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Chapter 14 - PowerPoint PPT Presentation

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Chapter 14

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  1. Chapter 14 Energy from Fossil Fuels

  2. Mountaintop removal mining • An economical way of reaching coal seams • It has devastated parts of West Virginia, Kentucky, Tennessee, and Virginia • 470 mountains have been affected • 1,500 miles of streams have been buried or degraded • Residents who refuse to move have been threatened • In 2002, the law prohibiting dumping of waste into stream valleys was changed to allow this “fill” to be dumped • Grassroots organizations face formidable politicians and industrialists who say this mining is necessary

  3. Oil spills and drills • With millions of gallons of oil in constant transit, it is inevitable that spills will occur • In 1989, the Exxon Valdez spilled 11 million gallons • In 2008, two ships collided, spilling 420,000 gallons • Drilling for oil in the Arctic National Wildlife Refuge (ANWR) is a political firefight • President Bush wanted to open it to drilling • At present, with a Democratic Congress and President, it will probably remain closed for the moment

  4. Caribou in ANWR

  5. Energy sources and uses • Advancing technological civilization has been tied to energy • In early times human muscle and livestock provided energy • Slaves, servants, minimally paid workers • Domestic animals were used in agriculture and transportation • Water, wind, and sun power also provided power • Inventors in the early 1700s designed machines • The steam engine provided power for ships, shovels, tractors, trains, sawmills, textile mills, etc.

  6. Energy sources and uses • Advancing technological civilization has been tied to energy • In early times human muscle and livestock provided energy • Slaves, servants, minimally paid workers • Domestic animals were used in agriculture and transportation • Water, wind, and sun power also provided power • Inventors in the early 1700s designed machines • The steam engine provided power for ships, shovels, tractors, trains, sawmills, textile mills, etc.

  7. Coal • Coal was substituted for fuel • Firewood for steam engines became scarce • It was used for steam engines, heating, cooking, and industrial processes • By 1920, coal provided 80% of all U.S. energy • Drawbacks of coal • Smoke and fumes polluted cities • It is hazardous to mine and dirty to handle • Steam engines are bulky and hard to operate

  8. Steam engine

  9. Oil • By the late 1800s oil provided an alternative to coal • Due to the internal combustion engine, drilling, and refinement of oil into fuels • Benefits of oil • It was more convenient and burned more cleanly • The internal combustion engine is much lighter than a steam engine • Oil is now the major energy source for the world • Coal still predominates in eastern Europe and China

  10. Global primary energy supply

  11. Gas, naturally • Natural gas: found in association with oil or drilling for oil • Natural gas consists mainly of methane, which produces carbon dioxide and water when burned • It burns more cleanly than coal or oil • Pipelines now allow it to be transported, instead of venting it to the atmosphere • It is used for heating, cooking, industry • It is clean, convenient, and inexpensive • Gas satisfies 24% (U.S.) and 21% (world) of energy demand

  12. Energy consumption: United States

  13. Electrical power production • Electrical power: the amount of work done by an electric current over a given time • Most energy we use comes from fossil fuels • Energy carrier: the electricity itself that transfers energy from a primary energy source (coal, water power) to the point of use • Electricity enables modern technological society • Computers, appliances, lights, the Internet • More than 33% of fossil fuel production is used to generate electricity in the U.S.

  14. Generators • Electric generators were invented in 1831 by Michael Faraday • An electric generator: a coil of wire that rotates in a magnetic field • Or a stationary wire within a rotating magnetic field • It converts mechanical energy into electrical energy • Energy is lost through resistance and heat • Energy is also lost through transmission through wires • Three units of primary energy make one unit of electricity • But electricity is so useful and indispensible

  15. Turbogenerators • Generating electricity requires a primary energy source • Coal, oil, nuclear, refuse, solar, geothermal energy • Which boils water to produce steam • Which drives a turbine (a sophisticated paddle wheel) • Which is coupled to a generator • Turbogenerator: the turbine and generator • Other generators = gas-, water-, and wind-driven turbines • Burning gas drives the turbine directly • A hydroturbogenerator uses water from a dam or pipe

