Petition for Writ of Certiorari — The North American Coal Corporation, Petitioner v. Environmental Protection Agency, et al.
Supreme Court briefApr 30, 2021
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APPENDIX
1a
APPENDIX A
United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued: October 8, 2020
Decided: January 19, 2021
No. 19-1140
AMERICAN LUNG ASSOCIATION AND AMERICAN PUBLIC
HEALTH ASSOCIATION,
PETITIONERS
v.
ENVIRONMENTAL PROTECTION AGENCY AND ANDREW
WHEELER, ADMINISTRATOR,
RESPONDENTS
AEP GENERATING COMPANY, ET AL.,
INTERVENORS
Consolidated with 19-1165, 19-1166, 19-1173,
19-1175, 19-1176, 19-1177, 19-1179, 19-1185,
19-1186, 19-1187, 19-1188
On Petitions for Review of a Final Action
of the Environmental Protection Agency
2a
Steven C. Wu, Deputy Solicitor General, Office of the
Attorney General for the State of New York, argued
the cause for the State and Municipal petitioners and
intervenor Nevada. With him on the briefs were
Letitia James, Attorney General, Barbara D.
Underwood, Solicitor General, Matthew W. Grieco,
Assistant Solicitor General, Michael J. Myers, Senior
Counsel, Andrew G. Frank, Assistant Attorney
General of Counsel, Xavier Becerra, Attorney General,
Office of the Attorney General for the State of
California, Robert W. Byrne, Senior Assistant Attorney
General, David A. Zonana, Supervising Deputy
Attorney General, Jonathan A. Wiener, M. Elaine
Meckenstock, Timothy E. Sullivan, Elizabeth B.
Rumsey, and Theodore A.B. McCombs, Deputy
Attorneys General, William Tong, Attorney General,
Office of the Attorney General for the State of
Connecticut, Matthew I. Levine and Scott N.
Koschwitz, Assistant Attorneys General, Kathleen
Jennings, Attorney General, Office of the Attorney
General for the State of Delaware, Valerie S. Edge,
Deputy Attorney General, Philip J. Weiser, Attorney
General, Office of the Attorney General for the State
of Colorado, Eric R. Olson, Solicitor General, Robyn L.
Wille, Senior Assistant Attorney General, Clare E.
Connors, Attorney General, Office of the Attorney
General for the State of Hawaii, William F. Cooper,
Deputy Attorney General, Aaron M. Frey, Attorney
General, Office of the Attorney General for the State
of Maine, Laura E. Jensen, Assistant Attorney
General, Brian E. Frosh, Attorney General, Office of
the Attorney General for the State of Maryland, John
B. Howard, Jr., Joshua M. Segal, and Steven J.
Goldstein, Special Assistant Attorneys General,
3a
Maura Healey, Attorney General, Office of the
Attorney General for the Commonwealth of
Massachusetts, Melissa A. Hoffer and Christophe
Courchesne, Assistant Attorneys General, Megan M.
Herzog and David S. Frankel, Special Assistant
Attorneys General, Dana Nessel, Attorney General,
Office of the Attorney General for the State of
Michigan, Gillian E. Wener, Assistant Attorney
General, Keith Ellison, Attorney General, Office of the
Attorney General for the State of Minnesota, Peter N.
Surdo, Special Assistant Attorney General, Aaron D.
Ford, Attorney General, Office of the Attorney General
for the State of Nevada, Heidi Parry Stern, Solicitor
General, Gurbir S. Grewal, Attorney General, Office of
the Attorney General for the State of New Jersey, Lisa
J. Morelli, Deputy Attorney General, Hector Balderas,
Attorney General, Office of the Attorney General for
the State of New Mexico, Tania Maestas, Chief Deputy
Attorney General, Joshua H. Stein, Attorney General,
Office of the Attorney General for the State of North
Carolina, Asher Spiller, Assistant Attorney General,
Ellen F. Rosenblum, Attorney General, Office of the
Attorney General for the State of Oregon, Paul
Garrahan, Attorney-in-Charge, Steve Novick, Special
Assistant Attorney General, Josh Shapiro, Attorney
General, Office of the Attorney General for the
Commonwealth of Pennsylvania, Ann R. Johnston,
Senior Deputy Attorney General, Aimee D. Thomson,
Deputy Attorney General, Peter F. Neronha, Attorney
General, Office of the Attorney General for the State
of Rhode Island, Gregory S. Schultz, Special Assistant
Attorney General, Thomas J. Donovan, Jr., Attorney
General, Office of the Attorney General for the State
of Vermont, Nicholas F. Persampieri, Assistant
4a
Attorney General, Mark Herring, Attorney General,
Office of the Attorney General for the Commonwealth
of Virginia, Donald D. Anderson, Deputy Attorney
General, Paul Kugelman, Jr., Senior Assistant
Attorney General and Chief, Environmental Section,
Caitlin Colleen Graham O’Dwyer, Assistant Attorney
General, Robert W. Ferguson, Attorney General, Office
of the Attorney General for the State of Washington,
Christopher H. Reitz and Emily C. Nelson, Assistant
Attorneys General, Joshua L. Kaul, Attorney General,
Office of the Attorney General for the State of
Wisconsin, Gabe Johnson-Karp, Assistant Attorney
General, Karl A. Racine, Attorney General, Office of
the Attorney General for the District of Columbia,
Loren L. AliKhan, Solicitor General, Tom Carr, City
Attorney, Office of the City Attorney for the City of
Boulder, Debra S. Kalish, Senior Counsel, Mark A.
Flessner, Corporation Counsel, Office of the
Corporation Counsel for the City of Chicago, Benna
Ruth Solomon, Deputy Corporation Counsel, Jared
Policicchio, Supervising Assistant Corporation
Counsel, Kristin M. Bronson, City Attorney, Office of
the City Attorney for the City and County of Denver,
Lindsay S. Carder and Edward J. Gorman, Assistant
City Attorneys, Michael N. Feuer, City Attorney,
Office of the City Attorney for the City of Los Angeles,
Michael J. Bostrom, Assistant City Attorney, James E.
Johnson, Corporation Counsel, New York City Law
Department, Christopher G. King, Senior Counsel,
Marcel S. Pratt, City Solicitor, City of Philadelphia
Law Department, Scott J. Schwarz and Patrick K.
O’Neill, Divisional Deputy City Solicitors, and Thomas
F. Pepe, City Attorney, City of South Miami. Morgan
A. Costello and Brian M. Lusignan, Assistant
5a
Attorneys General, Office of the Attorney General for
the State of New York, Gavin G. McGabe, Deputy
Attorney General, Anne Minard, Special Assistant
Attorney General, Office of the Attorney General for
the State of New Mexico, Cynthia M. Weisz, Assistant
Attorney General, Office of the Attorney General for
the State of Maryland, entered appearances.
Kevin Poloncarz argued the cause for Power
Company Petitioners. With him on the briefs were
Donald L. Ristow and Jake Levine.
Mark W. DeLaquil argued the cause for Coal
Industry Petitioners. With him on the briefs were
Shay Dvoretzky, Charles T. Wehland, Jeffery D.
Ubersax, Robert D. Cheren, and Andrew Grossman.
Theodore Hadzi-Antich argued the cause for
Robinson Enterprises Petitioners. With him on the
briefs were Robert Henneke and Ryan D. Walters.
Sean H. Donahue and Michael J. Myers argued the
causes for Public Health and Environmental
Petitioners. On the briefs were Ann Brewster Weeks,
James P. Duffy, Susannah L. Weaver, Joanne
Spalding, Andres Restrepo, Vera Pardee, Clare
Lakewood, Howard M. Crystal, Elizabeth Jones,
Brittany E. Wright, Jon A. Mueller, David Doniger,
Benjamin Longstreth, Melissa J. Lynch, Lucas May,
Vickie L. Patton, Tomas Carbonell, Benjamin Levitan,
Howard Learner, and Scott Strand. Alejandra Nunez
entered an appearance.
David M. Williamson argued the cause and filed the
briefs for Biogenic Petitioners.
Gene Grace, Jeff Dennis, and Rick Umoff were on
the brief for petitioners American Wind Energy
Association, et al.
6a
Theodore E. Lamm and Sean B. Hecht were on the
brief for amicus curiae Thomas C. Jorling in support
of petitioners.
Gabriel Pacyniak, Brent Chapman, and Graciela
Esquivel were on the brief for amici curiae the
Coalition to Protect America’s National Parks and the
National Parks Conservation Association in support of
petitioners.
Deborah A. Sivas and Matthew J. Sanders were on
the brief for amici curiae Administrative Law
Professors in support of petitioners.
Hope M. Babcock was on the brief for amici curiae
the American Thoracic Society, et al. in support of
petitioners.
Richard L. Revesz and Jack Lienke were on the brief
for amicus curiae the Institute for Policy Integrity at
New York University School of Law in support of
petitioners.
Steph Tai was on the brief for amici curiae Climate
Scientists in support of petitioners.
Michael Burger and Collyn Peddie were on the brief
for amici curiae the National League of Cities, et al. in
support of petitioners.
Keri R. Steffes was on the brief for amici curiae
Faith Organizations in support of petitioners.
Shaun A. Goho was on the brief for amici curiae
Maximilian Auffhammer, et al. in support of
petitioners.
Ethan G. Shenkman and Stephen K. Wirth were on
the brief for amici curiae Patagonia Works and
Columbia Sportswear Company in support of
petitioners.
7a
Mark Norman Templeton, Robert Adam Weinstock,
Alexander Valdes, and Benjamin Nickerson were on
the brief for amicus curiae Professor Michael
Greenstone in support of petitioners.
Nicole G. Berner and Renee M. Gerni were on the
brief for amicus curiae the Service Employees
International Union in support of petitioners.
Elizabeth B. Wydra, and Brianne J. Gorod were on
the brief for amici curiae Members of Congress in
support of petitioners.
Jonas J. Monast was on the brief for amici curiae
Energy Modelers in support of petitioners.
Katherine Konschnik was on the brief for amici
curiae Former Commissioners of the Federal Energy
Regulatory Commission in support of petitioners.
Michael Landis, Elizabeth S. Merritt, and Wyatt G.
Sassman were on the brief for amici curiae
Environment America and National Trust for Historic
Preservation in support of petitioners.
Cara A. Horowitz was on the brief for amici curiae
Grid Experts in support of petitioners.
Eric Alan Isaacson was on the brief for amici curiae
U.S. Senators in support of petitioners.
Jonathan D. Brightbill, Principal Deputy Assistant
Attorney General, U.S. Department of Justice, and
Meghan E. Greenfield and Benjamin Carlisle,
Attorneys, argued the causes for respondents. With
them on the brief was Jeffrey Bossert Clark, Assistant
Attorney General.
Lindsay S. See, Solicitor General, Office of the
Attorney General for the State of West Virginia,
argued the cause for State and Industry intervenors in
8a
support of respondents regarding Affordable Clean
Energy Rule. With her on the brief were Patrick
Morrisey, Attorney General, Thomas T. Lampman,
Assistant Solicitors General, Thomas A. Lorenzen,
Elizabeth B. Dawson, Rae Cronmiller, Kevin G.
Clarkson, Attorney General at the time the brief was
filed, Office of the Attorney General for the State of
Alaska, Clyde Sniffen Jr., Attorney General, Leslie
Rutledge, Attorney General, Office of the Attorney
General for the State of Arkansas, Nicholas J. Bronni,
Solicitor General, Vincent M. Wagner, Deputy Solicitor
General, Dylan L. Jacobs, Assistant Solicitor General,
Steve Marshall, Attorney General, Office of the
Attorney General for the State of Alabama, Edmund
G. LaCour, Jr., Solicitor General, Christopher M.
Carr, Attorney General, Office of the Attorney General
for the State of Georgia, Andrew A. Pinson, Solicitor
General, Derek Schmidt, Attorney General, Office of
the Attorney General for the State of Kansas, Jeffrey
A. Chanay, Chief Deputy Attorney General, Curtis T.
Hill, Jr., Attorney General, Office of the Attorney
General of Indiana, Thomas M. Fisher, Solicitor
General, Andrew Beshear, Governor, Office of the
Governor for the Commonwealth of Kentucky, S.
Travis Mayo, Chief Deputy General Counsel, Taylor
Payne, Deputy General Counsel, Joseph A. Newberg,
Deputy General Counsel and Deputy Executive
Director, Jeff Landry, Attorney General, Office of the
Attorney General for the State of Louisiana, Elizabeth
B. Murrill, Solicitor General, Harry J. Vorhoff,
Assistant Attorney General, Eric S. Schmitt, Attorney
General, Office of the Attorney General for the State
of Missouri, D. John Sauer, Solicitor General, Julie
Marie Blake, Deputy Solicitor General, Timothy C.
9a
Fox, Attorney General at the time the brief was filed,
Office of the Attorney General for the State of
Montana, Matthew T. Cochenour, Deputy Solicitor
General, Wayne Stenehjem, Attorney General, Office
of the Attorney General for the State of North Dakota,
Paul M. Seby, Special Assistant Attorney General,
Douglas J. Peterson, Attorney General, Office of the
Attorney General for the State of Nebraska, Justin D.
Lavene, Assistant Attorney General, Dave Yost,
Attorney General, Office of the Attorney General of
the State of Ohio, Benjamin M. Flowers, Solicitor
General, Cameron F. Simmons, Principal Assistant
Attorney General, Mike Hunter, Attorney General,
Office of the Attorney General for the State of
Oklahoma, Mithun Mansinghani, Solicitor General,
Jason R. Ravnsborg, Attorney General, Office of the
Attorney General for the State of South Dakota,
Steven R. Blair, Assistant Attorney General, Alan
Wilson, Attorney General, Office of the Attorney
General for the State of South Carolina, James Emory
Smith, Jr., Deputy Solicitor General, Ken Paxton,
Attorney General, Office of the Attorney General for
the State of Texas, Kyle D. Hawkins, Solicitor General,
Sean Reyes, Attorney General, Office of the Attorney
General for the State of Utah, Tyler R. Green, Solicitor
General, Bridget Hill, Attorney General, Office of the
Attorney General for the State of Wyoming, James
Kaste, Deputy Attorney General, Todd E. Palmer,
William D. Booth, Obianuju Okasi, Carroll W.
McGuffey, III, Misha Tseytlin, C. Grady Moore, III,
Julia Barber, F. William Brownell, Elbert Lin, Allison
D. Wood, Scott A. Keller, Jeffrey H. Wood, Jeremy Evan
Maltz, Steven P. Lehotsky, Michael B. Schon, Emily
Church Schilling, Kristina R. Van Bockern, David M.
10a
Flannery, Kathy G. Beckett, Edward L. Kropp, Amy M.
Smith, Janet J. Henry, Melissa Horne, Angela Jean
Levin, Eugene M. Trisko, John A. Rego, Reed W. Sirak,
Michael A. Zody, Jacob Santini, Robert D. Cheren,
Mark W. DeLaquil, and Andrew M. Grossman. C.
Frederick Beckner, III, James R. Bedell, Margaret C.
Campbell, Erik D. Lange, and John D. Lazzaretti
entered an appearance.
James P. Duffy argued the cause for Public Health
and Environmental Intervenors in support of
respondents. With him on the brief were Ann Brewster
Weeks, Sean H. Donahue, Susannah L. Weaver,
Joanne Spalding, Andres Restrepo, Vera Pardee, Clare
Lakewood, Elizabeth Jones, Brittany E. Wright, Jon A.
Mueller, David Doniger, Benjamin Longstreth, Melissa
J. Lynch, Lucas May, Vickie L. Patton, Tomas
Carbonell, Benjamin Levitan, Howard Learner, and
Scott Strand.
Letitia James, Attorney General, Office of the
Attorney General for the State of New York, Michael
J. Myers, Senior Counsel, Brian Lusignan, Assistant
Attorney General of Counsel, Barbara D. Underwood,
Solicitor General, Steven C. Wu, Deputy Solicitor
General, Matthew W. Grieco, Assistant Solicitor
General, Xavier Becerra, Attorney General, Office of
the Attorney General for the State of California,
Robert W. Byrne, Senior Assistant Attorney General,
David A. Zonana, Supervising Deputy Attorney
General, Jonathan A. Wiener, M. Elaine Meckenstock,
Timothy E. Sullivan, Elizabeth B. Rumsey, and
Theodore A.B. McCombs, Deputy Attorneys General,
William Tong, Attorney General, Office of the
Attorney General for the State of Connecticut,
Matthew I. Levine and Scott N. Koschwitz, Assistant
11a
Attorneys General, Kathleen Jennings, Attorney
General, Office of the Attorney General for the State
of Delaware, Valerie S. Edge, Deputy Attorney
General, Philip J. Weiser, Attorney General, Office of
the Attorney General for the State of Colorado, Eric R.
Olson, Solicitor General, Robyn L. Wille, Senior
Assistant Attorney General, Clare E. Connors,
Attorney General, Office of the Attorney General for
the State of Hawaii, William F. Cooper, Deputy
Attorney General, Aaron M. Frey, Attorney General,
Office of the Attorney General for the State of Maine,
Laura E. Jensen, Assistant Attorney General, Brian
E. Frosh, Attorney General, Office of the Attorney
General for the State of Maryland, John B. Howard,
Jr., Joshua M. Segal, and Steven J. Goldstein, Special
Assistant Attorneys General, Maura Healey, Attorney
General, Office of the Attorney General for the
Commonwealth of Massachusetts, Melissa A. Hoffer
and Christophe Courchesne, Assistant Attorneys
General, Megan M. Herzog and David S. Frankel,
Special Assistant Attorneys General, Dana Nessel,
Attorney General, Office of the Attorney General for
the State of Michigan, Gillian E. Wener, Assistant
Attorney General, Keith Ellison, Attorney General,
Office of the Attorney General for the State of
Minnesota, Peter N. Surdo, Special Assistant Attorney
General, Aaron D. Ford, Attorney General, Office of
the Attorney General for the State of Nevada, Heidi
Parry Stern, Solicitor General, Gurbir S. Grewal,
Attorney General, Office of the Attorney General for
the State of New Jersey, Lisa J. Morelli, Deputy
Attorney General, Hector Balderas, Attorney General,
Office of the Attorney General for the State of New
Mexico, Tania Maestas, Chief Deputy Attorney
12a
General, Joshua H. Stein, Attorney General, Office of
the Attorney General for the State of North Carolina,
Asher Spiller, Assistant Attorney General, Ellen F.
