain Reaction After about three years of operation, fuel rods don’t have enough radioactive material remaining to sustain a chain reaction, thus spent fuel rods are replaced by new ones. Spent rods are still very radioactive.

Pump Pump Pump Pump Water source (river, lake, ocean) Small amounts of radioactive gases Uranium fuel input (reactor core) Control rods Containment shell Waste heat Heat exchanger Steam Turbine Generator Hot coolant Useful electrical energy about 25% Hot water output Pump Pump Coolant Pump Figure 9-15 This water-cooled nuclear power plant, with a pressurized water reactor, pumps water under high pressure into its core where nuclear fission takes place. Some nuclear plants withdraw the water they use from a nearby source, such as a river, and return the heated water to that source, as shown here. Other nuclear plants transfer the waste heat from the intensely hot water to the atmosphere by using one or more gigantic cooling towers. Question: How does this plant differ from the coal-burning plant in Figure 9-10? Pump Waste heat Cool water input Moderator Shielding Pressure vessel Coolant passage Water Condenser Periodic removal and storage of radioactive wastes and spent fuel assemblies Periodic removal and storage of radioactive liquid wastes Water source (river, lake, ocean) Fig. 9-15

Why is this Non Renewable? Decommissioning of reactor Fuel assemblies Reactor Enrichment of UF6 Fuel fabrication (conversion of enriched UF6 to UO2 and fabrication of fuel assemblies) Temporary storage of spent fuel assemblies underwater or in dry casks Conversion of U3O8 to UF6 Uranium-235 as UF6 Plutonium-239 as PuO2 Spent fuel reprocessing Low-level radiation with long half-life Figure 9-16 Using nuclear power to produce electricity involves a complex set of technologies and processes that make up the nuclear fuel cycle. Question: Do you think the market price of nuclear-generated electricity should include all the costs of the nuclear fuel cycle? Explain. Geologic disposal of moderate and high-level radioactive wastes Mining uranium ore (U3O8) Why is this Non Renewable? Open fuel cycle today Recycling of nuclear fuel Fig. 9-16

Dealing with Radioactive Wastes Produced by Nuclear Power Is a Difficult Problem High-level radioactive wastes Must be stored safely for 10,000 to 240,000 years Where to store it Deep burial: safest and cheapest option There is still no such facility

Case Study: High-Level Radioactive Wastes in the United States 1987: DOE announced plans to build a repository for high-level radioactive wastes Yucca Mountain desert region (Nevada) Problems Cost: $96 billion Unsuitable location: rock fractures Project was abandoned in 2010

What Should We Do with Worn-Out Nuclear Power Plants? Decommission (retire) the power plant Some options 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

Will Nuclear Fusion Be a Viable Energy Resource? Nuclei fused to form a heavier nucleus Releases energy No risk of meltdown or large radioactivity release Still in the laboratory phase After 50 years of research and $25 billion dollars

Will Nuclear Fusion Be a Viable Energy Resource? 2006: U.S., China, Russia, Japan, South Korea, and European Union Will build a large-scale experimental nuclear fusion reactor by 2026

Experts Disagree about the Future of Nuclear Power Slowest-growing form of commercial energy Why? Economics Poor management Low net yield of energy of the nuclear fuel cycle Safety concerns Need for greater government subsidies

Figure 9-18 Some critics of nuclear power say that any new generation of nuclear power plants should meet all of these five criteria. Question: Do you agree or disagree with these critics? Explain. Fig. 9-18

Trade-Offs Conventional Nuclear Fuel Cycle Advantages Disadvantages Low environmental impact (without accidents) Low net energy yield High overall cost Emits 1/6 as much CO2 as coal Produces long-lived, harmful radioactive wastes Figure 9-19 Using the nuclear power fuel cycle (Figure 9-16) to produce electricity has advantages and disadvantages (Concept 9-5). Questions: Which single advantage and which single disadvantage do you think are the most important? Why? Low risk of accidents in modern plants Promotes spread of nuclear weapons Fig. 9-19