  16. Electrical power generation

  17. Fluctuations in demand • Most utility companies are linked into pools • They balance electricity supply and demand • Regardless of daily or seasonal fluctuations • Pools must accommodate daily and weekly demand • Generating capacity is measured in megawatts (MW) • 1 MW is enough electricity to power 800 homes • The demand cycle: shows the typical pattern of U.S. electrical demand • The baseload: the constant supply of power provided by large coal-burning and nuclear power plants

  18. The electrical demand cycle • As demand increases above the baseload, the utility draws on power plants (intermediate and peak-load power sources) that can be turned on and off • These power sources are gas, diesel, and hydroelectric plants • Brownouts: result from a deficiency in available power • Cause a reduction in voltage • Blackout: a total loss of power • These events may occur during peak demand

  19. Weekly electrical demand cycle

  20. Clean energy? • Electric power is clean and nonpolluting only at the point of use • Electricity is an expensive way to heat homes • It is generated mainly from fossil fuels and nuclear energy • Coal-burning plants: the major source of U.S. electricity • Implicated in acid deposition and climate change • Nuclear energy is distrusted • Potential for accidents, disposal of waste, and mining of uranium ore

  21. Transferring pollution • Energy from fossil fuels transfers pollution • Only renewable sources are nonpolluting • Producing electricity from fossil fuels is 30–35% efficient • Energy is lost in several ways • Heat energy goes up the firebox and out the chimney • Heat energy remains in the spent steam • Transmission of electricity through wires • Conversion losses: an unavoidable loss of energy • A consequence of keeping high temperature differences between incoming steam and the receiving turbine

  22. Dealing with heat energy • Heat energy cannot be recycled in the turbine • A condenser turns steam into water • Cooling towers are on coal-burning and nuclear plants • An alternative to cooling towers? • Waste heat is transferred into water from a river, lake, or ocean • Kills planktonic organisms and impacts the ecosystem • Thermal pollution: waste heat discharged into natural water

  23. Cooling towers

  24. Matching sources to uses • We must consider more than the energy source to determine current and future energy supplies • Some forms of energy do well in some uses but not others • Transportation (cars, trucks, tractors, planes, trains) depends on liquid oil • Nuclear and coal will not reduce the demand for oil • Energy use is divided into transportation, industrial processes, commercial and residential use (heating, cooling, lighting, appliances), and electrical power

  25. Energy flow • Transportation: 29% of U.S. energy use • Depends on petroleum • Nuclear, coal, water power are used to produce electricity • Natural gas and oil are more versatile sources • Too much consumed energy goes to waste heat • Some waste is inevitable (Second Law of Thermodynamics) • But efficiency can be doubled for cars, appliances, etc. • Saving energy is equivalent to increasing energy supplies • Conservation, efficiency, and management decrease use

  26. Pathways: energy sources to uses in the U.S.

  27. Exploiting crude oil • U.S. coal, natural gas, or nuclear power supplies are adequate • But we must import 66% of our crude oil • Increasing dependence on imported oil causes trade imbalances, military actions, economic disruptions, coastal oil spills • Fossil fuels (crude oil, coal, natural gas) were formed 100–500 million years ago in swamps and shallow seas • Anaerobic conditions slowed decomposition • Pressure and heat converted vegetation to fossil fuels • It takes 1,000 years to obtain 1 day’s worth of fossil fuel use

  28. Energy flow through fossil fuels

  29. Estimates of oil reserves • Proven reserves depend on economics of extraction • Reserves may be higher or lower depending on the price of oil • Higher oil prices justify exploiting more expensive reserves • Law of Supply and Demand • Demand and supply depend on price