Rosenblum, Attorney General, Office of the Attorney
General for the State of Oregon, Paul Garrahan,
Attorney-in-Charge, Steve Novick, Special Assistant
Attorney General, Josh Shapiro, Attorney General,
Office of the Attorney General for the Commonwealth
of Pennsylvania, Ann R. Johnston, Senior Deputy
Attorney General, Aimee D. Thomson, Deputy
Attorney General, Peter F. Neronha, Attorney
General, Office of the Attorney General for the State
of Rhode Island, Gregory S. Schultz, Special Assistant
Attorney General, Thomas J. Donovan, Jr., Attorney
General, Office of the Attorney General for the State
of Vermont, Nicholas F. Persampieri, Assistant
Attorney General, Mark Herring, Attorney General,
Office of the Attorney General for the Commonwealth
of Virginia, Donald D. Anderson, Deputy Attorney
General, Paul Kugelman, Jr., Senior Assistant
Attorney General and Chief, Environmental Section,
Caitlin Colleen Graham O’Dwyer, Assistant Attorney
General, Robert W. Ferguson, Attorney General, Office
of the Attorney General for the State of Washington,
Christopher H. Reitz and Emily C. Nelson, Assistant
Attorneys General, Karl A. Racine, Attorney General,
Office of the Attorney General for the District of
Columbia, Loren L. AliKhan, Solicitor General, Tom
Carr, City Attorney, Office of the City Attorney for the
City of Boulder, Debra S. Kalish, Senior Counsel,
Mark A. Flessner, Corporation Counsel, Office of the
Corporation Counsel for the City of Chicago, Benna
Ruth Solomon, Deputy Corporation Counsel, Jared
Policicchio, Supervising Assistant Corporation
13a
Counsel, Kristin M. Bronson, City Attorney, Office of
the City Attorney for the City and County of Denver,
Lindsay S. Carder and Edward J. Gorman, Assistant
City Attorneys, Michael N. Feuer, City Attorney,
Office of the City Attorney for the City of Los Angeles,
Michael J. Bostrom, Assistant City Attorney, James E.
Johnson, Corporation Counsel, New York City Law
Department, Christopher G. King, Senior Counsel,
Marcel S. Pratt, City Solicitor, City of Philadelphia
Law Department, Scott J. Schwarz and Patrick K.
O’Neill, Divisional Deputy City Solicitors, and Thomas
F. Pepe, City Attorney, City of South Miami were on
the brief for the State and Municipal Intervenors in
support of respondents. Jeremiah Langston, Assistant
Attorney General, Office of the Attorney General for
the State of Montana, Stephen C. Meredith, Solicitor,
Office of the Attorney General for the Commonwealth
of Kentucky, Margaret I. Olson, Assistant Attorney
General, Office of the Attorney General for the State
of North Dakota, and Erik E. Petersen, Assistant
Attorney General, Office of the Attorney General for
the State of Wyoming, and Robert A. Wolf entered
appearances.
Patrick Morrisey, Attorney General, Office of the
Attorney General for the State of West Virginia,
Lindsay S. See, Solicitor General, Thomas T.
Lampman, Assistant Solicitor General, Scott A. Keller,
Jeffrey H. Wood, Jeremy Evan Maltz, Steven P.
Lehotsky, Michael B. Schon, Thomas A. Lorenzen,
Elizabeth B. Dawson, Rae Cronmiller, Steve Marshall,
Attorney General, Office of the Attorney General for
the State of Alabama, Edmund G. LaCour, Jr.,
Solicitor General, Kevin G. Clarkson, Attorney
General, Office of the Attorney General for the State
14a
of Alaska at the time the brief was filed, Clyde Sniffen,
Jr., Attorney General, Leslie Rutledge, Attorney
General, Office of the Attorney General for the State
of Arkansas, Nicholas J. Bronni, Solicitor General,
Vincent M. Wagner, Deputy Solicitor General, Dylan
L. Jacobs, Assistant Solicitor General, Christopher M.
Carr, Attorney General, Office of the Attorney General
for the State of Georgia, Andrew A. Pinson, Solicitor
General, Derek Schmidt, Attorney General, Office of
the Attorney General for the State of Kansas, Jeffrey
A. Chanay, Chief Deputy Attorney General, Curtis T.
Hill, Jr., Attorney General, Office of the Attorney
General of Indiana, Thomas M. Fisher, Solicitor
General, Andrew Beshear, Governor, Office of the
Governor for the Commonwealth of Kentucky, S.
Travis Mayo, Chief Deputy General Counsel, Taylor
Payne, Deputy General Counsel, Joseph A. Newberg,
Deputy General Counsel and Deputy Executive
Director, Jeff Landry, Attorney General, Office of the
Attorney General for the State of Louisiana, Elizabeth
B. Murrill, Solicitor General, Harry J. Vorhoff,
Assistant Attorney General, Eric S. Schmitt, Attorney
General, Office of the Attorney General for the State
of Missouri, D. John Sauer, Solicitor General, Julie
Marie Blake, Deputy Solicitor General, Timothy C.
Fox, Attorney General at the time the brief was filed,
Office of the Attorney General for the State of
Montana, Matthew T. Cochenour, Deputy Solicitor
General, Wayne Stenehjem, Attorney General, Office
of the Attorney General for the State of North Dakota,
Paul M. Seby, Special Assistant Attorney General,
Douglas J. Peterson, Attorney General, Office of the
Attorney General for the State of Nebraska, Justin D.
Lavene, Assistant Attorney General, Dave Yost,
15a
Attorney General, Office of the Attorney General of
the State of Ohio, Benjamin M. Flowers, Solicitor
General, Cameron F. Simmons, Principal Assistant
Attorney General, Mike Hunter, Attorney General,
Office of the Attorney General for the State of
Oklahoma, Mithun Mansinghani, Solicitor General,
Jason R. Ravnsborg, Attorney General, Office of the
Attorney General for the State of South Dakota,
Steven R. Blair, Assistant Attorney General, Alan
Wilson, Attorney General, Office of the Attorney
General for the State of South Carolina, James Emory
Smith, Jr., Deputy Solicitor General, Ken Paxton,
Attorney General, Office of the Attorney General for
the State of Texas, Kyle D. Hawkins, Solicitor General,
Sean Reyes, Attorney General, Office of the Attorney
General for the State of Utah, Tyler R. Green, Solicitor
General, Bridget Hill, Attorney General, Office of the
Attorney General for the State of Wyoming, James
Kaste, Deputy Attorney General, Todd E. Palmer,
William D. Booth, Obianuju Okasi, Carroll W.
McGuffey, III, Misha Tseytlin, C. Grady Moore, III,
Julia Barber, F. William Brownell, Elbert Lin, Allison
D. Wood, Emily Church Schilling, Kristina R. Van
Bockern, David M. Flannery, Kathy G. Beckett,
Edward L. Kropp, Amy M. Smith, Janet J. Henry,
Melissa Horne, Angela Jean Levin, Eugene M. Trisko,
John A. Rego, Reed W. Sirak, Michael A. Zody, Jacob
Santini, Robert D. Cheren, Mark W. DeLaquil, and
Andrew M. Grossman were on the brief for State and
Industry Intervenors in support of respondents
regarding Clean Power Plan Repeal.
Wayne Stenehjem, Attorney General, Office of the
Attorney General for the State of North Dakota, and
Paul M. Seby, Special Assistant Attorney General,
16a
were on the brief for intervenor State of North Dakota
in support of the respondents. Jerry Stouck entered an
appearance.
Thomas J. Ward, Megan H. Berge, and Jared R.
Wigginton were on the brief for amicus curiae National
Association of Builders in support of respondents.
Before: MILLET, PILLARD, and WALKER, Circuit
Judges.
Opinion for the Court filed PER CURIAM.
Opinion concurring in part, concurring in the
judgment in part, and dissenting in part filed by
Circuit Judge WALKER.
17a
TABLE OF CONTENTS
I.
II.
Background ..................................................... 17
A.
The Clean Air Act ...................................... 17
B.
Electricity and Climate Change................ 21
1.
Electricity ......................................... 21
2.
Climate Change and the
Federal Government ........................ 24
C.
The Clean Power Plan ............................... 29
D.
The ACE Rule ............................................ 32
1.
Repeal of the Clean Power Plan ....... 32
2.
Best System of Emission
Reduction ........................................... 33
3.
Degree of Emission
Limitation Achievable ....................... 36
4.
Implementing Regulations ................ 38
E.
Petitions for Review .................................. 38
F.
Jurisdiction and Standard of Review ....... 39
Section 7411 ..................................................... 40
A.
B.
C.
Statutory Context ...................................... 40
1.
Text .................................................... 46
2.
Statutory History, Structure,
and Purpose ....................................... 59
3.
Compliance Measures ....................... 71
The Major Questions Doctrine .................. 74
1.
The EPA’s Regulatory Mandate ....... 75
2.
Best System of Emission
Reduction ........................................... 80
Federalism ................................................. 92
18a
III. The EPA’s Authority to Regulate Carbon
Dioxide Emissions Under Section 7411 ..... 98
A.
B.
The Coal Petitioners’ Challenges .............. 98
1.
Endangerment Finding ..................... 99
2.
Section 7411 and Section 7412’s
Parallel Operation ........................... 111
The Robinson Petitioners’ Challenges .... 132
IV. Amendments to the Implementing
Regulations ................................................... 138
V.
Vacatur and Remand .................................. 146
VI. Conclusion ..................................................... 147
19a
As the Supreme Court recognized nearly fourteen
years ago, climate change has been called “the most
pressing environmental challenge of our time.”
Massachusetts v. EPA, 549 U.S. 497, 505 (2007)
(formatting modified). Soon thereafter, the United
States government determined that greenhouse gas
emissions are polluting our atmosphere and causing
significant and harmful effects on the human
environment. Endangerment and Cause or Contribute
Findings for Greenhouse Gases Under Section 202(a)
of the Clean Air Act (2009 Endangerment Finding), 74
Fed. Reg. 66,496, 66,497–66,499 (Dec. 15, 2009). And
both Republican and Democratic administrations have
agreed: Power plants burning fossil fuels like coal “are
far and away” the largest stationary source of
greenhouse gases and, indeed, their role in greenhouse
gas emissions “dwarf[s] other categories[.]” EPA Br.
169; see also Standards of Performance for
Greenhouse Gas Emissions from New, Modified, and
Reconstructed Stationary Sources: Electric Utility
Generating Units (New Source Rule), 80 Fed. Reg.
64,510, 64,522 (Oct. 23, 2015) (fossil-fuel-fired power
plants are “by far the largest emitters” of greenhouse
gases).
The question in this case is whether the
Environmental Protection Agency (EPA) acted
lawfully in adopting the 2019 Affordable Clean Energy
Rule (ACE Rule), 84 Fed. Reg. 32,520 (July 8, 2019),
as a means of regulating power plants’ emissions of
greenhouse gases. It did not. Although the EPA has
the legal authority to adopt rules regulating those
emissions, the central operative terms of the ACE Rule
and the repeal of its predecessor rule, the Clean Power
Plan, 80 Fed. Reg. 64,662 (Oct. 23, 2015), hinged on a
20a
fundamental misconstruction of Section 7411(d) of the
Clean Air Act. In addition, the ACE Rule’s amendment
of the regulatory framework to slow the process for
reduction of emissions is arbitrary and capricious. For
those reasons, the ACE Rule is vacated, and the record
is remanded to the EPA for further proceedings
consistent with this opinion.
I. BACKGROUND
A. THE CLEAN AIR ACT
In 1963, Congress passed the Clean Air Act, 42
U.S.C. § 7401 et seq., “to protect and enhance the
quality of the Nation’s air resources so as to promote
the public health and welfare and the productive
capacity of its population[,]” id. § 7401(b)(1).
Animating the Act was Congress’ finding that “growth
in the amount and complexity of air pollution brought
about by urbanization, industrial development, and
the increasing use of motor vehicles[] has resulted in
mounting dangers to the public health and welfare[.]”
Id. § 7401(a)(2).
Section 111 of the Clean Air Act, which was added
in 1970 and codified at 42 U.S.C. § 7411, directs the
EPA to regulate any new and existing stationary
sources of air pollutants that “cause[], or contribute[]
significantly to, air pollution” and that “may
reasonably be anticipated to endanger public health or
welfare.” 42 U.S.C. § 7411(b)(1)(A); see id. § 7411(d), (f)
(providing that the EPA Administrator “shall”
regulate existing and new sources of air pollution). A
“stationary source” is a source of air pollution that
cannot move, such as a power plant. See id.
§ 7411(a)(3) (defining “stationary source” as “any
building, structure, facility, or installation which
21a
emits or may emit any air pollutant[]”). An example of
a common non-stationary source of air pollution is a
gas-powered motor vehicle. See Utility Air Regulatory
Group v. EPA (UARG), 573 U.S. 302, 308 (2014).
Within 90 days of the enactment of Section 7411, the
EPA Administrator was to promulgate a list of
stationary source categories that “cause[], or
contribute[] significantly to, air pollution[.]” 42 U.S.C.
§ 7411(b)(1)(A). In 1971, the Administrator included
fossil-fuel-fired steam-generating power plants on
that list. Air Pollution Prevention and Control: List of
Categories of Stationary Sources, 36 Fed. Reg. 5,931
(March 31, 1971); see also New Source Rule, 80 Fed.
Reg. at 64,527–64,528. Today’s power plants fall in
that same category. ACE Rule, 84 Fed. Reg. at 32,557
n.250.
Once a stationary source category is listed, the
Administrator must promulgate federal “standards of
performance” for all newly constructed sources in the
category. 42 U.S.C. § 7411(b)(1)(B). The Act defines a
“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 nonair quality health and environmental
impact
and
energy
requirements)
the
Administrator determines has been adequately
demonstrated.
Id. § 7411(a)(1).
Once such a new source regulation is promulgated,
the Administrator also must issue emission guidelines
22a
for already-existing stationary sources within that
same source category. 42 U.S.C. § 7411(d)(1)(A)(ii); see
also American Elec. Power Co., Inc. v. Connecticut
(AEP), 564 U.S. 410, 424 (2011).
While the new source standards are promulgated
and enforced entirely by the EPA, the Clean Air Act
prescribes a process of cooperative federalism for the
regulation of existing sources. Under that structure,
the statute delineates three distinct regulatory steps
involving three sets of actors—the EPA, the States,
and regulated industry—each of which has a flexible
role in choosing how to comply. See 42 U.S.C.
§ 7411(a)(1), (d). This allows each State to work with
the stationary sources within its jurisdiction to devise
a plan for meeting the federally promulgated
quantitative guideline for emissions. See id. § 7411(d).
The process starts with the EPA first applying its
expertise to determine “the degree of emission
limitation achievable through the application of the
best system of emission reduction” that “has been
adequately demonstrated.” 42 U.S.C. § 7411(a)(1); see
40 C.F.R. § 60.22a. That system must “tak[e] into
account the cost of achieving such reduction and any
nonair quality health and environmental impact and
energy requirements[.]” 42 U.S.C. § 7411(a)(1). Once
the Administrator identifies the best system of
emission reduction, she then determines the amount
of emission reduction that existing sources should be
able to achieve based on the application of that system
and adopts corresponding emission guidelines. Id.; see
also, e.g., ACE Rule, 84 Fed. Reg. at 32,523; Clean
Power Plan, 80 Fed. Reg. at 64,719.
23a
Each State then submits to the EPA a plan that (i)
establishes standards of performance for that State’s
existing stationary sources’ air pollutants (excepting
pollutants already subject to separate federal
emissions standards), and (ii) “provides for the
implementation and enforcement of such standards of
performance[]” by the State. 42 U.S.C. § 7411(d)(1); see
40 C.F.R. § 60.23a. The standards of performance
must “reflect[]” the emission targets that the EPA has
determined are achievable. 42 U.S.C. § 7411(a)(1). In
this context, a state standard need not adopt the best
system identified by the EPA to “reflect[]” it. Id.; see
40 C.F.R. § 60.24a(c). Instead, the Clean Air Act
affords States significant flexibility in designing and
enforcing standards that employ other approaches so
long as they meet the emission guidelines prescribed
by the Agency.
If a State fails to submit a satisfactory plan, the
EPA may prescribe a plan for that State. 42 U.S.C.
§ 7411(d)(2)(A); see 40 C.F.R. § 60.27a(c)–(e).
Similarly, if the State submits a plan but fails to
enforce it, the EPA itself may enforce the plan’s terms.
Id. § 7411(d)(2)(B).
The third and final set of relevant actors are the
regulated entities themselves, to which, under the Act,
the States may afford leeway in crafting compliance
measures. See Clean Power Plan, 80 Fed. Reg. at
64,666; ACE Rule, 84 Fed. Reg. at 32,555.
The EPA has exercised its authority under Section
7411 over the years to set emission limitations for
different types of air pollution from various categories
of existing sources. See 42 Fed. Reg. 12,022 (March 1,
1977) (fluorides from phosphate fertilizer plants); 42
24a
Fed. Reg. 55,796 (Oct. 18, 1977) (acid mist from
sulfuric acid plants); 44 Fed. Reg. 29,828 (May 22,
1979) (total reduced sulfur from kraft pulp plants); 45
Fed. Reg. 26,294 (April 17, 1980) (fluorides from
primary aluminum plants); 60 Fed. Reg. 65,387 (Dec.
19, 1995) (various pollutants from municipal waste
combustors); 61 Fed. Reg. 9905 (March 12, 1996)
(landfill gases from municipal solid waste landfills); 70
Fed. Reg. 28,606 (May 18, 2005) (mercury from coalfired power plants).
The Clean Air Act is a comprehensive statute that
includes a variety of regulatory programs for tackling
air pollution in addition to Section 7411. Regulated
parties may be subject to one or more programs. As
relevant here, the National Ambient Air Quality
Standards (NAAQS) provisions, 42 U.S.C. §§ 7408–
7410, govern the levels of specified air pollutants that
may be present in the atmosphere to protect air
quality and the public health and welfare. The
Hazardous Air Pollutants program, id. § 7412, directs
the EPA to establish strict emission limitations for the
most dangerous air pollutants emitted from major
sources. Section 7411’s cooperative federalism
program for existing sources operates as a gap-filler,
requiring the EPA to regulate harmful emissions not
controlled under those other two programs. Id.
