# EPA’s Affordable Clean Energy Rule and Related Issues: Frequently Asked Questions > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/crs%3AR46482 ## Record - **Collection:** Congressional research report - **Document type:** CRS Report - **Published:** August 13, 2020 - **Citation:** R46482 ## Text EPA’s Affordable Clean Energy Rule and Related Issues: Frequently Asked Questions August 13, 2020 Congressional Research Service https://crsreports.congress.gov R46482 SUMMARY EPA’s Affordable Clean Energy Rule and Related Issues: Frequently Asked Questions In 2019, the U.S. Environmental Protection Agency (EPA) completed its reconsideration of a Clean Air Act (CAA) rulemaking for greenhouse gas (GHG) emissions from existing fossil-fuelfired power plants. Specifically, the agency repealed the Clean Power Plan (CPP) and promulgated new guidelines for coal-fired power plants in the Affordable Clean Energy (ACE) rule. EPA based these actions on its conclusion that the CPP exceeded CAA authority by using measures that applied to the power sector as a whole rather than measures implemented at an individual facility. EPA also promulgated new general regulations to implement the ACE rule and any future emission guidelines issued under CAA Section 111(d). EPA promulgated the CPP in 2015 to limit GHG emissions—specifically, carbon dioxide (CO2)—from existing fossil-fuel-fired power plants. The CPP was the subject of ongoing litigation and never went into effect. In 2017, EPA reviewed the CPP in response to Executive Order (E.O.) 13783, which directed federal agencies to “review existing regulations and policies that potentially burden the development or use of domestically produced energy resources.” EPA’s review concluded that the CPP exceeded EPA’s statutory authority. The agency therefore proposed repeal of the CPP in 2017 and a rule to replace it in 2018. R46482 August 13, 2020 Kate C. Shouse, Coordinator Analyst in Environmental Policy Jonathan L. Ramseur Specialist in Environmental Policy Linda Tsang Legislative Attorney The structure and major provisions of the final ACE rule largely resemble those EPA proposed in August 2018. For example, the ACE rule defines the best system of emission reduction (BSER) for existing, coal-fired power plant CO2 emissions as “heat rate improvement” measures, also known as efficiency improvements. EPA stated that it lacked adequate information to establish a BSER for other types of existing fossil-fuel-fired units, particularly natural-gas-fired units. Similar to the proposal, the ACE rule does not establish a binding, numeric performance standard for CO 2 emissions from existing coalfired units. Rather, EPA identified six candidate technologies, which it characterized as the “most impactful” in the 2018 proposal, along with operating and maintenance practices that states must evaluate in establishing a standard of performance for each source in their state plans under CAA Section 111(d). Noting that many state and industry commenters requested a presumptive standard or additional clarity, EPA specified the level of emissions reductions achievable using the candidate technologies. States, however, must ultimately establish a rate-based standard and have the option to establish performance standards reflecting a heat rate improvement that falls outside of these ranges. EPA analyzed the ACE rule and the CPP repeal impacts separately, projecting emission changes under each rule in 2025, 2030, and 2035. The agency projected “modest” CO2 reductions (less than 1%) under the final ACE rule compared to a baseline, which excludes the CPP. In its separate CPP repeal analysis, EPA projected CO2 reductions ranging from zero to 3.5% under several CPP implementation scenarios compared to a baseline without the CPP. EPA considered these projections as well as power sector trends and concluded that “the most likely result” of implementing the CPP would be “no change in emissions.” Others have modeled different assumptions than EPA to assess the CPP repeal and reached different conclusions about projected emission changes. EPA also finalized revisions to the general implementing regulations under CAA Section 111. The revisions codify EPA’s current interpretation that states have “broad discretion” to establish and apply emission standards consistent with the BSER. Among other things, EPA lengthened the timeline specified in federal regulations for development and review of state plans. EPA did not finalize the proposed revision to the applicability test for certain power plants under New Source Review (NSR). The NSR program generally requires emission limits based on the best available control technology when new facilities are built or when an existing facility makes a change that increases emissions above specified thresholds. Historically, NSR applicability determinations have been contentious and extensively litigated. According to EPA, the NSR changes that were included in the ACE proposal would prevent NSR from discouraging the installation of energy-efficiency measures. EPA stated that it intends to take final action on the proposed NSR changes at a later date. Twenty-three states, the District of Columbia, and seven municipalities are challenging the CPP repeal and ACE rule in the U.S. Court of Appeals for the D.C. Circuit. A coalition of 21 states has intervened in the litigation in support of EPA. Various other public interest organizations, industry groups, and Members of Congress are also participating in the litigation. Congressional Research Service Contents Introduction ..................................................................................................................................... 1 Background ..................................................................................................................................... 2 Q: How much does the generation of electricity contribute to total U.S. GHG emissions? ........................................................................................................................ 2 Q: How much progress has the United States made in reducing GHG emissions and meeting emission targets? ......................................................................................... 5 Q: What are the Clean Air Act (CAA) Section 111 requirements? ..................................... 6 Q: How does the CAA Section 111 define standards of performance and best system of emission reduction? .......................................................................................... 7 Q: What is a “state plan”? ................................................................................................... 7 Q: What is the difference between a “state plan” and a “state implementation plan”? ............................................................................................................................... 8 Q: What was the Clean Power Plan (CPP)? ........................................................................ 9 Q: Did the CPP ever take effect? ........................................................................................ 9 Q: Did EPA promulgate GHG performance standards for new and modified power plants under the CAA? .......................................................................................... 9 Q: What is the status of GHG performance standards for new and modified power plants? ............................................................................................................................ 10 Q: Do the CPP repeal and ACE rules have implications for EPA’s other GHG rulemakings or the endangerment finding?..................................................................... 11 Repeal of the Clean Power Plan ..................................................................................................... 11 Q: Why did EPA repeal the CPP? ...................................................................................... 11 Q: How has EPA’s interpretation of Section 111 authority changed from its interpretation in the CPP? .............................................................................................. 12 Q: Has anyone challenged the CPP repeal in court? ......................................................... 13 Affordable Clean Energy (ACE) Final Rule ................................................................................. 13 Q: What is the ACE rule?.................................................................................................. 13 Q: Why did EPA promulgate the ACE rule? ..................................................................... 14 Q: To whom does the ACE rule directly apply? ............................................................... 14 Q: What types of facilities are affected by the final rule? ................................................. 14 Q: What is the BSER under the ACE rule? ....................................................................... 15 Q: What are the ACE rule’s performance standards for CO2 emissions? ......................... 15 Q: Why did EPA not establish a numeric or presumptively approvable CO2 performance standard in the ACE rule? ......................................................................... 16 Q: What are the candidate technologies under the ACE rule? .......................................... 17 Q: How will states establish CO2 emission performance standards? ................................ 19 Q: Can states establish CAA Section 111(d) performance standards less stringent than otherwise expected from implementing the BSER? .............................................. 19 Q: What are the next steps to implement the ACE rule and what is the timeline?............ 21 Q: When do existing coal-fired EGUs have to comply with performance standards established by states under the ACE rule? ..................................................... 22 Q: What information must a state include in the state plan submission for existing coal-fired units? ............................................................................................................. 22 Q: How does the ACE rule interact with existing GHG emission reduction programs in the states, such as the Regional Greenhouse Gas Initiative and California’s climate policies? ........................................................................................ 23 Congressional Research Service Q: Can states use emission reduction measures outside the “candidate technologies” list to establish the ACE rule’s performance standards? ......................... 24 Q. Why did EPA exclude natural gas co-firing from the BSER? ...................................... 25 Q: Why didn’t EPA establish a BSER for other fossil-fuel-fired units? ........................... 26 Litigation Challenging the CPP Repeal and the ACE Rule ........................................................... 28 Q: Who is challenging the CPP Repeal, the ACE rule, and the revised implementing regulations? ............................................................................................. 28 Q: Who are the respondents and intervenors in support of the rules?............................... 30 Q: What are the main legal issues in the litigation? .......................................................... 30 Q: What is the status of the litigation? .............................................................................. 35 EPA’s Updated Analysis of the CPP Repeal and the ACE Rule: Emission Impacts, Benefits, and Costs ..................................................................................................................... 35 Q: How did EPA estimate the emission impacts of the final rules repealing the CPP and promulgating the ACE rule?............................................................................ 35 Q: What CO2 emission effects did EPA estimate from the CPP repeal and from the ACE rulemakings? ................................................................................................... 37 Q: How do the CO2 emission projections in the final ACE rule compare with prior EPA CO2 emission projections? ............................................................................ 40 Q: What non-CO2 emission effects did EPA estimate from the CPP repeal and ACE rulemakings? ......................................................................................................... 42 Q: Would the ACE rule’s HRI lead to potential “rebound effects”? ................................. 44 Q: What are EPA’s estimated costs and benefits of the proposed repeal of the CPP? .............................................................................................................................. 47 Q: What are EPA’s estimated costs and benefits of the final ACE rule? .......................... 47 Q: How did EPA estimate the climate benefits? ............................................................... 48 Q: What are the implications of using the “interim SC-CO2” estimates to estimate climate benefits? ............................................................................................................ 49 Q: How did EPA estimate the human health co-benefits? ................................................ 50 Q: What are the implications of EPA’s approach to co-benefits in the ACE analysis?......................................................................................................................... 52 General Implementing Regulations for Section 111(d) ................................................................ 54 Q: What are the general implementing regulations for Section 111(d)? ........................... 54 Q: What changes did EPA make to the schedules for submission and review of state plans and federal plans?......................................................................................... 55 Q: Why did EPA establish new schedules for submission and review of state plans and federal plans? .......................................................................................................... 55 EPA Postpones Decision Regarding New Source Review (NSR) Changes .................................. 56 Q: What changes to New Source Review applicability did EPA propose in August 2018?.............................................................................................................................. 56 Q: Why did EPA propose changes to NSR applicability in the ACE proposal? ............... 57 Q: What is the status of the changes EPA proposed for NSR in the ACE proposal? ........ 57 Issues for Congressional Consideration ........................................................................................ 57 CAA Regulation of GHG Emissions ....................................................................................... 