Share of coal power plants with air pollution controls in the U.S. 1995-2022, by type

The installation of state of the art air pollution controls at existing U.S. coal-fired power plants has increased significantly over the past three decades. As of 2022, roughly 82 percent of the existing U.S. coal fleet were retrofitted with flue gas desulfurization (FGD) controls. Also known as scrubbers, these technologies are used by power plants to reduce emissions of air pollutants such as nitrogen oxides (NOx) and Sulfur dioxide (SO₂). Meanwhile, 58 percent of coal plants had been retrofitted with selective catalytic reduction (SCR). Such technologies have helped significantly reduce NOx and SO₂ emissions from electric utilities. Nevertheless, there are still numerous operational coal power plants that remain uncontrolled.