Coal stockpiles are falling and will continue to fall, government says

Stockpiles of coal are at their lowest point in four years. Stockpiles of coal are at their lowest point in four years. Photo: Spencer Weiner / Los Angeles Times Photo: Spencer Weiner / Los Angeles Times Image 1 of / 1 Caption Close Coal stockpiles are falling and will continue to fall, government says 1 / 1 Back to Gallery

U.S. coal inventories are at their lowest point in four years, the result of electricity generators in Texas and elsewhere retiring their coal-fired power plants.

Stockpiles of coal in May totaled 128 million short tons, 21 percent less than they were a year ago and the lowest they'd been since 2014, according to the U.S. Department of Energy.

Coal inventories typically increase during the spring and fall when demand for power is relatively low and then dip during the summer and winter when demand is relatively high. But beginning in about 2016, stockpiles of coal have been dropping because power plants are closing their coal-fired units as natural gas has become a cheaper source of fuel.

About 10 percent of the nation's coal-fired capacity since 2014 has been retired, which represents nearly 31 gigawatts of power. Most of the closures were in the Midwest and South, including three coal-fired power plants in Texas owned by Vistra Energy that combined produced about 4,200 megawatts of power. One megawatt is enough to power about 200 Texas homes on a hot summer day.

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The Energy Department is expecting more coal-fired facilities to retire this year and next. Government forecasters predict power producers will retire 7.9 gigawatts of coal-fired capacity by the end of this year and another 4 gigawatts in 2019. One gigawatt is roughly equivalent to the power produced by 431 wind turbines.