  30. Recovery • Production from a field does not proceed at a steady rate • Oil is trapped in pore spaces of sedimentary rock • At first, pressurized oil may gush from a well • But only 25% of oil can be removed using conventional pumping (primary recovery) • Secondary recovery can remove up to 50% of oil • By injecting steam or brine into the wells • Enhanced recovery injects carbon dioxide to break up oil • Allows even more oil to be obtained

  31. Economics determines exploitation • The price of a barrel of oil determines the extent to which reserves are exploited • At $10/barrel (late 1960s) only 25–35% of oil was extracted • Higher prices (1970s, 1980s) justified reopening old fields in Texas and Louisiana • In 2008, oil peaked at $145/barrel but declined sharply • Demand dropped due to the global economic crisis • Low prices are good for consumers • But bad for companies, because they need stable markets

  32. Declining U.S. reserves • Up to 1970, the U.S. was oil independent • In 1970, production decreased but consumption increased • The Hubbert peak: M. King Hubbert proposed that oil production followed a bell-shaped curve • It would peak between 1965 and 1970 • Half of available oil would have been withdrawn • Production would then decline • The U.S., Europe, and Japan increased imports from the Middle East • Cheap, available oil seemed to present few problems

  33. Oil production and consumption in the U.S.

  34. The oil crisis of the 1970s • The U.S. and other industrialized countries increased their dependence on imported oil • The Organization of Petroleum Exporting Countries (OPEC) • Mostly Arab countries • Restrained production and initiated an embargo to increase prices • Resulted in shortages, panic, and long lines at gas stations • The U.S. willingly paid four times the previous price • Devastating results: inflation, unemployment, and recessions • We buy more from others than we sell as exports

  35. Adjusting to higher prices • In response to higher prices, the U.S. and other nations • Increased domestic production, e.g., the Alaskan pipeline, re-opening old fields • Increased fuel efficiency standards, e.g., lowered speed limits (to 55 mph) • Promoted appliance and building efficiencies • Developed alternative energy sources • Created a strategic oil reserve in Louisiana to store 702 million barrels of oil (33 days of oil at 21 million barrels/day use)

  36. Recovery • 1980s: consumption declined and production increased • Discoveries in Mexico, Africa, and the North Sea reduced OPEC’s influence • More production than consumption caused an oil glut • Prices crashed • Lower prices undercut efficiency and alternate energies • Exploration declined and older fields were closed • Conservation efforts and incentives were stopped • Tax incentives and subsidies for alternate energy were stopped

  37. U.S. imports are up and rising • U.S. oil production is down • U.S. oil consumption is up • More cars are driven more miles each year • Large, fuel-inefficient cars are driven (e.g., SUVs) • U.S. dependence on foreign oil has increased • We import 66% of our oil • Imports are still increasing

  38. U.S. oil consumption, production and imports

  39. The consequences of U.S. dependency • U.S. dependency on foreign oil has three costs: • Costs of buying oil • Risk of supply disruptions (e.g., political instability in the Middle East) • Ultimate resource limitations • In 2000, the U.S. paid $300 billion in oil imports • Since 2000, imports increased 24% and oil’s price rose fivefold

  40. Persian Gulf oil • First oil crisis (1973): the unexpected Arab boycott • The U.S. keeps a military capability in the region • Recognizes the political instability • Ensures access to Persian Gulf oil • Saddam Hussein of Iraq invaded Kuwait (1990) • U.S.-led Persian Gulf War threw Hussein out • The U.S.’s ongoing presence angered radical Islamic Al Qaeda • Led to the September 11, 2001 attack on the U.S.

  41. Two more wars • In 2001, U.S. and British forces invaded Afghanistan • To capture bin Laden, destroy Al Qaeda training camps, and overthrow the ruling Taliban • The Afghan war was a consequence of U.S. presence • The war is still in progress • bin Laden still hasn’t been caught • In 2003, Britain and U.S. troops invaded Iraq • To overthrow Hussein and eliminate suspected weapons of mass destruction • Was the motivation to gain access to Iraq’s oil?