Friday, June 3, 2011

The role of coal in the United States

Due to its relatively low cost and abundance, coal is used to generate about half of the electricity consumed in the United States. Coal is the largest domestically-produced source of energy. Coal use, however, results in higher amounts of carbon dioxide per unit of energy than the use of oil or natural gas.

Coal is an Abundant U.S. Resource with Multiple Uses

The United States is home to the largest recoverable reserves of coal in the world. In fact, we have enough coal to last more than 200 years, based on current consumption levels. Coal is produced in 25 States spread across three coal-producing regions, but approximately 72% of current production originates in just five States: Wyoming, West Virginia, Kentucky, Pennsylvania, and Montana.

About 93% of U.S. coal consumption is in the electric power sector, but coal also has certain industrial applications such as cement making and conversion to coke for the smelting of iron ore at blast furnaces to make steel. A small amount of coal is also burned to heat commercial, military, and institutional facilities, and an even smaller amount is used to heat homes.

Over the past 10 years, about 5% of the coal produced in the United States, on average, has been exported. The United States also imports a small amount of coal; some power plants along the Gulf Coast and the Atlantic Coast find it cheaper to import coal by sea from South America than to have it transported from domestic coal mines.

The United States has more than 1,400 coal-fired electricity generating units in operation at more than 600 plants across the country. Together, these power plants generate almost half of the electricity produced in the United States and consume about one billion short tons of coal per year.



The share of our electricity generated from coal is expected to decrease by 2035. However, our growing demand for electricity is expected to lead to an increase in the actual amount of coal used, in the absence of new policies to limit or reduce emissions of carbon dioxide and other greenhouse gases. Such new policies could significantly change the outlook for coal use.

Coal Is a Relatively Inexpensive Fuel

Although some natural gas plants are more efficient than coal plants at generating electricity, the fuel cost of generating one kilowatthour of electricity from natural gas generally is higher than that of coal. In addition, coal prices have historically been much less volatile than those of natural gas due, in large part, to the existence of long-term coal supply contracts.

Environmental Effects from Using Coal

Coal is plentiful and fairly cheap relative to the cost of other sources of electricity, but its use produces several types of emissions that adversely affect the environment. Coal emits sulfur dioxide, nitrogen oxide, and mercury, which have been linked to acid rain, smog, and health issues. Coal also emits carbon dioxide, a greenhouse gas that has been in the news because of its link to climate change. Coal accounted for 37% of the total U.S. emissions of carbon dioxide released into the Earth’s atmosphere in 2010. Without proper care, coal mining can have a negative impact on ecosystems and water quality, and alter landscapes and scenic views.






Outlook for Future Coal Use

The economics of burning coal may change if the U.S. Congress approves legislation that restricts or otherwise controls carbon dioxide emissions. For example, a cap-and-trade program to regulate carbon dioxide emissions would likely increase the cost of burning coal because of its carbon content, and thereby cause power companies to consider using less carbon-intensive generating technologies such as nuclear, renewables, and natural gas. Efforts are now underway to develop new technologies to burn coal without emitting as much carbon dioxide into the atmosphere.

Scientists are working on ways to lower the costs and improve the efficiency of various carbon capture and sequestration (CCS) technologies with a goal of capturing approximately 90% of the carbon dioxide from coal plants before it is emitted into the atmosphere and then storing it below the Earth's surface. CCS would theoretically address much of coal's carbon dioxide emissions but does face some substantial economic and technological hurdles.


Ref: http://www.eia.gov

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