Evaluating Multi-pollutant Impacts of Sulfur Reduction Strategies in the United States: A Cost-Benefit Approach

Abstract

Electricity generation units (EGUs) emit a mix of health- and climate-relevant air emissions through coal combustion, with the potential to impact multiple emissions. Previous studies have focused on evaluating the cobenefits of climate policies on air quality, studies that consider how air pollution controls affect carbon emissions remain relatively sparse. To evaluate different emission reduction strategies’ impacts on multiple air pollutants and carbon dioxide (CO₂), here we apply a multi-pollutant analysis framework, focused on sulfur dioxide (SO₂) controls on coal-fired EGUs in the United States (U.S.). Eighty-nine EGUs without SO₂ controls in the contiguous U.S. as of 2020 are identified and investigated. Results show that add-on pollution controls like flue gas desulfurization (FGD) reduce SO₂ emissions from coal combustion, but increase emissions of nitrogen oxides (NOx), fine particulate matter (PM_2.5), volatile organic compounds (VOCs), and CO₂. A coal-to-natural gas transition reduces all pollutants except VOCs. A coal-to-renewable transition reduces all studied pollutants. We find that add-on SO₂ controls could generate a total annual net benefit of $13.4 billion nationwide when considering a multi-pollutant portfolio of emissions, as compared with $32.9 billion total annual net benefits from coal-to-natural gas transition and $40.5 billion from coal-to-renewable transition. Our results highlight the potential of implementing the multi-pollutant analysis framework to evaluate multi-pollutant emission reduction strategies.