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Environment: The Science behind the Stories

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1 Environment: The Science behind the Stories
Lecture Outlines Chapter 19 Environment: The Science behind the Stories 4th Edition Withgott/Brennan

2 This lecture will help you understand:
Our energy sources Coal Natural gas Crude oil Alternative fossil fuels Environmental impacts of fossil fuels Political, social, and economic aspects Conserving energy and enhancing efficiency

3 Central Case: Oil or wilderness on Alaska’s North Slope?
Alaska’s remote North Slope A pristine wilderness to some Untapped oil riches to others The Arctic National Wildlife Refuge is the focus of intense debate Should the “1002 Area” be opened to drilling? Opponents fear that drilling will sacrifice our national heritage For little gain

4 The three regions of Alaska’s North Slope
The National Petroleum Reserve–Alaska (NPR–A) Supposed to remain untapped unless the nation faces an emergency Open ecologically sensitive areas for drilling in 2006 Prudhoe Bay consists of state lands that are drilled for oil Which is transported via the trans-Alaska pipeline to the port of Valdez The Arctic National Wildlife Refuge (ANWR) Federal land set aside for wildlife and to preserve pristine ecosystems It has been called the “Serengeti of North America”

5 Alaska’s North Slope

6 We use a variety of energy sources
We use energy in our homes, machinery, and vehicles and to provide comfort and conveniences Most of our energy comes from the sun Solar, wind, hydroelectric, photosynthesis, biomass Fossil fuels = highly combustible substances from the remains of organisms from past geologic ages A great deal of energy emanates from Earth’s core Geothermal power Immense amounts of energy reside in an atom’s bonds This energy provides us with nuclear power

7 Fossil fuels: our dominant source of energy
Oil, coal, and natural gas have replaced biomass as our dominant sources of energy Global consumption is at its highest level ever The high-energy content of fossil fuels makes them efficient to burn, ship, and store Electricity = a secondary form of energy that is easy to transfer and apply to a variety of uses

8 The energy stream of the U.S. is complex
The U.S. energy stream is dominated by coal, oil, and natural gas

9 Resources are renewable or nonrenewable
Renewable energy = supplies will not be depleted by our use Sunlight, geothermal energy, and tidal energy Nonrenewable energy = we will use up Earth’s accessible store in decades to centuries Oil, coal, natural gas, nuclear energy To replenish the fossil fuels we have depleted so far would take millions of years

10 Fossil fuels are created from fossils
Fossil fuels were formed from organisms that lived 100–500 million years ago Aerobic decomposition = organic material is broken down and recycled in the presence of air Anaerobic decomposition = occurs with little or no air Deep lakes, swamps Produces fossil fuels

11 Fossil fuel reserves are unevenly distributed
Some regions have substantial reserves Whereas others have very few How long a nation’s reserves will last depends on how much the nation extracts, uses, exports, and imports Nearly 67% of the world’s proven reserves of crude oil lie in the Middle East Russia holds the most natural gas The U.S. possesses more coal than any other country

12 Developed nations consume lots of energy
People in developed regions consume far more energy than those in developing nations Using 100 times more energy per person Energy use in industrialized nations is evenly divided between transportation, industry, and other uses Developing nations use energy for subsistence activities Agriculture, food preparation, and home heating They use manual or animal energy, not fossil fuels

13 Regions vary greatly in energy consumption
The U.S. has 4.5% of the population but uses 20% of the world’s energy

14 It takes energy to make energy
We don’t get energy for free To harness, extract, process, and deliver energy requires substantial inputs of energy Drilling for oil requires roads, wells, vehicles, storage tanks, pipes, housing, etc. All this requires energy Net energy = the difference between energy returned and energy invested Net energy = energy returned – energy invested

15 Energy returned on investment (EROI)
Energy returned on investment (EROI) = energy returned/energy invested Higher ratios mean we receive more energy than we invest Fossil fuels have high EROI EROI ratios can change They decline when we extract the easiest deposits first We now must work harder to extract the remaining reserves U.S. oil EROI ratios have gone from 100:1 to 5:1

16 Coal The world’s most abundant fossil fuel
Created 300–400 million years ago Coal = organic matter (woody plant material) Compressed under very high pressure in swamps to form dense, solid carbon structures Very little decomposition occurred

17 Coal is mined using two major methods
Strip mining = for deposits near the surface Heavy machinery removes huge amounts of earth to expose the coal Subsurface mining = underground deposits are reached by digging tunnels to follow seams (layers) of coal Mountaintop removal = entire mountaintops are cut off Environmentally destructive Common in the Appalachian Mountains

