Coal Questions and Answers

Q: What is coal, and how is it formed?

A: Coal is a natural dark brown-to-black solid used as a fuel formed from fossilized plants. Coal can be ignited and burned to produce energy in the form of heat. It consists of various organic and inorganic compounds. About 300 million years ago, much of the United States was swampland covered with giant ferns, reeds and other plants. When the plants died, they fell underwater. Underwater, the oxygen level prevented them from decaying completely, which resulted in the formation of peat. As the seas deposited layers of other materials over the peat through the centuries, the peat was tightly compacted and dried. The peat hardened in the final step of this natural process to become coal. Because coal is composed of once living material, it is known as a "fossil fuel" and is capable of being burned.

Q: What are the advantages of coal compared to other fossil fuels?

A: First, the price of coal has remained relatively stable in recent years in comparison to the costs of competing fuels. Second, present day technology permits the burning of coal in a much cleaner fashion than in the past. Third, and also very important, is the ready availability of coal: it represents more than four-fifths of America’s known recoverable fossil fuel reserves.

Q: Is there a shortage of coal?

A: No. Coal is present under 458,600 square miles of the United States, about 13 percent of the country’s land area. Coal is found in at least 38 states and mined in 27.

It is estimated that the United States has about 35 percent of the world’s potentially minable coal reserves, the largest of any nation. The Federal Energy Information Administration reports that the United States has close to 500 billion tons of demonstrated reserves (minable with current technology). According to the U.S. Geological Survey, the United States may have as much as four trillion tons of coal resources (total coal deposits, regardless of whether they can now be mined.)

Q: Are there any disadvantages to using Midwestern coal?

A: Although Midwestern coal can be mined safely, economically and with minimal effects to the environment, it does present one barrier - - its sulfur content. The burning of coal containing sulfur leads to the formation of sulfur dioxide, an air pollutant. Sulfur can be removed from smokestack emissions, but it is an expensive process. Illinois is a leader in developing clean coal technologies that allow high-sulfur coal to be used in an environmentally sound manner.

Q: How is the challenge of developing clean coal technologies being met?

A: Clean coal technologies (CCTs) are being researched and developed though Illinois’ Department of Commerce and Community Affairs and the Illinois Clean Coal Institute. These technologies are the keys in restoring Midwestern coal to its strong competitive position in large coal markets.

CCTs being researched and tested include micronized coal, coal/water slurry, fluidized bed combustion, limestone injection, gas reburning- sorbent injection and advanced flue gas desulfurization. A vigorous research and development effort is under way to tackle the sulfur problem. CCT projects remove sulfur before, during and after coal combustion.

Q: How is sulfur found in coal?

A: Sulfur in coal takes two distinct forms. The first is as an iron compound called "pyrite". The second is organic sulfur, which is chemically bound in the molecular structure of coal itself.

Q: How is sulfur removed from coal?

A: Pyritic sulfur is relatively easy to remove. Since pyrite particles are much heavier than coal itself, most pyrite is removed through washing before coal is shipped. Coal washing has contributed greatly to the reduction of sulfur content.

The remaining organic sulfur is a problem. Ordinary coal washing cannot remove it. Today, this sulfur is normally removed after combustion, using flue gas desulfurization devices called "scrubbers". Under the 1977 revisions to the Clean Air Act, all new coal fired units have to be equipped with emission control devices. Revisions in 1990 to the Clean Air Act require additional reductions to sulfur dioxide this year and the year 2000. Coal fired power plants targeted for compliance this year are located in Alabama, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Michigan, Minnesota, Mississippi, Missouri, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Tennessee, West Virginia and Wisconsin.

Q: What is a scrubber?

A: A scrubber is any of several forms of chemical/physical devices that remove sulfur compounds formed during coal combustion. The process involves spraying a limestone slurry into the gas stream before it is released into the environment. The slurry attaches to sulfur, and the newly formed compound is removed for disposal or sold as a recycled by-product.

Q: What are some other clean coal technologies?

A: The answer for many existing coal burning power plants and industrial boilers may be limestone injection. Limestone is introduced into the boiler, either at the point of combustion or immediately after. The limestone decomposes into the lime, which reacts with sulfur dioxide gas (SO2) to form calcium sulfate, a solid waste product that is easily collected and removed. SO2 can also be removed by injecting lime into the flue gas duct. A limestone and lime injection installation does not require the great amount of physical space that a scrubber does.

Another advanced technology is called circulating fluidized bed combustion (CFBC). CFBC is a process that removes sulfur from coal during combustion. In a fluidized bed boiler, crushed coal and limestone are suspended in the bottom of a boiler by an upward stream of hot air. As coal burns, sulfur gases from the coal combine with limestone to form a solid compound that is recovered with ash. CFBC units could be used for new power plant construction and can replace steam generation equipment at existing power plants.

Q: Are sulfur dioxide emissions increasing or decreasing?

A: Sulfur dioxide emissions have decreased. The U.S. Department of Energy has noted that during the last decade, such emissions from coal-fired power plants declined 19 percent while coal used by these facilities increased 23 percent. Emissions in Illinois have declined 35 percent.

Q: Are sulfur dioxide emissions really an environmental concern?

A: According to the National Acid Precipitation Assessment Program (NAPAP) -- a 10-year, $570 million federal effort to have 3,000 independent scientists investigate and assess the acid rain phenomenon -- there is no direct correlation between Midwestern power plants and acid rain.

Q: What is the difference between Midwestern coal and Western coal?

A: While Western coal has a lower sulfur content than Midwestern coal, it generally has a lower Btu rating, or heat-producing ability, than Midwestern coal.

Q: How does coal affect us as a nation?

A: Coal is a key ingredient to the United States’ economic momentum and preservation of national security. It is a resource of international importance, holding the potential to greatly improve the balance of trade. It is in the best interest of the United States for coal to be recognized as an important energy resource for the 1990s and the 21st century for two reasons: increased reliance on coal could lead to a decrease in the nations’ reliance on oil imports to supply a substantial percentage of the nation’s energy mix; and using more coal and less imported oil would benefit the national trade deficit, because foreign oil imports are attributable to a full third of the national trade deficit.

Q: Are there other competitors of Midwestern coal in the marketplace?

A: Yes. Nuclear energy constitutes the major alternative to coal in the future for the utility industry. This opinion prevails in spite of continuing controversy over safety and other issues in the development of nuclear power. In fact, no new plants have been brought on line in the last 10 years. Ongoing concerns with nuclear waste, the uncertainty of absolute safety controls and vivid reminders of past nuclear plant accidents at Three Mile Island and Chernobyl all have contributed to the slower than anticipated growth of the industry.