58 Federal and State Roles to Implement the ACE Rule ............................................................. 59 Role of Benefit-Cost Analysis in CAA Rulemakings ............................................................. 60 Congressional Research Service Figures Figure 1. GHG Emissions by Economic Sector .............................................................................. 3 Figure 2. Percentage of Total Electricity Generation by Energy Source ......................................... 4 Figure 3. U.S. GHG Emissions (Net) .............................................................................................. 6 Figure 4. States and Municipalities Participating in the ACE Rule and CPP Repeal Litigation .................................................................................................................................... 29 Figure 5. EPA Projections of CO2 Emissions in the Electric Power Sector .................................. 39 Figure 6. Comparison of EPA Reference Case Scenarios ............................................................. 41 Figure 7. EPA Estimates of CO2 Emissions Changes Under ACE Rule Policy Scenario Compared to the Reference Case (2030) .................................................................................... 45 Figure 8. EPA Estimates of SO2 Emissions Changes Under ACE Rule Policy Scenario Compared to the Reference Case (2030) .................................................................................... 46 Figure 9. EPA Estimates of NOx Emissions Changes Under ACE Rule Policy Scenario Compared to the Reference Case (2030) .................................................................................... 47 Tables Table 1. EPA Projections of CO2 Emissions in the Electric Power Sector .................................... 38 Table 2. EPA Projected Non-CO2 Emissions in the Electric Power Sector ................................... 42 Table 3. EPA Projected Changes in Non-CO2 Emissions in the Electric Power Sector ................ 43 Table 4. Timing Requirements ...................................................................................................... 55 Contacts Author Information........................................................................................................................ 62 Congressional Research Service Introduction In 2019, the U.S. Environmental Protection Agency (EPA) finalized its repeal of the Clean Power Plan (CPP) rulemaking and promulgated new emissions guidelines for existing coal-fired electric utility generating units (EGUs), more commonly referred to as power plants,1 in the Affordable Clean Energy (ACE) rule.2 These actions stem from a legal interpretation of Section 111 of the Clean Air Act (CAA). EPA also finalized new general regulations to implement the ACE rule and any future emission guidelines issued under CAA Section 111(d). EPA promulgated the CPP in 2015 to limit greenhouse gas (GHG) emissions—specifically, carbon dioxide (CO2)3—resulting from the combustion of fossil fuels at existing fossil-fuel-fired EGUs. CO2 emissions account for about 82% of U.S. GHG emissions and over 98% of the GHG emissions in the electric power sector.4 The CPP was litigated and never went into effect due to a stay issued by the Supreme Court in February 2016. Challenges to the CPP centered on the rule’s legal justification and EPA’s methodology to establish national CO2 emission performance rates. In 2017, EPA reviewed the CPP under Executive Order (E.O.) 13783, which directed federal agencies to “review existing regulations and policies that potentially burden the development or use of domestically produced energy resources.”5 EPA’s review concluded that the CPP exceeded EPA’s statutory authority by using measures that applied to the power sector as a whole rather than measures carried out within an individual facility. The agency therefore proposed repeal of the CPP in 2017. In 2018, the EPA proposed three actions in the ACE rule.6 First, EPA proposed to replace the CPP with new emission guidelines for existing coal-fired EGUs. Second, EPA proposed revised regulations to implement emission guidelines under CAA Section 111(d). Third, EPA proposed to modify an applicability determination for New Source Review (NSR), a CAA preconstruction permitting program for new and modified stationary sources.7 Debate surrounding CO2 performance standards and EPA’s interpretation of its CAA authority continues with the repeal of the CPP and issuance of the ACE rule. Stakeholders have expressed divergent views regarding EPA’s interpretation of its CAA authority and its best system of emission reduction (BSER) determination under Section 111(d). Twenty-three states, the District of Columbia, seven municipalities, and various stakeholders are challenging the CPP repeal and 1 The term power plant is a general term referring to a facility that has at least one electric utility generating unit to generate electricity. This report uses the terms power plant and electric utility generating unit (EGU) interchangeably. 2 EPA, “Repeal of the Clean Power Plan; Emission Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units; Revisions to Emission Guidelines Implementing Regulations,” 84 Federal Register 32534, July 8, 2019 (hereinafter “ACE Final Rule”). 3 Under the CAA, the pollutants regulated in the CPP and the ACE rule are GHGs with standards expressed in the form of CO2 limits. See 40 C.F.R. §60.5705a (for the ACE rule); 40 C.F.R. §60.5705(a) (for the repealed CPP). 4 EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2017, April 2019. 5 Executive Order 13783, 82 Federal Register 16093 §7 (March 31, 2017). For more information on this executive order, see CRS Legal Sidebar WSLG1789, New Executive Order Directs Agencies to Revise or Rescind Climate Change Rules and Policies, by Linda Tsang. 6 EPA, “Emission Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units; Revisions to Emission Guideline Implementing Regulations; Revisions to New Source Review Program,” 83 Federal Register 44761, August 31, 2018 (hereinafter “ACE Proposal”). 7 For more information see CRS Report R45393, EPA’s Affordable Clean Energy Proposal, by Kate C. Shouse, Jonathan L. Ramseur, and Linda Tsang. Congressional Research Service 1 ACE rule.8 Twenty-one states and other stakeholders have intervened in the litigation in support of the CPP repeal and ACE rule.9 In order to provide information about the repeal of the CPP, promulgation of the ACE rule and related actions, and litigation, this report presents a series of questions and responses and concludes with a discussion of issues for congressional consideration. For a detailed discussion of EPA’s 2018 ACE proposal, see CRS Report R45393, EPA’s Affordable Clean Energy Proposal, by Kate C. Shouse, Jonathan L. Ramseur, and Linda Tsang. For a detailed discussion of the legal issues, see CRS Legal Sidebar LSB10325, EPA Replaces the Clean Power Plan with the Affordable Clean Energy Rule, by Linda Tsang; and CRS Legal Sidebar LSB10199, EPA Proposes New Permitting Test for Power Plant Modifications, by Linda Tsang. Background Q: How much does the generation of electricity contribute to total U.S. GHG emissions? A: Anthropogenic (i.e., man-made) GHG emissions are generated throughout the United States from millions of discrete sources: vehicles, power plants, industrial facilities, households, commercial buildings, and agricultural activities (e.g., soils and livestock).10 According to EPA, since 1990, GHG emissions from fossil fuel combustion—coal, natural gas, and petroleum—have accounted for 74%-78% of total U.S. GHG emissions.11 As illustrated by Figure 1, the electricity sector historically accounted for the largest percentage of U.S. GHG emissions from fossil fuel combustion. However, due to declines in the electricity sector emissions over the past decade, the transportation sector surpassed electricity in 2016. In 2018, the transportation sector accounted for 28% and the electricity sector accounted for 27% of total U.S. GHG emissions. 8 See Docket, Am. Lung Assoc. v. EPA, No. 19-1140 (D.C. Cir.). 9 See Docket, Am. Lung Assoc. v. EPA, No. 19-1140 (D.C. Cir.). 10 GHGs in the atmosphere trap radiation as heat, warming the earth’s surface and oceans. The primary GHGs emitted by humans (and estimated by EPA in its annual inventories) include CO2, methane, nitrous oxide, sulfur hexafluoride, chlorofluorocarbons, hydrofluorocarbons, and perfluorocarbons. While both natural and human-related sources release GHGs and influence climate, “current climate scientific assessment states high confidence (extremely likely) that human influence is the dominant cause of the observed warming over the past half-century.” For additional discussion, see CRS Report R45086, Evolving Assessments of Human and Natural Contributions to Climate Change, by Jane A. Leggett. 11 In 2018 (the most recent year of available data), these emissions accounted for 75% of total U.S. GHG emissions. See Table ES-2 in EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2018, April 2020. Congressional Research Service 2 Figure 1. GHG Emissions by Economic Sector 1990-2018 Source: Prepared by CRS; data from EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2018, April 2020, Table 2-10, https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-19902018. Notes: Million metric tons of CO2 equivalent is used because GHGs vary by global warming potential (GWP). GWP is an index developed by the Intergovernmental Panel on Climate Change (IPCC) that allows comparisons of the heat-trapping ability of different gases over a period of time, typically 100 years. Consistent with international GHG reporting requirements, EPA’s most recent GHG inventory (April 2020) uses the GWP values presented in the IPCC’s 2007 Fourth Assessment Report. The IPCC has since updated the 100-year GWP estimates, with some increasing and some decreasing. CO2 emissions from fossil fuel combustion account for over 98% of the GHG emissions in the electric power sector.12 Multiple factors have played a role in the CO2 emission decrease in the electricity sector. One key factor is the electricity generation portfolio. Electricity is generated from a variety of fuels and sources in the United States. Some fuels and sources—nuclear, hydropower, and some renewables—directly produce no CO2 emissions with their electricity generation. Fossil fuels, on the other hand, generate different amounts of CO2 emissions per unit of generated electricity. The amount of CO2 emitted during fossil-fuel-fired electricity generation is dependent upon the carbon content of the fuel and the efficiency of the generating unit in which it is combusted, among other variables. For example, natural-gas-fired electricity from a combined cycle unit typically yields approximately 43% of the CO2 emissions of coal-fired 12 See Table 2-11 in EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2018, April 2020. Congressional Research Service 3 electricity from a steam unit per kilowatt-hour of electricity.13 Therefore, shifting the U.S. electricity generation portfolio to lower-emissions fuel sources and more efficient technologies would likely (all else being equal) reduce CO2 emissions from the electricity sector, which in turn, would likely reduce total U.S. GHG emissions. Figure 2 illustrates the changes in the electricity portfolio from 2005 to 2019. Highlighted changes include the following:    Coal’s contribution to total electricity generation decreased from 50% to 23%. Natural gas’s contribution to total electricity generation increased from 19% to 38%. Non-hydro renewable energy (wind and solar) generation increased from 2% to 11%. Figure 2. Percentage of Total Electricity Generation by Energy Source 2005-2019 Source: Prepared by CRS; data from EIA, Electric Power Monthly, Table 1.1, http://www.eia.gov/beta/epm/. Notes: Renewable sources include wind, utility scale solar, wood fuels, landfill gas, biogenic municipal solid waste, other biomass, and geothermal. Petroleum includes petroleum liquids and petroleum coke. Estimates of small-scale solar generation are not included in the above figure. EIA started estimating this generation in 2014. If estimated small-scale solar generation were included in the renewables generation for 2019, the percentage of total generation for renewables (non-hydro) would increase from 11% to 12%. Several factors likely played a role in these recent changes, including technological advances in energy production (e.g., hydraulic fracturing) and federal and state policies, including federal tax policies14 and states’ renewable portfolio standards.15 These factors have influenced the 13 For further discussion, see CRS Report R44090, Life-Cycle Greenhouse Gas Assessment of Coal and Natural Gas in the Power Sector, by Richard K. Lattanzio. 14 See CRS Report R44852, The Value of Energy Tax Incentives for Different Types of Energy Resources, by Molly F. Sherlock. 15 See, for example, Database of State Incentives for Renewables and Efficiency, Map of Renewable Portfolio Standard Congressional Research Service 4 deployment of these technologies and resources and impacted the relative price differences between energy sources, particularly coal, natural gas, and renewable sources. These market forces have played a role in the retirement of coal-fired power plants: Between 2007 and 2018, the number of coal-fired power plants decreased from 351 to 206, and according to the Energy Information Administration (EIA), more retirements are planned in coming years.16 Q: How much progress has the United States made in reducing GHG emissions and meeting emission targets? A: Figure 3 illustrates total U.S. GHG emissions between 1990 and 2018. As the figure indicates, U.S. GHG emissions increased 20% between 1990 and 2007. The economic downturn in 2008 and 2009 resulted in a decrease of energy consumption (including electricity) across all economic sectors. This decline played a key role in the 10% decrease in emission levels during that time. Between 2010 and 2017, emissions continued to decrease by 8%. Between 2017 and 2018, emissions increased by 3% and were roughly equivalent to emission levels in 1995. As discussed above, changes in the nation’s electricity generation portfolio played a key role in this more recent decline. In addition, Figure 3 compares recent U.S. GHG emission levels to the 2020 and 2025 emissions goals previously made by the United States pursuant to the United Nations Framework Convention on Climate Change’s 2009 Copenhagen Accord and 2015 Paris Agreement, respectively.17 As the figure indicates, 2018 U.S. GHG emission levels were 10% less than 2005 emissions levels. For more information about trends in CO2 emissions from electricity generation and the factors that impact emission levels in that sector, see CRS Report R45453, U.S. Carbon Dioxide Emissions in the Electricity Sector: Factors, Trends, and Projections, by Jonathan L. Ramseur. For an overview of U.S. energy issues, including U.S. energy consumption and changes in the fuels used to generate electricity, see CRS Report R44854, 21st Century U.S. Energy Sources: A Primer, coordinated by Michael Ratner. Policies, as of June 2019, https://www.dsireusa.org/resources/detailed-summary-maps/. 