18 Coal use has a long history
Cultures have used coal for centuries Ancient China, Roman Empire, the Hopi nation Coal helped drive the Industrial Revolution It fueled furnaces to produce steam Coal is used to generate electricity Converting water to steam, which turns a turbine The U.S. and China are the primary producers and consumers of coal It provides half the U.S. electrical generating capacity

19 A typical coal-fired power plant

20 Coal varies in its qualities
Coal varies in water and carbon content and its amount of potential energy Peat = organic material that is broken down anaerobically It is wet, near the surface, and not well compressed Additional pressure, heat, and time turn peat into coal Lignite = least compressed Sub-bituminous and bituminous Anthracite = most compressed and has the most energy

21 Coal contains impurities
It has sulfur, mercury, arsenic, and other trace metals The sulfur content depends on whether coal was formed in salt water or freshwater Coal in the eastern U.S. is high in sulfur because it was formed in marine sediments Impurities are emitted when coal is burned Unless pollution control measures are used Ways to reduce pollution must be found The Earth holds enough coal to last a few hundred years

22 Natural gas burns more cleanly than coal
The fastest growing fossil fuel in use today 25% of global commercial energy consumption It is versatile and clean-burning Emits ½ as much CO2 as coal, ⅔ as much as oil It is used to generate electricity, heat homes, and cook Liquefied natural gas (LNG) = gas converted to liquid Can be shipped but there are risks of explosions Russia leads the world in production The U.S. leads the world in use World supplies are projected to last about 60 more years

23 Natural gas is formed in two ways
Natural gas = methane (CH4) and other volatile hydrocarbons Biogenic gas = pure methane created at shallow depths by bacterial anaerobic decomposition of organic matter “Swamp gas” Thermogenic gas = methane and other gases arise from compression and heat deep underground Most of the gas that is extracted commercially Kerogen = organic matter that results when carbon bonds begin breaking Source material for natural gas and crude oil

24 Natural gas is often wasted
Coalbed methane = from coal seams Leaks to the atmosphere during mining Contributes to climate change In remote oil-drilling areas, natural gas is flared (burned off) In Alaska, gas captured during oil drilling is being reinjected into the ground for future use Landfills produce biogenic natural gas Operators are capturing and selling it

25 Natural gas extraction becomes challenging
The first gas fields simply required an opening The gas moved upward Most remaining fields require pumping by horsehead pumps Most accessible reserves have been depleted Fracturing pumps high-pressure salt water into rocks to crack them

26 Offshore drilling on the seafloor
Requires technology to withstand wind, waves, and currents Produces 1/3 of our oil and 13% of our natural gas In 2008, Congress lifted a drilling moratorium along U.S. coasts In 2010, President Obama said vast areas would be opened for drilling British Petroleum’s Deepwater Horizon exploded Producing the worst oil spill in U.S. history

27 Heat and pressure form petroleum
Oil is the world’s most used fuel Accounts for 35% of world’s energy use The U.S. uses the most, but China’s and India’s use is increasing Crude oil (petroleum) = a mixture of hundreds of different types of hydrocarbon molecules Formed 1.5–3 km (1–2 mi) underground Dead organic material was buried in marine sediments and transformed by time, heat, and pressure

28 Petroleum geologists find deposits
Petroleum occurs in isolated deposits Collecting in porous layers under impermeable layers Geologists drill cores and survey the ground and air to predict where fossil fuels may lie Of the 11.6–31.5 billion barrels of oil in the Arctic National Wildlife Refuge, only 4.3–11.8 billion barrels are “technologically recoverable” with current technology

29 Not all oil can be extracted
Some oil is so hard to extract, it is not worth the cost As prices rise, economically recoverable amounts approach technically recoverable amounts Technology limits what can be extracted Economics determines how much will be extracted Proven recoverable reserve = the amount of oil (or any other fossil fuel) that is technically and economically feasible to remove under current conditions

30 We drill to extract oil Exploratory drilling = small, deep holes to determine whether extraction should be done Oil is under pressure and often rises to the surface Drilling reduces pressure, and oil becomes harder to extract Primary extraction = the initial drilling and pumping of available oil Secondary extraction = solvents, water, or steam is used to remove additional oil, but it is expensive We lack the technology to remove every bit of oil As prices rise, it becomes economical to reopen a well

31 Primary and secondary oil extraction

32 Oil refineries create petroleum products
Refining = hydrocarbons are separated into different size classes and are chemically transformed Creating specialized fuels for many uses

