The U.S. Environmental Protection Agency (EPA) has announced a proposal to tighten limits on nitrogen oxides (NOx) emissions from new, modified, and reconstructed fossil fuel-fired stationary combustion turbines. The goal is to reduce air pollution exposure for nearby communities. This initiative aims to ensure that new turbines at power plants or industrial facilities are efficient and low-emitting.
EPA Assistant Administrator for Air and Radiation Joseph Goffman stated, “This proposal ensures that new turbines at power plants or industrial facilities will minimize emissions of harmful, smog-forming nitrogen oxides.” He added that these stronger standards are necessary for better protection of community health.
NOx emissions contribute to several health issues such as asthma and respiratory infections. They also react with volatile organic compounds to form ozone and fine particulate matter. Children, the elderly, and individuals with chronic diseases are most vulnerable.
The proposed New Source Performance Standards (NSPS) focus on combustion controls and selective catalytic reduction (SCR), a common technology used to limit NOx emissions. The EPA plans to maintain current sulfur dioxide limits due to effective control measures already in place. These updated NOx standards will apply to facilities starting construction or modification after the publication date in the Federal Register.
According to EPA estimates, this rule could reduce NOx emissions by 198 tons in 2027 and 2,659 tons by 2032. The net benefits could reach up to $340 million, translating into an annual value of $46.4 million.
To enhance NOx performance standards for new stationary combustion turbines, the EPA proposes identifying combustion controls combined with post-combustion SCR as the best system of emission reduction (BSER). Additionally, more protective standards are suggested for sources using hydrogen fuel alongside natural gas or non-natural gas fuels.
Environmental justice concerns were considered during the proposal's development. The anticipated changes should lessen emission impacts on affected communities through advanced control technologies.
Size-based subcategories have been introduced based on base load heat input: large (>850 MMBtu/h), medium (>250 ≤850 MMBtu/h), and small (≤250 MMBtu/h) combustion turbines. Further classification considers operating loads—high (>40% capacity factor), intermediate (>20% ≤40%), or low (≤20%).
For smaller sizes and variable operations where SCR technology may not be cost-effective per ton basis, standards will rely on combustion controls without SCR technology.
Public comments are open for 90 days following publication in the Federal Register under Docket ID No. EPA-HQ-OAR-2024-0419 via www.regulations.govExit EPA’s website.