16 EIA, Electric Power Annual, Table 4.1, https://www.eia.gov/electricity/annual/; and EIA, “More U.S. Coal-Fired Power Plants Are Decommissioning as Retirements Continue,” July 26, 2019, https://www.eia.gov/todayinenergy/ detail.php?id=40212. 17 For more on U.S. commitments and pledges under the UNFCCC (U.S. Treaty Document 102-38), see CRS Report R44092, Greenhouse Gas Pledges by Parties to the United Nations Framework Convention on Climate Change and CRS Report R44609, Climate Change: Frequently Asked Questions About the 2015 Paris Agreement. Congressional Research Service 5 Figure 3. U.S. GHG Emissions (Net) Compared to 2020 and 2025 Emissions Targets Source: Prepared by CRS; data from EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2018, 2020, https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks. Notes: Net GHG emissions includes net carbon sequestration from land use, land use change, and forestry. This involves carbon removals from the atmosphere by photosynthesis and storage in vegetation. See the note in Figure 1regarding “Million metric tons of CO2-equivalent.” Q: What are the Clean Air Act (CAA) Section 111 requirements? A: CAA Section 111 requires EPA to establish nationally uniform, technology-based standards for categories of industrial facilities, also referred to as stationary sources of air pollution.18 These standards were intended to help prevent new pollution problems and to “level the playing field for states competing for industrial growth,” for example, by removing incentives for states or communities to weaken air pollution standards in order to attract industry.19 CAA Section 111(b) directs EPA to establish maximum emission levels (called New Source Performance Standards, or NSPS) for new and modified major stationary sources—power plants, steel mills, and smelters, for example. To set the emission levels, EPA determines the BSER that has been “adequately demonstrated,” taking costs and any non-air-quality health and environmental impacts and energy requirements impacts into account.20 Section 111 also addresses existing stationary sources of pollution. Section 111(d) requires EPA to promulgate regulations, which EPA has historically referred to as “emission guidelines.”21 These 18 42 U.S.C. §7411(b). 19 Robert J. Martineau Jr. and Michael K. Stagg, “New Source Performance Standards,” in The Clean Air Act Handbook, ed. Julie R. Domike and Alec C. Zacaroli, 4th ed. (Chicago: American Bar Association, 2016). 20 42 U.S.C. §7411(a)(1). 21 For emission guidelines promulgated prior to ACE, EPA defines emission guideline at Title 40, Section 60.21(e), of the Code of Federal Regulations. For ACE and any future emission guidelines, EPA defines emission guideline at Title Congressional Research Service 6 emission guidelines establish binding requirements that states must address when they develop plans to regulate the existing sources, which EPA refers to as “designated facilities.”22 In particular, states must establish performance standards reflecting the BSER for existing sources, which is determined by EPA. States, in their plans, provide for implementation and enforcement of the standards. EPA cannot compel a state to submit a state plan pursuant to CAA Section 111(d). However, if a state does not submit a satisfactory plan by EPA’s regulatory deadline, CAA Section 111(d) directs EPA to prescribe a plan for the state, often described as a federal plan (42 U.S.C. §7411(d)(2)). Q: How does the CAA Section 111 define standards of performance and best system of emission reduction? A: The term standards of performance appears multiple times in CAA Section 111, including in both the Section 111(b) provisions relating to new sources and the Section 111(d) provisions relating to existing sources in a source category. Section 111(a) defines standard of performance as [A] standard for emissions of air pollutants which reflects the degree of emission limitation achievable through the application of the best system of emission reduction which (taking into account the cost of achieving such reduction and any non-air quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated.23 Under this definition, EPA must determine the BSER that is “adequately demonstrated,” considering certain factors. Then, EPA or states, as applicable, must base the emissions standard on the degree of emission limitation that is “achievable” through the BSER. The CAA does not define these component terms within the definition of standard of performance. Courts have expanded on the CAA Section 111 definition of the term standards of performance and EPA’s interpretation of its component terms, but they have done so generally with respect to NSPSs under Section 111(b) rather than emission guidelines for existing sources under Section 111(d).24 For detailed discussion about EPA’s current interpretation of its authority to determine the BSER under Section 111, see the questions and answers in the “Repeal of the Clean Power Plan” section. Q: What is a “state plan”? A: A “state plan” refers to a plan that provides for the implementation and enforcement of CAA Section 111(d) performance standards.25 For example, under the ACE rule, states are to develop plans detailing the implementation and enforcement of performance standards for CO2 emissions 40, Section 60.21a(e). 22 42 U.S.C. §7411(d)(1). For EPA’s definition of designated facility for emission guidelines promulgated prior to ACE, see 40 C.F.R. §60.21(b). For EPA’s definition of designated facility for ACE and any future emission guidelines established after July 8, 2019, see 40 C.F.R. §60.21a(b). 23 CAA §111(a)(1), 42 U.S.C. §7411(a)(1). 24 See, for example, Lignite Energy Council v. EPA, 198 F.3d 930, 933 (D.C. Cir. 1999); Sierra Club v. Costle, 657 F.2d 298 (D.C. Cir. 1981); ASARCO Inc. v. EPA, 578 F.2d 319 (D.C. Cir. 1978); Essex Chemical Corp. v. Ruckelshaus, 486 F.2d 427 (D.C. Cir. 1973); Portland Cement Ass’n v. Ruckelshaus, 486 F.2d 375, 391 (D.C. Cir. 1973). 25 42 U.S.C. §7411(d)(1). States also prepare “state plans” under CAA Section 129, which authorizes air emission limits for solid waste incineration units. See 42 U.S.C. §7429(b)(2). Congressional Research Service 7 from coal-fired EGUs. In general, states develop Section 111 plans based on the emission guidelines, which include the BSER determination, issued by EPA and in accordance with federal procedural requirements and then submit them to EPA for review.26 The state plans approved by EPA are published in federal regulatory code (40 C.F.R. Part 62).27 If a state does not submit a satisfactory plan by EPA’s regulatory deadline, CAA Section 111(d) directs EPA to prescribe a plan for the state, described as a federal plan in the ACE rule.28 Q: What is the difference between a “state plan” and a “state implementation plan”? A: These terms refer to plans developed by states under different sections of the CAA. A “state plan” is a plan that provides for the implementation and enforcement of CAA Section 111(d) performance standards.29 A “state implementation plan” (SIP) is the collection of regulations and documents developed under CAA Section 110 to ensure compliance with federal air quality standards, known as National Ambient Air Quality Standards (NAAQS).30 State plans and SIPs establish limits for different kinds of air pollutants and differ in scope of sources covered.31 A SIP sets forth procedures for compliance with NAAQS for six pollutants, known as “criteria pollutants” (carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide [SO2]).32 A SIP establishes an emissions budget for diverse emission sources in the state, including power plants, industrial plants, incinerators, and motor vehicles. The scope of a state plan is relatively narrower than a SIP, given that EPA has historically issued Section 111(d) performance standards for “specialized types of emission sources that emit discrete types of pollutants.”33 State plans apply to “designated pollutants,” which EPA has defined to include performance standards for new sources under Section 111(b) and to exclude criteria pollutants and hazardous air pollutants (HAPs).34 Examples of designated pollutants 26 EPA cannot compel a state to submit a state plan pursuant to CAA Section 111(d). If a state does not submit a satisfactory plan by EPA’s regulatory deadline, CAA Section 111(d) directs EPA to prescribe a plan for the state (42 U.S.C. §7411(d)). 27 This part also contains federal plans issued for states that did not submit adequate plans. 28 42 U.S.C. §7411(d)(2). 29 42 U.S.C. §7411(d)(1). States also prepare “state plans” under CAA Section 129, which authorizes air emission limits for solid waste incineration units (42 U.S.C. §7429(b)(2)). 30 42 U.S.C. §7410. See also EPA, Basic Information about Air Quality SIPs, https://www.epa.gov/sips/basicinformation-air-quality-sips. 31 EPA guidance explains that because “emissions standards applicable to industries on a nationwide basis” (such as Section 111 performance standards and Section 112 National Emission Standards for Hazardous Air Pollutants) are codified in the Code of Federal Regulations, they are not included in federally approved SIPs. EPA observed that while states “typically adopt” federal emission standards into their SIPs, EPA does not adopt those provisions into the federally approved SIP because such provisions are already enforceable through the federal Code of Federal Regulations. See EPA, SIP Processing Manual, “What’s Not in a SIP,” https://cfpub.epa.gov/oarwebadmin/sipman/ sipman/mContent.cfm?chap=1&filePos=8. 32 42 U.S.C. §§ 7408(a)(1), 7410. For more information about NAAQS requirements, see CRS Report RL30853, Clean Air Act: A Summary of the Act and Its Major Requirements, by Kate C. Shouse and Richard K. Lattanzio. For a summary of current NAAQS for all six criteria pollutants and links to the history of standards for each of these pollutants, see EPA, “NAAQS Table,” https://www.epa.gov/criteria-air-pollutants/naaqs-table. 33 See generally 40 C.F.R. Part 62. See also Martineau and Stagg, “New Source Performance Standards,” pp. 342-343. 34 40 C.F.R. §60.21(e). Congressional Research Service 8 include sulfuric acid mist from sulfuric acid plants, fluoride emissions from phosphate fertilizer plants, and nonmethane organic emissions from landfills.35 Q: What was the Clean Power Plan (CPP)? A: EPA promulgated the CPP in 2015 to limit CO2 emissions from existing fossil-fuel-fired power plants.36 EPA set national performance standards for CO2 emissions from existing fossil-fuel-fired power plants under the authority of CAA Section 111(d). One national performance standard would have applied to existing electric steam generating units (which are mostly coal), and the other applied to existing stationary combustion turbines—for example, natural gas combined cycle (NGCC) units. EPA based these standards on the BSER, a statutory term used to define a performance standard under CAA Section 111. EPA determined the BSER for the CPP based on a collection of measures that it referred to as three “building blocks”: (1) improving the heat rate at coal-fired units, (2) shifting generation from coal-fired units to lower-emitting natural gas units, and (3) shifting generation from fossil fuel units to renewable energy generation. The CPP also set individual state targets for average emissions from existing power plants based on the CO2 performance standards. Although EPA set state-specific targets, states were to determine how to reach these goals. For additional details about the CPP as EPA promulgated it in 2015, see CRS Report R44341, EPA’s Clean Power Plan for Existing Power Plants: Frequently Asked Questions, by James E. McCarthy et al. Q: Did the CPP ever take effect? A: No. The CPP was the subject of ongoing litigation and was never implemented due to a stay from the Supreme Court.37 The Court dismissed the litigation challenging the CPP as moot after EPA finalized its repeal of the CPP and the ACE rule.38 Q: Did EPA promulgate GHG performance standards for new and modified power plants under the CAA? A: Yes. In 2015, EPA promulgated GHG performance standards for new and modified power plants under CAA Section 111(b) concurrent to the 111(d) standards for existing plants in the CPP.39 Once EPA lists a source category, such as fossil-fuel-fired EGUs, Section 111(b) requires EPA to establish NSPS for new and modified sources within a listed source category.40 Once EPA promulgates NSPS under Section 111(b) for new or modified sources in that category, Section 111(d) then directs EPA to establish procedures for the states to submit plans establishing 35 See generally 40 C.F.R. Part 62. See also Martineau and Stagg, “New Source Performance Standards,” pp. 342-343. 36 The pollutants regulated in the CPP and the ACE rule are GHGs with standards expressed in the form of CO 2 limits. 40 C.F.R. §60.5705a (for the ACE rule); 40 C.F.R. §60.5705(a) (for the repealed CPP). EPA, “Carbon Pollution Emission Guidelines for Existing Stationary Sources: Final Rule,” 80 Federal Register 64661, October 23, 2015 (hereinafter CPP Final Rule). 37 The Supreme Court in 2016 stayed the implementation of the CPP pending resolution of the lawsuit challenging its legality. Order in Pending Case, West Virginia v. EPA (S. Ct. No. 15A773, Feb. 9, 2016), https://www.supremecourt.gov/orders/courtorders/020916zr_21p3.pdf. 38 Order, West Virginia v. EPA, No. 15-1363 (D.C. Cir. Sept. 17, 2019). 39 EPA, “Standards of Performance for Greenhouse Gas Emissions from New, Modified, and Reconstructed Stationary Sources: Electric Generating Units; Final Rule,” 80 Federal Register 64510, October 23, 2015. 