§ 7411(d)(1)(i).
B. ELECTRICITY AND CLIMATE CHANGE
1. Electricity
Electricity powers the world. Chances are that you
are reading this opinion on a device that consumes
electricity. Yet two distinct characteristics of
electricity make its production and delivery in the
25a
massive quantities demanded by consumers an
exceptionally complex process. First, unlike most
products, electricity is a perfectly fungible commodity.
Grid Experts Amicus Br. 6. A watt of electricity is a
watt of electricity, no matter who makes it, how they
make it, or where it is purchased. Second, at least as
of now, this highly demanded product cannot be
effectively stored at scale after it is created. Paul L.
Joskow, Creating a Smarter U.S. Electricity Grid, 26
J. Econ. Persp. 29, 31–33 (2012).1 Instead, electricity
must constantly be produced, and is almost
instantaneously consumed. See Clean Power Plan, 80
Fed. Reg. at 64,677, 64,692; Grid Experts Amicus Br.
8.
Those unique attributes led to the creation of the
American electrical grid.2 The grid has been called the
Change in storage capacity is picking up speed. See
generally Richard L. Revesz & Burcin Unel, Managing the Future
of the Electricity Grid: Energy Storage and Greenhouse Gas
Emissions, 42 HARV. ENV’T L. REV. 139, 140–141 (2018)
(describing ongoing declines in cost of storage); LAZARD, LAZARD’S
LEVELIZED COST OF STORAGE ANALYSIS—VERSION 6.0 (2020)
(noting “storage costs have declined across most use cases and
technologies, particularly for shorter-duration applications, in
part driven by evolving preferences in the industry”).
Nevertheless, the grid’s production capacity still far exceeds its
present storage capacity. Univ. of Mich. Ctr. for Sustainable Sys.,
GRID
ENERGY
STORAGE
(Sept.
2020),
U.S.
http://css.umich.edu/sites/default/files/US%20Grid%20Energy%
20Storage_CSS15-17_e2020.pdf (last visited Jan. 11, 2021)
(United States has 1,100 gigawatts of installed generation
capacity and just 23 gigawatts of storage capacity).
1
Technically, “grids.” There are three regional grids in the
contiguous United States: Eastern, Western, and Texas. Grid
Experts Amicus Br. 9; see also United States Dep’t of Energy,
North
American
Electric
Reliability
Corporation
2
26a
“supreme engineering achievement of the 20th
century,” MASS. INST. OF TECH., THE FUTURE OF THE
ELECTRIC GRID 1 (2011) (formatting modified), and it
is an exceptionally complex, interconnected system.
“[A]ny electricity that enters the grid immediately
becomes a part of a vast pool of energy that is
constantly moving[.]” New York v. FERC, 535 U.S. 1,
7 (2002). That means that units of electricity as
delivered to the user are identical, no matter their
source. On the grid, there is no coal-generated
electricity or renewable-generated electricity; there is
just electricity. See Clean Power Plan, 80 Fed. Reg. at
64,692; Grid Experts Amicus Br. 7–8. Also, because
storing electricity for any length of time remains
technically challenging and often costly, the
components of the grid must operate as a perfectly
calibrated machine to deliver the amount of electricity
that all consumers across the United States need at
the moment they need it. Grid Experts Amicus Br. 8,
10–11; see also 80 Fed. Reg. at 64,677. “If [someone] in
Atlanta on the Georgia [leg of the] system turns on a
light, every generator on Florida’s system almost
instantly is caused to produce some quantity of
additional electric energy which serves to maintain
the balance in the interconnected system[.]” Federal
Power Comm’n v. Florida Power & Light Co., 404 U.S.
453, 460 (1972) (citation omitted). “Like orchestra
conductors signaling entrances and cut-offs, grid
operators use automated systems to signal particular
generators to dispatch more or less power to the grid
as needed over the course of the day, thus ensuring
Interconnections,
https://www.energy.gov/oe/downloads/northamerican-electric-reliability-corporation-interconnections (last
visited Jan. 11, 2021).
27a
that power pooled on the grid rises and falls to meet
changing demand.” Grid Experts Amicus Br. 11.
Most generators of electricity on the American grid
create power by burning fossil fuels like coal, oil, and
natural gas. See United States Energy Information
Administration (EIA), Frequently Asked Questions:
What Is U.S. Electricity Generation by Energy Source?
(Nov.
2,
2020),
https://www.eia.gov/tools/faqs/faq.php?id=427&t=3
(last visited Jan. 11, 2021) (fossil fuels represented
62.6 percent of electricity generation in 2019). Some of
those power plants take a fossil fuel (usually coal) and
burn it in a water boiler to make steam. Other power
plants take a different fossil fuel (usually natural gas),
mix it with highly compressed air, and ignite it to
release a combination of super-hot gases. Either way,
that steam or superheated mixture is piped into giant
turbines that catch the gases and rotate at extreme
speeds. Those turbines turn generators, which spin
magnets within wire coils to produce electricity. EIA,
Electricity
Explained
(Nov.
9,
2020),
https://www.eia.gov/energyexplained/electricity/howelectricity-is-generated.php (last visited Jan 11, 2021).
2. Climate Change and the Federal
Government
Electrical power has become virtually as
indispensable to modern life as air itself. But
electricity generation has come into conflict with air
quality in ways that threaten human health and wellbeing when power generated by burning fossil fuels
emits carbon dioxide and other polluting greenhouse
gases into the air.
28a
Since the late 1970s, the federal government has
focused “serious attention” on the effects of carbon
dioxide pollution on the climate. Massachusetts v.
EPA, 549 U.S. at 507. In 1978, Congress adopted the
National Climate Program Act, Pub. L. No. 95-367, 92
Stat. 601, which directed the President to study and
devise an appropriate response to “man-induced
climate processes and their implications[,]” id. § 3; see
Massachusetts v. EPA, 549 U.S. at 507–508. In
response, the National Academy of Sciences’ National
Research Council reported “no reason to doubt that
climate changes will result” if “carbon dioxide
continues to increase,” and “[a] wait-and-see policy
may mean waiting until it is too late.” Massachusetts
v. EPA, 549 U.S. at 508 (quoting CLIMATE RESEARCH
BOARD, CARBON DIOXIDE & CLIMATE: A SCIENTIFIC
ASSESSMENT, at viii (1979)).
In 1987, Congress passed the Global Climate
Protection Act, which found that “manmade
pollution[,]” including “the release of carbon dioxide,
* * * may be producing a long-term and substantial
increase in the average temperature on Earth[.]” Pub.
L. No. 100-204, Title XI, § 1102(1), 101 Stat. 1407,
1408 (codified at 15 U.S.C. § 2901 note). The Climate
Protection Act directed the EPA to formulate a
“coordinated national policy on global climate change.”
Id. § 1103(b), 101 Stat. at 1408; see Massachusetts v.
EPA, 549 U.S. at 508.
It was no until the Supreme Court’s 2007 decision
in Massachusetts v. EPA, however, that the Court
confirmed that carbon dioxide and other greenhouse
gas emissions constituted “air pollutant[s]” covered by
the Clean Air Act. See 549 U.S. at 528. The Supreme
Court explained that the Clean Air Act’s “sweeping
29a
definition of ‘air pollutant’ includes ‘any air pollution
agent or combination of such agents, including any
physical, chemical . . . substance or matter which is
emitted into or otherwise enters the ambient air[.]’” Id.
at 528–529 (quoting 42 U.S.C. § 7602(g)). The Act, the
Supreme Court held, “is unambiguous” in that regard.
Id. at 529. “On its face, the definition embraces all
airborne compounds of whatever stripe, and
underscores that intent through the repeated use of
the word ‘any.’” Id. And “[c]arbon dioxide” and other
common greenhouse gases are “without a doubt”
chemical substances that are “emitted into . . . the
ambient air.” Id. (quoting 42 U.S.C. § 7602(g)).
Given that statutory command, the Supreme Court
ruled that the EPA “can avoid taking further action”
to regulate such pollution “only if it determines that
greenhouse gases do not contribute to climate change”
or offers some reasonable explanation for not resolving
that question. Massachusetts v. EPA, 549 U.S. at 533.
Taking up the mantle, the EPA in 2009 found
“compelling[]” evidence that emissions of greenhouse
gases are polluting the atmosphere and are
endangering human health and welfare by causing
significant damage to the environment. 2009
Endangerment Finding, 74 Fed. Reg. at 66,497; see id.
(“[T]he Administrator finds that greenhouse gases in
the atmosphere may reasonably be anticipated both to
endanger public health and to endanger public
welfare. * * * The Administrator has determined that
the body of scientific evidence compellingly supports
this finding.”); id. at 66,497–66,499. The EPA
concluded that “‘compelling’ evidence supported the
‘attribution of observed climate change to
anthropogenic’ [that is, human-influenced] emissions
30a
of greenhouse gases[.]” AEP, 564 U.S. at 417 (quoting
74 Fed. Reg. at 66,518). The “[c]onsequent dangers of
greenhouse gas emissions,” the EPA determined,
include
increases in heat-related deaths; coastal
inundation and erosion caused by melting icecaps
and rising sea levels; more frequent and intense
hurricanes, floods, and other “extreme weather
events” that cause death and destroy
infrastructure; drought due to reductions in
mountain snowpack and shifting precipitation
patterns; destruction of ecosystems supporting
animals and plants; and potentially “significant
disruptions” of food production.
Id. (quoting 74 Fed. Reg. at 66,524–66,535).
Not long thereafter, the Supreme Court ruled that
the significant greenhouse gas pollution caused by
fossil-fuel-fired power plants is subject to regulation
under Section 7411 of the Clean Air Act. AEP, 564 U.S.
at 424 (holding that Section 7411 “speaks directly to
emissions of carbon dioxide from [fossil-fuel-fired]
plants[]”) (internal quotation marks omitted). The
Court concluded that the EPA’s expertise made it “best
suited to serve as primary regulator of greenhouse gas
emissions.” Id. at 428.
In 2015, with the 2009 carbon dioxide
endangerment finding continuing in effect, the EPA
reaffirmed that greenhouse gases “endanger public
health, now and in the future.” New Source Rule, 80
Fed. Reg. at 64,518. The EPA explained that, “[b]y
raising average temperatures, climate change
increases the likelihood of heat waves, which are
associated with increased deaths and illnesses[,]”
31a
particularly among “[c]hildren, the elderly, and the
poor[.]” Id. at 64,517. In addition, the EPA found that
“[c]limate change impacts touch nearly every aspect of
public welfare.” Id. Among the “multiple threats
caused by human emissions of [greenhouse gases],”
the EPA pointed to climate changes that “are expected
to place large areas of the country at serious risk of
reduced water supplies, increased water pollution, and
increased occurrence of extreme events such as floods
and droughts.” Id. The EPA “emphasize[d] the urgency
of reducing [greenhouse gas] emissions due to * * *
projections that show [greenhouse gas] concentrations
climbing to ever-increasing levels in the absence of
mitigation[,]” citing independent assessments finding
that, “without a reduction in emissions, CO2
concentrations by the end of the century would
increase to levels that the Earth has not experienced
for more than 30 million years.” Id. at 64,518.
The federal government’s consistent recognition of
the danger to public health and welfare caused by
climate change, and the signal contribution of
greenhouse gas emissions from power plants to global
warming, continues to the present. In 2018, President
Trump’s administration concluded that “Earth’s
climate is now changing faster than at any point in the
history of modern civilization, primarily as a result of
human activities.” U.S. GLOBAL CHANGE RESEARCH
PROGRAM, FOURTH NATIONAL CLIMATE ASSESSMENT,
VOLUME II: IMPACTS, RISKS, AND ADAPTATION IN THE
UNITED STATES (REPORT-IN-BRIEF) 24 (2018). The
administration added that “the evidence of humancaused climate change is overwhelming and continues
to strengthen,” and “the impacts of climate change are
intensifying across the country[.]” Id. at 26 (emphasis
32a
omitted). “Climate-related changes in weather
patterns and associated changes in air, water, food,
and the environment are affecting the health and wellbeing of the American people, causing injuries,
illnesses, and death.” Id. at 102. The administration’s
report concluded that urgent action is needed to
mitigate these dangers because “[f]uture risks from
climate change depend primarily on decisions made
today.” Id. at 13.
In preparing the ACE Rule, the EPA expressly
acknowledged its continued adherence to the 2015
endangerment finding. 84 Fed. Reg. at 32,533 (The
2015 New Source Rule “continues to provide the
requisite predicate for applicability of [Clean Air Act]
section 111(d).”); id. at 32,557 n.250; see also Emission
Guidelines for Greenhouse Gas Emissions from
Existing Electric Utility Generating Units; Revisions
to Emission Guideline Implementing Regulations;
Revisions to New Source Review Program: Proposed
Rule, 83 Fed. Reg. 44,746, 44,751 (Aug. 31, 2018)
(confirming that the 2015 New Source Rule “remains
on the books[]”); EPA Br. 217.
That endangerment finding provided the essential
factual foundation—and triggered a statutory
mandate—for the EPA to regulate greenhouse gas
emissions from both new and existing power plants.
See New Source Rule, 80 Fed. Reg. at 64,527, 64,529–
64,532; Clean Power Plan, 80 Fed. Reg. at 64,683–
64,690; see also 42 U.S.C. §§ 7411(b)(1)(A)–(B) (duty to
regulate new stationary sources that contribute
significantly to dangerous pollution identified in
endangerment finding), 7411(d)(1)(A)(ii) (duty to
regulate existing stationary sources that would be
regulated under § 7411(b) if they were new stationary
33a
sources). Recall, Section 7411(b)(1)(A) provides that
the EPA Administrator “shall” regulate any category
of sources that, “in his judgment * * * causes, or
contributes significantly to, air pollution which may
reasonably be anticipated to endanger public health or
welfare.” The EPA endangerment findings reflect such
well-established risks.
C. THE CLEAN POWER PLAN
In the last decade, the EPA has heavily focused its
regulation of greenhouse gases on the power sector
because “power plants are far and away the largest
stationary-category source of greenhouse gases[,]” and
“power plants’ contributions to CO2 pollution * * *
dwarf[] other categories[.]” EPA Br. 169.
In October 2015, the EPA issued greenhouse gas
emission standards for new and modified power
plants. See New Source Rule, 80 Fed. Reg. at 64,510.
In so doing, the EPA found that, “[a]ll told, these fossil
fuel-fired [power plants] emit almost one-third of all
U.S. [greenhouse gas] emissions, and are responsible
for almost three times as much as the emissions from
the next ten stationary source categories combined.”
Id. at 64,531. That rule and finding remain in effect
and are not challenged in this litigation.
The EPA then turned to the regulation of existing
power plants. The EPA began, as the Clean Air Act
requires, by determining the best system of emission
reduction that has been adequately demonstrated for
existing fossil-fuel-fired power plants. See 42 U.S.C.
§ 7411(a)(1); Clean Power Plan, 80 Fed. Reg. at 64,718.
In identifying that system, the EPA chose to build on
the established grid system and methods of operation
already adopted by and familiar to the power sector.
34a
See 80 Fed. Reg. at 64,725, 64,727–64,728. The
regulations and standards that the EPA formulated
came to be known as the Clean Power Plan. Id. at
64,663.
In the Clean Power Plan, the EPA determined that
a combination of three existing methods of emission
reduction—which the Plan referred to as building
blocks, 80 Fed. Reg. at 64,667—formed the “best
system of emission reduction,” 42 U.S.C. § 7411(a)(1).
First,
the
system
incorporated
heat-rate
improvements—that is, technological measures that
improve efficiency at coal-fired steam power plants
and, in that way, reduce the amount of coal that must
be burned to produce each watt of electricity to the
grid. 80 Fed. Reg. at 64,667.
Second, the system added the “substitut[ion of]
increased generation from lower-emitting existing
natural gas combined cycle units for generation from
higher-emitting affected steam generating” power
plants, which are mostly coal-fired. 80 Fed. Reg. at
64,667.
Third, the system prioritized the use of electricity
generated from zero-emitting renewable-energy
sources over electricity from the heavily greenhousegas-polluting fossil-fuel-fired power plants. 80 Fed.
Reg. at 64,667.
Those second and third methods of emission control
are often referred to as “generation shifting” because
the reductions occur when the source of power
generation shifts from higher-emission power plants
to less-polluting sources of energy. See Clean Power
Plan, 80 Fed. Reg. at 64,728–64,729. As the EPA
observed, such shifts in generation already occur all
35a
the time as a matter of grid mechanics. That is, within
the grid’s “Constrained Least-Cost Dispatch” system,
production from “generators with the lowest variable
costs” will be dispatched “first, as system operational
limits allow, until all demand is satisfied.” Grid
Experts Amicus Br. 12. “[R]enewable energy
generators typically receive dispatch priority because
they have lower variable costs than fossil-fuel-fired
generators, which must purchase fuel.” Id. at 13
(citing 80 Fed. Reg. at 64,693). The EPA found that
most electricity is generated by diversified utilities
that could achieve most or all of the shift to lower- or
no-emission generation by reassessing the dispatch
priority of their own assets. See 80 Fed. Reg. at 64,796,
64,804.
As required by Section 7411(a)(1), the EPA then
quantified the degree of emission reduction achievable
under that three-tier best system for the relevant
fossil-fuel-fired power plants and translated it into
state-specific emissions goals for 2030. Clean Power
Plan, 80 Fed. Reg. at 64,824–64,825. To permit
additional flexibility, the Plan actually provided two
alternative types of targets: rate-based goals,
reflecting the rate of emission per certain amount of
generation, and mass-based goals, reflecting the total
emission from a State’s sources. Id. at 64,820, 64,824–
64,825 Tables 12, 13. The alternative metrics were an
added source of flexibility for States in choosing how
they would meet the federal limits.
Under the Clean Air Act, States could then propose
plans that set standards of performance for their
existing power plants that would meet those emission
goals. Clean Power Plan, 80 Fed. Reg. at 64,664. In
doing so, the States and their power plants were under
36a
no obligation to use the three specific methods that the
EPA had identified in determining the best system of
emission reduction. Rather, consistent with Section
7411(d)’s cooperative federalism approach, States
were free to choose any measures, approaches, or
technologies that they deemed appropriate to meet the
federal guidelines. For example, they could adopt
technological controls already in use by some power
plants like carbon capture and sequestration (by
which carbon dioxide is captured from the plant’s flue
gas before it is emitted and then securely stored so it
cannot reach the atmosphere) or co-firing (where fuels
that release less carbon dioxide are burned alongside
fuels that release more to reduce the amount of the
latter used). See id. at 64,883. The EPA also suggested
that States might rely on emissions-trading programs
(often referred to as cap-and-trade) and other potential
compliance strategies. Id. at 64,887.
