The Big Picture

Fossil fuels (coal, oil, and natural gas) are highly concentrated forms of partially decomposed organisms that have been trapped in the Earth's lithosphere. They represent the storage of carbon compounds from the primary production and food webs that existed during the last 300 million years. These fuels now compose 90 % of our energy sources worldwide. We have rapidly used these resources in the past 100 years and we will have used them all, if we keep consuming them at current rates, in just 500 years. This may seem like a long period of time to an individual human, but this is an instant in geological time. Thus, in a relatively short period of time, we have released a great deal of carbon (CO₂) into the atmosphere that had been accumulating in the rocks for a long period of time. This rapid release of CO₂ has very serious implications for the human race and the climate (See Chapter 21 - The Atmosphere, Climate, and Global Warming). The other reality is that these fossil fuels are essentially non-renewable. The rate at which they are being produced naturally is slow relative to the rate at which we use them. In the past, we have been fortunate to find undiscovered reserves at a rate equal to our rate of use, but we don't know how much longer that will occur. We are bound to exhaust economically exploitable reserves sooner or later; the amount of fossil fuels are finite. Eventually we need to discover alternative sources of energy. In this chapter, the authors discuss how fossil fuels were formed, how they are extracted, how large the reserves are for each fuel, and what environmental impacts occur during the extraction, transportation and use of fossil fuels.

Frequently Asked Questions

• The three main types of fossil fuels are coal, oil (or petroleum) and natural gas.
• Oil shale and tar sands are also fossil fuels.
• They are "fossil" fuels because they were formed a very long time ago (300 million years) by ancient organisms that died and have partially decomposed. They are fossils.

• Oil shale is a fine-grained sedimentary rock containing organic matter (kerogen).
• If heated to 500 ^oC, it will produce hydrocarbons (60 L/ton or 14 gal/ton)
• The production of petroleum from oil shale is called synfuel production.
• This practice is not currently economically feasible

• Tar sands are sedimentary rocks or sands impregnated with tar oil, asphalt, or bitumen.
• Tar sands can be mined and heated with water to remove the oil
• This practice is not currently economically feasible

• Oil & natural gas - These two fuels are often found together in rock formations, so they were most likely formed in a similar way. Marine organisms, mostly marine diatoms, were deposited in marine sediments. After they had been covered with 500 m or so of sediment and rock layers during the last 300 million years, intense temperature and pressure have produced deposits of oil and natural gas, trapped in porous layers of rock, but under non-porous layers (See Figure 16.2 in text).
• Coal - Terrestrial and wetland vegetation became buried in sedimentary rock about 300 million years ago during the Carboniferous period (See Figure 16.6 in text).

• Oil - There are about 1000 billion barrels of proven reserves
• Most (65 % by volume) of this oil is in the Mideastern nations (See Figure 16.3 in text).
• In 1972, there were only 350 billion barrels, so we have discovered about 650 billion barrels in excess of what we have used then.
• Natural Gas - 140 trillion m³ of proven reserves.
• Coal - 1000 billion metric tons of proven reserves, mostly distributed between the USA, Russia, and China. (See Figure 16.7 in text).

• This is a reserve that is known to exist now and is economically exploitable.
• There are also undiscovered reserves, which we suspect exist, but don't know for sure where they are.

• We assume that use will continue at current rates of consumption; the actual rate of use may be lower or higher, depending on how many people there are and what people choose to do.
• We may also find more of each fuel; this will change the time at which we run out of fuel (the error estimate associated with these estimates is probably large).
• "Running out" means that it will no longer be economically effective to extract any more of the fossil fuel resource. We will never really extract all the oil, for example, because the cost will exceed the benefit at some point, leaving behind a minute amount of oil.
• Oil - 42 years.
• Natural gas - 70 years (30 years in USA alone)
• Coal - 250 years