40 42 U.S.C. §7411(b)(1). Congressional Research Service 9 standards of performance for existing sources that would be subject to NSPS if they were new, unless they are subject to an exclusion under Section 111(d).41 As promulgated in 2015, the NSPS for new and modified power plants would have relied in part on carbon capture and sequestration (CCS) technology to reduce emissions by about 20% compared to the emissions of what was then considered a state-of-the-art coal-fired plant without CCS. Stakeholders challenged the 2015 GHG performance standards for new and modified power plants in court, but the court paused the litigation pending completion of EPA’s review and any resulting rulemaking.42 Q: What is the status of GHG performance standards for new and modified power plants? A: The GHG performance standards for new and modified power plants remain in effect, though EPA proposed to revise them on December 6, 2018.43 The December 2018 proposal is a separate rulemaking from the CPP repeal and ACE rulemakings. In the December 2018 proposal for new and modified power plants, EPA determined that the BSER for newly constructed coal-fired units would be the most efficient demonstrated steam cycle in combination with the best operating practices from exiting units. This proposed BSER would replace the determination from the 2015 rule, which identified the BSER as partial CCS. According to the agency, “the primary reason for this proposed revision is the high costs and limited geographic availability of CCS.”44 The semiannual regulatory agenda estimated a final decision by December 2020.45 As of July 2020, EPA has not yet finalized this proposal. According to EPA’s status report in the paused litigation challenging the 2015 GHG performance standards for new and modified power plants, the agency continues to review the comments submitted on the proposed rule and plans to send the final rule package to the Office of Management and Budget (OMB) for interagency review in the early summer of 2020.46 41 42 U.S.C. §7411(d)(1). One of the legal issues raised in the CPP and ACE rule litigation challenges EPA’s interpretation of CAA Section 111(d)(1)(A). This provision excludes, among other things, from Section 111(d) regulation “any existing source for any air pollutant (i) for which air quality criteria have not been issued or which is not included on a list published under section 108(a) or emitted from a source category which is regulated under [CAA] section 112.” Id. The Section 108(a) exclusion refers to “criteria” air pollutants under the NAAQS program. Id. §§7408-7410. The Section 108(s) exclusion does not apply because EPA has not listed GHGs as criteria pollutants. Under the CPP, EPA explained that the Section 112 exclusion “does not bar the regulation under CAA section 111(d) of non-HAP [hazardous air pollutants] from a source category, regardless of whether that source category is subject to standards for HAP under CAA section 112.” CPP Final Rule at 64711-15. See also Section 112 Exclusion discussion in CRS Report R44480, Clean Power Plan: Legal Background and Pending Litigation in West Virginia v. EPA, by Linda Tsang. Petitioners that challenged the CPP and are challenging the ACE rule argue that sources, and not air pollutants, regulated under other CAA Section 112 to limit HAPs, such as existing fossil-fuel-fired EGUs, are excluded from EPA’s scope of Section 111(d) authority. Id. See also “Q: What are the main legal issues in the litigation?” 42 EPA Status Report, North Dakota v. EPA at 3-4, No. 15-1381 (D.C. Cir. Apr. 24, 2020). In 2017, the court ordered the petitions for review of the 2015 GHG performance standards for new and modified power plants to be held in abeyance (paused) pending further order of the court. 43 EPA, “Review of Standards of Performance for Greenhouse Gas Emissions from New, Modified, and Reconstructed Stationary Sources: Electric Utility Generating Units,” 83 Federal Register 65424, December 20, 2018. 44 Additional information, including a link to the proposed rule, a fact sheet, and an economic impact analysis, can be found at https://www.epa.gov/stationary-sources-air-pollution/proposal-nsps-ghg-emissions-new-modified-andreconstructed-egus. 45 Office of Management and Budget (OMB), Semiannual Regulatory Agenda, EPA, RIN 2060-AU58, Spring 2020, https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202004&RIN=2060-AU58. 46 EPA Status Report, North Dakota v. EPA at 4, No. 15-1381 (D.C. Cir. Apr. 24, 2020). In 2017, the court ordered the Congressional Research Service 10 Q: Do the CPP repeal and ACE rules have implications for EPA’s other GHG rulemakings or the endangerment finding? A: In 2009, EPA issued two findings under CAA Section 202, referred to collectively as the “GHG endangerment finding.” EPA found (1) that GHGs currently in the atmosphere potentially endanger public health and welfare and (2) that new motor vehicle emissions cause or contribute to that pollution.47 EPA subsequently promulgated regulations under CAA authority to limit GHG emissions from motor vehicles, the power sector, the oil and gas industry, and other sources. Neither the CPP repeal nor the promulgation of the ACE rule reconsiders EPA’s 2009 GHG endangerment finding.48 Without reconsidering the GHG endangerment finding, EPA appears to have a continuing obligation to limit GHG emissions under the CAA.49 Separate from the CPP repeal and ACE rulemaking, EPA has proposed specific changes to other GHG regulations, including those for motor vehicles and for the oil and gas sector. For a brief overview of these proposed changes, see CRS Report R45451, Clean Air Act Issues in the 116th Congress, by James E. McCarthy, Kate C. Shouse, and Richard K. Lattanzio. Repeal of the Clean Power Plan Q: Why did EPA repeal the CPP? A: EPA bases the CPP repeal on a change in its legal interpretation of its authority under CAA Section 111 from its interpretation in the CPP. EPA concluded that the CPP exceeded CAA statutory authority in setting the BSER as a combination of on- and off-site emission reduction measures that applied to the entire existing source category.50 Because the CPP BSER was based, in part, on “beyond-the-source” measures (i.e., measures that apply to the source category as a whole or to entities entirely outside the regulated source category), EPA, after reconsidering the relevant statutory text, structure, and purpose of CAA Section 111, asserts that the CPP petitions for review of the 2015 GHG performance standards for new and modified power plants to be held in abeyance (paused) pending further order of the court. Id. at 3-4. 47 Specifically, EPA’s first finding was that “elevated concentrations of greenhouse gases in the atmosphere may reasonably be anticipated to endanger the public health and to endanger the public welfare of current and future generations.” See EPA, “Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act,” Final Rule, 74 Federal Register 66496 and 66516, December 15, 2009. The Supreme Court upheld EPA’s “endangerment finding” in Util. Air Regulatory Group v. EPA, 134 S. Ct. 2427 (2014). 48 In the lawsuits challenging the CPP and the ACE rule, petitioners claimed that EPA failed to make the required endangerment finding under CAA Section 111 and that EPA could not rely on the endangerment finding that it made in 2009 in the context of CAA Section 202 for motor vehicles. See, for example, Brief of Pac. Legal Found., Tex. Pub. Policy Found., Morning Star Packing Co., Merit Oil Co., Loggers Ass’n of N. Cal., and Norman Brown in Supp. of Pet’rs 20-24, West Virginia v. EPA, No. 15-1363 (D.C. Cir. Feb. 23, 2016) (challenging the CPP); Statement of Issues to be Raised by Petitioner Texas Public Policy Foundation, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Oct, 7, 2019) (challenging the ACE rule). 49 See Massachusetts v. EPA, 549 U.S. 497, 533 (2007) (“Under the clear terms of the Clean Air Act, EPA can avoid taking further action only if it determines that greenhouse gases do not contribute to climate change or if it provides some reasonable explanation as to why it cannot or will not exercise its discretion to determine whether they do.”). 50 The CPP repeal is one of three separate and distinct rulemakings published in the same Federal Register notice. The CPP repeal is published at pp. 32522-32 in EPA, “Repeal of the Clean Power Plan; Emission Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units; Revisions to Emission Guidelines Implementing Regulations,” 84 Federal Register 32534, July 8, 2019. Hereinafter, “CPP repeal” refers to pp. 32522-32 of this Federal Register notice. Congressional Research Service 11 “significantly exceeded” its authority.51 Based on this revised interpretation, EPA repealed the CPP and limited the BSER in the ACE rule to emission reduction measures that owners and operators can apply directly on site at individual existing EGUs. In the CPP repeal and ACE rule, EPA contends that it has discretion to change its interpretation of its legal authority so long as it provides a “reasonable explanation” for the change.52 The Supreme Court has explained that “[a]gencies are free to change their existing policies as long as they provide a reasoned explanation for the change…. But the agency must at least ‘display awareness that it is changing position’ and ‘show that there are good reasons for the new policy.’ … [A]n ‘[u]nexplained inconsistency’ in agency policy is ‘a reason for holding an interpretation to be an arbitrary and capricious change from agency practice.’”53 Q: How has EPA’s interpretation of Section 111 authority changed from its interpretation in the CPP? A: EPA’s interpretation of its CAA Section 111 authority in the ACE rule is narrower than its previous interpretation in the CPP. As discussed above, CAA Section 111(a) requires standards of performance to reflect the emissions reductions achievable through “application” of the BSER. In the CPP, EPA reasoned that the “system” in the BSER reflected the “overall source category,” taking into account the “unique characteristics of CO2 pollution and the unique, interconnected and interdependent manner in which affected EGUs and other generating sources operate within the electricity sector.”54 Under this interpretation, EPA based the CPP BSER for existing fossilfuel-fired EGUs on three “building blocks”: (1) improving the heat rate at coal-fired units, (2) shifting generation to lower-emitting natural gas units, and (3) shifting generation from fossil fuel units to renewable energy generation.55 In the CPP repeal, EPA presents a different view of its authority to determine the BSER under Section 111. EPA asserts that the “application” of the BSER referenced in CAA Section 111(a) “unambiguously limits the BSER to those systems” that can be “applied” or “put into operation at a building, structure, facility, or installation.”56 In other words, EPA contends that the CAA does not authorize the agency to select as the BSER measures that apply to the source category as a whole or to entities entirely outside the regulated source category. EPA states that the CPP “beyond-the-source” approach “ignored or misinterpreted” the plain text of the CAA that “clearly precluded the unsupportable reading” of Section 111 used in the CPP to choose emission reduction measures that are not directly applied to the regulated EGU.57 To support its interpretation that the BSER must be source-specific, EPA points to an “explicit statutory link” between the CAA’s Section 165 Prevention of Significant Deterioration (PSD) permitting program and Section 111 standards.58 Section 111 emission standards (as derived from 51 CPP Repeal, p 32523. 52 ACE Final Rule, p. 32523. 53 Encino Motorcars, LLC v. Navarro, 136 S. Ct. 2117, 2125-26 (2016), quoting FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515 (2009) and National Cable & Telecommunications Assn. v. Brand X Internet Services, 545 U.S. 967, 981 (2005) (internal citations omitted). 54 CPP Final Rule, p. 64726. 55 See “Q: What was the Clean Power Plan (CPP)?” for a discussion of the CPP “building blocks.” 56 CPP Repeal, p. 32524. 57 CPP Repeal, p. 32527. 58 CPP Repeal, p. 32525. Congressional Research Service 12 the BSER) act as a “floor” (minimum) for emission limits in PSD permits.59 The permitting authority bases the PSD emission limits only on source- or facility-specific best available emission control technologies. EPA contends that if Section 111 emission standards are the “floor” for source-specific emission limits in PSD permits, EPA must base the BSER (and the emission standards established by applying the BSER) only on what is achievable at an individual source.60 In comparison, in the CPP, EPA did not apply PSD program policies or interpretations to its BSER determination because it interpreted the PSD permitting program as distinct from Section 111(d) emission guidelines.61 In the CPP, EPA observed that the PSD permitting program applies to individual modified or new sources in contrast to Section 111(d) guidelines that apply to an entire source category.62 The ACE rule and the CPP also diverge in their interpretation of the Section 111(d) provision that allows states to consider the “remaining useful life of an existing source” and “other factors” when “applying” a standard of performance to a particular source. In the ACE rule, EPA interprets this provision to allow states to consider these factors when “establishing” emission standards, including the costs of implementing heat rate improvement (HRI) and technical feasibility.63 EPA acknowledges that consideration of such factors could result in source-specific emission standards “that reflect a value of HRI that falls outside” the emission reduction ranges that EPA identified for each technology.64 The CPP, in contrast, allowed states to consider these factors only when determining how to apply the national emission standards to existing EGUs and prohibited states from making “adjustments” to the mandatory statewide emission reduction goals based on these source-specific factors.65 Q: Has anyone challenged the CPP repeal in court? A: Yes. Parties have filed petitions in the U.S. Court of Appeals for the D.C. Circuit challenging CPP repeal and the ACE rule as of July 8, 2019.66 See “Litigation Challenging the CPP Repeal and the ACE Rule” below for questions related to the litigation. Affordable Clean Energy (ACE) Final Rule Q: What is the ACE rule? A: The final ACE rule establishes emission guidelines for states to use when they develop and submit plans to EPA that establish standards to reduce CO2 emissions67 from existing coal-fired 59 42 U.S.C. §7479(3). 60 CPP Repeal, p. 32525. 61 EPA, Response to Comments, CPP Final Rule, chap. 1.2, pp. 100-01. 62 EPA, Response to Comments, CPP Final Rule, chap. 1.2, pp. 100-01. 63 ACE Final Rule, p. 32549. 64 ACE Final Rule, p. 32549. 65 CPP Final Rule, p. 64870. 66 See Petition for Review, Am. Lung Assoc. v. EPA, No. 19-1140 (D.C. Cir. July 8, 2019). 