Please Note: All materials in these notes are the property of
Pearson Benjamin Cummings Publishing company and are taken from
Study Guide for Environment: The Science Behind the Stories. These notes are for classroom use only.
Chapter 17 - Nonrenewable Energy Sources
and their Environmental Impacts
Oil or Wilderness on Alaska's North Slope?
Few Americans have visited the land above the Arctic Circle, at the top of the North American continent, yet it
symbolizes a struggle between two values in our modern life.
For some U.S. citizens, Alaska's North Slope is the last place humans have left untouched, and simply knowing
that this wilderness still exists is of tremendous value.
For others, this land represents a source of petroleum, and it seems wrong to leave such an important resource
sitting unutilized in the ground.
Drilling advocates accuse preservationists of neglecting the country's economic interests, while wilderness
advocates argue that drilling will sacrifice the nation's natural heritage for a few people's private financial gain.
Alaska's North Slope is divided into three areas; the westernmost portion (called the National Petroleum ReserveAlaska) was set aside in 1923 by the U.S. government as an emergency reserve for petroleum, although
commercial oil development began in 1999.
The central part of the North Slope is opened to drilling and has been the site of widespread oil development and
extraction since 1968.
The oil is transported across Alaska by the 800-mile trans-Alaska pipeline south to the port of Valdez, where it is
loaded onto tankers for shipment to the lower 48 states.
The third region contains the Arctic National Wildlife Refuge (ANWR), an area the size of South Carolina
consisting of federal lands set aside in 1960 and 1980 to protect wildlife and preserve pristine ecosystems of
tundra, mountains, and seacoast.
This scenic region is home to dozens of species, and in most years, thou- sands of caribou spend the summer here,
giving birth to and raising their calves.
ANWR has been the focus of intense debate for decades, including between two native Alaskan groups in the
area; the Gwiich'in, who fear that oil industry activity will reduce caribou herds, and the Inupiat, who see oil
extraction as a source of economic development.
The U.S. Congress put most of the refuge off-limits to oil extraction but reserved for future decision making a
1.5-million-acrearea of coastal plain, called the 1002 Area.
The 1002 Area can be opened for development by a simple vote of both houses of Congress, and in 2003, the
House of Representatives voted to open the area for drilling but the Senate voted against it.
Beyond the debate, geologists have tried to determine how much oil lies underneath the refuge, while biologists
have tried to predict the impacts of oil drilling on Arctic ecosystems.
Sources of Energy
The debate over drilling in the ANWR pits the culturally new concept of wilderness preservation against the
desire to mine a resource that guides the world's economy.
Humans have long exploited energy sources
Since they discovered fire, humans have used wood and wood products for energy, and harnessed animals, wind,
and water as energy sources for mechanical work in fields, mills, and granaries.
As deforestation led to decreased wood supplies, the invention of the steam engine in 1765 used coal for a variety
of mechanical purposes as our economies industrialized.
In the 20th century, fossil fuels - highly combustible substances formed from the remains of animals and plants
from past geological ages- became the dominant source of power in industrialized countries, and then in
developing nations.
Of coal, oil, and natural gas, oil predominates today because it is easiest to bum, ship, and store.
A variety of renewable and nonrenewable energy sources are available today
The vast majority of our energy sources come ultimately from the sun in the form of solar power, wood, wind
power, hydroelectric power, and fossil fuels.
Energy sources like sunlight, geothermal, and tidal energy are considered renewable because their supplies will
not be depleted no matter how much we use.
In contrast, energy sources like oil, coal, gas, and nuclear power are considered nonrenewable, because at our
current rates of consumption 'we will use up Earth's accessible store of them in a "matter of decades to centuries.'
To replenish the amount of fossil fuels currently remaining in the world would take many millions of years.
Developed nations consume more energy than developing nations
Developed nations consume far more energy than developing countries; they devote major portions of their
energy budgets to running factories, and vast amounts of energy for transportation.
Developing nations devote a greater proportion of their energy use to home heating, and food growing.
Developing countries also use manual or animal energy sources, while equipment and technology in industrialized
nations use fossil fuels.
In the United States, fossil fuels make up 87% of the nation s energy needs; the majority of energy is supplied by
19.5 million barrels of oil per day.