• The extraction of oil and natural gas is accomplished using similar methods.
• Of all the fossil fuels, natural gas is the preferred one to minimize environmental damage, because it burns cleanly into CO₂ and produces less CO₂ per unit of heat released than the others.
• The following is a list of environmental damages and changes that can occur:
• Land disruption - Oil and gas wells, storage tanks, and roads must all be constructed; this disturbs native ecological communities.
• Surface and ground water pollution - Broken pipes and ruptured storage tanks can contaminate water supplies. Water, steam or other chemicals are used to force out remaining oil after the well has stopped producing on its own; these can contaminate ground water. (Note: the oil and gas are found > 500 m deep, so that they are normally held in a different layer than ground waters used for drinking. Thus, contamination can happen when oil is drilled and the non-porous layer trapping the oil below is breached.) During refining process, or "fractional distillation" as it is called, groundwater contamination has been documented to occur (See Chapter 20 in text).
• Air pollution - CO₂ is released from all fossil fuels when they are burned. Oil and natural gas both produce less CO₂ per unit energy than coal. Hydrocarbons are released into the air during extraction and refining of oil, and burning it as a fuel in cars and trucks. These airborne hydrocarbon compounds form urban smog (see Chapter 22 in text).
• Land subsidence - As oil and gas are withdrawn, the land above the reserve sinks or subsides, because there is no longer anything occupying that space in the ground. This can cause property damage.
• Wildlife habitat may be disrupted. - For example, The Arctic National Wildlife Refuge is near oil reserves in Alaska; there is controversy over whether or not to allow drilling near this sensitive area. In marine systems, oil drilling can have the impact of creating more habitat structure in the open ocean, which can actually attract fish to the rigs. The fish populations may be affected by having higher fishing harvest rates than prior to the rigs.
• Drilling mud releases - Drilling "muds" or drilling fluids are used to lubricate the drill bit; they contain various mixtures of toxic (heavy metals) and non-toxic (barium) chemicals. These are often dumped over the side of the rig, contaminating the benthic environment around the rig.
• Aesthetic values are impaired - Oil rigs are considered unsightly by some people.
• Oil spills during transportation - Oil tankers spill oil into marine waters routinely. The pollution affects are short-term (10's of years), but the immediate impact on seabirds, marine fishes, invertebrates, and wildlife are devastating. Human communities suffer from lost tourism revenues and soiled beaches.

• There are four types of coal:
• Anthracite - High energy (30-34 J/kg), low sulfur
• Bituminous - Intermediate energy (23-34 J/kg) , high sulfur
• Sub-bituminous - Intermediate energy (16-23 J/kg), low sulfur
• Lignite - Low energy (13-16 J/kg), low sulfur
• Low sulfur coal creates less air pollution (sulfur dioxide from burning coal makes acid rain; see Chapter 22)

• Coal mining is very damaging to ecosystems where coal is located (See Figure 16.8).
• There are several negative environmental impacts of using coal for fuel:
• Strip mining - This is the most commonly used method to mine coal. It involves removing the rock overlying the coal deposit (this is called the overburden) and thus it severely disrupts the land. Reclamation of land after strip mining takes a long time and has been successfully avoided by many coal companies. Only half of the land damaged by strip mining has been reclaimed. Unclaimed areas are visible from satellite imagery of Eastern Pennsylvania.
• Mine fires - Coal is also mined by digging shafts down into the earth to extract the coal. Abandoned underground mines often catch fire. These mine fires continue to burn out of control in some areas, threatening life and property of the people above. They produce hazardous fumes.
• Land subsidence - Subsidence occurs when the ground above a mine tunnel collapses, causing a pit to form. These occur in Pennsylvania and West Virginia regularly. A parking lot and a crane fell in such a pit in Scranton, PA recently.
• Acid drainage from mines - When coal mines and spoil banks are created, surface and ground water drains from the mines and dumps, bringing sulfuric acid into nearby streams and rivers. The Lackawanna River and the Lehigh River in eastern Pennsylvania have been made barren of aquatic life by acid mine drainage, although they are now both recovering.
• Air pollution from burning coal for electricity - Coal burning releases 70 % of the total sulfur dioxides, 30 % of the nitrogen oxides, and 35 % of the CO₂ produced in the USA. It is thus a significant contributor to acid rain and global warming (see Chapters 21 and 22). Coal creates the most pollution of the fossil fuels.

