1
How important is coal as an energy source, and how is it used to generate electricity?
INFOGRAPHIC 18.1
True or False: Worldwide and in the United States, coal is used to produce more than half of all electricity.
FALSE
Which of the following is not true about coal?
It produces more air pollution than other fossil fuels.
It is difficult to ship.
Extraction is relatively inexpensive.
The United States has an abundant supply of it.
B
Coal can be used to generate electricity by:
sending a current though the pulverized coal.
melting the coal and sending its electrons across conductive wires.
pouring liquefied coal over a turbine, which triggers the release of electrons from copper wire.
burning the coal to make steam, which turns a generator that makes electricity.
D
2
What is coal, how is it formed, and what regions of the world have coal deposits that are accessible?
INFOGRAPHICS 18.2 AND 18.3
How long are coal reserves expected to last in West Virginia?
50 years
100 years
500 years
Forever
A
Which country has the largest coal reserves?
China
The United States
Canada
Russia
B
In your own words, describe the process of coal formation. Why is coal a finite resource?
Coal is formed when areas of plant material are buried and there is little oxygen for decomposition. Decomposition of the plant material proceeds slowly (on a geologic time scale), ultimately forming peat. That peat is subjected to geologic processes of pressure and high heat, forming coal. Initially, soft coal (lignite) is formed. If heat and pressure continue for thousands of years longer, harder types of coal (bituminous and anthracite) form. This process occurs on a geologic time scale—millions of years. This means no more coal will be produced on a time scale that is relevant to our use. Therefore, what coal currently exists is all we can depend on, making coal a finite resource.
3
What methods are used to mine coal, and what are the advantages and disadvantages of each?
INFOGRAPHICS 18.4 AND 18.5
Surface strip mining techniques are used when:
mines are located close to human settlements.
coal is located in thin seams in mountainous areas.
thick coal seams are close to the surface in relatively flat areas.
it is too dangerous to use explosive charges to access the coal.
C
Compare and contrast the two coal mining methods used in Appalachia: mountaintop removal and subsurface mining.
Both methods can be used to access coal in this region but subsurface mining is the older technique and it employs more workers than MTR. Subsurface mining is only useful for thick seams of coal whereas MTR is used when coal is present in many thinner seams. MTR is safer for the worker but not for the surrounding community; it does more damage to the area around the mine and leaves behind a very different ecosystem. Subsurface mining is more dangerous for workers but has less impact on the surrounding community and ecosystem. Both mining methods can lead to the production of acid mine drainage as water washes through mined areas picking up acidic compounds but this is more of a problem with subsurface mines, even mine shafts that are closed or no longer used.
4
What are the advantages and disadvantages of burning coal?
INFOGRAPHIC 18.6
True or False: If we paid the true costs of using fossil fuels like coal, the price of our electricity would likely go up.
TRUE
Emissions from a coal-fired power plant include all of the following except
oxygen.
carbon dioxide.
mercury.
arsenic.
A
An advantage of subsurface (underground) coal mining is that it:
employs more people than surface mining techniques and thus creates more jobs.
is safer for the miners than surface mining techniques.
is cheaper than surface mining techniques.
All of these are advantages.
A
What health problems are associated with coal burning?
Water pollution of toxic substances can contribute to a wide variety of health problems, depending on the toxin. Air pollution can directly impact the respiratory system. Overall health impacts from air and water pollution include birth defects and lung, heart and kidney disease. There is also the danger of being hit by falling rocks and debris.
5
What new technologies allow us to burn coal with fewer environmental and health problems? How can mining damage be repaired, and how effective is this restoration?
INFOGRAPHICS 18.7 AND 18.8
True or False: Mine reclamation projects at mountaintop removal sites focus on re-creating the mountain habitat and then reintroducing native plants and animals.
FALSE
Which of the following is an example of reclamation?
Reworking coal mines to extract more coal
Replanting the site of mountaintop removal with grass and pine trees
Returning land to the people who originally owned it
Filling in a subsurface mine
B
Define and describe the process of carbon capture and sequestration. Why is this process necessary? What are the costs and benefits of the process?
Carbon capture and sequestration is a process whereby industrial facilities that normally release CO2 into the atmosphere prevent its release and instead capture and store it. In one model, as the waste gas is expelled it travels through a solvent that binds to CO2. The solvent and CO2 are separated and some of the CO2 can be used by industry to carbonate beverages, etc. The remaining CO2 is piped deep underground into old oil wells, unmineable coal seams, or deep salt formations. The process is necessary because CO2 is a primary greenhouse gas. The increased use of coal and other fossil fuels by humans has resulted in too much CO2 in the atmosphere, leading to increases in planetary temperatures. Therefore, we are trying to limit our impact by reducing the amount of CO2 we contribute to the atmosphere. The benefit is that less CO2 is added to the atmosphere. The cost is in the extra energy required for the process—estimates range from 25-40% more energy (and thus more coal) to power the process.
359