Energy in Brief
What is the role of coal in the United States?
Last Updated: January 19, 2016
The United States has the world's largest estimated recoverable reserves of coal, and it is a net exporter of coal. In 2014, U.S. coal mines produced about 1 billion short tons of coal, the first increase in annual coal output in three years. More than 90% of the coal produced in the United States was used by U.S. power plants to generate electricity. Although coal has been the largest source of electricity generation in the United States for more than 60 years, its annual share of total net generation declined from nearly 50% in 2007 to 39% in 2014.
Coal is an abundant U.S. resource
The United States is home to the largest estimated recoverable reserves of coal in the world. The country has enough estimated recoverable reserves of coal to last more than 200 years based on current production levels. Coal is produced in 25 states that are located in three major coal-producing regions.
In 2014, approximately 70% of U.S. coal production originated in five states:
- Wyoming (396 million short tons)
- West Virginia (112 million short tons)
- Kentucky (77 million short tons)
- Pennsylvania (62 million short tons)
- Illinois (58 million short tons)
Most U.S. coal is used to generate electricity
About 93% of the coal consumed in the United States is used for generating electricity. The United States has about 1,300 coal-fired electricity generating units in operation at almost 560 plants across the country. Together, these power plants consumed more than 851 million short tons of coal to generate about 39% of the electricity produced in the United States during 2014.
Although coal-fired generation still holds the largest share among all fuel sources used to generate electricity, its use has declined since 2007 because of a combination of slow growth in electricity demand, strong price competition from natural gas, increased use of renewable energy sources, and new environmental regulations that have added to the cost of using coal. See related article—Today in Energy, July 31, 2015.
Although the share of total net electricity generated from coal in the United States is expected to decrease by 2040, coal is still expected to remain an important fuel for generating electricity in the United States absent policies designed to reduce emissions of carbon dioxide and other greenhouse gases. However, the implementation of new policies to limit carbon dioxide emissions from power generation could change the outlook for the use of coal to generate electricity.
In addition to its role in generating electricity, coal also has industrial applications. Coal is used in cement production and coke conversion for the smelting of iron ore at blast furnaces used to make steel. A small amount of coal is also burned to heat commercial, military, and institutional facilities, and an even smaller amount of coal is used to heat homes.
The United States exports coal to other countries
Between 2000 and 2014, about 6.5% of the coal produced in the United States, on average each year, was exported to other countries. In 2014, the share of U.S. coal production exported was 9.7%, totaling 97.3 million short tons. However, the overall volume of coal exports in 2014 declined by about 17% from 117.7 million short tons in 2013.
Europe and Asia continue to be the top destinations for U.S. coal exports. Coal exports come in two forms:
- Metallurgical coal, which is usually used for steel production
- Steam coal, which is used for electricity generation and in industrial applications for the production of steam and direct heat
The United States exported more metallurgical coal than steam coal in 2014. Brazil (7.5 million short tons) was the largest importer of U.S. metallurgical coal, and the Netherlands (6.7 million short tons) was the largest importer of U.S. steam coal.
The United States also imports coal (about 11.3 million short tons in 2014) with most of that coal coming from Colombia. The operators of some coal-fired electric generating units along the U.S. Gulf and Atlantic coasts find it cheaper to import coal than to have domestic coal transported by rail or barge from coal-producing regions in the United States.
Coal is a relatively inexpensive fuel
Although some natural gas-fired power plants are more efficient at generating electricity than coal plants, in the past, the cost of fuel to generate one kilowatthour of electricity from natural gas had typically been higher than that of coal. However, coal began losing its price advantage over natural gas for electricity generation in some parts of the country in 2009, particularly in the eastern United States. Increasing natural gas production from U.S. shale basins helped reduce the price of natural gas, making it more competitive for use in generating electricity. See related article—Today in Energy, October 7, 2015.
Environmental effects of using coal
When coal is burned it produces several types of emissions that adversely affect the environment and human health. Coal emits sulfur dioxide, nitrogen oxide, heavy metals (such as mercury and arsenic), and acid gases (such as hydrogen chloride), which have been linked to acid rain, smog, and other environmental and health-related concerns. Coal also emits carbon dioxide, the greenhouse gas most responsible for climate change. In 2014, coal accounted for about one-third of the energy-related carbon dioxide emissions from the United States.
Outlook for future coal use
The economics of burning coal have changed now that the U.S. government has adopted regulations that restrict or otherwise control carbon dioxide (CO2) emissions, which require coal-fired power plant operators to either incur costs to retrofit power plants or to receive less revenue because of lower levels of operation.
In August 2015, the U.S. Environmental Protection Agency (EPA) approved the final rule of the Clean Power Plan (CPP). The CPP is intended to reduce CO2 emissions at existing coal-fired power plants 32% below 2005 levels by 2030. Retirements of coal-fired power plants are expected to increase in response to the implementation of the CPP.
In January 2014, the EPA issued a revised new source performance standard proposal for CO2 emissions that requires new coal-fired power plants to limit emissions to 1,100 pounds of CO2 per megawatthour. The proposed emission limit would effectively require new coal-fired electric generating units to use carbon capture and sequestration technologies to reduce emissions of CO2 by approximately 50%.
In March 2013, the EPA finalized the Mercury and Air Toxics Standards (MATS) to reduce emissions of mercury and other air toxics from new and existing coal- and oil-fired electric generating units. Power plants are responsible for more mercury emissions than any other man-made source. See related article—Today in Energy, March 28, 2014. The standards were challenged in court, but they were upheld by a federal appeals court in April 2014.
Separately, recent efforts to control nitrogen oxide (NOx) and sulfur dioxide (SO2) emissions from power plants could also have an effect on the use of coal in electricity generation. The EPA's Cross-State Air Pollution Rule (CSAPR), finalized in July 2011, seeks to reduce SO2 and NOx emissions from power plants in 28 states. The rule was challenged, but in April 2014, the U.S. Supreme Court upheld the CSAPR requirements.
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Did you know?
In 2014, Wyoming produced 396 million short tons of coal, or 40% of the coal mined in the United States. West Virginia was the second-largest producer with 112 million short tons, equal to 11% of U.S. coal output.
U.S. coal mines produce more coal than the nation consumes.
Coal is the largest source of U.S. electricity generation.
Did you know?
Different types of coal have different characteristics including sulfur content, mercury content, and heat content. Heat content, along with other factors such as carbon content and stickiness when heated, is used to group coal into four distinct categories, known as ranks: anthracite, bituminous, subbituminous, and lignite. Generally, these ranks are in decreasing order of heat content. There are far more bituminous coal mines in the United States than the other ranks, accounting for 90% of total mines.