Response of Power Plant Emissions to Ambient Temperature in the Eastern United States

Past studies have established strong connections between meteorology and air quality, via chemistry, transport, and natural emissions. A less understood linkage between weather and air quality is the temperature-dependence of emissions from electricity generating units (EGUs), associated with high electricity demand to support building cooling on hot days. This study quantifies the relationship between ambient surface temperatures and EGU air emissions (CO₂, SO₂, and NO_X) using historical data. We find that EGUs in the Eastern U.S. region from 2007 to 2012 exhibited a 3.87% ± 0.41% increase in electricity generation per °C increase during summer months. This is associated with a 3.35%/°C ± 0.50%/°C increase in SO₂ emissions, a 3.60%/°C ± 0.49%/°C increase in NO_X emissions, and a 3.32%/°C ± 0.36%/°C increase in CO₂ emissions. Sensitivities vary by year and by pollutant, with SO₂ both the highest sensitivity (5.04% in 2012) and lowest sensitivity (2.19% in 2007) in terms of a regional average. Texas displays 2007-2012 sensitivities of 2.34%/°C ± 0.28%/°C for generation, 0.91%/°C ± 0.25%/°C for SO₂ emissions, 2.15%/°C ± 0.29%/°C for NO_X emissions, and 1.78%/°C ± 0.22%/°C for CO₂ emissions. These results suggest demand-side and supply side technological improvements and fuel choice could play an important role in cost-effective reduction of carbon emissions and air pollution.