The EPA found that its proposed approach was
“consistent with, and in some ways mirrors, the
interconnected, interdependent and highly regulated
nature of the utility power sector[]” and its grid, as
well as “the daily operation of affected [power plants]
within this framework, and the critical role of utilities
in providing reliable, affordable electricity at all times
and in all places within this complex, regulated
system.” Clean Power Plan, 80 Fed. Reg. at 64,678.
The Clean Power Plan was challenged in this court.
West Virginia v. EPA, No. 15-1363 (and consolidated
cases) (D.C. Cir. Oct. 23, 2015). After we heard
argument en banc, but before we issued a decision,
that litigation was held in abeyance and ultimately
dismissed as the EPA reassessed its position. No. 151363, Docs. 1673071, 1806952.
37a
D. THE ACE RULE
In 2019, the EPA issued a new rule that repealed
and replaced the Clean Power Plan: The Affordable
Clean Energy (ACE) Rule. See 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 Fed. Reg. 32,520 (July
8, 2019). That Rule is the subject of this litigation.
1. Repeal of the Clean Power Plan
At the outset, the ACE Rule repealed the Clean
Power Plan. The EPA explained that it felt itself
statutorily compelled to do so because, in its view, “the
plain meaning” of Section 7411(d) “unambiguously”
limits the best system of emission reduction to only
those measures “that can be put into operation at a
building, structure, facility, or installation.” ACE
Rule, 84 Fed. Reg. at 32,523–32,524. Because the
Clean Power Plan’s best system was determined by
using some emission control measures that the EPA
characterized as physically operating off the site of
coal-fired power plants—such as some forms of
generation shifting and emissions trading—the EPA
concluded that it had no choice but to repeal the Plan.
Id. The EPA emphasized “that [its] action is based on
the only permissible reading of the statute and [it]
would reach that conclusion even without
consideration of the major question doctrine,” while
adding that application of that latter doctrine
“confirms the unambiguously expressed intent” of
Section 7411. Id. at 32,529.
38a
2. Best System of Emission Reduction
Considering its authority under Section 7411 to be
confined to physical changes to the power plants
themselves, the EPA’s ACE Rule determined a new
best system of emission reduction for coal-fired power
plants only. The EPA left unaddressed in this
rulemaking (or elsewhere) greenhouse gas emissions
from other types of fossil-fuel-fired power plants, such
as those fired by natural gas or oil. ACE Rule, 84 Fed.
Reg. at 32,533.
The EPA’s proposed system relied solely on heatrate improvement technologies and practices that
could be applied at and to existing coal-fired power
plants. ACE Rule, 84 Fed. Reg. at 32,525, 32,537. The
EPA selected only seven heat-rate improvement
techniques as components of its best system. Id. at
32,537. Six of those measures were new-to-the-plant
technologies or “equipment upgrades.” Id. at 32,536–
32,537 (naming as part of the best system (1) adding
or upgrading neural networks and intelligent
sootblowers; (2) upgrading boiler feed pumps; (3)
replacing or upgrading air heater and duct leakage
control devices; (4) adding variable frequency drives in
feed pumps and induced-draft fans; (5) blade path
upgrades; and (6) redesigning or replacing
economizers). The seventh measure was the use of
“best operating and maintenance practices”
implementing heat-rate improvement techniques. Id.
at 32,537, 32,540. The EPA limited itself to techniques
that could be “applied broadly” to the Nation’s coalfired plants, which primarily amounted to upgrades to
existing equipment. Id. at 32,536.
39a
The EPA explained that only five of the seven listed
techniques directly reduce the heat rate of power
plants. See ACE Rule, 84 Fed. Reg. at 32,538–32,540.
The other two techniques—replacing or upgrading the
boiler feed pump and installing variable frequency
drives—serve to reduce the amount of energy that a
power plant must use to run its own general
operations. Id. at 32,538–32,539.3 So those two
techniques do not make a power plant more efficient
in turning coal into power, but instead allow power
plants to dispatch more of the power they produce to
the grid rather than using it internally. Id.
The EPA identified two of its other chosen
techniques—blade path and economizer upgrades—as
the measures that, of all the considered technologies,
were “expected to offer some of the largest [heat-rate]
improvements.” ACE Rule, 84 Fed. Reg. at 32,537
(showing
table
predicting
highest
heat-rate
improvement range in economizer redesign or
replacements and blade path upgrades).4
The boiler feed pump is a device that is used to pump water
into the boiler. 84 Fed. Reg. at 32,538. It consumes a “large
fraction” of the power used to run the plant. Id. Because the boiler
feed pump requires so much energy, the EPA suggested that
“maintenance on these pumps should be rigorous to ensure both
reliability and high-efficiency operation.” Id. Variable frequency
drives “enable[] very precise and accurate speed control” of both
boiler feed pumps and “induced draft (ID) fans,” which “maintain
proper flue gas flow through downstream air pollutant control
equipment[.]” Id. at 32,539. This precise control would reduce the
excess use of fans and pumps, requiring less energy. See id.
3
“Blade path upgrades” consist of upgrades to the steam
turbine. Economizers are heat-exchange devices that “capture
waste heat from boiler flue gas” and use that captured heat to
help heat the boiler feedwater. Id. at 32,540.
4
40a
But the EPA then stated that it expected some
power plants would not adopt those two technologies
because their use could trigger additional regulation
that the companies would find burdensome. 84 Fed.
Reg. at 32,537 (“[B]ased on public comments * * *,
[blade path upgrades and economizer redesign or
replacement]
are
[heat-rate
improvement]
technologies that have the most potential to trigger
[New Source Review] requirements.”). In fact, the EPA
did not model those two techniques in its regulatory
impact analysis precisely because it was unlikely that
they would be adopted. J.A. 1656–1657.
Finally, the EPA acknowledged that the proposed
technologies could create a “rebound effect.” ACE
Rule, 84 Fed. Reg. at 32,542. A rebound effect means
that net carbon dioxide emissions actually increase as
a result of the efficiency improvements made by power
plants. Id. This happens because, as the efficiency
upgrades make coal-based energy cheaper to produce,
coal-fired power plants will have an incentive to run
more often, thereby increasing their overall emissions.
Id. The EPA found that risk of increased emissions
irrelevant because its best system of emission
reduction “is aimed at improving a source’s emissions
rate performance at the unit-level,” rather than
reducing the overall volume of emissions by individual
sources. Id. at 32,543.
In choosing its seven proposed power-plant-based
heat-rate improvement technologies, the EPA
excluded from its best system several other suggested
methods of reducing emissions, including (1) natural
gas co-firing, repowering, and refueling; (2) biomass
co-firing; and (3) carbon capture and storage
technologies. ACE Rule, 84 Fed. Reg. at 32,543–
41a
32,547. The EPA rejected biomass co-firing primarily
because “any potential net reductions in emissions
from biomass use occur outside of the regulated
source,” and so do not fall within the EPA’s reading of
Section 7411(d) as confined to emission limits imposed
at and to individual plants. Id. at 32,546. The EPA
excluded natural gas co-firing and carbon capture and
storage from its own best system, citing cost,
geographical, and operational concerns. Id. at 32,544–
32,545, 32,547–32,548. The EPA provided that sources
could choose to use natural gas co-firing or carbon
capture—but not biomass co-firing—to meet stateestablished standards of performance. Id. at 32,555.
3. Degree of Emission Limitation Achievable
Having determined its best system of emission
reduction, the EPA then purported to prescribe the
“degree of emission limitation achievable,” which
States could use to create their own standards of
performance. 42 U.S.C. § 7411(a)(1). What the EPA
produced as its emission guidelines was a chart that
prescribed heat-rate improvement “ranges” for each of
the EPA’s chosen heat-rate improvement technologies,
organized by power plants of differing sizes. ACE Rule,
84 Fed. Reg. at 32,537. The ranges show how much
heat-rate improvement can be “expected” from use of
each of the identified technologies. Id.
The EPA was explicit, though, that the “potential”
range of heat-rate reduction was only illustrative and
that the actual reduction for each of the EPA’s chosen
technologies would be “unit-specific” and would
“depend upon a range of unit-specific factors.” ACE
Rule, 84 Fed. Reg. at 32,537–32,538. In that way, the
ACE Rule made States responsible for evaluating
42a
“[heat-rate
improvement]
potential,
technical
feasibility, and applicability for each of the [best
system of emission reduction] candidate technologies”
on a power-plant-by-power-plant basis. Id. at 32,538.
The ACE Rule expressly left States free to establish
their own standards of performance for their power
plants that “reflect a value of [heat-rate improvement]
that falls outside” the ranges provided in the EPA’s
chart. Id. (emphasis added). In other words, the
minimums listed in the EPA’s emission-reduction
chart were only suggestions.
The EPA explained that its non-mandatory ranges
of efficiency reduction were valid because the
applicability of the heat-rate improvement techniques
to different plants and the effectiveness of each power
plant’s existing technology may vary. See ACE Rule,
84 Fed. Reg. at 32,538 (stating that “not all” of the
technologies would be “applicable or warranted at the
level of a particular facility due to source-specific
factors such as the site-specific operational and
maintenance history, the design and configuration,
[or] the expected operating plans”).
The EPA predicted that its ACE Rule would reduce
carbon dioxide emissions by less than 1% from
baseline emission projections by 2035. J.A. 1651. That
calculation did not reflect emission increases that
could result from the rebound effect.
4. Implementing Regulations
The ACE Rule included some new regulations under
Section 7411(d). ACE Rule, 84 Fed. Reg. at 32,575–
32,584 (codified at 40 C.F.R. pt. 60, subpart Ba). As
relevant here, the regulations significantly extend the
States’ deadlines for the development and submittal of
43a
their plans for emission reduction from nine months to
three years. See 40 C.F.R. § 60.23a(a)(1). Similarly,
the new regulations extend the EPA’s deadline to act
on those plans from four months to one year. 40 C.F.R.
§ 60.27a(b). The new regulations also extend the
EPA’s deadline to substitute its own plan for a noncompliant State’s plan from six months after the
submission deadline to two years after a finding that
the plan was incomplete, disapproved, or
unsubmitted. Seeb40 C.F.R. § 60.27a(c). Finally, the
requirement that States demonstrate compliance
progress is now triggered only where a State’s
compliance schedule stretches more than two years
from when its plan was originally due, as opposed to
the one-year period in the prior regulations. See 40
C.F.R. § 60.24a(d).
E. PETITIONS FOR REVIEW
Twelve petitions for review of the ACE Rule were
timely filed in this court and consolidated in this case.
Nos. 19-1140 (lead case), 19-1165, 19-1166, 19-1173,
19-1175, 19-1176, 19-1177, 19-1179, 19-1185, 19-1186,
19-1187, 19-1188. The petitioners fall into three
groups.
The first grouping consists of petitioners who seek
review of the ACE Rule’s conclusion that Section 7411
only permits emission reduction measures that can be
implemented at and applied to the source. Those
petitioners include (i) a coalition of State and
municipal governments; (ii) power utilities; (iii) trade
associations from the renewable energy industry; and
44a
(iv) several public health and environmental advocacy
groups.5
The second grouping is petitioners who challenge
the ACE Rule’s imposition of any emission limits as
unlawful because, in their view, (i) the EPA failed to
make a specific endangerment finding for carbon
dioxide emitted from existing power plants; (ii) the
EPA’s regulation of mercury emissions from coal-fired
power plants under Section 7412 precludes the
regulation of greenhouse gas emissions under Section
7411; and (iii) the EPA should have regulated carbon
dioxide from stationary sources, including power
plants, under the NAAQS program, 42 U.S.C.
§§ 7408–7410.
The third petitioner group is the Biogenic CO2
Coalition. They object only to the ACE Rule’s
determination that States may not count biomass cofiring as a method of complying with numerical
emission limits.
F. JURISDICTION AND STANDARD OF REVIEW
This court has jurisdiction to review these petitions
under the Clean Air Act. 42 U.S.C. § 7607(b)(1); see
also Sierra Club v. EPA, 955 F.3d 56, 61 (D.C. Cir.
2020).
We may set aside the ACE Rule if it is “arbitrary,
capricious, an abuse of discretion, or otherwise not in
accordance with law.” 42 U.S.C. § 7607(d)(1)(C),
(d)(9)(A); see also Maryland v. EPA, 958 F.3d 1185,
1196 (D.C. Cir. 2020) (“[W]e apply the same standard
The public health and environmental advocacy groups also
challenge the third prong of the ACE Rule—the new
implementing regulations—as arbitrary and capricious.
5
45a
of review under the Clean Air Act as we do under the
Administrative Procedure Act.”) (quoting Allied Local
& Reg’l Mfrs. Caucus v. EPA, 215 F.3d 61, 68 (D.C. Cir.
2000)).
II. SECTION 7411
A. STATUTORY CONTEXT
In enacting the Clean Air Act, “Congress delegated
to EPA the decision whether and how to regulate
carbon-dioxide
emissions
from
powerplants.”
American Elec. Power Co. v. Connecticut (AEP), 564
U.S. 410, 426 (2011). As the Supreme Court has
observed, 42 U.S.C. § 7411 “speaks directly to” and
outlines the framework for that regulation. Id. at 424
(internal quotation marks omitted). Specifically,
Section 7411 marks out a pair of distinct regulatory
tracks for stationary sources of air pollutants. See 42
U.S.C. § 7411(a)(2), (6). The first track applies to new
sources, id. § 7411(b), and the second to existing
sources, id. § 7411(d). The statute calls for federalstate cooperation in regulating existing sources,
affording distinct roles to the federal and state
agencies in arriving at what Section 7411 calls
“standards of performance” for the emission of air
pollutants. Id. § 7411(a)(1), (c), (d)(1).
The regulatory regimes for new and existing sources
differ in the process by which such standards are
established—and the roles played by the respective
regulatory actors. The Act assigns the EPA the main
regulatory role in specifying the new-source pollution
controls: After the EPA determines that a particular
“category of sources * * * causes, or contributes
significantly to, air pollution which may reasonably be
anticipated to endanger public health or welfare,” it
46a
publishes regulations establishing standards of
performance for new sources in that category. Id.
§ 7411(b)(1).
The process for regulating existing sources—which
raise distinct concerns about sunk costs and the health
and environmental effects of older processes—involves
more actors and steps. Regulation of a given category
of existing sources is triggered by the same EPA airpollution determination as for new sources. But for
existing sources the Act adopts a cooperativefederalism approach that leaves the States discretion
in determining how their State and industry can best
meet quantitative emissions guidelines established by
the EPA. See AEP, 564 U.S. at 424. Under Section
7411(d), the EPA and the States thus have distinct but
complementary roles subject to different procedures
and limitations. See 42 U.S.C. § 7411 (a)(1), (d)(1).
This case concerns the mechanics of that cooperative
framework for existing sources and, specifically,
restrictions the Agency now claims the statute
imposes on regulation of the air pollutants those
sources emit.
Two provisions of Section 7411 shape the existingsource framework. Subsection (a)(1) defines a
standard of performance, by reference to the “degree
of emission limitation” that the EPA determines is
“achievable,” 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 nonair quality health and environmental
47a
impact
and
energy
requirements)
the
Administrator determines has been adequately
demonstrated.
42 U.S.C. § 7411(a)(1).
Subsection (d)(1), in turn, requires the
Administrator to set up a system by which willing
States can submit to the EPA “a plan which []
establishes standards of performance for any existing
source.” Id. § 7411(d)(1). Only “where [a] State fails to
submit a satisfactory plan” may the EPA step in and
directly promulgate standards of performance for
existing sources. Id. § 7411(d)(2).
Putting these two provisions together results in
what are best understood as three distinct steps
involving three sets of actors, each exercising a degree
of leeway in choice of control measures. See ACE Rule,
84 Fed. Reg. at 32,533, 32,549–32,550; Clean Power
Plan, 80 Fed. Reg. at 64,665–64,666.
First, under subsection (a)(1), the EPA determines
the “best system of emission reduction” that is
“adequately demonstrated,” taking into consideration
certain enumerated statutory criteria: cost, any nonair
quality health and environmental impacts, and energy
requirements. 42 U.S.C. § 7411(a)(1). The Agency then
issues emission guidelines that quantify the “degree of
emission
limitation
achievable
through
the
application of the best system” it has identified. Id.; 40
C.F.R. § 60.22a; see AEP, 564 U.S. at 424; EPA Br. 21–
22; ACE Rule, 84 Fed. Reg. at 32,523, 32,551.
Second, under subsection (d)(1), States issue
standards of performance for existing sources that
comply with the EPA’s emission guidelines and
“reflect” the achievable degree of emission limitation
48a
set in those guidelines. AEP, 564 U.S. at 424; 42 U.S.C.
§ 7411(d)(1); 40 C.F.R. § 60.23a; see also Clean Power
Plan, 80 Fed. Reg. at 64,666. That the standards must
“reflect” the emission guidelines does not mean that
they must embody the methods EPA contemplated in
identifying the best system; rather, the States have
flexibility in determining the specifics of the standards
they issue so long as they accomplish the “degree of
emission limitation” the EPA calculated based on its
“best system.”
Third, the operators of regulated stationary sources
implement measures to ensure they will in practice
comply with the standards of performance their state
agency has established for them. See ACE Rule, 84
Fed. Reg. at 32,555. States often grant regulated
entities some discretion in how they meet those
standards. See, e.g., N.Y. COMP. CODES R. & REGS. TIT.
6 § 201-6.4(f) (2013) (describing the “operational
flexibility” afforded to Title V facility owners in New
York State to “propose a range of operating conditions
that will allow flexibility [for a facility] to operate
under more than one operating scenario”).
