US thermal coal exporters recorded more than $5 billion in overseas sales in 2023, shipping upwards of 32.5 million metric tons of the high-polluting power fuel, according to Reuters, citing data from ship-tracking firm Kpler. These coal export earnings were the second highest since 2017, trailing only behind 2022's $5.7 billion. This comes as US utility coal usage for electricity generation tumbles to the lowest in this century. Reuters points out diverging trends between sliding domestic coal use at power plants and a surge in coal exports.…