67 In the ACE rule, EPA states that the “air pollutant regulated in this final action is GHGs. However, the standards in this rule are expressed in the form of limits solely on emissions of CO2, and not the other constituent gases of the air pollutant GHGs.” CPP Repeal, p. 32534. See 40 C.F.R. §60.5705a. Congressional Research Service 13 units. The ACE rule’s emission guidelines present EPA’s BSER determination for CO2 emissions from existing coal-fired EGUs.68 Q: Why did EPA promulgate the ACE rule? A: EPA’s promulgation of NSPS GHG standards for new and modified EGUs under CAA Section 111(b) triggered the requirements for existing sources under CAA Section 111(d).69 Repeal of the CPP—the 111(d) rulemaking that EPA promulgated concurrent to the GHG NSPS in 2015— meant that EPA had to promulgate a new rule to fulfill its obligation under CAA Section 111(d) for existing sources. Q: To whom does the ACE rule directly apply? A: The final ACE rule directs the governor (or the governor’s designee) of each state in the contiguous United States to submit a state plan to EPA by July 8, 2022.70 A state plan should establish standards of performance based on the BSER for designated facilities in that state’s jurisdiction and provide for the implementation and enforcement of those standards. The final rule also requires states in the contiguous United States without any designated facilities (i.e., coal-fired EGUs) to submit a “negative declaration letter” to EPA in lieu of a state plan. EPA expects state plan submissions from 43 of the 48 contiguous states and negative declarations from the remaining five (California, Idaho, Maine, Rhode Island, and Vermont).71 The final ACE rule does not explain why its emission guidelines do not apply to non-contiguous states.72 The 2015 CPP final rule likewise did not apply to non-contiguous states. The final CPP rule stated that EPA did not have the information or tools required to establish the BSER in noncontiguous states and U.S. territories, concluding that it would determine how to address CAA Section 111(d) requirements in those areas at a later date.73 Q: What types of facilities are affected by the final rule? A: Under the ACE rule, state plans will establish CO2 performance standards for each “affected steam generating unit,” which EPA refers to as a “designated facility.”74 EPA defined designated facility as a coal-fired electric utility steam generating unit (coal-fired EGU) that was in operation or had commenced construction on or before January 8, 2014, exceeds a specified nameplate capacity and base load rating, and burns coal for more than 10% of the average annual heat input during the three previous calendar years.75 EPA did not establish the BSER for integrated gasification combined cycle (IGCC) units, oil- or natural-gas-fired utility boilers, or fossil-fuel-fired stationary combustion turbines and therefore 68 ACE Final Rule, p. 32521. 69 EPA described the existing Section 111(b) requirements as the “requisite predicate for applicability of CAA section 111(d).” ACE Final Rule, p. 32533. 70 40 C.F.R. §60.5710a and §60.5800a. 71 ACE Final Rule, p. 32573. 72 Similarly, the preamble to the 2018 ACE proposal does not discuss why it excludes non-contiguous states. 73 For additional discussion, see CRS Report R44341, EPA’s Clean Power Plan for Existing Power Plants: Frequently Asked Questions, by James E. McCarthy et al. 74 40 C.F.R. §60.5700a. 75 ACE Final Rule, p. 32533. See also 40 C.F.R. §60.5805a. Congressional Research Service 14 excluded these EGUs from the definition of designated facility.76 For more information, see “Q: Why didn’t EPA establish a BSER for other fossil-fuel-fired units?” Q: What is the BSER under the ACE rule? A: EPA determined that efficiency improvements, also known as “heat rate improvements” or HRI, are the BSER to reduce CO2 emissions from existing coal-fired EGUs.77 The “heat rate” measures the amount of energy that a power plant uses to generate one kilowatthour of electricity.78 A power plant with a lower, more efficient heat rate uses less fuel to generate the same amount of electricity as a power plant with a higher heat rate. Using less fuel per kilowatt-hour may result in lower emissions of CO2 as well as lower levels of SO2 and nitrogen oxides (NOx).79 HRI is affected by a number of factors, such as the age and type of EGU. For more information, see CRS Report R43343, Increasing the Efficiency of Existing Coal-Fired Power Plants, by Richard J. Campbell. For more information about HRI and potential emission impacts, see “Q: Would the ACE rule’s HRI lead to potential “rebound effects”?” EPA identified other “systems of GHG emission reduction”—such as natural gas co-firing, use of biomass, and CCS—that the agency concluded did not meet the criteria for the BSER.80 For information about EPA’s consideration of natural gas co-firing, see “Q. Why did EPA exclude natural gas co-firing from the BSER?” For information about EPA’s consideration of biomass, CCS, and other systems of GHG emission reduction, see “Q: Can states use emission reduction measures outside the “candidate technologies” list to establish the ACE rule’s performance standards?” Q: What are the ACE rule’s performance standards for CO2 emissions? A: Similar to the ACE proposal, the final ACE rule does not establish a binding, numeric performance standard for CO2 emissions from existing coal-fired units. Rather, EPA established a list of candidate technologies, comprising six HRI measures and improved operation and maintenance practices, which states “must evaluate in establishing a standard of performance for that source in their state plans under CAA section 111(d).”81 As in the proposal, the final ACE rule presents ranges of expected HRI improvements for the candidate technologies, expressed as a percentage improvement, for three size-based categories of coal-fired EGUs.82 The estimated potential HRI improvements for the six candidate technologies at existing coal-fired EGUs ranges 76 ACE Final Rule, p. 32533. See also 40 C.F.R. §60.5780a 77 ACE Final Rule, p. 32532. 78 EIA, Analysis of Heat Rate Improvement Potential at Coal-Fired Power Plants, May 19, 2015, https://www.eia.gov/ analysis/studies/powerplants/heatrate/. 79 EIA, Analysis of Heat Rate Improvement Potential at Coal-Fired Power Plants. 80 ACE Final Rule, pp. 32543-32549. EPA clarified that states can use natural gas co-firing as a compliance measure, however. See ACE Final Rule, p. 32555. 81 ACE Final Rule, p. 32536. 82 For final rule, see ACE Final Rule, Table 1, p. 32537. For proposal, see ACE Proposal Table 1, p. 44757. Congressional Research Service 15 from 0.1% to 2.9%.83 States must ultimately establish a rate-based standard. They also have the option to establish performance standards reflecting an HRI “that falls outside of these ranges.”84 Q: Why did EPA not establish a numeric or presumptively approvable CO2 performance standard in the ACE rule? A: EPA discussed several reasons why it did not establish a numeric CO2 performance standard or specify a standard that, while not required, would meet the requirements for EPA approval (i.e., “presumptively approvable”). First, EPA asserted that “CAA Section 111(d)(1) squarely places the responsibility of establishing a standard of performance for an existing designated facility on the state as part of developing a state plan.”85 Second, EPA determined that it could not establish national performance standards due to variation among existing coal-fired units.86 Factors that may affect HRI potential for a particular unit include, but are not limited to, the EGU’s “past and projected utilization rate, maintenance history, and remaining useful life.”87 Third, EPA concluded that states are best positioned to account for site-specific considerations that influence HRI potential.88 According to EPA, many commenters supported this “unit-specific, state-led” approach because “it is not possible to adopt uniform, nationally applicable standards of performance based on implementation of particular HRI technologies because each individual unit is subject to a unique combination of factors that can affect the unit’s heat rate and HRI potential, many of which are geographically driven and outside the control of a source.”89 EPA noted that Section 111(d) of the CAA directs the agency “to permit states to take such factors into consideration as they develop plans to establish performance standards for existing sources within their jurisdiction.”90 Other commenters disagreed with this “unit-specific, state-led” approach and viewed it as inconsistent with the CAA legislative history as well as past practice to determine BSER based on a specific emission reduction technology. These commenters concluded that the unit-specific, state-led approach would not result in significant emission reductions. EPA disagreed, responding that designating a “specific set of emission reduction technologies” and operational practices as the BSER are consistent with the statute. EPA responded further that this approach “recognizes the challenges of applying a single specific emission reduction technology within such a diverse population of designated facilities.”91 Some commenters maintained that EPA has a statutory responsibility to establish the level of stringency for the performance standards. According to EPA, these commenters stated that “EPA is legally obligated to identify ‘the degree of emission limitation achievable through the application of the [BSER]’ (i.e., a level of stringency) because such degree of emission limitation is inextricably linked with the determination of the BSER, which is the EPA’s statutory role and 83 ACE Final Rule, p. 32537. 84 ACE Final Rule, p. 32538. 85 ACE Final Rule, p. 32550. 86 ACE Final Rule, p. 32536. 87 ACE Final Rule, p. 32536. 88 ACE Final Rule, pp. 32535-6. 89 ACE Final Rule, pp. 32535-6. 90 ACE Final Rule, p. 32536. 91 ACE Final Rule, p. 32536. Congressional Research Service 16 responsibility.”92 EPA responded that the ACE rule’s presentation of ranges of expected HRI improvements fulfills the agency’s statutory obligation to specify the “level of emissions reductions achievable using the candidate technologies.”93 The lack of a numeric performance standard introduces uncertainty about the level of stringency expected from implementation of HRI measures under the ACE rule. EPA reported that “numerous” state and industry commenters requested a presumptive standard or additional clarity about the CO2 performance standards. Other states commented that they “heartily approve” of the CPP repeal and of aspects of the proposed ACE rule, in particular that, in their view, the proposal affords “the States sufficient flexibility to comply with federal environmental mandates without disrupting the flow of affordable, reliable electricity to their citizens and the nation as a whole.”94 The National Association of Clean Air Agencies (NACAA), which represents air pollution control agencies in 35 states, the District of Columbia, four territories and 116 metropolitan areas,95 recommended that EPA provide states “presumptively approvable” language for state plans as well as “presumptively approvable standards.”96 NACAA commented that such presumptively approvable language or standards “need not restrict state flexibilities” and that “EPA could present these as options in the rule and specify in all cases that states remain free to craft alternative compliance approaches consistent with the emission guidelines.”97 EPA did not identify “presumptively approvable” standards in the final ACE rule. EPA concluded that it was “reasonable” for the agency to present “the ‘degree of emission limitation achievable through application of the BSER’ as a set of ranges of values, rather than a single number, that reflects application of the candidate technologies as a whole,” given that source-specific factors may result in “varying degrees of reductions” when implementing the BSER at a particular unit.98 Q: What are the candidate technologies under the ACE rule? A: EPA finalized a list of “candidate technologies”—six HRI measures and improved operating and maintenance (O&M) procedures—that constitute the BSER.99 Under the ACE rule, states “will consider” the candidate technologies and “other factors when establishing unit-level standards of performance.”100 92 ACE Final Rule, p. 32537. 93 ACE Final Rule, p. 32537. See ACE Final Rule, Table 1, p. 32537, for ranges of the percentage of potential HRI improvement. 94 CRS did not identify comments from these states regarding their views on presumptively approvable standards. See letter from the States of West Virginia, Alabama, Arkansas, Georgia, Indiana, Kansas, Kentucky, Louisiana, Michigan, Missouri, Montana, Nebraska, Ohio, Oklahoma, South Carolina, South Dakota, Texas, Utah, Wisconsin, and Wyoming and the Mississippi Department of Environmental Quality and the Mississippi Public Service Commission to EPA, ACE rulemaking docket, EPA-HQ-OAR-2017-0355-24627, October 31, 2018, pp. 6-9, https://www.regulations.gov/. 95 As of March 2020. See NACAA, “About NACAA,” http://www.4cleanair.org/about. 96 NACAA recommends that “[a]t a minimum” EPA “provide example calculations that convert sample HRI percentages drawn from EPA’s candidate technologies, both individually and in combination, across a representative inventory of sources into the rate-based CO2/MWh emission rate standard EPA is requiring for the performance standards.” Letter from NACAA to EPA, ACE rulemaking docket, EPA-HQ-OAR-2017-0355-23788, October 31, 2018, p. 4, https://www.regulations.gov/. 97 Letter from NACAA to EPA, p. 4. 98 ACE Final Rule, p. 32538. 99 ACE Final Rule, pp. 32536-37. 100 ACE Proposal, p. 44757. Congressional Research Service 17 The candidate technologies list has not changed from the ACE proposal.101 It includes the following:        Neural Network/Intelligent Sootblowers Boiler Feed Pumps Air Heater and Duct Leakage Control Variable Frequency Drives Blade Path Upgrade (Steam Turbine) Redesign/Replace Economizer Improved O&M Practices. According to EPA, these are the “most impactful” candidate technologies “because they can be applied broadly and are expected to provide significant HRI without limitations due to geography, fuel type, etc.”102 EPA estimated that HRI potential from the six HRI measures on the candidate technologies list ranges from 0.1% to 2.9%, and that HRI potential from O&M practices may range from zero to less than 2.0% depending on the unit’s historical O&M practices.103 The two candidate technologies reported in the EPA analysis showing highest HRI potential are steam turbine blade upgrades and the redesign/replacement of the economizer for cooling system heat recovery. These two technologies also have, according to EPA, the greatest potential of the candidate technologies to trigger preconstruction permitting requirements under the NSR program.104 EPA has asserted, based on stakeholder comments, that “if such HRI trigger NSR, the resulting requirements for analysis, permitting, and capital investments will greatly increase the cost of implementing those HRI technologies and, in the absence of NSR reforms, states will be more likely to determine that those technologies are not cost-effective when analyzing ‘other factors’ in determining a standard of performance for an individual facility.”105 EPA has proposed, but not yet finalized, a revision to the applicability test for certain power plants under NSR. EPA stated in the final ACE rule that it intends to take final action on the proposed NSR changes at a later date.106 EPA decided to retain the two candidate technologies— steam turbine blade upgrades and redesign/replace economizer—on the final list of candidate technologies because the agency “still expects these technologies to be generally applicable across the fleet of existing EGUs, and because the costs of the technologies are generally economical and reasonable.”107 EPA estimated the potential impact of applying the candidate technologies and projected “modest” emission changes under the ACE rule policy scenario compared to the reference scenario. See “Q: What CO2 emission effects did EPA estimate from the CPP repeal and from the ACE rulemakings?” For more information about EPA’s determination that HRI is the best system of emission reduction to reduce CO2 emissions from 101 ACE Proposal, p. 44757. 