The issue before us arises at the first step—the
EPA’s determination of the best system of emission
reduction. In the Clean Power Plan, the Agency
determined that the best system was one that both
improved the heat rate at power plants and prioritized
generation from lower-emitting plants ahead of highemitting plants. Clean Power Plan, 80 Fed. Reg. at
64,707. The EPA then calculated specific emission
reductions achievable through application of that best
system that it published as emission guidelines for
States. Id. Had the Clean Power Plan gone into effect,
States would then have submitted to the EPA plans
49a
based on the Agency’s guidelines that established
standards of performance for sources in their
jurisdictions, as provided for in subsection (d)(1). The
Clean Power Plan left States flexibility in the
measures they included in their plans, so long as they
achieved a reduction in emissions at least as great as
that achieved by EPA-established quantitative
guidelines. See, e.g., id. at 64,665, 64,756–64,757,
64,734–64,737, 64,832–64,837. And it further allowed
States, at their option, to give leeway to sources to
select alternate compliance measures to make the
requisite reductions. See id. at 64,834–64,835.
Based on what it now perceives to be an express and
unambiguous textual limitation in Section 7411 that
it says the Clean Power Plan overlooked, the EPA
repealed that Plan and replaced it with the ACE Rule.
The EPA’s new reading of the statute requires the
Agency, in modeling its “best system of emission
reduction,” to consider only emission-reduction
measures that “can be applied at and to a stationary
source.” ACE Rule, 84 Fed. Reg. at 32,534; see also id.
at 32,526–32,532.
We address below the EPA’s arguments regarding
how the text and structure of Section 7411 purportedly
support this limitation. That discussion is necessarily
somewhat abstract and technical. So, for starters, it is
worth bringing the matter more concretely into view.
Consider the effect the EPA’s new statutory
interpretation had on its resulting Rule. First, because
generation shifting is not, in the EPA’s view, a
measure that can be applied “at and to” any one
individual source, the ACE Rule limits the best system
of emission reduction to heat-rate improvements
50a
alone. 84 Fed. Reg. at 32,534–32,535. Then, instead of
publishing emission guidelines quantifying emission
reductions achievable through application of the best
system, the ACE Rule identifies what the Agency has
determined are the most effective heat-rate
technologies available and a potential range of heatrate improvements achievable through application of
each of those technologies. Id. 32,535–32,537.
As under the Clean Power Plan, the ACE Rule
grants States flexibility in establishing standards of
performance for sources pursuant to the Agency’s
emission guidelines. Unlike the Clean Power Plan,
however, the ACE Rule does not require that the
States reach any specified minimum emission
reduction. Instead, States must merely “evaluate the
applicability of each of the candidate technologies” to
sources within their jurisdiction and report their
conclusions back to the Agency. ACE Rule, 84 Fed.
Reg. at 32,550, 32,538–32,561.
The Rule recites that regulated entities have “broad
discretion” in meeting state-established standards,
ACE Rule, 84 Fed. Reg. at 32,555, yet at the same time
the Rule deems impermissible any compliance
measure that cannot be applied at and to the source,
id. The ACE Rule thereby disqualifies compliance by,
for example, burning biofuel, id. at 32,557–32,558,
which emits recently captured carbon dioxide, in
contrast to fossil fuels’ release of carbon dioxide stored
away millions of years ago. See generally Center for
Biological Diversity v. EPA, 722 F.3d 401, 405–06
(D.C. Cir. 2013).
The question here is a relatively discrete one. We
are not called upon to decide whether the approach of
51a
the ACE Rule is a permissible reading of the statute
as a matter of agency discretion. Instead, the sole
ground on which the EPA defends its abandonment of
the Clean Power Plan in favor of the ACE Rule is that
the text of Section 7411 is clear and unambiguous in
constraining the EPA to use only improvements at and
to existing sources in its best system of emission
reduction.
The EPA contends that its current interpretation is
“the only permissible interpretation of the scope of the
EPA’s authority.” ACE Rule, 84 Fed. Reg. at 32,535.
Our task is to assess whether Section 7411 in fact
compels the EPA’s new interpretation. And because
“deference to an agency’s interpretation of a statute is
not appropriate when the agency wrongly believes
that interpretation is compelled by Congress,” Peter
Pan Bus Lines, Inc. v. Fed. Motor Carrier Safety
Admin., 471 F.3d 1350, 1354 (D.C. Cir. 2006) (quoting
PDK Labs., Inc. v. DEA, 362 F.3d 786, 798 (D.C. Cir.
2004) (internal quotation marks omitted)), we may not
defer to the EPA’s reading if it is but one of several
permissible interpretations of the statutory language,
see Negusie v. Holder, 555 U.S. 511, 521 (2009). That
is, the “regulation must be declared invalid, even
though the agency might be able to adopt the
regulation in the exercise of its discretion, if it ‘was not
based on the agency’s own judgment but rather on the
unjustified assumption that it was Congress’
judgment that such a regulation is desirable” or
required. Prill v. NLRB, 755 F.2d 941, 948 (D.C. Cir.
1985) (quoting FCC v. RCA Commc’ns, 346 U.S. 86, 96,
(1953) (formatting modified)); accord Arizona v.
Thompson, 281 F.3d 248, 259 (D.C. Cir. 2002) (quoting
Prill, 755 F.2d at 948).
52a
For the reasons explained below, Section 7411 does
not, as the EPA claims, constrain the Agency to
identifying a best system of emission reduction
consisting only of controls “that can be applied at and
to a stationary source.” ACE Rule, 84 Fed. Reg. at
32,534. The EPA here “failed to rely on its own
judgment and expertise, and instead based its decision
on an erroneous view of the law.” Prill, 755 F.2d at
956. We accordingly must vacate and remand to the
Agency “to interpret the statutory language anew.”
Peter Pan Bus Lines, 471 F.3d at 1354.
1. Text
As just noted, Section 7411 contemplates distinct
roles for the EPA and the States in regulating existing
stationary sources. See 42 U.S.C. § 7411(a)(1)
(granting authority to the EPA to designate the best
system and determine achievable degree of emissions
reduction); id. § 7411(d)(1) (outlining the States’ role
in setting standards of performance for their sources).
Nevertheless, the EPA now contends that language in
Section 7411(a)(1) and (d)(1) “unambiguously limits
the [best system of emission reduction] to those
systems that can be put into operation at a building,
structure, facility, or installation.” ACE Rule, 84 Fed.
Reg. at 32,524 (emphasis in original); see id. at 32,528;
EPA Br. 70.
In the Agency’s current view, the only pollutioncontrol methods the Administrator can consider in
selecting the “best system of emission reduction”
within the meaning of Section 7411(a) are add-ons or
retrofits confined to the level of the individual fossilfuel-fired power plant. ACE Rule, 84 Fed. Reg. at
32,524. That is so even though the record before the
53a
EPA shows that generation shifting to prioritize use of
the cleanest sources of power is one of the most costeffective means of reducing emissions that plants have
already adopted and that have been demonstrated to
work, and that generation shifting is capable of
achieving far more emission reduction than controls
physically confined to the source. See, e.g., Clean
Power Plan, 80 Fed. Reg. at 64,693, 64,728–64,729; 2
J.A. 598; Grid Experts Amicus Br. 13–16. In other
words, the EPA reads the statute to require the
Agency to turn its back on major elements of the
systems that the power sector is actually and
successfully using to efficiently and cost-effectively
achieve the greatest emission reductions. See Grid
Experts Amicus Br. 22 (observing that the ACE Rule
“imposes greater abatement costs on industry than
other approaches would to achieve the same effect”).
The Clean Power Plan could not stand, the EPA now
concludes, because its consideration of generation
shifting exceeded the Agency’s narrow authority under
Section 7411’s plain text. ACE Rule, 84 Fed. Reg. at
32,526–32,527. In promulgating the Clean Power
Plan, the EPA read “system of emission reduction” to
mean “a set of measures that work together to reduce
emissions and that are implementable by the sources
themselves.” Clean Power Plan, 80 Fed. Reg. at
64,762. And it concluded that both heat-rate
improvements
and
generation
shifting
“are
components of a best system of emission reduction for
the affected [electricity generating units] because they
entail actions that the affected [units] may themselves
undertake that have the effect of reducing their
emissions.” Id. at 64,709 (internal quotation marks
omitted).
54a
All of that is wrong, the EPA has since decided.
“[T]he Agency now recognizes that Congress ‘spoke to
the precise question’ of the scope of [42 U.S.C.
§ 7411](a)(1) and clearly precluded the unsupportable
reading of that provision asserted in the [Clean Power
Plan].” ACE Rule, 84 Fed. Reg. at 32,527. The EPA
insists that its current reading is mandated by the
statutory text.
It is the EPA’s current position that is wrong.
Nothing in Section 7411(a)(1) itself dictates the “at
and to the source” constraint on permissible
ingredients of a “best system” that the Agency now
endorses. For the EPA to prevail, its reading must be
required by the statutory text. Peter Pan Bus Lines,
471 F.3d at 1354. It fails for at least three reasons, any
of which is alone fatal.
First, the plain language of Section 7411(a)(1), the
root of the EPA’s authority to determine the best
system, announces its own limitations. Those
limitations simply do not include the source-specific
caveat that the EPA now interposes and casts as
unambiguous.
Second, there is no basis—grammatical, contextual,
or otherwise—for the EPA’s assertion that the sourcespecific language of subsection (d)(1) must be read
upstream into subsection (a)(1) to equate the EPA’s
“application of the best system” with the controls
States eventually will apply “at and to” an individual
source. As the EPA at times acknowledges, the two
subsections address distinct steps in the regulatory
process, one focused on the EPA’s role and the other
focused on the States’. Any question as to which
limitations pertain to each regulatory actor cannot
55a
reasonably be said to have been resolved by Congress
in favor of the unambiguous meaning the EPA now
advocates.
Third, even if subsections (a)(1) and (d)(1) were read
together in the way the EPA proposes, they would not
confine the EPA to designating a best system
consisting of at-the-source controls. The EPA’s entire
theory hinges on the Agency’s unexplained
replacement of the preposition “for” in “standards of
performance for any existing source” with the
prepositions “at” and “to.” Yet the statutory text calls
for standards of performance “for” existing sources.
Emission-reduction measures “for” sources may
readily be understood to go beyond those that apply
physically “at” and “to” the individual source.
Emissions trading, for example, might be a way “for”
a source to meet a standard of performance.
The shortcomings of its statutory interpretation are
more than enough to doom the Agency’s claim that
Section 7411 announces an unambiguous limit on the
best system of emission reduction. The issue is not
whether the EPA’s counterarguments to each of these
points might show its interpretation to be permissible
as an exercise of discretion. Again, the EPA has not
claimed to be exercising any such discretion here. It
insists instead that the unambiguous terms of the
statute tie its hands.
After reviewing what Section 7411 clearly says
about the nature and limits of the “best system of
emission reduction” that Congress called on the EPA
to determine, we take up each of the EPA’s arguments
to show why Section 7411 does not unambiguously
support its at-the-source restriction.
56a
a. Section 7411(a) Defines the Best System
The EPA acknowledges, as it must, that Section
7411(a) is the source of the EPA’s authority and
responsibility to determine the best system of
emission reduction for existing sources and set
corresponding emission guidelines. See, e.g., ACE
Rule, 84 Fed Reg. at 32,534. Indeed, that is the only
subsection in which the term “best system of emission
reduction” appears. But the EPA offers no reading of
subsection (a)(1) itself.
Section 7411(a)(1) expresses Congress’ expectation
that the EPA will study all “adequately demonstrated”
means of emission reduction. And it directs the EPA to
draw on “adequately demonstrated” methods to
determine the “best” system to reduce emissions.
Congress imposed no limits on the types of measures
the EPA may consider beyond three additional
criteria: cost, any nonair quality health and
environmental impacts, and energy requirements. 42
U.S.C. § 7411(a)(1). Congress largely called on the
expert judgment of the EPA to determine for a
particular source category and pollutant which
already-demonstrated methods compose the “best
system.”
Because it did not set out separate definitions for
either “system” or “best,” those words take their
ordinary meanings. See Sandifer v. United States Steel
Corp., 571 U.S. 220, 227 (2014). Webster’s Dictionary
offers a representative definition of “system”
contemporaneous with the Act’s adoption: “[A]
complex unity formed of many often diverse parts
subject to a common plan or serving a common
THIRD
NEW
purpose.”
System,
WEBSTER’S
57a
INTERNATIONAL DICTIONARY OF THE ENGLISH
LANGUAGE UNABRIDGED 2322 (2d ed. 1968). The
superlative “best” as applied to a “system of emission
reduction” plainly places a high priority on efficiently
and effectively reducing emissions. See Best, MerriamWebster,
https://www.merriamwebster.com/dictionary/best (last visited Jan. 11,
2021) (“excelling all others,” “offering or producing the
greatest advantage, utility, or satisfaction”).
The ordinary meanings of these terms “reflect[] an
intentional effort to confer the flexibility necessary”
for effective regulation appropriate to the context.
Massachusetts v. EPA, 549 U.S. 497, 532 (2007). As the
Supreme Court has acknowledged, “the degree of
agency discretion that is acceptable varies according
to the scope of the power congressionally conferred.”
Whitman v. American Trucking Ass’n, 531 U.S. 457,
475 (2001); see Gaughf Props., L.P. v. Commissioner,
738 F.3d 415, 424–425 (D.C. Cir. 2013); Sabre, Inc. v.
Department of Transp., 429 F.3d 1113, 1122, 1124–
1125 (D.C. Cir. 2005). Congress in Section 7411
deliberately charged the EPA with identifying the best
system of emission reduction to keep pace with
escalating threats to air quality, and, within expressed
limits, empowered it to make the judgments how best
to do so.
The Agency simply ignores how the statutory text
defines the “best system of emission reduction,”
asserting instead that definitional language does not
confer regulatory authority. See, e.g., EPA Br. 58–59
(“[I]t is not Section 7411(a) (‘Definitions’) that grants
the agency authority to act.”). Section 7411(a)(1)’s
designation as a definitional provision deprives it of
standalone meaning, the EPA contends. The EPA
58a
instead reads it as “subsidiary” to Section 7411(d),
regarding state standards of performance for existing
sources. EPA Br. 58. But Congress does indeed use
definitional provisions to confer regulatory authority.
See, e.g., Weinberger v. Bentex Pharm., Inc., 412 U.S.
645, 652–653 (1973) (holding that the statutory
definition of “new drug” confers authority upon the
FDA). That is precisely what it did in Section
7411(a)(1). See Sierra Club v. Costle, 657 F.2d 298, 321
(D.C. Cir. 1981) (describing Section 7411(a)(1) as
authorizing the EPA to determine the best system of
emission reduction and regulate accordingly); 40
C.F.R. 60.22a.
The EPA offers no support—apart from its own
newfound version of “statutory interpretation 101,”
EPA Br. 65—for ignoring how the Act itself defines
and limits the “best system” determination. Nor does
it offer any sound justification for importing language
from a different provision governing States’
“standards of performance.” The EPA’s “at and to the
source” limitation on “best system” finds no footing in
the text of Section 7411(a)(1).
b. Section 7411(d)(1) Does Not Change
the Definition
Even taking the EPA’s argument on its own terms
does not work because Section 7411(d)(1)’s text and
statutory context get it no further. To support its
narrow reading of the EPA’s authority to determine
the “best system,” the Agency focuses on the phrase
“through the application of” in Section 7411(a)(1).
That provision defines a “standard of performance” as
an emission standard that “reflects the degree of
emission
limitation
achievable
through
the
59a
application of the best system of emission reduction[.]”
The EPA says the “application” phrase “requires both
a direct object and an indirect object.” ACE Rule, 84
Fed. Reg. at 32,524; accord EPA Br. 66–68. And, it
continues, Congress cannot have meant to leave its
indirect object undefined. The EPA says that,
grammatically speaking, someone must apply
something (the direct object) to something else (the
indirect object). EPA Br. 115–116, 118–119. It then
picks its preferred, narrow indirect object from a
different statutory subsection and casts that object as
the only statutorily permissible choice. See 84 Fed
Reg. at 32,524.
The EPA locates an indirect object in Section
7411(d). Unlike subsection (a)(1), subsection (d)—
entitled “Standards of performance for existing
sources”—explicates an indirect object. 42 U.S.C.
§ 7411(d). Borrowing from subsection (d), then, the
EPA imports into subsection (a)(1) a limitation of the
“best system of emission reduction” to measures that
can be applied “to and at an individual existing
source—i.e., any building or facility subject to
regulation.” EPA Br. 58 (emphasis added); see also
ACE Rule, 84 Fed. Reg. at 32,534.
But the language to which the EPA points supplies
the indirect object only of “standards of performance”
adopted by States pursuant to Section 7411(d)(1), not
of the EPA’s “best system of emission reduction”
determined pursuant to Section 7411(a)(1). The latter
phrase does not even appear in Section 7411(d)(1). To
reach its preferred result, the Agency invokes surmise
rather than statutory text. It insists that the
limitations on States’ standards of performance in
Section 7411(d)(1)—the second step in the regulatory
60a
process—must be read upstream to limit the EPA’s
“best system of emission reduction” in subsection
(a)(1). Nothing in the statute so requires.
In the text, States’ standards of performance need
only “reflect” the emission guidelines (or “degree of
emission limitation achievable”) the EPA calculates
based on the “best system of emission reduction” it
determines. As laid out in the statute and explained
above,
those
state-developed
“standards
of
performance” follow on but are legally and
functionally distinct from the “best system” that the
EPA develops. The EPA is simply wrong that the
statute clearly and unambiguously requires that the
unstated indirect object of “application of the best
system of emission reduction” under Section
7411(a)(1) must be the same as the indirect object of
States’ standards of performance as stated in Section
7411(d)(1).
Neither does the grammatical rule the EPA invokes
to bridge the gap between these subsections hold up.
The crux of the EPA’s textual argument is that “the
verb ‘to apply,’ requires both a direct object and an
indirect object.” ACE Rule, 84 Fed. Reg. at 32,524;
EPA Br. 66–68. The first obvious problem is that, in
the relevant passage of Section 7411(a)(1), Congress
did not use the verb “apply,” but rather the noun
“application.” The EPA acknowledges this distinction
in passing in the ACE Rule, but dismisses it without
discussion, offering only that “‘application’ is derived
from the verb ‘to apply[.]’” 84 Fed. Reg. at 32,524. That
is, of course, true, as far as it goes. The phrase
“application of the best system of emission reduction”
is what is called a nominalization, a “result of forming
a noun or noun phrase from a clause or a verb.”