Case Study: The 2011 Nuclear Power Plant Accident in Japan Accident triggered by a major offshore earthquake that caused a severe tsunami Key factors that contributed to the accident and its aftermath Protective walls not high enough Design flaws that exposed emergency cooling system controls and backup generators Slow response to the crisis Insufficient regulation

The Three Mile Island nuclear plant in Pennsylvania experienced a partial core meltdown on March 28, 1979. Chernobyl is a small city in Ukraine, north of Kiev. It is the site of the world’s largest nuclear accident, which occurred April 26, 1986. There were 37 deaths; 500 people hospitalized (237 with acute radiation sickness); 116,000 people evacuated.

Use of Nonrenewable Energy Violates the Principles of Sustainability Using nonrenewable fossil fuels and nuclear power Results in serious long-term environmental and health problems Current technologies Disrupt the earth’s chemical cycles by emitting large quantities of pollutants and greenhouse gases

What 1 invention completely made humans dependent on Oil?

The invention of the automobile dramatically increased the demand for oil products. Better roads permitted higher speeds. Higher speeds permitted bigger, faster cars. Bigger, faster cars required better roads. People could live farther from work, leading to sprawling cities and suburbs. We expect to see Florida oranges, California lettuces, and Central American bananas in any supermarket in North America.

Nuclear fuel cycle Hydrogen Electricity Energy efficiency Hydropower Wind Coal Natural gas Geothermal energy Solar cells Nuclear fuel cycle Hydrogen Space Heating Passive solar Oil Active solar Heavy shale oil Heavy oil from tar sands Electricity Hydrogen Net Energy Yield High High High High Medium Medium Low to medium Low Negative (Energy loss) High Medium Medium Low Low Negative (Energy loss) Figure 9-3 Generalized net energy yields for various energy resources and systems (Concept 9-1). Question: Based on these data, which two resources in each category should we be using? (Compiled by the authors using data from the U.S. Department of Energy; U.S. Department of Agriculture; Colorado Energy Research Institute, Net Energy Analysis, 1976; Howard T. Odum and Elisabeth C. Odum, Energy Basis for Man and Nature, 3rd ed., New York: McGraw-Hill, 1981; and Charles A.S. Hall and Kent A. Klitgaard, Energy and the Wealth of Nations, New York: Springer, 2012) Yegor Korzh/Shutterstock.com (top left), Donald Aitken/National Renewable Energy Laboratory (bottom left), Serdar Tibet/ Shutterstock.com (top right), Michel Stevelmans/Shutterstock.com (bottom right) Fig. 9-3

High-Temperature Industrial Heat Energy efficiency (cogeneration) Coal Natural gas Oil Heavy shale oil Heavy oil from tar sands Direct solar (concentrated) Hydrogen Net Energy Yield High High Medium Medium Low Low Low Negative (Energy loss) Transportation Net Energy Yield High High Medium Medium Medium Low Low Low Low Negative (Energy loss) Energy efficiency Gasoline Natural gas Ethanol (from sugarcane) Diesel Gasoline from heavy shale oil Gasoline from heavy tar sand oil Ethanol (from corn) Biodiesel (from soy) Hydrogen Figure 9-3 (cont’d.) Generalized net energy yields for various energy resources and systems (Concept 9-1). Question: Based on these data, which two resources in each category should we be using? (Compiled by the authors using data from the U.S. Department of Energy; U.S. Department of Agriculture; Colorado Energy Research Institute, Net Energy Analysis, 1976; Howard T. Odum and Elisabeth C. Odum, Energy Basis for Man and Nature, 3rd ed., New York: McGraw-Hill, 1981; and Charles A.S. Hall and Kent A. Klitgaard, Energy and the Wealth of Nations, New York: Springer, 2012) Yegor Korzh/Shutterstock.com (top left), Donald Aitken/National Renewable Energy Laboratory (bottom left), Serdar Tibet/ Shutterstock.com (top right), Michel Stevelmans/Shutterstock.com (bottom right) Fig. 9-3