Fossil Fuels
Use of the three main fossil fuels has been rising for years; natural gas is increasing fastest and has
nearly surpassed coal production.
Fossil fuels are indeed fuels created from "fossils"
Fossil fuels were formed from the tissues of organisms that lived millions of years ago.
The chemical energy in these organisms' tissues was concentrated as these tissues decomposed and their
hydrocarbon compounds were altered and compressed.
Most organisms that die do not end up as a coal, gas, or oil deposit, because they undergo aerobic decomposition,
in which bacteria and other organisms use oxygen to break plant and animal remains into simpler molecules that
are recycled through the ecosystem.
Fossil fuels are produced only when organic material is broken down in deep lakes, swamps, and shallow seas in
an anaerobic environment, one that has little or no oxygen.
Which fossil fuel was formed depends on the chemical composition of the starting material, the temperatures and
pressures to which the material was eventually subjected, the presence or absence of anaerobic decomposers, and
time.
Coal, organic matter that was compressed under very high pressure, forms when little decomposition takes place
because the material cannot be digested or appropriate decomposers are not present.
Natural gas (primarily methane, CH4) is produced as a by-product when bacteria decompose organic material
under anaerobic conditions.
Natural gas can also be created from the enormous pressure and temperature generated when organic matter
becomes buried.
Crude oil, or petroleum, is formed with the temperature and pressure created 1-2 miles below the surface.
Crude oil is a mixture of hundreds of different types of hydrocarbon molecules characterized by carbon chains of
different lengths; oil refineries separate the various chains to make products such as gasoline, tar, and asphalt.
Petroleum geologists infer the location and size of fossil-fuel deposits
Geologists searching for oil, gas, or coal map underground rock formations to understand geological history, and
thereby to predict where fossil- fuel deposits might lie.
Geologists use ground surveys, air surveys, drilling of rock cores, and/or seismic surveys followed by exploratory
well drilling to confirm the presence of suspected deposits.
By analyzing how sound waves behave when sent underground, geologists can infer the nature of subterranean
structures and draw these structures in cross-sectional seismic profiles.
By using such techniques, geologists from the U.S. Geological Survey (USGS) in 1998 estimated that the total
amount of oil underneath ANWR's 1002 Area averaged 20.7 billion barrels.
Because not all of the total amount of petroleum can be extracted, estimates are made of "technically recoverable"
amounts of fuels, and the USGS calculated that technically recoverable amounts of oil under the 1002 Area
averaged 7.7 billion barrels.
The amount of oil a company drills for is determined by the expense of extraction and the current price of oil,
which is termed "economically recoverable" reserves; at a price of $30 per barrel, between 3.0 and l0.4 billion
barrels would be economically worthwhile to recover, but at prices of less than $13 per barrel, none of the oil
would be worth extracting.
The amount of a given fossil fuel in a deposit that is technologically and economically feasible to remove under
current conditions is termed the "proven recoverable reserve" of that fuel.
Fossil-fuel reserves are unevenly distributed
Because fossil fuels are unequally distributed, some nations have substantial proven reserves of fossil fuels and
others have very few, and nations may be rich in one fuel but poor in another.
Nearly two-thirds of the world's proven reserves of crude oil are in the Middle East.
Russia contains more than twice as much natural gas as any other country, while the United States possesses the
most coal.
Oil
Worldwide use of oil, the world's most used fuel, over the past decade has grown over 1.1 % per year-slightly
slower than natural gas but much faster than coal.
The age of oil began in the mid-19th century
People have used solid (i.e., tar and asphalt) and liquid forms of oil for millennia. In the 1850s, miners
encountered oily rocks and sold the crude oil as a healing aid, unaware that crude oil is carcinogenic and
poisonous.
This rock oil was also used to light lamps and lubricate machinery, and the world's first oil well was drilled in
Titusville, Pennsylvania, in 1859.
We drill to extract oil
Geologists read the structure and history of subterranean rock to find likely repositories of oil for petroleum
companies, which invest millions of dollars in drilling at these sites.
Once geologists locate a potential oil field, the oil company drills small, exploratory wells; if oil is encountered,
extraction begins.