• Gasoline for trucks and cars produces 25 % of the CO₂ released each year.
• Each gallon of gasoline burned creates 19 lbs of CO₂ to the atmosphere.
• An average car over its lifetime (100,000 at 27.5 mpg) emits 35 metric tons of CO₂.

• A free-market approach called allowance trading for air pollutants has recently been introduced by the Clear Air Act of 1990.
• The US EPA grants tradable allowances for polluting to utility companies that burn coal. One allowance unit is good for up to 1 ton of sulfur dioxide emissions per year. Pollution allowances can then be sold on a commodity market.
• If a utility company pollutes less than its allowance, it may sell the unused portion of the pollution allowance to another utility that pollutes more than its allowance. In this way the second company avoids a government fine.
• If a company invests in pollution control technology or changes its process to create less pollution, it may now profit from the reduction in pollution. There is a financial incentive for decreasing pollution.
• The overall level of pollution should not increase under such a scheme. It may even decrease, especially if environmental groups buy the pollution allowances first and remove them from the market.

• The suggestion has been made that if we increase the tax on fuels like gasoline by $1 per gallon, people will respond by using the fuels more conservatively (walk instead of drive, buy more fuel-efficient cars, etc.). This tax would lower air pollution and decrease CO₂ emissions from automobiles.
• The revenues raised from such an increase would help pay for improvements in mass transit and could even pay off our national debt.
• Presently taxes in the US on gasoline are low, about 30 cents/gallon; in European countries it is between $1 and $3 per gallon. Consequently, people in those countries drive much less than Americans.
• Some people are opposed to such an increase, because they believe that it would be unfair to people in western states who drive greater distances because of the sparse population. Westerners only spend 9 % more on fuel, however. These opponents also claim that poor people would be impacted, because they must drive and couldn't afford an increase. But poor people spend the same proportion of their income on transportation as rich people.
• This is a difficult social issue about which Americans are divided (in 1993 52 % favored a 15-cent increase, 46 % opposed it).

Ecology In Your Backyard

• Whenever you use electricity, most of that energy comes from a fossil-fuel electrical generation facility. Thus, by using electricity, we make CO2 and release it into the atmosphere. The Environmental Defense Fund (see Ecolinks section below for their webpage) estimates that each person in the USA creates 40,000 pounds of CO₂ per year. Use the following chart to list of all the activities you do each day that cause fossil fuels to be burned and total up the savings in CO₂ that you make by being more conservative with energy:

• Please respond to these questions or send your thoughtful examples and comments to:

BackYard@wiley.com

The best responses will be posted on the Wiley Environet Website, so check the page regularly for updates to see if your e-mail is posted!

Hardcopy Links In The Library

• Corcoran, E. 1992. Cleaning up coal. Scientific American, May 1992. Can coal be made cleaner? The technologies are being developed now to do this, but this clean coal will be more costly and still cause damage from strip mining.
• Fulkerson, W. R.R. Judkins, and M. K. Sanghvi. 1990. Energy from fossil fuels. Scientific American, September 1990.
• Home Energy Magazine, 2124 Kittredge Street, No. 95, Berkeley, CA, 94704-9942. (510) 524-5405. Home Energy Magazine is a source of information on reducing energy consumption.
• Holloway, M. 1991. Soiled shores. Scientific American, October 1991. A report on the Exxon Valdez spill and the clean-up.
• Hubbard, H. M. 1991. The real cost of energy. Scientific American, April 1991. This article is about the subsidies provided for energy producers by the U.S. government and how market forces need to be allowed to act upon energy prices.
• Lenssen, N. 1993. All the coal in China. World Watch, March/April 1993, pp. 22-29. If China begins to use coal at the rate that other industrial nations have in the past, global warming will get a lot worse. China has abundant coal resources and intends to use them as it industrializes.

Ecolinks On The Web

• http://www.fe.doe.gov/ - Fossil Energy. An electronic "gateway" to the Department of Energy's Office of Fossil Energy. There are links here about the Strategic Oil Reserve, which was a plan to stockpile oil in a big hole in the ground in case we needed it during wartime. There is an online survey of what you think should be done with the Strategic Oil Reserve.

