EPA proposes to revise the Cross-State Air Pollution Rule Update

by Paul Ciampoli
APPA News Director
October 23, 2020

The Environmental Protection Agency on Oct. 15 proposed the Revised Cross-State Air Pollution Rule (CSAPR) Update in order to fully address the outstanding interstate pollution transport obligations of 21 states for the 2008 ozone National Ambient Air Quality Standards (NAAQS).

Starting in the 2021 ozone season, the proposed rule would require additional emissions reductions of nitrogen oxides (NOx) from power plants in 12 states.

The action addresses the remand of the CSAPR Update by the U.S. Court of Appeals for the D.C. Circuit on September 13, 2019, in Wisconsin v. EPA. The court found that EPA failed to fully eliminate significant contribution to nonattainment and interference with maintenance of the 2008 ozone NAAQS from upwind states by downwind areas’ attainment dates.

EPA is proposing that for 9 of the 21 states for which the CSAPR Update was found to be only a partial remedy (Alabama, Arkansas, Iowa, Kansas, Mississippi, Missouri, Oklahoma, Texas, and Wisconsin), their projected NOx emissions in the 2021 ozone season and thereafter will not significantly contribute to a continuing downwind nonattainment and/or maintenance problem.

Therefore, the states’ CSAPR Update federal implementation plans or the state implementation plans subsequently approved to replace certain states’ CSAPR Update Federal Implementation Plans fully address their interstate ozone transport obligations for the 2008 ozone NAAQS.

For the remaining 12 states (Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, New Jersey, New York, Ohio, Pennsylvania, Virginia, and West Virginia), their projected 2021 emissions were found to contribute at or above a threshold of 1 percent of the NAAQS to the identified nonattainment and/or maintenance problems in downwind states.

EPA is proposing to issue new or amended federal implementation plans to revise state emission budgets that reflect additional emissions reductions from electric generating units beginning with the 2021 ozone season (May 1 – September 30).

The federal implementation plans would require power plants in the 12 linked states to participate in a new CSAPR NOx Ozone Season Group 3 Trading Program. The new program largely replicates the existing CSAPR NOx Ozone Season Group 2 Trading Program, with the main differences being the geography and budget stringency.

In addition, EPA is proposing to adjust these states’ emission budgets for each ozone season (2021-2024) thereafter until air quality projections demonstrate resolution of the downwind nonattainment and/or maintenance problems for the 2008 ozone NAAQS.

The emission budgets signify a control strategy that reflects the full optimization of existing selective catalytic reduction controls (SCRs), optimize idled SCRs and upgrades of low NOx burners for the 2022 ozone season, with an estimated marginal cost of $1,600 per ton. Based on EPA’s analysis the proposal is projected to result in a reduction of 17,000 tons of NOx during the summertime ozone season in 2021 and subsequent years.

EPA is proposing to authorize a one-time conversion of allowances banked from 2017 to 2020 under the CSAPR NOx Ozone Season Group 2 Trading Program into a limited number of allowances that can be used for compliance in the CSAPR NOx Ozone Season Group 3 Trading Program.

For non-electric generating units (EUGs) and emissions sources, EPA analyzed whether any emissions reductions should be required from non- EGUs to address significant contribution under the 2008 ozone NAAQS.

The agency’s analysis suggests that there are relatively fewer emissions reductions available at a cost threshold comparable to the cost threshold selected for EGUs.

Emission reductions from non- EGUs are estimated to have a relatively small effect on any downwind receptor in the year by which such controls could likely be installed. Therefore, EPA proposes that limits on ozone season NOx emissions from non-EGU sources are not required to eliminate “significant” contribution under the 2008 ozone NAAQS.

EPA is under a court order to finalize the proposal by March 15, 2021. There will a 45-day public comment period once the proposed rule is published in the Federal Register.

EPA plans to host a virtual public hearing in November 2020.