Chapter 14 Energy from Fossil Fuels. Mountaintop removal mining An economical way of reaching coal seams It has devastated parts of West Virginia, Kentucky,

Chapter 14

Energy from Fossil Fuels

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

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

Caribou in ANWR

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.

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.

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

Steam engine

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

Global primary energy supply

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

Energy consumption: United States

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.

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

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

Electrical power generation

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

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

Weekly electrical demand cycle

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

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

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

Cooling towers

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

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

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

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

Energy flow through fossil fuels

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

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

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

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

Oil production and consumption in the U.S.

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

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)

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

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

U.S. oil consumption, production and imports

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

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.

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?