33 Petroleum products have many uses
Petroleum products are central to our lives

34 We may have depleted half our reserves
We have used up 1.1 trillion barrels of oil Half our reserves Reserves-to-production ratio (R/P ratio) = the amount of total remaining reserves divided by the annual rate of production (extraction and processing) At current levels of production (30 billion barrels/year), we have about 40 years of oil left We will face a crisis not when we run out of oil, but when the rate of production begins to decline

35 We are facing an oil shortage
Peak oil = rate of production peaks and then declines We experience an immediate oil shortage Production declines once reserves are depleted halfway This crisis will begin within the next several years Geologist M. King Hubbard predicted that oil production would peak around 1970 His prediction was accurate, and U.S. production continues to fall Hubbard’s peak = the peak in U.S. production

36 U.S. oil production has already peaked

37 Global oil production is peaking
Discoveries of new oil fields peaked 30 years ago, and we are using more oil than we are discovering

38 Predicting an exact date for peak oil is hard
We won’t recognize that we have passed peak production until several years have passed Companies and governments do not disclose their amount of oil supply Disagreement among geologists about reserves Some estimates predict greater than expected reserves Peak production will occur Our lives will be profoundly affected

39 The long emergency “The long emergency”: lacking cheap oil to transport goods, our economies collapse and become localized Large cities could not be supported without urban agriculture Fewer petroleum-based fertilizers and pesticides would mean increase in hunger Suburbs will become the new slums, a crime-ridden landscape littered with the hulls of rusted-out SUVs More optimistic observers argue that as supplies dwindle, conservation and alternative energies will kick in We will be saved from major disruptions

40 Canada is mining oil sands
Oil sands (tar sands) = sand deposits with bitumen A form of petroleum rich in carbon, poor in hydrogen Degraded and chemically altered crude oil deposits Removed by strip mining Requires special extraction and refining processes Most is in Venezuela and Alberta

41 Oil shale is abundant in the U.S. west
Oil shale = sedimentary rock filled with kerogen (organic matter) Can be burned like coal or baked in the presence of hydrogen (called pyrolysis) to extract liquid petroleum World’s supplies may equal 600 billion barrels 40% is in the U.S., mostly on federally owned land in Colorado, Wyoming, and Utah Low prices for crude oil have kept investors away But as oil prices increase, oil shale is attracting interest

42 Methane hydrate shows potential
Methane hydrate (methane ice) = molecules of methane in a crystal lattice of ice molecules Occurs in arctic locations and under the seafloor Formed by bacterial decomposition in anaerobic environments or deep thermogenic formation Immense amounts could be present From 2 to 20 times the amount of natural gas We do not know how to extract it safely Extraction could cause landslides and tsunamis Releasing large amounts of methane – a greenhouse gas

43 Alternative fossil fuels have downsides
Their net energy values are low because they are expensive to extract and process They have low energy returned on investment (EROI) ratios (about 2:1 compared to oil’s 5:1) Extraction devastates the landscape and pollutes waterways Oil sands and oils use strip mining and pollute water Alberta’s oil sands mined 30 years ago still have not recovered Combustion emits as much greenhouse gases and pollution as oil, coal, and gas

44 Fossil fuel emissions pollute
Carbon dioxide is released into the air Driving changes in global climate Emissions cause severe health problems Cancer, irritation, poisoning Technology and legislation can reduce pollution Carbon dioxide is the greatest impact of fossil fuel use

45 Clean coal technologies
Clean coal technologies = technologies, equipment, and approaches to remove chemical contaminants while generating electricity from coal Scrubbers chemically convert or remove pollutants Removing sulfur dioxide or nitrogen oxides Coal that contains lots of water can be dried Gasification = coal is converted into cleaner synthesis gas (syngas) Which can be used to turn a gas or steam turbine These technologies have reduced pollution But clean coal is still a dirty way to generate power

46 Can we capture and store carbon?
Even very clean coal still releases greenhouse gases Carbon capture and carbon storage (sequestration) CCS captures CO2 emissions Then converts it to a liquid and stores it underground or in the ocean The $1.5 billion FutureGen project will design, construct, and operate a coal-burning power plant for electricity while capturing and storing carbon underground This technology is still too unproven to depend on It prolongs our dependence on fossil fuels