Because most oil deposits consist of small droplets adhering to the surfaces of holes in porous rocks, pressure is
required in order to extract the oil from porous rock.
Various sources of pressure already exist, including groundwater, trapped gas, or natural gas dissolved in the oil,
so that when the drill punctures the rock, the pressure is relieved, and oil can rise to the surface.
Once pressure is relieved, oil becomes more difficult to extract, and may need to be pumped out.
As much as two-thirds of the total deposit may remain in the ground after primary extraction, the initial drilling
and pumping of available oil. In secondary extraction, solvents, steam, or water are used to flush out additional
oil.
Even after secondary extraction, however, quite a bit of oil can remain be- cause we lack the technology to
remove every last drop of oil from a deposit.
Secondary extraction is more expensive than primary extraction and many U.S. deposits did not undergo
secondary extraction when they were first drilled because the price of oil was too low to make the procedure
economical, but when oil prices rise, deposits are reopened for secondary extraction.
Offshore drilling produces much of our oil
Over 25% of the crude oil and natural gas extracted in the United States comes from offshore sites. These sites are
estimated to contain about 15% of the nation's proven reserves for oil and natural gas and more than 50% of the
remaining undiscovered reserves of these fossil fuels.
Oil and petroleum products have many uses
Because crude oil is a complex mix of hydrocarbons, many types of oil products can be created by separating it
into its different components.
The first oil product was kerosene, used for lighting, heating, and cooking, but with the development of the
internal combustion engine the market for petroleum products grew.
Crude oil is refined into gasoline and diesel oil to fuel cars, trucks, buses, and ships; jet fuel for airplanes; fuel in
power plants; and for lubricants, plastics, pharmaceuticals, and fertilizers.
Because of its low perceived cost and ease of use, oil is almost the only fuel source for transportation, and other
means of powering automobiles, such as natural gas, electricity, and solar power, have been slow in developing.
Oil supply and prices affect the economies of nations
So many modern technologies and services depend on oil that nations, corporations, and institutions that control
the trade in oil have extraordinary power.
The price of oil can affect U.S. government policies and the energy-using habits of the nation.
In 1973, because of opposition to U.S. support of Israel, the predominantly Arab nations of the Organization of
Petroleum Exporting Countries (OPEC) stopped selling oil to the United States, creating panic among western oil
companies and investors and causing oil prices to skyrocket. In response, the U.S. government enacted policies to
reduce reliance on foreign oil, including searching for more domestic reserves, resuming drilling at other sites,
and importing oil from other nations.
The government also stored oil underground in salt caverns in Louisiana, called the Strategic Petroleum Reserve,
which contains over 600 million barrels of oil, a one-month supply at current rates of consumption.
Conservation in the United States has been a function of economic need
In 1973, conservation measures were also implemented, such as increased fuel efficiency of automobiles, a
reduced national speed limit of 55 miles per hour, and funding of research into non-oil-based energy sources such
as solar power.
Now that high costs and shortages no longer motivate policymakers, many of the conservation policies developed
after the 1973 oil crisis have been abandoned.
Government funding for research into alternative energy sources has decreased, speed limits have increased, and a
bill to raise the mandated aver age fuel efficiency of vehicles to 35 miles per gallon (mpg) recently failed in
Congress.
The average fuel efficiency of new vehicles has fallen from a high of 22.1 mpg in 1988 to 20.8 mpg in 2003,
which has increased U.S. oil consumption.
Critics of oil drilling in ANWR point out the waste in fuel-inefficient automobiles, and argue that a small amount
of conservation would save the nation far more oil than would ever be obtained from ANWR.
Oil consumption in the United States shows little sign of abating, and U.S. consumption has increased by 15.7%
over the past decade, slightly outpacing that in the rest of the world.
We may have already depleted half our oil reserves
In 1956, geologist M. King Hubbert announced that U.S. oil production would peak about 1970, a prediction
that proved to be accurate; U.S. production is now falling.
Experts estimate that, at current levels of exploitation, world supplies of crude oil will last about another 40 years;
supplies of natural gas are projected to last roughly 60 years, and coal could last 200-250 years.
