The U.S. Environmental Protection Agency (EPA) on March 15 finalized revisions to the Cross-State Air Pollution Rule (CSAPR) Update to help areas affected by emissions emitted by power plants in other states meet the 2008 national ambient air quality standards (NAAQS) for ground-level ozone.
The rule responds to a September 2019 ruling by the U.S. Court of Appeals for the D.C. Circuit (Wisconsin v. EPA) by addressing the “significant contribution” of pollution from particular upwind states to downwind states under the authority provided in the Clean Air Act’s “good neighbor” section 110(a)(2)(D)(i)(I), in order to help downwind states meet and maintain compliance with the 2008 ozone standard.
The EPA proposed the Revised CSAPR Update in October 2020.
Power plants in 12 states
Starting this summer, power plants in 12 states will be required to cut emissions of nitrogen oxides (NOx) by installing, improving or upgrading pollution controls.
EPA estimates that the Revised CSAPR Update will reduce NOx emissions from power plants in 12 states in the eastern United States by 17,000 tons beginning in 2021 compared to projections without the rule.
Due to this rulemaking and other changes already underway in the power sector, ozone season NOx emissions in the 12 states will be nearly 25,000 tons lower in 2021 than in 2019, a reduction of 19 percent, the federal agency said.
The additional emissions reductions are based on both improving the performance or utilization of pollution controls already installed beginning in the 2021 ozone season and installation or upgrade of state-of-the-art NOx combustion controls beginning in the 2022 ozone season.
The EPA said that the reductions in NOx emissions will lead to significant improvements in air quality beginning in the 2021 ozone season, which starts in May.
During warm weather months, NOx emissions from power plants can react in the atmosphere to create ground-level ozone, or smog, the agency noted. These pollutants can travel great distances, often crossing state lines and making it difficult for other states to meet and maintain the air quality standards for ozone that EPA establishes to protect public health.
Projected 2021 emissions from power plants in Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, New Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia were found to contribute to NOx emission levels that would harm the ability of downwind states to meet or maintain the 2008 ozone NAAQS, according to EPA.
Details on final rule
In a fact sheet related to the final rule, EPA noted that the action fully resolves 21 states’ remaining “good neighbor” obligations under the 2008 ozone NAAQS.
For nine out of the 21 states for which the CSAPR Update was previously found to be only a partial remedy (Alabama, Arkansas, Iowa, Kansas, Mississippi, Missouri, Oklahoma, Texas, and Wisconsin), projected 2021 emissions do not significantly contribute to nonattainment or maintenance problems for the 2008 ozone NAAQS in downwind states.
Thus, no further emission reductions beyond those under the CSAPR Update are required for these states to address interstate air pollution under the 2008 ozone NAAQS, the EPA said.
For the 12 remaining states (Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, New Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia), projected 2021 emissions were found to contribute at or above a threshold of 1% of the NAAQS (0.75 ppb) to the identified nonattainment and/or maintenance problems in downwind states.
After further analysis of emission-reduction potential, cost-effectiveness of controls, and downwind air quality improvement, EPA determined additional emission reductions relative to the CSAPR Update were necessary from all 12 of these states.
Specifically, emission reductions are required at power plants in these 12 states based on optimization of existing, selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) controls beginning in the 2021 ozone season, and installation or upgrade of state-of-the-art NOX combustion controls beginning in the 2022 ozone season.
“EPA is issuing new or amended Federal Implementation Plans (FIPs) for 12 states that revise state emission budgets that reflect these additional emission reductions beginning with the 2021 ozone season,” the agency said.
EPA will also adjust these 12 states’ emission budgets for each ozone season thereafter to incentivize ongoing operation of identified emission controls until such time that air quality projections demonstrate resolution of these states’ linkages to downwind nonattainment and/or maintenance problems for the 2008 ozone NAAQS.
As such, EPA is adjusting emission budgets for each state for each ozone season for 2021 through 2024. Budgets from 2022 to 2024 are updated to account for known future unit retirements as well as construction of new units. Updates to the 2022-2024 budgets resulted in a 3- 4.5% increase from proposal to the final rule. After the 2024 ozone season, no further adjustments would be required for the purposes of this rule.
The new requirements for the 12 states to make further emission reductions will take effect 60 days after publication of the notice of final rulemaking in the Federal Register. This date is expected to fall before a July 20, 2021 attainment date for the 2008 ozone NAAQS.
“This will enable improvements in downwind ozone and associated public health benefits by the 2021 ozone season,” EPA said.
The final rule establishes a new Group 3 trading program starting May 1, 2021 (the first day of the 2021 ozone season), EPA said it is issuing supplemental allowances to ensure that the increased stringency reflected in the new emission budgets will not take effect before the rule’s effective date.
The amount of supplemental allowances issued for each state reflects the difference between the state’s budgets under the Group 2 trading program and the new Group 3 trading program for the portion of the 2021 ozone season between May 1 and the rule’s effective date.
“It is important to note that this action is taken only with respect to good neighbor obligations under the 2008 ozone NAAQS, not the more stringent 2015 ozone NAAQS,” EPA said. “Nonetheless, emission reductions and associated improvements in air quality achieved in this action are beneficial towards attaining the 2015 ozone NAAQS.”
In addition, EPA is including a “safety valve” to provide further compliance flexibility. The safety valve will allow Group 3 sources to access additional Group 3 allowances by converting banked Group 2 allowances that remain after creation of the initial bank.
Additional information is available here.