47 Carbon capture and sequestration

48 Fossil fuels pollute water and air
For 3 months, the Deepwater Horizon’s explosion spilled millions of barrels of oil into the Gulf of Mexico We have never had to deal with a spill so deep The Gulf of Mexico suffered many impacts Countless animals (birds, shrimp, fish, etc.) died Coastal marsh plants died, leading to erosion Fisheries were devastated and fishermen lost jobs Oil from non-point sources enters waterways and aquifers Alternative fossil fuels worsens the impacts They use and pollute massive amounts of water

49 Coal mining devastates natural systems
Acid drainage = chemical runoff from strip mining enters waterways Sulfuric acid leaches metals from rocks U.S. regulations require companies to restore strip- mined land, but complete restoration is impossible Mountaintop removal removes tons of rock and soil Destroying immense amounts of habitat and creeks Loosening of regulations in 2002 allowed companies to legally dump debris into valleys and rivers Regardless of the consequences

50 Mountaintop removal Mountaintop removal has greater impacts than strip mining

51 The public pays the environmental costs
Costs of alleviating environmental impacts are high The public pays for them Costs are not internalized in the market price of fossil fuels External costs are paid for in medical expenses, environmental cleanup, and decreased quality of life Gas prices and utility bills don’t cover production costs Government subsidies keep fossil fuel prices cheap Fossil fuel industries get more than renewable ones Part of our tax dollars pay for our fossil fuel energy use

52 Extraction modifies the environment
More than drilling is involved in developing oil or gas Roads, exploration Infrastructure (housing, roads, pipes, waste piles) Ponds collect toxic sludge Groundwater is depleted and made saltier Substantial and wide-ranging damage to vegetation, air and water quality, and wildlife if ANWR were drilled Others say damage would be minimal Directional drilling = wells are drilled in directions outward from a drilling pad, requiring fewer pads

53 Many nations depend on foreign energy
We are vulnerable to supplies becoming unavailable or costly Seller nations control prices, causing panic and inflation The U.S. imports 67% of its crude oil, meaning other nations control our energy supplies

54 The oil embargo of the 1970s caused panic
OPEC’s (Organization of Petroleum Exporting Countries) oil embargo caused panic and skyrocketing prices, spurring inflation

55 Oil supply and prices affect economies
Hurricanes Katrina and Rita (2005) destroyed offshore platforms, causing oil and gas prices to spike The politically volatile Middle East has the majority of oil reserves Causing a constant concern for the U.S. The U.S. has a close relationship with Saudi Arabia Despite Saudi Arabia’s lack of democracy Because it owns 22% of the world’s oil reserves Iraq has 10% of the world’s oil Many believe this is why the U.S. invaded it in 2003

56 The U.S. has policies to reduce foreign oil
The U.S. is developing its own reserves Many want drilling in ANWR Despite charges that drilling won’t help much It imports oil from several countries Companies are resuming extraction at closed sites The government funds research into renewable energy sources The Strategic Petroleum Reserve stockpiles oil in caverns under Louisiana as a buffer against shortages But this reserve equals just one month’s U.S. supply

57 The global trade in oil is lopsided

58 Residents may or may not benefit
Oil companies provide jobs for millions Paying dividends to millions of investors Citizens in Alaska are paid dividends by the government Many support developing ANWR for jobs, health care, other services Money from multi-national companies may not reach residents Residents are not compensated for pollution, land degradation, and displacement Many still live in poverty, without water or electricity

59 How will we convert to renewable energy?
Fossil fuel supplies are limited, and their use has consequences Nations have several options for future energy use: Continue relying on fossil fuels until they are no longer economically practical Immediately increase funding to develop alternative energy sources dramatically Steer a middle course and gradually reduce our reliance on fossil fuels We need to prolong fossil fuels through conservation

60 Consequences of our reliance on fossil fuels

61 Energy efficiency and conservation
We need to minimize energy use from dwindling fossil fuel supplies Energy efficiency = obtaining a given amount of output while using less energy input Results from technological improvements Energy conservation = reducing energy use Results from behavioral choices We can extend our nonrenewable energy supplies Be less wasteful Reduce our environmental impact

62 Automobile efficiency affects conservation
The OPEC embargo of 1973 caused increased conservation, but it didn’t last Without high prices and shortages, there was no incentive to conserve Government research into alternative energy decreased Speed limits increased Policy makers failed to raise the corporate average fuel efficiency (CAFE) standards Low U.S. gas prices do not account for external costs

63 CAFE standards CAFE standards mandate higher fuel efficiency in cars
Fuel efficiencies fell from 22 mpg (1984) to 19 (2004) They climbed to 21.1 in 2009 In 2009 Congress mandated that cars must get 35 mpg by 2020 European and Japanese cars are twice as efficient as U.S. cars