Coal
Coal is the world's most abundant fossil fuel, resulting from the proliferation of swampy environments 300-400
million years ago, in which dead organic material was deposited.
The United States has one-quarter of the world's coal, and coal provides for one-quarter of the world's commercial
energy consumption.
Coal usage has a long history
People have been burning coal for thousands of years to cook food, heat homes, and make pottery.
The first commercial coal mines were established in Virginia in the 1700s, and coal was used to boil water that
produced the steam for powering engines used in manufacturing, harvesting, and powering trains and boats.
While people continued to use coal in their homes for heating and cooking, the steel and electricity industries
increased the demand for coal.
Coal is still popular in the United States because the country has such large reserves of it and it is relatively cheap.
However, the cheap market price of coal does not reflect the true costs of extracting and using coal, such as
impacts on human health and the environment.
Coal varies in its qualities
Scientists classify coal into four types; from the least energy rich to the most energy rich: lignite, sub-bituminous,
bituminous, and anthracite.
Organic material being broken down anaerobically, but that remains wet, near the surface, and not well
compressed, is called peat, which is widely used as a fuel.
As peat decomposes, it gets buried under sediments, and as pressure and heat increase, and time passes, water is
squeezed out of the material and the compounds are packed more tightly together, forming coal.
Lignite is the least compressed type of coal, and anthracite is the most compressed and contains the most energy.
Coal formed in the eastern United States contains lots of sulfur because it was formed in marine sediments that
contain sulfur, which, when burned, produces sulfate air pollution, leading to industrial chronic acid precipitation.
Scientists are seeking ways to clean coal of sulfur so that it can be used while minimizing harm to the
environment.
Coal is mined from the surface and from below ground
To reach subsurface deposits of coal, shafts are dug deep into the ground, and networks of tunnels are dug or
blasted out to follow coal seams.
In strip mining, huge amounts of earth are removed by heavy machinery to expose the coal deposits lying at or
near the surface, which is dug out directly.
In some cases, strip mining uses an environmentally destructive process called mountaintop removal, in which
entire mountaintops are lopped off, a common occurrence in parts of the Appalachian Mountains.
Natural Gas
Natural gas is the fastest growing fossil fuel in use today, and provides, like coal, one-quarter of global
commercial energy consumption.
Natural gas was long known, but has only recently been widely used in homes
Natural seepages of gas from underground deposits through cracks and passages are not uncommon, and some
were used to light streets and buildings in the United States in the 1800s.
During much of the 19th century, technology did not exist to pipe gas safely, so the early uses of gas were on
local scales to fuel gas-fired lamps along city streets.
When electric lights replaced gas lamps in the 1890s, gas companies found uses for their gas in heating and
cooking in order to stay in business.
Even with advances in technology and transportation, natural gas did not replace coal and oil in homes until after
World War II, but during the 1950s and 1960s, thousands of miles of underground pipelines were laid throughout
the United States.
Natural gas is formed in two ways
Biogenic gas, also called swamp gas, is created at shallow depths by anaerobic decomposition of organic matter
by bacteria.
Thermogenic gas occurs at deep depths due to geothermal heating, and can be formed directly (along with crude
oil) or it can be formed from crude oil that is heated.
Most gas extracted is thermogenic, and is often found above deposits of coal or crude oil.
Deposits of natural gas are most numerous in Russia and the United States, and these two nations lead the world
in both gas production and gas consumption.
Natural gas extraction becomes more challenging with time
To access some natural gas deposits, prospectors drill an opening to allow gas to flow to the surface, because
pressure drives the gas upward naturally.
Most fields require that gas be pumped to the surface by a horse head pump, which moves a rod in and out of a
shaft, creating pressure to pull both oil and natural gas to the surface.
As with oil and coal, many of the most easily accessible natural gas reserves have already been exhausted, so
natural gas extraction uses sophisticated techniques.
One "fracturing technique" pumps saltwater under high pressure into the rocks to crack them and extract gas, and
sand or small glass beads are inserted to hold the cracks open once the water is withdrawn.
Until natural gas became a saleable commodity due to its expanded use, much of the gas that rose to the surface
during oil drilling was burned off because capturing the gas and transporting it to markets was too expensive.
