Exploring the trend of stream sulfate concentrations as U.S. power plants shift from coal to shale gas
2021
Niu, Xianzeng | Wen, Tao | Brantley, Susan L.
Since the early 2000s, an increasing number of power plants in the U.S. have switched from burning coal to burning gas and thus have released less SO₂ emissions into the atmosphere. We investigated whether stream chemistry (i.e., SO₄²⁻) also benefits from this transition. Using publicly available data from Pennsylvania (PA), a U.S. state with heavy usage of coal as fuel, we found that the impact of SO₂ emissions on stream SO₄²⁻ can be observed as far as 63 km from power plants. We developed a novel model that incorporates an emission-control technology trend for coal-fired power plants to quantify potentially avoided SO₂ emissions and stream SO₄²⁻ as power plants switched from coal to gas. The results show that, if 30% of the electricity generated by coal in PA in 2017 had been replaced by that from natural gas, a total of 20.3 thousand tons of SO₂ emissions could have been avoided and stream SO₄²⁻ concentrations could have decreased as much as 10.4%. Extrapolating the model to other states in the U.S., we found that as much as 46.1 thousand tons of SO₂ emissions per state could have been avoided for a similar 30% coal-to-gas switch, with potential amelioration of water quality near power plants. The emission-control technology trend model provides a valuable tool for policy makers to assess the benefits of coal-to-gas shifts on water quality improvements as well as the effectiveness of emission control technologies.
显示更多 [+] 显示较少 [-]