61a
Nominalization,
Merriam-Webster
Dictionary
https://www.merriamwebster.com/dictionary/nominalization (last visited
Jan. 11, 2021). Grammar assigns direct or indirect
objects only to verbs—not nouns. No objects are
needed to grammatically complete the actual
statutory phrase. So much for the grammatical
imperative.
Even if we were to take the EPA’s leap to the verb
“apply” from the noun “application” that actually
appears in the statute, the Agency comes up short. The
EPA is incorrect to insist that the verb “apply”
requires an indirect object. There is nothing
ungrammatical about the sentence “In its effort to
reduce emissions, the EPA applied the best system of
emission reduction.” The verb “apply,” like its
nominalization, may properly be used in a sentence
with or without an explicit indirect object. See Apply,
THOMAS HERBST ET AL., A VALENCY DICTIONARY OF
ENGLISH 41–42 (Ian F. Roe et al. eds., 2004) (listing
examples of grammatically correct uses with and
without direct and indirect objects).6
The EPA’s shift from nominalization to verb does
not, in any event, accomplish much. Either way, the
6
Take, for instance, the following sentences: “It appears to
violate GATT regulations, but the rules for applying the
regulations are vague and the Netherlands has so far escaped
censure”; “This information may not apply in Scotland, which has
a different legal system.” Apply, THOMAS HERBST ET AL., A
VALENCY DICTIONARY OF ENGLISH 41–42 (examples from sections
D1 and D5). Additional examples abound. See, e.g., Apply,
OXFORD ENGLISH DICTIONARY (3d ed. 2008) (def. I.9) (“Crest
bought the firm[,] and, by applying its marketing and distribution
muscle, has turned it into a $200 million category killer.”).
62a
lack of an explicit indirect object in Section 7411(a)(1)
does not require that one be borrowed from Section
7411(d)(1). Equally logical indirect objects include, for
example, the entire category of stationary sources, or
the air pollutant to be limited. In any event, the best
system cannot reasonably be said to be unambiguously
applicable only to the indirect object the EPA suggests.
The EPA faults the Clean Power Plan for reading
“application of” to be functionally equivalent to
“implementation of,” because “implement” “does not
require an indirect object.” EPA Br. 73. But neither
does “application.” So “application” textually supports
adoption of the Clean Power Plan just as well as
“implementation.” Again, so much for grammar
mandating the EPA’s result.
The argument fails either way, but the fact is that
Congress used the nominalization “application of” the
best system of emission reduction. A nominalization
enables the drafter to leave certain information
unspecified—namely, who is acting and where their
action is directed. See, e.g., George D. Gopen, Who
Done It? Controlling Agency in Legal Writing, Part II,
39 LITIG. 12, 12–13 (Spring 2013) (describing how
nominalizations create ambiguity). Legal writers,
including Congress, employ nominalizations all the
time. And they do so with the full awareness that their
use preserves flexibility.
Congress reasonably built in leeway for the EPA to
exercise technical expertise in applying Section 7411,
given the variety of pollution problems that it covers
and the importance of allowing States maneuvering
room under the cooperative federalism scheme.
Congress may avoid specifying subjects, objects, or
63a
other grammatical information because a degree of
adaptability suits the statutory role and purpose. One
way Congress can denote that it has delegated to an
agency’s judgment the task of filling in the on-theground details of a statutorily defined program is by
declining
to
dictate
grammatically
optional
information, see Lehrfeld v. Richardson, 132 F.3d
1463, 1465–1466 (D.C. Cir. 1998); Appalachian Power
Co. v. EPA, 135 F.3d 791, 808–810 (D.C. Cir. 1998),
including an indirect object that the rules of grammar
do not require be explicitly stated, see, e.g., Peter Pan
Bus Lines, 471 F.3d at 1353–1354.
Even if an implicit indirect object can be surmised,
there is more than one plausible candidate here, and
the statute does not unambiguously dictate the object.
There certainly is no rule—grammatical or
otherwise—that the specific indirect object must be
the one to which the EPA now points. At the least,
other contextually appropriate indirect objects of the
“best system” include the source category or the
emissions. The EPA has failed to establish that the
sole and unambiguous indirect object must be the
individual source. The EPA, of course, “may fill the
gap[s] the Congress left,” and any such “regulation is
entitled to deference.” Gaughf Props., 738 F.3d at 424;
see also Appalachian Power, 135 F.3d at 811–812. But
in the ACE Rule and in its briefing here, the EPA has
assiduously denied the existence of any gap at all.
That was error.
c. EPA’s Reading Itself Falls Short
The third and equally fatal flaw in the EPA’s textual
analysis is its unexplained substitution of the
prepositions “at” and “to” where the text it would have
64a
us borrow from subsection (d)(1) actually says “for” in
referencing “standards of performance for any existing
source.” See, e.g., ACE Rule, 84 Fed. Reg. at 32,534. As
we do with any words enacted by Congress, we must
give effect to the preposition it chose. Cf.
Telecommunications Res. & Action Ctr. v. FCC, 801
F.2d 501, 517–518 (D.C. Cir. 1986) (finding decisive
Congress’ use of the preposition “under” instead of
“by”). The word Congress actually used—“for” the
source—lacks the site-specific connotation on which
the EPA’s case depends.
In its brief, the EPA presents the compound
construction it says inexorably follows from reading
text from subsection (a)(1) together with text from
subsection (d)(1), and says it is restricted to
determining a “best system of emission reduction for
any building, structure, facility, or installation.” EPA
Br. 56 (formatting modified) (quoting 42 U.S.C.
§ 7411(a)(1), (a)(3), (a)(6), (d)(1)). The Agency then
asserts that “the natural reading” of its proffered
construction is that “the methods planned would be
‘for’ and act at the level of the singular, individual
source.” Id. at 62 (emphasis added).
In the preamble to the ACE Rule, the EPA went
further, fully substituting the prepositions “at” and
“to” in place of the preposition “for” that actually
appears in the text the Agency says must be borrowed
from subsection (d)(1). ACE Rule, 84 Fed. Reg. at
32,534. It relies on that further substitution to insist
that the best system of emission reduction designated
by the EPA must be limited to controls “that can be
applied at and to,” not “for,” “a stationary source.” Id.;
see also id. at 32,524 (“at”); id. at 32,532, 32,534,
32,556 (“at and to”); id. at 32,555, 32,529 (“to and at”);
65a
id. at 32,543 (“at or to”); id. at 32,526 n.65 (“to or at”);
EPA Br. 4, 58, 74. But nowhere in the ACE Rule does
the EPA explain this swap of one preposition for two
meaningfully more restrictive ones. See, e.g., 84 Fed.
Reg. at 32,523–32,524, 32,534–32,535.
The EPA rewrites rather than reads the plain
statutory text. Section 7411(a)(1), even if crossreferenced to subsection (d)(1) in the way the EPA says
it must be, calls for the Agency to determine “the
degree of emission limitation achievable through the
application of the best system of emission reduction for
any existing source”—not the application of the best
system “at” and “to” such a source. And the word “for”
lacks the physical on-site connotation that is so critical
to the EPA’s reading of the statutory text. Indeed, a
standard of performance or system of emission
reduction “for” a source just means that the system is
“with regard or respect to” or “concerning” the source.
See For, OXFORD ENGLISH DICTIONARY (2d ed. 1989)
(def. 26). In contrast, “at” and “to” tend to connote
direct physical proximity or contact. See At, OXFORD
ENGLISH DICTIONARY (3d ed. 2008) (def. 1.a) (“usually
determining a point or object with which a thing or
attribute is practically in contact”); To, OXFORD
ENGLISH DICTIONARY (3d. ed 2008) (def. 5.a) (“Into (or
in) contact with; on, against”). A best system “for” a
source thus might entail a broader array of controls
that concern but are not immediately physically
proximate to the source—such as, for instance,
generation shifting.
***
In sum, the straitened vision of the EPA’s best
system that the Agency espies in Section 7411 is
66a
simply not supported by the text, let alone plainly and
unambiguously required by it. The Act calls on the
EPA to determine the degree of emission limitation
achievable through “application of the best system of
emission reduction” without specifying the system’s
indirect object, and uses the preposition “for” when it
calls on the States to develop “standards of
performance for existing sources.” 42 U.S.C. § 7411(a),
(d). It simply does not unambiguously bar a system of
emission reduction that includes generation shifting.
The EPA’s position depends critically on words that
are not there. It erroneously treats a nominalization of
a verb as requiring an indirect object, collapses two
separate functions and provisions of the Act in order
to supply a borrowed indirect object, does so without
any evidence that the borrowed indirect object was
what Congress necessarily intended, and narrowly
focuses the Agency’s authority on that indirect object
by using a different preposition from the one that
actually appears in the borrowed text. Each of those
interpretive moves was a misstep. Read faithfully,
Section 7411(a)(1) lacks the straitjacket that the EPA
imposes.
Policy
priorities
may
change
from
one
administration to the next, but statutory text changes
only when it is amended. The EPA’s tortured series of
misreadings of Section 7411 cannot unambiguously
foreclose the authority Congress conferred. The EPA
has ample discretion in carrying out its mandate. But
it may not shirk its responsibility by imagining new
limitations that the plain language of the statute does
not clearly require.
67a
2. Statutory History, Structure, and Purpose
Even looking beyond the text does nothing to
substantiate the EPA’s proposed reading of Section
7411. See Kiewit Power Constructors Co. v. Secretary
of Labor, 959 F.3d 381, 395 (D.C. Cir. 2020)
(Henderson, J.) (“To discern the Congress’s intent, we
generally examine the statutory text, structure,
purpose and its legislative history.”) (quoting Lindeen
v. SEC, 825 F.3d 646, 653 (D.C. Cir. 2016)). These
other tools of statutory interpretation underscore the
flexibility of Section 7411(a)’s text, not the cabined
reading the EPA proposes.
We begin by acknowledging Section 7411’s role
within the Clean Air Act. It is a catch-all, intended to
ensure that the Act achieves comprehensive pollution
control by guaranteeing that there are “no gaps in
control activities pertaining to stationary source
emissions that pose any significant danger to public
health or welfare.” S. REP. NO. 91-1196, at 20 (1970).
In other words, Section 7411 is intended to reach
pollutants that do not fit squarely within the ambit of
the Act’s other regulatory provisions. It authorizes
regulation of pollutants not controlled by the other
programs under the Act. The EPA does not contest
that greenhouse gases emitted by powerplants fit that
description.
The Agency points to statutory structure and
history for evidence that Congress restricted the “best
system of emission reduction” under Section 7411(a) to
physical controls that are applied “at and to” an
existing source. But the history and structure only
confirm what the text shows: Nothing the EPA has
identified suggests that Congress in Section 7411
68a
meant to so constrict what might be part of a “best
system of emission reduction.”
The Congress that enacted Section 7411 was well
aware that what a “best system” might comprise is
necessarily dynamic and evolving. Congress’ main
limitation was that the “best system” selected by the
EPA must be “adequately demonstrated.” 42 U.S.C.
§ 7411(a)(1). And it stated three other key criteria—
cost, nonair quality health and environmental impact,
and energy requirements—as factors the EPA must
take into account. See id. With those parameters in
place, Congress largely left the identification of the
best system of emission reduction to the Agency’s
expert scientific judgment.
Consider cues from the Clean Air Act as a whole. In
contrast to other systemic benchmarks in the Act,
Section 7411(a)(1)’s prescription of the “best system of
emission reduction” is striking for its paucity of
restrictive language. References to more specific
categories of emission-reduction tools appear
elsewhere in the Act. A provision governing the
Nitrogen Oxides Emissions Reduction Program, for
example, directs the Administrator to establish limits
based on the “degree of reduction achievable through
the retrofit application of the best system of
continuous emission reduction, taking into account
available technology[.]” 42 U.S.C. § 7651f(b)(2)
(emphasis added). The Act’s regional haze program is
likewise specific in its call for use of the “best available
retrofit technology.” Id. § 7491(b)(2)(A), (g)(2). The
specificity of those other provisions highlights the
comparative generality of Section 7411(a)’s reference
to the “best system of emission reduction.”
69a
The sole provision the EPA highlights to shore up
its at-the-source theory only further undermines it.
The EPA points to the Act’s Prevention of Significant
Deterioration (PSD) program, 42 U.S.C. § 7475, and
its requirement of controls at least as stringent as
limits set under Section 7411, see id. § 7479(3), to
argue that that “the interrelationship between the two
types of standards”—the best system of emission
reduction and the best available control technology—
“is only intelligible if the standards are in pari
materia.” EPA Br. 85. But the distinct roles of the two
provisions make clear that the limits in Section 7475
have no place in Section 7411(a)(1).
To qualify for a permit under the PSD program
before a source may be built or modified, an applicant
must affirm that it will apply to each source the “best
available control technology,” or BACT, to limit its
emissions. 42 U.S.C. § 7475(a)(4). The statute defines
BACT as the degree of control that the permitting
agency “determines is achievable for such [major
emitting] facility through application of production
processes and available methods, systems, and
techniques, including fuel cleaning, clean fuels, or
treatment or innovative fuel combustion techniques[.]”
Id. § 7479(3). The statute further provides that BACT
cannot “result in emissions of any pollutants which
will exceed the emissions allowed by any applicable
standard established pursuant to [S]ection 7411 or
7412 of this title.” Id. § 7479(3). The listed BACT
options, EPA observes, are all physically applicable to
the source unit. EPA Br. 85.
But the EPA ignores a critical detail: The BACT
requirement applies only to newly constructed or
modified sources. See Alaska Dep’t of Env’t
70a
Conservation v. EPA, 540 U.S. 461, 472 (2004)
(describing 42 U.S.C. § 7475). Any standard
established under Section 7411 and also “applicable,”
per the statutory cross-reference, to a facility
regulated for prevention of significant deterioration
under Section 7475 would be a standard for new or
modified sources established pursuant to Section
7411(b). The BACT requirement does not apply to the
existing sources covered by the provision at issue here,
Section 7411(d). See New York v. EPA, 413 F.3d 3, 13
(D.C. Cir. 2005). Even if Section 7475 tracks Section
7411(b), there is simply no conflict between, on one
hand, requiring new source construction to employ the
newest and best at-the-source control technologies
and, on the other, empowering the EPA to look to a
wider range of ways to reduce emissions when it
regulates older, existing sources.
The anomaly of looking to Section 7475(a)(4) to
confine Section 7411 is highlighted by the fact that
BACT permits are required only in so-called
“attainment” areas of the country. See 42 U.S.C.
§§ 7407, 7472, 7474. We are unpersuaded that
Congress buried a limit on the EPA’s Section 7411
authority to address pollution from existing sources
throughout the Nation by making reference to a floor
for certain new facilities in certain parts of the
country.
The statutory history of the BACT requirement
further demonstrates that Congress did not intend
that it weaken Section 7411(d). Sections 7475 and
7479 were enacted in the 1977 Clean Air
Amendments, Pub. L. No. 95-95, §§ 165, 169, 91 Stat.
685, 735–742 (Aug. 7, 1977). In the very same
legislation, Congress restricted the best system of
71a
emission reduction for new sources to technological
methods while explicitly allowing the best system for
existing sources to include non-technological methods.
§ 109(c)(1)(A), 91 Stat. at 700. If Congress wanted to
confine Section 7411 to at-the-source technologies, it
would have done so directly rather than hiding such a
substantial limitation in an implicit inference from a
more remote statutory provision.
The Clean Air Act’s legislative history, including the
history of the 1970 enactment of Section 7411 and the
1977 and 1990 amendments, further shows that
Congress never imposed on the “best system of
emissions reduction” the constraints the EPA now
advocates. Before Congress settled on the best-system
language it enacted in 1970, the Senate bill proposed
to authorize the EPA to set standards for stationary
sources “reflect[ing] the greatest degree of emission
control” achievable through “the latest available
control technology, processes, operating methods, or
other alternatives.” S. 4358, 91st Cong. § 6 (1970). The
phrase “other alternatives” was understood to
encompass “[t]he maximum use of available means of
preventing and controlling air pollution”—without
limitation to technological or at-the-source means. S.
REP. NO. 91-1196, at 16. The Senate believed that was
“essential” to limit emissions from both new and
existing sources. Id. The House, for its part, proposed
an initial version of Section 7411 that would have
“require[d] new sources to ‘prevent and control [their]
emissions to the fullest extent compatible with the
available technology and economic feasibility,’” H.R.
17255, 91st Cong. § 5 (1970), but included no provision
regarding the regulation of existing sources.
72a
As enacted, Section 7411 simply requires that the
EPA identify as its benchmark for existing sources the
“best system of emission reduction.” 42 U.S.C.
§ 7411(a)(1). Nothing that the EPA identifies or that
we discern in the relevant history shows the enacting
Congress myopically “focused on steps that can be
taken at and by individual sources to reduce
emissions.” EPA Br. 69. And of course, even if
Congress at that time was only thinking of at-thesource controls, the EPA was well aware that
environmental problems and their solutions rapidly
evolve. At the end of the day, it is the statutory text
that governs. See Bostock v. Clayton County, 140 S. Ct.
1731, 1738 (2020).
Congress has consistently relied on the EPA’s
expert judgment in identifying the “best system” for
existing sources. Its action in making, and then
undoing, a limiting amendment to Section 7411’s “best
system of emission reduction” just for new and
modified sources—not existing sources—underscores
the point. First, Congress in 1977 amended the
standard for new sources to require use of “the best
technological system of continuous emission
reduction,” but did not make any parallel change to
the standard for existing sources to add those
“technological” and “continuous” limitations. Clean
Air Amendments Act of 1977, Pub. L. No. 95-95,
§ 109(c)(1)(A), 91 Stat. 685; see also id. at 700 (adding
Section 7411(a)(1)(C)). Then, in 1990, Congress again
amended Section 7411, this time to remove those
additional limitations, reverting for new sources to the
“best system of emission reduction” that had applied
all along to existing sources. Clean Air Act
73a
Amendments of 1990, Pub. L. No. 101-549, § 403(a),
104 Stat. 2399, 2631 (1990).
The amendment and re-amendment of the newsource “best system” language emphasizes that
Congress consistently avoided imposing any such
technological, at-the-source limitation on the
measures that EPA might include in the “best system”
for reducing emissions from existing-source
categories. And it shows that Congress had always
understood the existing-source “best system” language
to go beyond the technological restrictions that it
briefly imposed on the parallel new source provision.
