ISBN-13: 9781493520763 / Angielski / Miękka / 2013 / 56 str.
ISBN-13: 9781493520763 / Angielski / Miękka / 2013 / 56 str.
Coal is a key domestic fuel source and an important contributor to the U.S. economy. Most coal produced in the United States is used to generate electricity. In 2011, 1,387 coal-fueled electricity generating units produced about 42 percent of the nation's electricity. After decades of growth, U.S. coal production and consumption have fallen, primarily due to declines in the use of coal to generate electricity.