Natural gas is also produced in many landfills, because methane is a by- product of some bacterial decomposition.
Landfill owners can capture methane to sell as fuel, which decreases energy waste, makes money for owners, and
lowers the release of the pollutant into the atmosphere; this may reduce climate change because methane is a
greenhouse gas.
Environmental Impacts of Fossil-Fuel Use
Our heavy use of fossil fuels has boosted our material standard of living, but it has harmed the environment
and human health, causing many citizens and professionals to push for using renewable sources of energy that
exert less impact on natural systems.
Fossil-fuel emissions cause air pollution, drive climate change, and affect the carbon cycle
Carbon dioxide released from burning fossil fuels affects the global climate, so it is recognized as the greatest
unintended impact of fossil-fuel use on the environment.
When burned, the carbon in fossil fuels is taken from its underground reservoir (where it's been stored for
millennia) and released into the atmosphere, where it can change the atmospheric composition and the climate.
Any future reduction of carbon dioxide emissions will need to involve major changes in energy policies and/or
energy technologies among the world's nations.
Sulfur and nitrous oxides released from the combustion of fossil fuels can also harm human and environmental
health because they form acid rain and industrial smog.
Combustion of gasoline in vehicles releases ozone, which in the lower atmosphere is an eye and lung irritant, a
carcinogen, and a component of photochemical smog.
Gasoline combustion releases particles that irritate the nose, throat, and lungs.
Water pollution results from fossil-fuel use
Small spills and chronic nonpoint source pollution account for the vast majority of oil that reaches the oceans.
Oil from industries, homes, automobiles, gas stations, and businesses runs off from roadways and enters sewage
treatment facilities, to be discharged into streams and oceans.
Large, catastrophic oil spills can also have significant impacts on the marine environment that can last for
decades.
Crude oil's toxicity to most plants and animals frequently leads to high mortality among exposed organisms.
Coal mining affects the environment
Surface strip mining can destroy large areas of habitat and cause massive soil erosion and chemical runoff into
waterways of surrounding regions.
Although regulations in the United States require mining companies to restore strip-mined land, the impacts are
severe and long lasting, and most other nations exercise less oversight.
Mountaintop removal can have even greater impacts than conventional strip mining, because it is hard to prevent
rock and soil from sliding downhill, where large areas of habitat can be degraded or destroyed and creek beds
polluted and clogged.
Loosening of government restrictions in 2002 enabled mining companies to dump rock and soil into valleys and
rivers below, regardless of the con- sequences for ecosystems, wildlife, and local residents.
Coal and oil both can pose threats to human health
Coal mining, especially subsurface mining, threatens human health and is one of the world's most dangerous
occupations, because miners get trapped in shafts or tunnels that collapse or can be injured or killed by dynamite
blasts.
Constant inhalation of coal dust in the mines produces respiratory diseases, including black lung disease that can
shorten miners' lives. Certain hydrocarbons, such as benzene and toluene, in oil appear to be carcinogens, and
gases such as hydrogen sulfide can evaporate from crude oil and irritate the eyes and throat and cause
asphyxiation.
Crude oil contains lead and arsenic, and people working in drilling operations, gasoline manufacturing, and other
jobs can develop serious health problems, including cancer.
Leaks from oil operations contaminate soil and water supplies, posing dangers for the public and threatening
groundwater supplies.
Oil extraction can harm the environment
Although drilling activities have fairly minimal impact, much more than drilling is involved in the development of
an oil field.
Road networks and the extensive infrastructure that must be constructed can fragment habitats and be noisy and
disruptive enough to affect many forms of wildlife.
Each year during drilling or transport, billions of gallons of crude oil are accidentally released into the
environment.
Many oil reserves are located in arctic, desert, or semi-arid areas, where ecosystems are so fragile that even minor
changes can have long-lasting repercussions.
Whether oil operations have negatively impacted the Artic region's caribou is widely debated.
Supporters of oil drilling use the increase in the caribou herd to argue that oil development is actually good for
caribou. Other studies show that female caribou and their calves avoid all parts of the oil complex, including the
roads laid down to support it, sometimes detouring miles to do so, and the reproductive rate of these female
caribou is lower than that of those in undeveloped areas.