102 ACE Final Rule, p. 32536. 103 ACE Final Rule, p. 32537. 104 The NSR program generally requires emission limits based on the best available control technology when new facilities are built or when existing facilities make a change that increases emissions above specified thresholds. Historically, NSR applicability determinations have been contentious and extensively litigated. 105 ACE Final Rule, p. 32537. 106 ACE Final Rule, p. 32521. 107 ACE Final Rule, p. 32537. Congressional Research Service 18 existing coal-fired EGUs. For the agency’s consideration of other systems of GHG emission reduction, see “Q: What is the BSER under the ACE rule?” The final ACE rule does not limit states’ consideration of performance standards to the candidate technologies list, though EPA clarified that certain measures, such as biomass co-firing, cannot be used for compliance. See “Q: Can states use emission reduction measures outside the “candidate technologies” list to establish the ACE rule’s performance standards?” for additional discussion. Q: How will states establish CO2 emission performance standards? A: Although the ACE rule does not require a specific method for states to develop performance standards, EPA described two steps that it views as a “reasonable” approach for states to follow and document in their state plans.108 First, EPA expects states to establish unit-specific CO2 performance standards by calculating an emissions rate reflecting application of the BSER—that is, the candidate technologies—at each unit.109 For example, a state might apply the BSER to a designated facility’s average emission rate from the previous three years or to a projected emission rate under specific conditions.110 Second, states have discretion to tailor the emission rates based on site-specific considerations, such as remaining useful life and cost.111 That is, states are to consider the candidate technologies listed as the BSER—including EPA’s estimated ranges of HRI potential—but states may calculate a performance standard for a particular unit that falls outside of the range of EPA’s estimated HRI potential due to site-specific factors.112 Under EPA’s current interpretation of CAA Section 111(d), states may establish performance standards that are less stringent than the “standard that would result from a direct application of the BSER identified by the EPA.”113 EPA also clarified that a state may determine that one or more of the six candidate technologies “should not be part of the methodology to calculate the EGU’s standard of performance because of remaining useful life or other factors.”114 Finally, the ACE final rule requires states to set a rate-based standard in the form of an allowable emission rate.115 Q: Can states establish CAA Section 111(d) performance standards less stringent than otherwise expected from implementing the BSER? A: EPA interprets the CAA as requiring the agency to allow states to establish Section 111(d) performance standards that, based on site-specific considerations, are less stringent than the “standard that that would result from a direct application of the BSER identified by the EPA.”116 The agency based this interpretation on CAA Section 111(d)(1)(B), which directs EPA to 108 EPA clarified that states may conduct these steps sequentially or concurrently. ACE Final Rule, p. 32550. 109 ACE Final Rule, pp. 32549-50. 110 ACE Final Rule, p. 32550. 111 ACE Final Rule, pp. 32550, 32551. 112 ACE Final Rule, p. 32551. 113 ACE Final Rule, p. 32553. 114 EPA noted that the state should document its rationale and analysis, for example, “by explaining that such technology has already been implemented by a particular source.” ACE Final Rule, p. 32550. 115 ACE Final Rule, p. 32555. 116 ACE Final Rule, pp. 32553, 32570. Congressional Research Service 19 promulgate federal regulations that “shall permit the State in applying a standard of performance to any particular source under a plan submitted under this paragraph to take into consideration, among other factors, the remaining useful life of the existing source to which such standard applies.”117 EPA concluded that “Congress explicitly envisioned under CAA section 111(d)(1)(B) that states could implement standards of performance that vary from the EPA’s emission guidelines under appropriate circumstances.”118 Prior to the ACE rule, the general regulations implementing CAA Section 111(d) specified that state plans for health-based pollutants must be as stringent as the emission guideline established by EPA unless the state demonstrates, on a case-by-case basis, that a source meets certain factors.119 Previously referred to as the “variance provision,”120 it allowed a state to apply less stringent standards for health-based pollutants if the state demonstrated any of the following factors applied to a particular emission source:    unreasonable cost of control resulting from plant age, location, or basic process design; physical impossibility of installing necessary control equipment; or other factors specific to the facility (or class of facilities) that make application of a less stringent standard or final compliance time significantly more reasonable.121 EPA noted that promulgation of this provision predated the statutory language in CAA Section 111(d)(1)(B) that “the EPA permit states to take into account remaining useful life and other factors.”122 As part of the new implementing regulations for Section 111(d) that EPA promulgated with the ACE rule, the agency included a provision intended to reflect CAA Section 111(d)(1)(B). The new provision, codified at Title 40, Section 60.24a(e), of the Code of Federal Regulations, incorporates the statutory phrase remaining useful life but otherwise presents the same sourcespecific factors that were previously codified at Section 60.24(f). The new provision reads as follows: (e) In applying a standard of performance to a particular source, the State may take into consideration factors, such as the remaining useful life of such source, provided that the State demonstrates with respect to each such facility (or class of such facilities): (1) Unreasonable cost of control resulting from plant age, location, or basic process design; (2) Physical impossibility of installing necessary control equipment; or (3) Other factors specific to the facility (or class of facilities) that make application of a less stringent standard or final compliance time significantly more reasonable.123 117 42 U.S.C. §7411(d)(1)(B). 118 ACE Final Rule, p. 32570. 119 40 C.F.R. §60.24(f). 120 EPA referred to the provision at Title 40, Section 60.24(f), of the Code of Federal Regulations as the “variance provision” prior to promulgation of ACE. EPA stated that it will no longer refer to this section or its corollary under the new implementing regulations as the “variance provision.” Instead, EPA will refer to these provisions as “remaining useful life and other factors.” ACE Final Rule, p. 32570. 121 40 C.F.R. §60.24(f). Paragraph c specifies that state plans for health-based pollutants must be as stringent as the emission guideline established by EPA. 122 ACE Final Rule, p. 32570. 123 40 C.F.R. §60.24a(e). Congressional Research Service 20 The final rule requires a state that factors remaining useful life or other site-specific considerations into their determination of performance standards to “describe, justify, and quantify how the considerations were made in its plan.”124 States may also consider factors not listed in Section 60.24a(e), provided the state “adopts a reasonable approach and adequately explains that approach in its submission to the EPA.”125 In describing the codified list of site-specific factors as “nonexclusive,” EPA concluded that it is not possible to define “each and every circumstance that states may consider when applying a standard of performance under CAA section 111(d).”126 EPA provided examples of other sitespecific factors that may “influence decisions to invest in technologies to meet a potential performance standard,” including “timing considerations like expected life of the source, payback period for investments, the timing of regulatory requirements, and … space or other physical barriers to implementing certain HRIs at specific units.”127 EPA concluded that ultimately “many of these ‘other factors’ that can affect the application of the BSER candidate technologies distill down to a consideration of cost.”128 Q: What are the next steps to implement the ACE rule and what is the timeline? A: States are to develop performance standards for designated facilities—that is, existing, coalfired EGUs129—in their jurisdictions and establish these performance standards through state plans.130 States will also provide for the implementation and enforcement of the performance standards in the state plans. State plans are due to EPA by July 8, 2022.131 EPA is to determine whether a state plan is complete within 60 days of receiving the plan but no later than six months of receipt.132 Within 12 months of the completeness determination, EPA is to determine whether the plans are “satisfactory” under CAA Section 111(d)(2)(A) and either approve or disapprove the plan or portion of the plan through a notice-and-comment rulemaking.133 EPA is to promulgate a federal plan if (1) the state fails to submit a plan, (2) EPA determines that the state plan is incomplete, or (3) EPA disapproves the state plan.134 After determining that any of these circumstances applies, EPA has two years to issue the federal plan. This schedule for state and federal plans is specified in the implementing regulations for CAA Section 111(d). For discussion about changes to this schedule promulgated in the ACE rule, see 124 ACE Final Rule, p. 32554. 125 ACE Final Rule, p. 32571. 126 40 C.F.R. §60.24a(e). See also ACE Final Rule, pp. 32553, 32571. 127 ACE Final Rule, p. 32553. 128 ACE Final Rule, p. 32553. 129 For purposes of ACE, EPA defined designated facility as a coal-fired electric utility steam generating unit (coal- fired EGU) that commenced construction as of January 8, 2014, exceeds a specified nameplate capacity and base load rating, and burns coal for more than 10% of the average annual heat input during the three previous calendar years. EPA clarified that a “designated facility refers to a single EGU that is affected” by the ACE emission guidelines. ACE Final Rule, p. 32533. 130 The final rule also requires states in the contiguous United States without any designated facilities to submit a “negative declaration letter” to EPA in lieu of a state plan. 40 C.F.R. §§60.5710a, 60.5800a. 131 40 C.F.R. §§60.5710a, 60.5800a. 132 40 C.F.R. §60.27a(g). 133 40 C.F.R. §60.27a(b). See also ACE Final Rule, p. 32568. 134 40 C.F.R. §60.27a(c). See also ACE Final Rule, p. 32568. Congressional Research Service 21 “Q: What changes did EPA make to the schedules for submission and review of state plans and federal plans?” Q: When do existing coal-fired EGUs have to comply with performance standards established by states under the ACE rule? A: The date that the performance standards go into effect will be determined by each state’s plan. As previously noted, states will first need to develop performance standards for each affected unit in their jurisdictions and provide for implementation and enforcement through the state plans. State plans that contain compliance schedules longer than two years from the date of state plan submission to EPA must also include provisions for increments of progress.135 Prior to the ACE rule, the requirement to include provisions for “increments of progress” applied to plans with compliance schedules longer than 12 months from the date of submission to EPA.136 EPA updated timing criteria for this requirement to align with the changes it finalized to the schedule of state plan submission and EPA review. For information about these schedule changes, see “Q: What changes did EPA make to the schedules for submission and review of state plans and federal plans?” Q: What information must a state include in the state plan submission for existing coal-fired units? A: State plans must establish Section 111(d) performance standards for designated units and provide for their implementation and enforcement.137 First, to document establishment of performance standards, state plans are to explain how the state applied the BSER to each source and how the state considered other factors, such as remaining useful life, into the determination of the unit-specific standard.138 State plans “must adequately document and demonstrate the process and underlying data used to establish standards of performance” under the ACE rule so that EPA can “understand and replicate” the state’s calculations.139 In particular, a state plan must identify each EGU within the state’s jurisdiction that is subject to the ACE rule along with the emissions and operational data used to establish the performance standard for each unit. A state that considers the remaining useful life of a unit must “specify the exact date by which” the unit will no longer supply electricity to the grid.140 States that determine that HRI are not feasible at any particular unit must present the basis for that conclusion, including supporting data or metrics. Second, each state plan must specify how the state will implement and enforce the performance standards so that “EPA can review and identify measures that assure transparent and verifiable implementation.”141 According to EPA, state plans should demonstrate that the performance standards will be “quantifiable, permanent, verifiable, and enforceable.”142 135 EPA regulations define increments of progress as “steps to achieve compliance which must be taken by an owner or operator of a designated facility.” 40 C.F.R. §60.21a(h). See also ACE Final Rule, p. 32568. 136 40 C.F.R. §§60.24(e)(1), 60.21(h). 137 ACE Final Rule, p. 32558. 138 EPA, Fact Sheet: The Affordable Clean Energy Rule, 2019, https://www.epa.gov/sites/production/files/2019-06/ documents/bser_and_eg_fact_sheet_6.18.19_final.pdf. 139 ACE Final Rule, p. 32558. 