64 The Cash for Clunkers program
In 2009, the Obama administration tried to improve fuel efficiency, stimulate economic activity, and save jobs The “Cash for Clunkers” program paid Americans $3,500 to $4,500 to turn in old cars and buy new, efficient ones The $3 billion program subsidized the sale or lease of 678,000 vehicles averaging 24.9 mpg Replacing vehicles averaging 15.8 mpg 824 million gallons of gasoline will be saved Preventing 9 million tons of greenhouse gases Creating social benefits worth $278 million

65 Drilling in ANWR will not fill U.S. oil demand
A little conservation and efficiency will save far more oil than ANWR has ANWR holds oil equal to 1 year’s supply of oil at current rates of use

66 Personal choice and efficiency
Energy conservation can be accomplished in two ways Individuals can make conscious choices to reduce energy consumption and increase conservation Drive less, turn off lights, buy efficient machines Energy-consuming devices can be made more efficient Cars and power plants lose ⅔ of energy as waste heat

67 We already have the technology we need
The U.S. has become more efficient, but we can do better Cars: efficient engines, electric cars, hybrids, etc. Cogeneration = excess heat produced during electrical generation is used to heat buildings Or produce other types of power It can double the efficiency of a power plant

68 Efficiency in homes and consumer products
Improvements can reduce energy to heat and cool homes Appliances have been reengineered to increase efficiency Federal standards reduce electricity used Consumers need to vote with their wallets by buying energy-efficient products If all Americans bought energy-efficient appliances, U.S. energy expenditures would be reduced by $200 billion

69 We need conservation and renewable energy
Conservation could save 6 million barrels of oil a day Conserving energy is better than finding a new reserve It decreases environmental impacts while extending our access to fossil fuels Conservation does not add to our supply of fuel We still need energy from somewhere The only sustainable guarantee of a long-term supply of energy is from renewable energy sources

70 Conclusion Fossil fuels have helped build our complex industrialized societies We are now approaching a turning point in history Fossil fuel production will begin to decline We can encourage conservation and alternative energy sources Or we can wait until fossil fuels are depleted Renewable energy sources are becoming feasible and economical We can envision giving up on our reliance on fossil fuels

71 QUESTION: Review Which energy source is versatile and emits the least CO2? Coal Natural gas Petroleum None of the above Answer: b

72 QUESTION: Review Which of the following describes when heavy machinery removes huge amounts of earth to expose coal? Strip mining Subsurface mining Mountaintop removal Illegal mining Answer: a

73 QUESTION: Review Which of the following does NOT describe natural gas that has been formed biogenically? It was created in shallow water. It was created by bacteria. It is also called swamp gas. It was created deep underground. Answer: d

74 QUESTION: Review _____ contains the most oil in the world, while ______ consumes the most Mexico, Japan Kuwait, France Saudi Arabia, the United States. The United States, the United States. Answer: c

75 QUESTION: Review It is estimated that we have already depleted ___% of our global oil reserves. 25% 50% 75% 100% Answer: b

76 QUESTION: Review Which statement about peak oil is NOT correct?
The United States has reached peak oil. Production declines once reserves are 75% depleted. Discoveries of new fields peaked 30 years ago. We are using more oil than we are discovering. Answer: b

77 QUESTION: Review What is a major problem of oil shale and tar sands?
Mining for them destroys the land. They release greenhouse gases. Mining and using them releases pollution. All of these are major problems of these sources of energy. Answer: d

78 QUESTION: Weighing the Issues
How is your life affected as oil becomes more expensive? What will you do? I will start conserving gasoline by walking more or carpooling. I need my car, so I will just have to earn more money. It won’t affect me, because I already minimize my driving. It won’t affect me, because I have enough money to afford gasoline. Answer: any

79 QUESTION: Weighing the Issues
Should the government raise taxes on gasoline to reflect its true cost? Yes; that would make people conserve gasoline. Yes, but poor people would need subsidies to help them buy gasoline. No; I don’t want to pay more for gasoline. I don’t care; I have enough money to pay for expensive gasoline. Answer: any

80 QUESTION: Interpreting Graphs and Data
According to this graph, the contribution of oil from ANWR over the next 50 years will be: a) Extremely significant b) Extremely insignificant c) Very high d) Worth drilling for Answer: b

81 QUESTION: Interpreting Graphs and Data
According to this graph, what would you best conclude? Fuel efficiency can increase in the United States. U.S. efficiency goes only upward. Fuel efficiency is not possible in the United States. The United States does not need efficiency. Answer: a


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