Most scientists anticipate negative environmental impacts of drilling in ANWR
Scientists have examined the effects of development on arctic vegetation, air quality, water quality, and wildlife to
predict possible ecological effects of drilling in the ANWR.
Scientists have examined the effects of road building, oil pad construction, worker presence, oil spills, accidental
fires, trash, melting permafrost, off-road vehicle trails, and dust from roads.
Many scientists anticipate damage to vegetation and wildlife if the ANWR is drilled, but oil company scientists
contend that drilling operations would have little impact on the environment.
Political, Social, and Economic Impacts of Fossil-Fuel Use
Although using fossil fuels has negative consequences, it is important to remember that their use has enabled
much of the world to achieve a higher material standard of living.
Nations can become overly dependent on foreign oil
Because so many nations' economies are tied to fossil fuels, those economies are tremendously vulnerable if oil
supplies were to become suddenly unavailable or extremely costly.
Seller nations can control the price of oil, forcing buyer nations to pay more and more as supplies dwindle.
Concern in the United States over foreign oil sources has repeatedly driven proposals to open the ANWR to
drilling, despite the fact that such drilling would do little to decrease the nation's dependence on foreign oil. With
the majority of world oil reserves in the politically unstable Middle East, many analysts argue that the U.S.
political stance with Iran, Iraq,
Kuwait, and Saudi Arabia has been driven more by a need for sources of oil than by goals such as peace or
justice.
To counter foreign oil dependence, the United States has diversified its sources of oil, and receives oil from
Venezuela, Mexico, and Nigeria.
People in regions with oil reserves mayor may not benefit from them
Many of the wealthiest corporations in the world are those that deal in oil or oil-related industries, and
development can payoff for people who live in oil-bearing areas.
Alaska has received billions of dollars in oil revenues, and state revenues associated with the oil industry are
placed into a fund that pays yearly dividends to all Alaska residents.
Development of the ANWR would add to this fund and create jobs; many of the Inupiat support oil drilling
because the income could be used to pay for health care, police and fire protection, and other services that are
currently scarce in their remote and impoverished region.
In most parts of the world where the oil industry has extracted oil, local residents have not seen great benefits, but
rather they have experienced disruption and harm to their way of life.
The money corporations pay to drill for oil has not trickled down to residents of the region from which the oil is
extracted.
Oil-rich developing countries have few environmental regulations, or existing regulations are not enforced.
Conversion to renewable energy lies in the future
Because of the limited supplies, health problems, and environmental dam- age caused by fossil fuels, the United
States and the world have different options for future energy use.
One option is to use every last drop of available fossil fuel, and develop other energy sources only when supplies
run out. A second option is to begin developing alternative energy sources now to reduce our reliance on fossil
fuels gradually. A third option is to end our usage of fossil fuels right away, use renewable sources, and institute
efficiency and conservation measures.
Nuclear Power
Nuclear power contributes significantly to the energy and electricity we consume and has expanded fifteen-fold
since 1970.
The United States is the leader in electricity production from nuclear power.
Nuclear power comes from uranium via a long process
The nuclear fuel cycle, which produces electricity, begins when the uranium is mined from underground deposits.
Uranium 235 constitutes less than 1 % of the total uranium, but is the source processed into enriched uranium
235.
Once processed into fuel rods, this uranium lasts several years, but then must be replaced with new uranium.
Some spent fuel is reprocessed, but much is disposed of as radioactive waste.
Fission releases energy we can harness
To harness the energy within atoms, it must be converted to thermal energy, which generates electricity.
Fusion, which forces the nuclei of lightweight elements together, has not yet been developed for power
generation.
Fission, which is splitting of the nuclei of uranium and plutonium, is used in power plants.
In a nuclear reactor, fission is controlled to release a constant output of energy.
To start the chain reaction, a moderator (such as water or graphite) slows the neutrons down, which allows fission
to proceed.
Control rods absorb excess neutrons that are released, and these rods can be moved to regulate and maintain the
reaction at a desired rate.
These reactions occur in the reactor core, where the energy from the reaction heats the moderator water, which
then heats other water, creating steam, which is used to turn a turbine that generates electricity.