The ACE Rule is the first EPA rule to read the
statute as so strictly boxing in the Agency. Although
agency practice cannot directly show whether
Congress had a specific intent on the matter in
question, it is notable that the regulators closest to the
issue never before saw what the EPA now insists is
obvious on the face of Section 7411.
Over the last half century, no prior Administrator
read the Act to foreclose from consideration in the
“best system” all but at-the-source means of emission
control. Rather, the EPA has exercised latitude to
consider any adequately demonstrated approach to
reducing harmful pollutants from existing source
categories that it believed met the cost, grid-reliability
and other statutory criteria. 42 U.S.C. § 7411(a)(1).
Where the characteristics of the source category and
the pollutant at issue point to emissions trading
programs or production shifts from higher- to loweremitting sources as components of the “best system,”
the EPA has in the past consistently concluded that it
had the authority to consider them.
74a
During the administration of President George W.
Bush, for example, the EPA adopted the Clean Air
Mercury Rule, 70 Fed. Reg. 28,606 (May 18, 2005),
which included a mercury cap-and-trade program as a
component of its best system of emissions reduction for
existing coal-fired power plants, see id. at 28,619–
28,620; id. at 28,617 (“EPA has determined that a capand-trade program based on control technology
available in the relevant timeframe is the best system
for reducing [mercury] emissions from existing coalfired Utility Units.”).7
The EPA’s Clinton-era regulation of nitrogen oxide
emissions from municipal solid waste combustors
likewise relied on Section 7411(d), together with the
EPA’s waste-management authority under Section
7429, to authorize States to include emissions-trading
programs in their State Plans. 40 C.F.R.
§ 60.33b(d)(2). Under state standards of performance
designed to meet guidelines the EPA derived from its
“best system,” regulated entities were permitted to
average the emission rates of multiple units within a
single plant as well as trade emission credits with
other plants. Municipal Waste Combustors Rule, 60
Fed. Reg. 65,387, 65,402 (Dec. 19, 1995).
7
We vacated the Mercury Rule for unlawfully delisting
mercury-emitting electric utility steam generating units from the
Section 7412 Hazardous Air Pollutants list. See New Jersey v.
EPA, 517 F.3d 574, 582–584 (D.C. Cir. 2008). Because we held
those mercury sources must be listed, and because Section 7411
cannot be used to regulate air pollutants listed under Section
7412, the existing-source rule the EPA had adopted under Section
7411(d) to control those same mercury emissions from power
plants failed as well.
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The EPA’s efforts to distinguish those other Section
7411(d)(1) programs do not work. The EPA claims that
the Mercury Rule did not primarily rely on a cap-andtrade or dispatch shifting program, but rather that the
best system rested on a “combination of a cap-andtrade mechanism and * * * the technology needed to
achieve the chosen cap level.” EPA Br. 72 n.20 (quoting
ACE Rule, 84 Fed. Reg. at 32,526). To be clear, that
sort of hybrid best system, involving both on-site and
system-wide elements, is precisely what the EPA now
insists is unprecedented and expressly barred by the
statute’s text.
Lest there be any doubt that the Mercury Rule’s
best system rested in significant part on the cap-andtrade mechanism, we note that the EPA in fact
approved state implementation plans that adopted
none of the on-site controls included in the best system
and instead relied entirely on implementation of the
best system’s cap-and-trade program. See, e.g., Notice
of Intent, 32 La. Reg. 869, 870 (May 20, 2006)
(proposing an implementation plan solely reliant on
cap-and-trade); Approval and Promulgation of State
Plan for Designated Facilities and Pollutants:
Louisiana, 72 Fed. Reg. 46,188, 46,188 (Aug. 17, 2007)
(approving Louisiana’s proposal on the basis that it
“would meet [Clean Air Mercury Rule] requirements
by participating in the EPA administered cap-andtrade program addressing [mercury] emissions”).
Contrary to the EPA’s assertions, e.g. EPA Br. 4, the
Agency plainly has previously embraced beyond-thesource measures of emission reduction as authorized
by the statutory text.
The EPA’s invocation of its own past practice under
Section 7411 falls wide of the mark. It errs in insisting
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that “the more than seventy Section 7411 rules”
promulgated for “roughly forty-five years” somehow
reflect a consistent adherence to the Agency’s new
view. EPA Br. 4, 88; see id. at 37–38, 88–89; ACE Rule,
84 Fed. Reg. at 32,526. Almost all of the rules to which
it refers are irrelevant to the issue at hand. They were
for new sources, subject to Section 7411(b), not
existing sources under Section 7411(d). See 84 Fed.
Reg. at 32,526.
Older facilities that may be capable only of
outdated, more polluting methods of generation
present different regulatory challenges than new
sources. As discussed above in connection with the
EPA’s reference to BACT requirements for new-source
permitting under the PSD program, a requirement
that owners and operators constructing new facilities
apply state-of-the-art, lowest-emitting equipment and
methods “at and to the source” might well be the best
available means of reducing emissions for that source
category. The same cannot be said for existing sources.
A central error of the ACE Rule is that it fails to
appreciate that difference. It identifies a handful of
measures applicable to and at the source that the EPA
suggests may achieve slight reductions. But industry
practice demonstrates that better, lower-emitting,
reliable, and cost-effective systems for reducing
emissions from existing power plants typically also
shift generation away from higher-emitting, fossilfuel-fired capacity when renewable or lower- or zeroemitting generation is an available substitute.
Because the best, most efficient and effective
systems for controlling emissions from existing
sources ordinarily differ from the best systems for new
sources, they are regulated via a distinct statutory
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track. Only the Section 7411(d) rules are relevant to
the EPA’s prior understanding of its authority to
regulate existing sources. Those prior EPA rules
contradict the EPA’s position here. Before its aboutface in the ACE Rule, all three of the Agency’s most
recent Section 7411(d) rules included emissions
trading or generation shifting to lower-emitting
sources. See Clean Power Plan, 80 Fed. Reg. at 64,755–
64,756; Clean Air Mercury Rule, 70 Fed. Reg. at
28,606, 28,617, 28,619–28,620; Municipal Waste
Combustors Rule, 60 Fed. Reg. 65,387, 65,402 (Dec.
19, 1995).
To put the EPA’s mistaken reading of Section 7411
in perspective, consider how it effectively relegates
federal regulators back to the sidelines where they
stood before Congress overhauled the Clean Air Act in
1970. The federal government had until then done
little more than provide information and guidance to
cheer on States’ air-quality regulators. See Train v.
NRDC, 421 U.S. 60, 64 (1975) (noting that the States’
response to earlier iterations of the Act focused on
information and incentives had been “disappointing”).
With the 1970 amendments, a virtually unanimous
Congress dramatically strengthened the federal
government’s hand in combatting air pollution. See
Train, 421 U.S. at 64 (“These Amendments sharply
increased federal authority and responsibility. * * *
The difference * * * was that the States were no longer
given any choice as to whether they would meet th[eir
statutory] responsibility.”); cf. EPA v. EME Homer
City Generation, LP, 572 U.S. 489, 497 (2014) (noting
this progression toward “increasing[ly] rigor[ous]”
federal regulation of interstate air pollution).
Congress did so “to protect and enhance the quality of
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the Nation’s air resources so as to promote the public
health and welfare and the productive capacity of its
population[.]” 42 U.S.C. § 7401(b)(1). The EPA’s newly
enhanced authority was “designed to provide the
basis” for “a massive attack on air pollution.” S. REP.
NO. 91-1196, at 1. Section 7411(d) ensured that there
would be “no gaps in control activities pertaining to
stationary source emissions that pose any significant
danger to public health or welfare.” Id. at 20.
Describing the Act shortly before its passage,
Republican Senator John Cooper explained that the
“philosophy of the bill abandons the old assumption of
requiring the use of only whatever technology is
already proven and at hand” and instead “set[s] out
what is to be achieved.” 116 CONG. REC. 32,919 (1970).
To that end, the Act did not finely detail specific
approaches to enumerated sources or types of air
pollution. See 116 CONG. REC. 32,901–32,902 (1970)
(statement of Sen. Muskie). Congress chose instead to
entrust the EPA with flexible powers to craft effective
solutions. Only by doing so could air quality regulation
hope to reflect developing understandings of
escalating problems and bring to bear as-yet-unseen
solutions.
American air quality is the proof of that approach.
The EPA has worked closely with industry, States,
and the public to develop the world’s most nimble,
responsive, and effective regime of air pollution
regulation. For example, in the half-century since the
1970 Act, “the combined emissions of * * * six key
pollutants regulated under the National Ambient Air
Quality Standards dropped by 73 percent” between
1970 and 2017. EPA Releases 2018 Power Plant
Emissions Demonstrating Continued Progress, EPA
79a
(Feb.
20,
2019),
https://www.epa.gov/newsreleases/epa-releases-2018power-plant-emissions-demonstrating-continuedprogress (last visited Jan. 11, 2021).
The EPA’s new reading of Section 7411 would
atrophy the muscle that Congress deliberately built
up. The EPA asserts it lacks authority to curb a
pollutant that the Agency itself has repeatedly deemed
a grave danger to health and welfare but that eludes
effective control under other provisions of the Act. We
do not believe that Congress drafted such an enfeebled
gap-filling authority in Section 7411.
***
In sum, traditional tools of statutory interpretation
reveal nothing in the text, structure, history, or
purpose of Section 7411 that compels the reading the
EPA adopted in the ACE Rule.
3. Compliance Measures
In the ACE Rule, the EPA also limited the measures
that sources may use to comply with the States’
standards of performance set under Section 7411(d).
Recognizing that sources generally have “broad
discretion” in how they comply with state standards,
84 Fed. Reg. at 32,555, the EPA nonetheless
categorically excluded two specific measures from the
States’ consideration: averaging and trading, and
biomass co-firing. It did so on the ground that these
measures do not meet two criteria it determined were
required of compliance measures: that they be (1)
“capable of being applied to and at the source” and (2)
“measurable at the source using data, emissions
monitoring equipment or other methods to
demonstrate compliance[.]” Id. The EPA identified
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these criteria on account of “both legal and practical
concerns[.]” Id.
The Agency’s legal concern was that non-sourcespecific compliance measures “would be inconsistent
with the EPA’s interpretation of the” best system of
emission reduction as itself plant-specific. ACE Rule,
84 Fed. Reg. at 32,555–32,556. In that way, the EPA
extended to States’ compliance measures the same
incorrect textual interpretation of the Clean Air Act
that underlay its determination of what best systems
may include—namely, that the system must be one
that can be applied to and at the individual source.
The EPA reasoned that “implementation and
enforcement of such standards should correspond with
the approach used to set the standard in the first
place.” Id. at 32,556.
The Agency’s practical concern was that compliance
measures that are not source-specific could result in
“asymmetrical regulation[,]” meaning the stringency
of standards could vary across sources. ACE Rule, 84
Fed. Reg. at 32,556. It argues here that such
regulation “could have significant localized adverse
consequences” in the case of many pollutants
regulated under Section 7411(d). EPA Br. 240.
Because we hold that the EPA erred in concluding
Section 7411 unambiguously requires that the best
system of emission reduction be source specific, we
necessarily reject the ACE Rule’s exclusion from
Section 7411(d) of compliance measures it
characterizes as non-source-specific. The Agency tied
that exclusion to its flawed interpretation of the
statute as unambiguously confined to measures taken
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“at” individual plants, so it falls with that decision.
ACE Rule, 84 Fed. Reg. at 32,555–32,556.
The statute says nothing about the measures that
sources may use to comply with the standards States
establish under Section 7411(d), and the EPA cites no
separate authority that would require compliance
measures to be source-specific, or that Congress meant
to so hogtie the States in devising standards of
performance. Regardless of any policy-based reasons
the EPA offers for limiting compliance measures, then,
its decision to exclude averaging and trading and
biomass co-firing is foreclosed by its legally erroneous
starting point.
Neither can the EPA’s policy-based reasons sustain
its decision to exclude its disfavored non-sourcespecific compliance measures in the context of carbon
dioxide emissions. Apart from its statutory
interpretation, the EPA’s only ground for excluding
those compliance measures is the Agency’s stated
concern to avoid asymmetrical regulation. ACE Rule,
84 Fed. Reg. at 32,556. It argues that asymmetrical
regulation “could have significant localized adverse
consequences for public health and the environment.”
EPA Br. 240. The Agency points to the case of
fluoride—another pollutant regulated under Section
7411(d)—to note that allowing sources to meet state
standards of performance by averaging emissions
across units or between facilities “could cause serious
environmental impacts on local communities where
pollution was under-controlled, causing localized
damage.” Id. In light of such considerations, the EPA
worried that a system of averaging and trading “would
undermine the EPA’s determination” of the best
system of emission reduction, leading to the sort of
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localized consequences the system is designed to guard
against. ACE Rule, 84 Fed. Reg. at 32,557.
But that point does not support the EPA’s
categorical rule, let alone prove that the statute
unambiguously compels the Agency’s reading. Unlike
pollutants such as fluoride, carbon dioxide emissions
do not pose localized concerns at the site of emission.
Whereas the EPA might determine that the best
system for reducing fluoride emissions is one that can
be applied to and at the source, and it would be
reasonable for the EPA in turn to limit compliance
measures to correspond with such a “best system,” the
same cannot be said of carbon dioxide. Indeed, the
EPA recognizes that “CO2 is a global pollutant with
global effects[,]” meaning “there may be few direct and
area public health consequences from asymmetrical
regulation of carbon dioxide within a State.” EPA Br.
239.
The Agency defends its concern about asymmetrical
regulation in the context of carbon dioxide emissions
with the unsupported contention that an
interpretation of Section 7411(d) that allowed nonsource-specific compliance measures “would not be
limited to carbon dioxide alone.” EPA Br. 240. But
there is no reason to conclude, and petitioners do not
argue, that the statute requires the EPA to permit
non-source-specific compliance measures for every
pollutant it regulates under Section 7411. The statute
is not so rigid as EPA supposes. In fact, Section 7411
itself does not textually restrict the States’ choice of
compliance measures for their sources at all. See also
Power Cos. Pet’rs Br. 25–26; Biogenic Pet’r Br. 16–17.
Even if the EPA might reasonably limit compliance
measures in specific situations based on its
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determination of the best system for reducing
particular types of emissions with localized
consequences, the statute imposes no requirement
that such limitations be uniform across the regulation
of different pollutants.
In sum, the EPA’s conclusion on compliance by
sources rises and falls with its legally flawed
interpretation of the statute. The Agency’s practical
concern about asymmetrical regulation could not, in
any event, support the exclusion of biomass co-firing
or averaging and trading in the particular context of
carbon dioxide emission regulation.
B. THE MAJOR QUESTIONS DOCTRINE
The EPA also references the so-called “major
questions” doctrine in defense of its statutory
interpretation and the ACE Rule. 84 Fed. Reg. at
32,529. But that doctrine does not confine the EPA to
adopting solely emission standards that can be
implemented physically to and at the individual plant.
The Supreme Court has said in a few cases that
sometimes an agency’s exercise of regulatory authority
can be of such “extraordinary” significance that a court
should hesitate before concluding that Congress
intended to house such sweeping authority in an
ambiguous statutory provision. See King v. Burwell,
576 U.S. 473, 485–486 (2015); Gonzales v. Oregon, 546
U.S. 243, 262, 266–267 (2006); FDA v. Brown &
Williamson Tobacco Corp., 529 U.S. 120, 159 (2000);
accord Utility Air Regulatory Group v. EPA (UARG),
573 U.S. 302, 324 (2014); see also MCI Telecommc’ns
v. AT&T, 512 U.S. 218, 231 (1994). Where there are
special reasons for doubt, the doctrine asks whether it
is implausible in light of the statute and subject
84a
matter in question that Congress authorized such
unusual agency action. See, e.g., UARG, 573 U.S. at
324 (considering whether the challenged rule would
“bring about an enormous and transformative
expansion in EPA’s regulatory authority without clear
congressional authorization”); Brown & Williamson,
529 U.S. at 161 (holding that the FDA could not
regulate tobacco because it was “plain that Congress
ha[d] not given the FDA the authority that it s[ought]
to exercise”).
In the ACE Rule, the EPA stated that, while its
interpretation of Section 7411 did not depend on the
“major question[s] doctrine[,]” the Agency believed
that “that doctrine should apply here[.]” 84 Fed. Reg.
at 32,529. The Agency reasoned that the Clean Power
Plan would have had “billions of dollars of impact on
regulated parties and the economy,” would have
“affected every electricity customer[,]” was “subject to
litigation involving almost every State,” and would
have upset the balance of regulatory authority
between federal agencies and the States. Id. For those
reasons, the Agency concluded that the “interpretive
question raised”—whether the “best system of
emission reduction” can include measures other than
improvements to and at the physical source—“must be
supported by a clear[]statement from Congress.” Id.
That was incorrect.
1. The EPA’s Regulatory Mandate
Unlike cases that have triggered the major
questions doctrine, each critical element of the
Agency’s regulatory authority on this very subject has
long been recognized by Congress and judicial
precedent.
85a
Most importantly, there is no question that the
regulation of greenhouse gas emissions by power
plants across the Nation falls squarely within the
EPA’s wheelhouse. The Supreme Court has ruled
specifically that greenhouse gases are “air pollutants”
covered by the Clean Air Act. Massachusetts v. EPA,
549 U.S. at 532. More to the point, the Court has told
the EPA directly that it is the Agency’s job to regulate
power plants’ emissions of greenhouse gases under
Section 7411. “Congress delegated to EPA the decision
whether and how to regulate carbon-dioxide emissions
from powerplants” through a “§ 7411 rulemaking[.]”
AEP, 564 U.S. at 426–427. The separate opinion
agrees. See Separate Op. at 14 (“Does the Clean Air
Act direct the EPA to make our air cleaner? Clearly
yes. Does it require at least some carbon reduction?
According to Massachusetts v. EPA, again yes.”).
On top of that, the issuance of regulations
addressing greenhouse gas pollution is mandatory
under the statute because of longstanding
endangerment findings. In Massachusetts v. EPA, the
Supreme Court directed the EPA either to make an
endangerment finding under the statute for
greenhouse gas pollution, or to explain why it would
not do so. 549 U.S. at 532–535. The EPA complied. For
now more than a decade—from 2009 to the present day
in the ACE Rule itself—the EPA has consistently and
repeatedly recognized the serious danger that
greenhouse gas pollution poses to human health and
welfare. See ACE Rule, 84 Fed. Reg. at 32,533; New
Source Rule, 80 Fed. Reg. at 64,530–64,531; 2009
Endangerment Finding, 74 Fed. Reg. at 66,496–
66,497. By statute, that finding triggers a mandatory
duty on the EPA to regulate greenhouse gas pollution.
