The primary factor driving the decline in coal use in the U.S. is the rise of natural gas production, which is more affordable and cleaner.

The rise of natural gas production has been the main driver behind the decline in coal use in the U.S. Over the past decade, the increased availability of natural gas, especially from shale formations, has made it a more affordable and cleaner alternative to coal for electricity generation. Natural gas plants emit less carbon dioxide and pollutants like sulfur dioxide and nitrogen oxides compared to coal plants. As a result, many coal-fired power plants have been replaced by natural gas plants, leading to a decrease in coal demand. This shift has also been influenced by environmental regulations and the growing focus on renewable energy.