140 A state may revise the state plan if the retirement date changes. ACE Final Rule, p. 32558. 141 ACE Final Rule, p. 32558. 142 ACE Final Rule, p. 32559. Congressional Research Service 22 Q: How does the ACE rule interact with existing GHG emission reduction programs in the states, such as the Regional Greenhouse Gas Initiative and California’s climate policies? A: Various U.S. states have already required power sector GHG emission reductions. California established a cap-and-trade program that took effect in 2013. California‘s cap covers multiple GHGs, which account for approximately 85% of California’s GHG emissions.143 In addition to its emissions cap, California has adopted a range of other climate change mitigation policies (e.g., renewable energy portfolio standards).144 A coalition of states from the Northeast and Mid-Atlantic regions established the Regional Greenhouse Gas Initiative (RGGI).145 RGGI is a cap-and-trade system that took effect in 2009 and currently involves 10 states.146 RGGI applies to CO2 emissions from electric power plants with capacities to generate 25 megawatts or more. While each state adopts its own regulations implementing RGGI, most have promulgated regulations similar to a model rule. In addition, Massachusetts has adopted GHG emission requirements beyond its commitment to RGGI.147 Pursuant to the 2008 Massachusetts Global Warming Solutions Act, the state’s Department of Environmental Protection promulgated regulations in 2017 requiring GHG emission reductions from several specific source categories. Some states raised concerns about how the ACE rule will interact with existing state and local programs. The interaction of the ACE rule and state and local GHG reduction programs has implications for state planning efforts. For example, it may be more efficient for states to rely on existing, non-federal GHG emission reduction programs to fulfill the ACE rule requirements rather than implementing separate state and federal standards for the same emission sources. NACAA observed that the ACE proposal was “silent on this topic” and described it as a “critical and complex issue for many air agencies.”148 NACAA requested EPA to ensure the final ACE rule “does not interfere with existing state and local programs including cap-and-trade programs and state-level GHG reduction goals” and that the ACE rule does not “prevent states from choosing to go further in stringency than the federal standard.”149 Additional state coalitions provided perspectives on federal-state interactions under the ACE rule. For example, the National Conference of State Legislatures commented that the proposed ACE rule would provide “significant authority and flexibility to states, allowing them to work within an overall framework while taking into account state and regional differences, ensuring sufficient flexibility for each state to determine how to best achieve nationally set goals.”150 Similarly, a 143 For more details, see the California Air Resources Board, “Cap-and-Trade Program,” https://www.arb.ca.gov/cc/ capandtrade/capandtrade.htm. 144 See California Air Resources Board, “Cap-and-Trade Program.” 145 See CRS Report R41836, The Regional Greenhouse Gas Initiative: Background, Impacts, and Selected Issues, by Jonathan L. Ramseur. 146 Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey (rejoined in 2020), New York, Rhode Island, and Vermont. 147 For more information, see Massachusetts Department of Environmental Protection, Background Document on Proposed, New and Amended Regulation, 2016, https://www.mass.gov/guides/reducing-ghg-emissions-under-section3d-of-the-global-warming-solutions-act. 148 Letter from NACAA to EPA, pp. 4-5. 149 Letter from NACAA to EPA, pp. 4-5. 150 The National Conference of State Legislatures (NCSL) represents the legislatures of states, territories, and commonwealths in the United States. Letter from NCSL to EPA, ACE rulemaking docket, EPA-HQ-OAR-2017-0355- Congressional Research Service 23 coalition of states commented that the proposed ACE rule affords “the States sufficient flexibility to comply with federal environmental mandates without disrupting the flow of affordable, reliable electricity to their citizens and the nation as a whole.”151 The final ACE rule does not prohibit states from implementing GHG programs under state authority. It is unclear, though, whether state plans that incorporate RGGI or other non-federal GHG emission reduction programs will meet the ACE rule requirements. First, EPA stated that it does not “prejudge the approvability of a state plan.”152 Second, the agency questioned whether it has statutory authority to approve state plans that include standards more stringent than those that would result from application of the BSER. While EPA found “merit” in some commenters’ view that the agency lacks authority to approve state plans establishing more stringent standards, the agency did not specify whether it agrees with this view.153 Instead, EPA concluded it would consider this question as it evaluates an individual state plan.154 EPA asserted that regardless of stringency, the agency lacks statutory authority to approve state plan requirements on entities other than existing, coal-fired EGUs—that is, those units qualifying as designated facilities under the ACE rule. According to EPA, CAA Section 111(d)(1) “clearly contemplates that state plans may only contain requirements for existing sources, and not other entities.”155 Q: Can states use emission reduction measures outside the “candidate technologies” list to establish the ACE rule’s performance standards? A: States may rely on measures that are not on the candidate technologies list to establish performance standards in their state plans provided that the measures meet EPA’s criteria.156 EPA’s criteria are as follows: (1) The compliance measures must be capable of being applied to and at the source and (2) compliance measure must be measurable at the source using data, emissions monitoring equipment or other methods to demonstrate compliance, such that they can be easily monitored, reported, and verified at the unit. 157 CCS is one example of an emission reduction measure excluded from the candidate technologies list that states may use as a compliance measure in state plans. EPA concluded that although CCS is not “broadly applicable to the entire existing coal-fired power plant fleet,” it may be a “technically feasible and an economically viable control option … under very specific circumstances.”158 Natural gas co-firing is another example.159 (For more information about why 23602, October 31, 2018, pp. 1-2, https://www.regulations.gov/. 151 Letter from the States of West Virginia, Alabama, Arkansas, Georgia, Indiana, Kansas, Kentucky, Louisiana, Michigan, Missouri, Montana, Nebraska, Ohio, Oklahoma, South Carolina, South Dakota, Texas, Utah, Wisconsin, and Wyoming; the Mississippi Department of Environmental Quality; and the Mississippi Public Service Commission to EPA, ACE rulemaking docket, October 31, 2018, EPA-HQ-OAR-2017-0355-24627, pp. 6-9 https://www.regulations.gov/. 152 ACE Final Rule, p. 32560. 153 ACE Final Rule, p. 32560. 154 ACE Final Rule, p. 32560. 155 ACE Final Rule, p. 32560. 156 ACE Final Rule, p. 32555. 157 ACE Final Rule, p. 32555. 158 ACE Final Rule, pp. 32547-48. 159 ACE Final Rule, p. 32555. Congressional Research Service 24 EPA excluded natural gas co-firing from the BSER, see “Q. Why did EPA exclude natural gas cofiring from the BSER?”). EPA prohibited certain measures from use in state plans as compliance measures based on its conclusion that they do not meet the compliance measure criteria. These measures are biomass co-firing and averaging-and-trading.160 EPA concluded that biomass co-firing did not meet the criteria because the “biomass firing in and of itself does not reduce emissions of CO2 emitted from that source. Specifically, when measuring stack emissions, biomass emits more CO2 per Btu than fossil fuels, thereby increasing the CO2 emission rate at the source.”161 The prohibition of averaging-and-trading—either across units at the same plant or between units located at different plants—as a compliance measure in the final rule marks a partial change from proposal. EPA had proposed to allow states to include in their plans “emissions averaging among [affected] EGUs across a single facility” but not between affected and non-affected units or between units at separate facilities.162 EPA’s definition of an individual EGU as a “designated facility” in the final rule led the agency to conclude that it could not allow emissions averaging across EGUs at the same plant. EPA concluded that it lacks authority to allow states to average emissions across multiple “designated facilities,” even if such units are located at the same plant.163 That is, EPA’s “determination that individual EGUs are subject to regulation under the ACE rule precludes the Agency from attempting to change the basic unit from an EGU to a combination of EGUs for purposes of the ACE rule implementation.”164 EPA stated more broadly that “trading is not permissible under CAA section 111.” EPA concluded that trading is not consistent with its current interpretation that CAA Section 111 requires a system of emission reduction to “be applied to and at an individual source and would lead to emission reductions from that source.” EPA observed that “the nature of trading as a compliance mechanism is such that some sources would not need to apply any pollution control techniques at all in order to comply with a cap-and-trade scheme.”165 Q. Why did EPA exclude natural gas co-firing from the BSER? A. EPA excluded natural gas co-firing166 from the ACE rule BSER based on its conclusion that a BSER based on natural gas co-firing would: (1) cost more than applying the HRI candidate technologies, (2) encourage inefficient use of natural gas, and (3) pose greater costs and 160 ACE Final Rule, p. 32555. 161 ACE Final Rule, pp. 32547, 32557-58. Stakeholders disagree about whether particular types of biomass are carbon neutral. EPA is developing a proposed action to establish the treatment of biogenic CO2 emissions from the use of certain biomass feedstocks at stationary sources under various CAA programs. See OMB, Semiannual Regulatory Agenda, EPA, RIN 2060-AU03, Fall 2019, https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=201910& RIN=2060-AU03; OMB, Semiannual Regulatory Agenda, EPA, RIN 2060-AU03, Spring 2020, https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202004&RIN=2060-AU03. A discussion of this topic is beyond the scope of this report. For more information about biomass, see CRS Report R41603, Is Biopower Carbon Neutral?, by Kelsi Bracmort. 162 ACE Proposal, p. 44767. 163 ACE Final Rule, pp. 32556-7. 164 ACE Final Rule, p. 32556. 165 ACE Final Rule, p. 32557. 166 According to EPA in the ACE rule, natural gas co-firing refers to the period when coal-fired utility boilers use natural gas for startup operations, for maintaining the unit in “warm standby,” or for nitrogen oxide control (either directly as a combustion fuel or in configuration referred to as natural gas reburn). ACE Final Rule, p. 32544. Congressional Research Service 25 challenges for units that currently have limited or no access to natural gas.167 Among other things, EPA analyzed fuel use data from the EIA. EPA concluded that while “nearly 35 percent of coalfired units” co-fired with natural gas in 2017, few of the units co-fired natural gas in an amount greater than 5% of the total annual heat input, suggesting to EPA that most of the natural gas was used as a secondary fuel for unit startup or to maintain the unit in “warm standby” rather than as a primary fuel to generate electricity.168 While EPA excluded natural gas co-firing from the BSER, the agency also noted that states may use natural gas co-firing as a compliance measure in state plans.169 For more information about use of non-BSER measures for compliance, see “Q: Can states use emission reduction measures outside the “candidate technologies” list to establish the ACE rule’s performance standards?” Stakeholder views regarding BSER and natural gas co-firing varied. Some stakeholders commented that natural gas co-firing should not be part of the BSER under the ACE rule because, for example, natural gas co-firing is not sufficiently cost-effective, there may not be a reliable supply of gas to co-fire, or it could negatively affect the unit’s heat rate.170 Other stakeholders disagreed and recommended natural gas co-firing as the BSER, based partly on analysis of the same fuel use data from EIA. According to EPA, these stakeholders concluded that natural gas cofiring at coal plants is “technically feasible, readily available, achieves significant emission reductions, and may be the most cost-effective option for some facilities.”171 One stakeholder estimated that “a highly cautious approach to increasing natural gas co-firing would more than double the emissions reductions under ACE” and observed that the costs of co-firing are comparable to the costs of heat rate improvements.172 Q: Why didn’t EPA establish a BSER for other fossil-fuel-fired units? A: EPA determined that it lacks “adequate information” to establish a BSER for other types of existing fossil-fuel-fired units, such as IGCC units and natural-gas-fired power plants.173 (Naturalgas-fired power plants, such as NGCC units, are also referred to as stationary combustion turbines.174) EPA reported that it “is still evaluating the data for EGUs not covered by the ACE 167 ACE Final Rule, p. 32545. 168 ACE Final Rule, p. 32543. 169 ACE Final Rule, p. 32555. 170 EPA, EPA’s Responses to Public Comments on the EPA’s Proposed Emission Guidelines for Greenhouse Gas Emissions From Existing Electric Utility Generating Units, June 2019, https://www.regulations.gov (Document ID EPA-HQ-OAR-2017-0355-26741, hereinafter “ACE RTC”). See chap. 4, p. 7. 171 Some stakeholders also recommended that EPA include natural gas co-firing on the list of HRI candidate technologies. ACE Final Rule, p. 32544. 172 See Resources for the Future, 10 Big Little Flaws in EPA’s Affordable Clean Energy Rule, July 2019, pp. 4-5, https://www.rff.org/documents/2138/IB_19-05_Burtraw_Keyes_4.pdf; and Resources for the Future, Letter to EPA Docket, EPA-HQ-OAR-2017-0355-25898, October 31, 2018, p. 24, https://www.regulations.gov. 173 ACE Final Rule, p. 32533. IGCC technology uses a gasifier to turn a feedstock—for example, coal or other carbonbased feedstock—into pressurized gas, which then fuels a combined cycle turbine to generate electricity. According to the National Energy Technology Laboratory, coal is the most commonly used feedstock in IGCC operations. See National Energy Technology Laboratory, “Commercial Power Production Based on Gasification,” https://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/igcc. The ACE final rule defines IGCC as “a combined cycle facility that it designed to burn fuels containing 50 percent (by heat input) or more solid-derived fuel not meeting the definition of natural gas plus any integrated equipment that provides electricity or useful thermal output to either the affected facility or auxiliary equipment.” 