In 2020, Americans used 447 million short tons (to distinguish from metric tons) of coal. That’s enough to fill 4 million railroad cars, which sounds like a lot. But it’s also the country’s lowest annual coal consumption since 1965, and even that barely hints at the historical territory coal may soon explore. A few more years at the downward pace of the past decade, and U.S. coal use will reach levels last seen in the 19th century.