Company: EAI
Filing Date: 2025-02-18
Form Type: 10-K
Source: 0000065984-25-000012
Chunk: 109

Company: ENTERGY ARKANSAS, LLC
Filing Date: 2025-02-18
Form: 10-K
Item: Item 1A
Chunk 109
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 in which the Utility operating companies operate, regulatory agency air monitor data from 2021-2023 for Pulaski County and Union County, Arkansas, West Baton Rouge Parish, Louisiana, Harris County, Texas and Hinds County, Mississippi reflect annual average PM2.5 concentrations in excess of this new standard and monitors for several other areas reflect concentrations between 8-9 ug/m3.  Initial attainment and nonattainment designations will be based on data from 2022-2024.  Entergy will continue to work with state environmental agencies on appropriate methods for assessing attainment and nonattainment with this revised fine particulate NAAQS.

Hazardous Air Pollutants

The EPA released the final Mercury and Air Toxics Standard (MATS) rule in December 2011, which had a compliance date, with a widely granted one-year extension, of April 2016.  The required controls have been installed and are operational at all affected Entergy units.  In May 2024 the EPA issued a final rule revising portions of the MATS rule, including a reduction to the emission limit for filterable particulate matter.  The revised standard will become effective July 2027 and could require additional capital investment and/or additional other operation and maintenance costs at Entergy’s coal-fired generating units.  An additional one-year extension is possible for the installation of controls, if necessary.  Entergy is currently evaluating its coal units to determine whether additional controls are necessary to comply with this new lower limit.

Good Neighbor Plan/Cross-State Air Pollution Rule

In March 2005 the EPA finalized the Clean Air Interstate Rule (CAIR), which was intended to reduce SO2 and NOx emissions from electric generation plants in order to improve air quality in twenty-nine eastern states.  The rule required a combination of capital investment to install pollution control equipment and increased operating costs through the purchase of emission allowances.  Entergy began implementation in 2007, including installation of controls at several facilities and the development of an emission allowance procurement strategy.  Based on several court challenges, CAIR and its subsequent versions, now known as the Cross-State Air Pollution Rule (CSAPR), have been remanded to and modified by the EPA on multiple occasions.

In June 2023 the EPA published its final Federal Implementation Plan (FIP), known as the Good Neighbor Plan, to address interstate transport for the 2015 ozone NAAQS which would increase the stringency of the CSAPR program in all four of the