40 C.F.R. §60.5805a. 174 Stationary combustion turbines that are used to generate electricity are generally fueled by natural gas. The ACE final rule defines simple cycle and combined cycle units as stationary combustion turbines. It defines stationary combustion turbine as the equipment “that provides electricity or useful thermal output to the combustion turbine Congressional Research Service 26 rule,” noting that “only a handful” of IGCC units are in operation.175 EPA stated that it “may issue emission guidelines” for stationary combustion turbines at a later date.176 Comment letters revealed support for and opposition to EPA’s decision not to identify a BSER for stationary combustion turbines in the ACE rule. According to EPA, some commenters observed that “natural gas-fired stationary combustion turbines are already highly efficient” and concluded, among other things, that “available emission reductions at natural gas-fired stationary combustion turbines would likely be expensive or would likely provide only small overall reductions.”177 Other commenters disagreed with EPA’s decision and, according to EPA, these commenters stated that because EPA issued regulations under Section 111(b) for new natural-gas-fired turbines (including both simple cycle and combined cycle natural gas units), EPA is required under Section 111(d) to issue emission guidelines for the same category of existing natural gas units.178 Commenters that favored setting a BSER for stationary combustion turbines further recommended that EPA consider various technology options, including HRI, natural gas co-firing, CCS, and generation shifting.179 Commenters likewise expressed varying opinions regarding EPA’s conclusion that it lacks “adequate information” to determine the BSER for existing stationary combustion turbines. According to EPA, some commenters who supported EPA’s determination cited a “lack of information currently in the record.”180 For example, commenters stated that the cost is rarely reported for “hot gas path upgrades,” which they described as a “key action to improve gas turbine performance” but with “limited applicability.”181 Other commenters, though, pointed to information contained in rulemaking records—for example, public comments and analyses developed through the 2015 rulemakings for new and modified EGUs and the CPP—and asserted that EPA has not explained why the available information is “insufficient for the EPA to include HRI technologies at gas-fired plants in the BSER.”182 Commenters noted, according to EPA, that the agency’s decision not to establish a BSER in the ACE rule “is not based on a reasoned rejection of the evidence or any thoughtful conclusion that the described emission reduction opportunities are not adequately demonstrated.”183 engine, heat recovery system or auxiliary equipment.” For the complete definitions, including the types of equipment specified, see 40 C.F.R. §60. 5805a. 175 ACE RTC, see chap. 2, p. 12. 176 ACE RTC, see chap. 2, p. 27. 177 ACE RTC, see chap. 2, p. 23. Others suggest that older combustion turbines may not be as efficient as NGCC units. See, for example, Darrell Proctor, “Efficiency Improvements Mark Advances in Gas Turbines,” Power Magazine, January 3, 2018, https://www.powermag.com/efficiency-improvements-mark-advances-in-gas-turbines/; and S. C. Bhatia, “Cogeneration,” in Advanced Renewable Energy Systems (New Delhi, India: Woodhead Publishing India, 2014), pp. 490-508. 178 Commenters stated that the GHG endangerment finding and the 2015 promulgation of CO performance standards 2 under CAA Section 111(b) for new and modified fossil-fuel-fired EGUs requires EPA to issue emission standards for existing stationary combustion turbines and IGCC units. ACE RTC, see chap. 2, p. 12. 179 ACE RTC, see chap. 2, pp. 13-21. EPA stated that “because basing BSER on generation shifting is precluded by CAA section 111, the Agency is repealing the CPP and cannot consider generation shifting as part of the BSER in any future action” (ACE RTC, chap. 2, p. 20). For more information about EPA’s interpretation of CAA Section 111, see “Repeal of the Clean Power Plan.” 180 According to EPA, “Commenters stated that the Agency should not set a BSER for NGCCs given the lack of information currently in the record.” ACE RTC, see chap. 2, p. 13. 181 ACE RTC, see chap. 2, p. 12. 182 ACE RTC, see chap. 2, p. 14. 183 ACE RTC, see chap. 2, p. 14. Congressional Research Service 27 Litigation Challenging the CPP Repeal and the ACE Rule Q: Who is challenging the CPP Repeal, the ACE rule, and the revised implementing regulations? A: The American Lung Association and the American Public Health Association were the first parties to file a petition for review of the CPP repeal, ACE rule, and revised implementing regulations (the “rules”) in the D.C. Circuit on the day the rules were published in the Federal Register, July 8, 2019.184 Soon after, 22 states, the District of Columbia, and seven municipalities filed petitions for review.185 The State of Nevada has intervened in support of the petitioning states and municipalities, raising the number of states challenging the rules to 23 states.186 See Figure 4 for states involved in the litigation. As identified in litigation documents,187 other petitioners challenging the rules include 11 environmental organizations,188 several energy trade associations,189 six power companies, and an association of power companies.190 Many of the petitioners challenging the rules intervened in support of EPA in the litigation challenging the CPP.191 Collectively, the court refers to this group of petitioners as the “Coordinating Petitioners.”192 Various stakeholders have submitted briefs as amici curiae in support of these petitioners.193 Several Members of Congress filed amici curiae briefs opposing the CPP repeal and ACE rule.194 184 See Petition for Review, Am. Lung Ass’n v. EPA, No. 19-1140 (D.C. Cir. July 8, 2019). 185 See Petition for Review, New York v. EPA, No. 19-1165 (D.C. Cir. Aug. 13, 2019) (California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, Washington, Wisconsin, the District of Columbia, City of Boulder, City of Chicago, City of Los Angeles, City of New York, City of Philadelphia, and City of South Miami). The City and County of Denver filed a separate petition for review. City and County of Denver, Colorado v. EPA, No. 19-1777 (D.C. Cir. Sept. 4, 2019). 186 The State of Nevada voluntarily withdrew its petition for review and intervened in support of the other petitioning states and municipalities. See Orders, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Nov. 18-19, 2019) (granting motion to voluntarily dismiss Nevada’s petition for review, No. 19-1189; granting motion to intervene in support of the state and municipalities petitioners). 187 Unopposed Motion of Coordinating Petitioners for Extension and Modification of Briefing Schedule, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Mar. 19, 2020). 188 See Petition for Review, Appalachian Mountain Club v. EPA, No. 19-1166 (D.C. Cir. Aug. 14, 2019); Chesapeake Bay Foundation, Inc. v. EPA, No. 19-1173 (D.C. Cir. Aug. 29, 2019); 189 See Petition for Review, Am. Wind Energy Ass’n, and Solar Energy Industries Ass’n v. EPA, No. 19-1173 (D.C. Cir. Sept. 6, 2019); Petition for Review, Biogenic CO2 Coalition v. EPA, No. 19-1185 (D.C. Cir. Sept. 5, 2019); Advanced Energy Economy v. EPA, No. 19-1186 (D.C. Cir. Sept. 6, 2019). 190 Consolidated Edison, Inc. v. EPA, No. 19-1188 (D.C. Cir. Sept. 6, 2019). 191 See CRS Report R44480, Clean Power Plan: Legal Background and Pending Litigation in West Virginia v. EPA, by Linda Tsang for discussion of parties involved in the CPP litigation. 192 Order, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Mar. 23, 2020). 193 See, e.g., State and Muni. Petitioners’ Opening Brief at v-vi, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Apr. 17, 2020) (listing amici curiae that notified the court that they would submit briefs in support of the Coordinating Petitioners). 194 See Brief for Members of Congress as Amici Curiae in Support of Petitioners, Am. Lung Ass’n. v. EPA, No. 191140 (D.C. Cir. Apr. 24, 2020) (opposing the CPP repeal); Brief for U.S. Senators Sheldon Whitehouse, Jeff Merkley, Kirsten Gillibrand, Brian Schatz, and Edward J. Markey as Amici Curiae in Supporting the State and Muni. Petitioners, Congressional Research Service 28 Several coal and mining companies and industry groups are challenging EPA’s underlying authority to issue the ACE rule under CAA Section 111(d).195 And the Biogenic CO2 Coalition is petitioning EPA’s refusal to recognize biogenic CO2 emission from biomass fuel as carbon neutral or exempt from regulation under the ACE rule.196 Under CAA Section 307(b), the deadline for filing a petition for review of the rules with the D.C. Circuit was September 6, 2019.197 The court has consolidated all the petitions into one lead case, American Lung Association v. EPA.198 Figure 4. States and Municipalities Participating in the ACE Rule and CPP Repeal Litigation Consolidated Petitions: American Lung Ass’n v. EPA, No. 19-1140 (D.C. Circuit) Source: Prepared by CRS from litigation filing in American Lung Ass’n v. EPA, No. 19-1140 (D.C. Cir.). Notes: The map also includes the petitioner, District of Columbia. Pub. Health and Envtl. Petitioners, Power Co. Petitioners, and Clean Energy Trade Ass’n. Petitioners, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Apr. 24, 2020) (opposing the ACE rule). 195 See Petition for Review, Westmoreland Mining Holdings LLC v. EPA, No. 1176 (D.C. Cir. Sept. 5, 2019); Petition for Review, North Am. Coal Corp. v. EPA, No. 19-1179 (D.C. Cir. Sept. 5, 2019); Robinson Enterprises, Inc. v. EPA, No. 19-1175 (D.C. Cir. Sept. 6, 2019). 196 See Petition for Review, Biogenic CO2 Coalition v. EPA, No. 19-1185 (D.C. Cir. Sept. 5, 2019). 197 42 U.S.C. §7607(b). 198 Clerk’s Order, Am. Lung Ass’n v. EPA, No. 19-1140 (D.C. Cir. Sept. 2019) (issuing various orders consolidating petitions through September 11, 2019). Congressional Research Service 29 Q: Who are the respondents and intervenors in support of the rules? A: Respondents in the litigation are EPA and its Administrator (as of July 2020), Andrew Wheeler, in his official capacity.199 Parties that have intervened in support of respondents include 21states.200 See Figure 4. In total, 44 states, seven cities, and the District of Columbia are participating in the litigation.201 Other parties intervening in support of the EPA include three labor unions, a public utility commission, a number of rural electric cooperatives and an association representing them, several industry and trade groups, and more than a dozen fossil-fuel-related companies and local electric utilities.202 The National Association of Home Builders has submitted an amicus curiae brief in support of the respondents.203 Petitioning states, municipalities, and public health and environmental organizations have intervened on behalf of EPA to defend the agency’s underlying CAA authority to issue the ACE rule and oppose a regulatory exemption or relaxation of emission standards for biogenic CO2 emissions.204 Q: What are the main legal issues in the litigation? A: Petitioners challenge various aspects of the CPP repeal and the ACE rule as “arbitrary, capricious and not in accordance with law.”205 Under CAA Section 307(d), a court may reverse an 199 See Joint Proposal on Briefing Schedule and Format by EPA and Other Parties, No. 19-1140 (D.C. Cir. Dec. 18, 2019). The Department of Justice represents the respondents. 200 See Order, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Nov. 18, 2019) (granting motions to intervene by Alabama, Alaska, Arkansas, Georgia, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Texas, Utah, West Virginia, Wyoming). The State of West Virginia led a coalition of 20 states, not including North Dakota, to intervene in support of the ACE rule and CPP repeal. Motion of West Virginia and 20 States, State Officers, and State Agencies to Intervene as Respondents, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Sept. 12, 2019). The State of North Dakota intervened separately. North Dakota’s Motion to Intervene, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Sept. 6, 2019). 201 The six states not participating in the litigation at this time are Arizona, Florida, Idaho, Iowa, New Hampshire, and Tennessee. Of these six states, Idaho is the only state that does not have any affected EGUs under the ACE rule. ACE Final Rule, p. 32573. 202 Orders, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Sept. 11, 2019, Nov. 18, 2019) (granting motions to intervene by various industry groups and associations and power companies). 203 Brief of Amicus Curiae National Association of Home Builders in Support of Respondents, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. June 23, 2020). 204 Order, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Nov. 18, 2019) (granting motions to intervene by various industry groups and associations and power companies). See Initial Brief for Pub. Health and Envtl. RespondentInterverors at 20, Am. Lung Ass’n. v. EPA, No. 19-1140 (July 16, 2020) (arguing that “neither science nor law supports Biogenic Petitioner’s claims that biomass combustion is categorically carbon neutral, or that EPA lacks authority to regulate biogenic emissions.”) [hereinafter Public Health and Env’tl Intervernors’ Br.]. 205 See, e.g., State and Muni. Petitioners’ Opening Brief at 22, Am. Lung Ass’n. v. EPA, No. 19-1140 (D.C. Cir. Apr. 17, 2020) [hereinafter States and Muni. Pet’rs Br.] Although several petitioners also challenged EPA’s revised Section 111 implementing regulations in their petitions for review and statement of the issues, these petitioners did not set forth their legal arguments related to the revised implementing regulations in their briefs. See, e.g., State and Muni. Nonbinding Statement of Issues at 6, New York v. EPA, No. 19-1165 (consolidated with No. 19-1140) (D.C. Cir Oct. 7, 2019); Public Health and Env’tl Petitioners’ Joint Nonbinding Statement of Issues at 8, Am. Lung Ass’n. v. EPA, Nos. 1140, 1166 (D.C. Cir. Oct. 7, 2019); Petitioner’s Nonbinding Statement of Issues at 8, Chesapeake Bay Found., Inc. v. EPA, (D.C. Cir. Oct. 7, 2019). In general, petitioners forfeit a legal argument if they fail to rais [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/crs%3AR46482. Public record. Not legal advice.