Final answer:
In 2017, coal-burning power plants generated between 30-40% of the United States' electricity, reflecting a decrease in reliance on coal as an energy source compared to previous years.
Step-by-step explanation:
In 2017, coal-burning power plants produced 30-40% of the electricity in the United States. This figure is derived from sources that indicate a decrease from previous years, as coal's contribution to US energy has significantly decreased over time due to various factors including environmental issues and the increase in alternative energy sources. With 600 coal-burning electric plants in the US, these facilities were responsible for a substantial part of the country's CO2 emissions, contributing to 40% of U.S. emissions and approximately 10% of global emissions.
Furthermore, these coal plants also produced a considerable amount of other pollutants, accounting for 64% of sulfur dioxide emissions, 26% of nitrous oxide emissions, and 33% of mercury emissions within the same timeframe. While coal used to account for nearly half of the electricity produced, by 2017 this percentage had reduced to between one-third and two-fifths of the total power generated, reflecting a trend of decreasing reliance on coal as an energy source.