• http://www.ornl.gov/fossil/ - Oak Ridge National Laboratory Fossil Energy Program. This research laboratory is attempting to find new ways to use fossil fuels while minimizing environmental pollution. For example, sulfur dioxide in coal can be removed before combusting, fed to bacteria and saleable elemental sulfur can be produced.

• http://www.edf.org/Want2Help/b_gw20steps.html - Environmental Defense Fund's 20 Simple steps to reduce global warming. This page gives the figures on carbon dioxide savings that can be achieved by some simple energy saving tips (see chart above in Ecology in your Backyard section). Since most electricity comes from coal-burning electric plants, using less electricity every day means less greenhouse gas emissions.

• http://www.dep.state.pa.us/dep/deputate/minres/BAMR/bamr.htm - Pennsylvania Department of Environmental Protection, Bureau of Abandoned Mine Reclamation Home Page. What are the environmental effects of mine fires, subsidence, and acid mine drainage? This web site describes Pennsylvania's abandoned coal mine problem and what's being done about it. So far, Pennsylvania has put only a small dent in it's $15 billion abandoned mine lands (AML) problem. With current funding levels from all sources, DEP estimates that it will take more than 50 years to eliminate just the high-priority AML hazards in Pennsylvania.

• http://www.dep.state.pa.us/dep/deputate/minres/centbrf.htm - Pennsylvania Department of Environmental Protection. This site gives a brief history of the Centralia, PA mine fire. The United States Office of Surface Mining (OSM) has acquired 545 properties that were in jeopardy sitting atop the longest-burning underground mine fire in the world (34 years). An OSM study estimated that $663 million would be required to extinguish the fire. A vital transportation link, Route 61, suffered severe subsidence damage from fire and today it is closed indefinitely. DER attempted to stabilize the roadway at a cost of approximately $0.5 million. U.S. Congress appropriated $42 million for voluntary acquisition and relocation of impacted businesses and residences due to dangers caused by fire (i.e. subsidence & noxious gases). 1993­Present. Fire continues to spread.

• Note: If any of these links are not working, please see if alternative links are available at the Ecolink Update Site.

Ecotest Online

1. Fossil fuels were made over 300 million years, but we could use them up in _________ years, if we keep on our current consumption rates.

a. 100

b. 50

c. 500

d. 1000

2. The type of fossil fuel that is the cleanest burning fuel is ___________________.

a. coal

b. oil

c. natural gas

d. tar sands

3. The size of the proven reserve for oil worldwide is _________________________.

a. 2000 barrels

b. 1000 billion barrels

c. 1 billion barrels

d. 350 billion barrels

4. Which fossil fuel can provide the world's energy needs for the longest time at current rates of consumption?

a. coal

b. natural gas

c. oil

d. shale oil

5. Which of these activities causes ground water pollution?

a. oil drilling

b. oil refining

c. oil recovery using steam or water

d. all of these are correct

6. In terms of energy content, which of the following rankings of coal types is correct?

a. bituminous > sub-bituminous > anthracite > lignite

b. bituminous > sub-bituminous > lignite > anthracite

c. anthracite > bituminous > sub-bituminous > lignite

d. lignite > anthracite > bituminous > sub-bituminous

7. Which of these environmental effects of coal mining is so extensive that one can see it from remotely sensed satellite images?

a. Mine fires

b. Acid mine drainage

c. land subsidence

d. land disruption from strip mining

8. Each gallon of gasoline burned produces ____________ pounds of CO_2.

a. 100

b. 1000

c. 10

d. 19-20

9. Pollution trading allowances will:

a. prevent further increases in pollution emissions

b. cause decreases in pollution emissions automatically through free-market incentives

c. slow the rate of increase in pollution emissions

d. prevent further increases and may lead to declines if allowances are bought and retired from the market.

10. Prices of gasoline are $3-4 per gallon in European countries, due largely to taxes. What have the taxes done to fuel consumption rates in those countries?

a. caused a reduction

b. caused an increase

c. no change

d. Fuel consumption rates have fluctuated due to factors unrelated to price.

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