86a
42 U.S.C. § 7521(a)(1) (motor vehicle emissions); 42
U.S.C. § 7411(b) (stationary sources that contribute
significantly to such dangerous pollution).8
So the EPA has not just the authority, but a
statutory duty, to regulate greenhouse gas pollution,
including specifically from power plants.
In that way, the pollution measures in the Clean
Power Plan do not fit the major-question mold of prior
cases. For example, in Brown & Williamson, the major
question was whether the agency had authority to
regulate tobacco at all. There, the Supreme Court
ruled that there was “reason to hesitate” before
concluding that the provisions of the Food, Drug, and
Cosmetic Act covering restricted devices, Brown &
Williamson, 529 U.S. at 134 (citing 21 U.S.C.
As discussed below with respect to the challenge brought
by the Coal Petitioners (infra at III.A.1), the legal basis for the
EPA’s regulation of greenhouse gas emissions from existing
power plants in both the Clean Power Plan and the ACE Rule
was the Agency’s prior 2015 decision to issue standards of
performance for carbon dioxide emitted from new power plants.
That decision, in turn, was based on the Agency’s recognition
(since the 1970s) that fossil-fuel-fired power plants contribute
significantly to air pollution, which “may reasonably be
anticipated to endanger the public health or welfare.” 42 U.S.C.
§ 7411(b)(1)(A); see Air Pollution Prevention and Control: List of
Categories of Stationary Sources, 36 Fed. Reg. 5931, 5931 (March
31, 1971); Air Pollution Prevention and Control: Addition to the
List of Categories of Stationary Sources, 42 Fed. Reg. 53,657,
53,657 (Oct. 3, 1977). The EPA also determined in 2015 that
power plants contribute significantly to greenhouse gas pollution
in particular. See New Source Rule, 80 Fed. Reg. at 64,531. That
determination, combined with the determination that
greenhouse gases are dangerous to public health and welfare,
triggers a mandatory duty to regulate under Section
7411(b)(1)(A).
8
87a
§ 360j(e)), gave the Food and Drug Administration the
authority to regulate tobacco given its “unique
political history” and its role as a “significant portion
of the American economy.” Id. at 159. The Court
reasoned based on the overall drug-regulatory scheme,
as well as Congress having “created a distinct
regulatory scheme for tobacco products,” that
Congress “could not have intended to delegate a
decision of such economic and political significance to
an agency in so cryptic a fashion.” Id. at 159–160.
That question of agency authority to regulate the
matter in question was absent for the Clean Power
Plan. In fact, the Supreme Court in Massachusetts v.
EPA rejected the analogy between regulation of
greenhouse gases as a pollutant under the Clean Air
Act and regulation of tobacco as a drug under the Food,
Drug, and Cosmetic Act. 549 U.S. at 530–531.
Treating tobacco as a drug would have been wholly
novel, requiring the agency to ban virtually all tobacco
products—a result the Court suspected Congress did
not intend. Id. at 531; Brown & Williamson, 529 U.S.
at 143. By contrast, the Supreme Court explained,
greenhouse gases are air pollutants that fall squarely
within the Clean Air Act’s coverage, and the Act would
subject such pollutants, if the agency makes the
necessary findings, only to regulation, not prohibition.
Massachusetts v. EPA, 549 U.S. at 531.
The Clean Air Act also contains its own limits on
regulation, like mandating that the EPA take into
account such factors as available technology and the
cost of compliance. Id. (citing 42 U.S.C. § 7521(a)(2));
see also 42 U.S.C. § 7411(a)(1) (requiring consideration
of health and environmental impacts, energy
requirements, and cost). In that way, Congress
88a
designed the Clean Air Act’s processes for regulating
air pollution to adapt to “changing circumstances and
scientific
developments”
without
imposing
unreasonable technological or financial burdens on
industry. Massachusetts v. EPA, 549 U.S. at 532. So,
unlike the major question of tobacco regulation in
Brown
&
Williamson,
there
is
“nothing
counterintuitive” about the EPA’s reasonable
regulation of dangerous airborne substances like
greenhouse gases. Id. at 531–532.
Similarly, the major question in UARG was whom
the EPA was attempting to regulate. In that case, the
Supreme Court held that the EPA’s statutory
permitting authority for the construction and
modification of stationary sources was “designed to
apply to, and cannot rationally be extended beyond, a
relative handful of large sources capable of
shouldering heavy substantive and procedural
burdens”—sources like power plants. 573 U.S. at 322.
The Court held that, without clear statutory
grounding, the EPA’s effort to extend permitting
requirements to literally millions of small sources of
greenhouse gas pollution but of no other regulated
pollutants—sources like schools, hospitals, churches,
and shopping malls—overshot its statutory authority.
Id. at 324, 328.
The Clean Power Plan, by contrast, regulated the
very entities the EPA was told by the Supreme Court
in AEP and UARG to regulate—fossil-fuel-fired power
plants. And it employed statutory tools that were
“suitable” for application to the long-regulated power
industry. See UARG, 573 U.S. at 323, 324 n.7.
American Electric Power pointed the Agency to
regulation under Section 7411 specifically, explaining
89a
that “Congress delegated to EPA the decision whether
and how to regulate carbon-dioxide emissions from
[new, modified, and existing] powerplants” using the
regulatory tools laid out in Section 7411. 564 U.S. at
424–426.
That is no doubt a significant task for the EPA. But
that is not because of any agency overreach. It is the
product of Congress’ charge that the EPA regulate air
pollution nationwide. And with respect to regulating
greenhouse gas pollution in particular, it reflects the
fact that fossil-fuel-fired power plants predominate
the power industry and are spread across the Nation.
See United States Energy Information Administration
(EIA), Frequently Asked Questions: What is U.S.
Electricity Generation by Source? (Nov. 2, 2020),
https://www.eia.gov/tools/faqs/faq.php?id=427&t=2
(last visited Jan. 11, 2021); EIA, U.S. Energy Mapping
System, https://www.eia.gov/state/maps.php (last
visited Jan. 11, 2021). So much so that they “are by
far” the greatest stationary contributor to greenhouse
gas pollution and the significant dangers it causes for
the public health and welfare. New Source Rule, 80
Fed. Reg. at 64,522.
2. Best System of Emission Reduction
So what the EPA may regulate (greenhouse gas
pollution), and whom it may target (power plants), and
how (under Section 7411) have all been resolved and
so do not trigger the major questions doctrine.
That leaves the EPA no place to house its majorquestion objection other than in the interpretation of
the statutory term “best system of emission
reduction,” 42 U.S.C. § 7411(a)(1). More specifically,
the EPA says the use of any emission-control
90a
measures that do not operate at the individual
physical plant level requires an express statement
from Congress, and that federal standards that might
encourage
generation-shifting
are
therefore
categorically forbidden under Section 7411.
But the major questions doctrine does not apply
there either for a number of reasons.
a. Statutory Design
For starters, the “best system of emission reduction”
plays a cabined role in the statutory scheme. The
determination of the best system of emission reduction
is entirely internal to the EPA. The EPA itself
evaluates relevant scientific, technological, and
economic evidence to identify, in its judgment, the
“best system of emission reduction” available, and the
“degree of emission limitation achievable” through it.
42 U.S.C. § 7411(a)(1).
In making that determination, the statute
significantly reins in the EPA’s judgment by requiring
the Agency to (1) “tak[e] into account the cost of
achieving such reduction,” (2) factor in “any nonair
quality health and environmental impact,” (3) balance
the effect on “energy requirements,” and (4) ensure
that
the
system
has
been
“adequately
demonstrated[.]” 42 U.S.C. § 7411(a)(1). To be
“adequately demonstrated[,]” we have explained, the
system must be shown to be reasonably “reliable,”
“efficient,” and “expected to serve the interests of
pollution control without becoming exorbitantly
costly[.]” Essex Chem. Corp. v. Ruckelshaus, 486 F.2d
427, 433 (D.C. Cir. 1973), cert. denied, 416 U.S. 969
(1974); see also Portland Cement Ass’n v. Ruckelshaus,
486 F.2d 375, 391 (D.C. Cir. 1973) (whether a system
91a
is adequately demonstrated “cannot be based on
‘crystal ball’ inquiry”).9
Once the EPA identifies a best system that meets
those requirements and calculates the degree of
emission limitation it allows, the Clean Air Act leaves
it to the States to set their own standards of
performance for their existing pollution sources. 42
U.S.C. § 7411(d). The cooperative-federalism design of
Section 7411(d) gives the States broad discretion in
achieving those emission limitations. See AEP, 564
U.S. at 428 (“The Act envisions extensive cooperation
between federal and state authorities, generally
permitting each State to take the first cut at
determining how best to achieve EPA emissions
standards within its domain[.]”) (internal citations
omitted). In addition, Section 7411(d) expressly allows
States, in setting their emission standards, to “take
into consideration, among other factors, the remaining
useful life” of its existing sources. 42 U.S.C. § 7411(d).
So the EPA’s scientific and technological
identification of the best system of emission reduction
cannot bear the major-question label. Determining the
system is a task expressly and indisputably assigned
by Congress to the EPA and requiring specialized
agency expertise. That system serves only as the basis
for the EPA to set the emission-reduction targets in its
quantitative guidelines. The States retain the choice
9
In addition to these statutory constraints, the EPA has tied
its own hands by requiring that the best system include only
actions touching three bases: (i) they reduce emissions (rather
than, for example, capturing emissions after they are released
into the air by planting trees), (ii) sources themselves can
implement them, and (iii) they target supply-side activities. See
Clean Power Plan, 80 Fed. Reg. at 64,776, 64,778–64,779.
92a
of how to meet those guidelines through standards of
performance tailored to their various sources. Neither
exercise entails resolution of a major question.
The EPA argues that its own best-system process
raised a major question by “impos[ing] ‘generation
shifting[.]’” EPA Br. 99. But under Section 7411(d), the
EPA does not impose the “best system of emission
reduction” on anyone. Instead, each State decides for
itself what measures to employ to meet the emission
limits, and in so doing may elect to consider the
“remaining useful life” of its plants and “other factors.”
42 U.S.C. § 7411(d). See Clean Power Plan, 80 Fed.
Reg. at 64,709–64,710, 64,783. The Clean Power Plan,
in fact, afforded States considerable flexibility in
choosing how to calculate and meet their emissions
targets. See, e.g., id. at 64,665, 64,756–64,757, 64,834–
64,837.10
The Clean Power Plan expressly contemplated that States
and sources might choose to meet their emissions targets by using
measures other than the specific heat-rate improvements and
generation shifting that the EPA had identified in its best system.
See 80 Fed. Reg. at 64,755–64,758. The EPA offered a list of
alternative available technologies that reduced power plants’
carbon dioxide emissions per megawatt, including carbon capture
and storage, heat-rate improvements at non-coal plants, fuel
switching to gas, fuel switching to biomass, and waste heat-toenergy conversion. Id. at 64,756. In certain situations, for
example, modifying coal-fired plants to burn natural gas could
“help achieve emission limits consistent with the [best system].”
Id. The Agency also identified a list of alternative measures that
States could implement to lower overall emissions from fossilfuel-fired plants. Those measures included, for example, demandside energy efficiency—a policy tool that the EPA expected some
States to use because “the potential emission reductions from
demand-side [energy efficiency] rival those from [generation
shifting] in magnitude[.]” Id.
10
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Congress already focused on the issue and made the
decision to rope the EPA’s selection of a best system of
emission reduction about with all of those substantive
and structural limitations. So the major questions
doctrine does not provide any basis for concluding that
the Clean Air Act categorically forecloses the EPA’s
consideration of even those generation-shifting
measures that are already widely in use by States and
power plants and have been demonstrated to be
reasonable, reliable, effective, and not unduly
disruptive to the regulated industry. See Clean Power
Plan, 80 Fed. Reg. at 64,735, 64,769.
In that respect, the EPA’s argument sounds much
like a second argument rejected by the Supreme Court
in UARG. In addition to the scope question discussed
above, the Court addressed whether the EPA could
require facilities that emit conventional pollutants
also to implement the “best available control
technology” for greenhouse gases. UARG, 573 U.S. at
329–333 (citing 42 U.S.C. § 7475(a)(4)). Like the EPA
here, the industry petitioners argued that the “best
available
control
technology”
standard
was
“fundamentally unsuited” to greenhouse gas
emissions because it had “traditionally” focused on
“end-of-stack controls.” Id. at 329–330. “[A]pplying it
to greenhouse gases,” the industry petitioners
insisted, would make the “best available control
technology” standard “more about regulating energy
use, which will enable regulators to control every
aspect of a facility’s operation and design[.]” Id. at 330
(internal quotation marks omitted).
The Supreme Court rejected that challenge. The
Court explained that the EPA’s guidance
contemplated both “end-of-stack”—type controls and
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energy efficiency measures. UARG, 573 U.S. at 330.
And, critically, the Court emphasized that the statute
and regulations already imposed “important
limitations on [best available control technology] that
may work to mitigate petitioners’ concerns about
‘unbounded’ regulatory authority.” Id. at 331. Among
those limitations was the EPA’s longstanding
statutory interpretation that the best available control
technology was required “only for pollutants that the
source itself emits,” and the EPA’s existing guidance
that permitting authorities should “consider whether
a proposed regulatory burden outweighs any reduction
in emissions to be achieved.” Id. The statute also
required the EPA to determine the best available
control technology with reference to “energy,
environmental, and economic impacts and other
costs.” 42 U.S.C. § 7479(3); see also UARG, 573 U.S. at
333 n.9.
So too here: The numerous substantial and explicit
constraints on the EPA’s selection of a best system of
emission reduction foreclose using the major questions
doctrine to write additional, extratextual, and
inflexibly categorical limitations into a statute whose
“broad language * * * reflects an intentional effort to
confer the flexibility necessary to forestall * * *
obsolescence.” Massachusetts v. EPA, 549 U.S. at 532;
see also Transmission Access Policy Study Group v.
FERC, 225 F.3d 667, 711 (D.C. Cir. 2000) (where
Congress has spoken, court upholds as within agency
authority an order that “fundamentally change[d] the
regulatory environment in which utilities operate” and
“introduc[ed] meaningful competition into an industry
that since its inception has been highly regulated and
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affecting all utilities in a similar way”), aff’d sub nom.
New York v. FERC, 535 U.S. 1 (2002).
The EPA points to the Supreme Court’s statement
in UARG that “[w]hen an agency claims to discover in
a long-extant statute an unheralded power to regulate
‘a significant portion of the American economy,’ we
typically greet its announcement with a measure of
skepticism.” 573 U.S. at 324 (quoting Brown &
Williamson, 529 U.S. at 159).
True. But, as already explained, the EPA made no
new discovery of regulatory power with the Clean
Power Plan. While power plants are significant
players in the American economy, they have been
subject to regulation under Section 7411 for nearly
half a century. See, e.g., Costle, 657 F.2d at 318; Oljato
Chapter of Navajo Tribe v. Train, 515 F.2d 654, 656–
57 (D.C. Cir. 1975). Their emission of massive
amounts of carbon dioxide has long been known. And
the source of the EPA’s duty to regulate that
greenhouse gas pollution from power plants was the
plain statutory text and Supreme Court precedent, not
something the EPA pulled out of a hat. See AEP, 564
U.S. at 425; Massachusetts v. EPA, 549 U.S. at 532.
In sum, the Clean Air Act expressly confers
regulatory authority on the EPA to set standards for
reducing greenhouse gas emissions from fossil-fuelfired power plants nationwide. Congress knew both
the scope and importance of what it was doing. And it
cabined the EPA’s authority with concrete and
judicially enforceable statutory limitations. The major
questions doctrine is meant to discern, not override,
such statutory judgments. Doubly so when the
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regulatory authority and its reach have been affirmed
and enforced by the Supreme Court.
b. Regulatory Consequences
The problems with the EPA’s approach to the majorquestion analysis do not stop there. The Agency also
conflates the significance of greenhouse gas regulation
of power plants generally with any significance
attributable solely to the EPA’s choice of a “best
system of emission reduction”—the statutory
provision where the EPA tried to anchor its majorquestion objection. Remember, the EPA concluded
that the major questions doctrine was triggered
centrally by (i) the Clean Power Plan’s “billions of
dollars of impact” on the economy; (ii) its effect on
“every electricity customer”; (iii) the number of
litigation challenges it spawned, “involving almost
every State”; and (iv) its perceived shifting of
regulatory authority between federal agencies and the
States. ACE Rule, 84 Fed. Reg. at 32,529.
Taking the characterizations as true, those
consequences are a product of the greenhouse gas
problem, not of the best-system’s role in the solution.
Given the number and dispersion of fossil-fuel-fired
power plants, any nationwide regulation of their
greenhouse gas pollution that meaningfully addresses
emissions will necessarily affect a broad swath of the
Nation’s electricity customers. Under the EPA’s grave
endangerment finding, so too would a failure to
regulate those greenhouse gas emissions. See 2009
Endangerment Finding, 74 Fed. Reg. at 66,496.
As for the “billions of dollars of impact[,]” the EPA
has offered no evidence tying that cost to generation
shifting rather than physical plant adjustments or a
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variety of other means States might choose for
complying with emission limits. As the EPA itself
previously acknowledged, generation shifting can be
cheaper than other demonstrated methods of reducing
greenhouse gas emissions, like carbon capture and
storage, that take place “at” the source (and thus fall
within the EPA’s current statutory vision). See Clean
Power Plan, 80 Fed. Reg. at 64,727.11 Moreover, the
Clean Power Plan’s significant projected economic
impact was not atypical for Clean Air Act rulemakings
by the EPA. See, e.g., Costle, 657 F.2d at 314
(upholding 1979 new source performance standards
governing emission control by coal-burning power
plants that imposed “tens of billions of dollars” of costs
on the power sector).
Even assuming that the EPA’s federalism concerns
could trigger the major questions doctrine (rather than
the federalism clear-statement canon), they carry no
material weight here. That is because the statutory
role of the best system of emission reduction under
Section 7411(d) textually preserves and enforces the
States’ independent role in choosing from among the
broadest range of options to set standards of
performance appropriate to sources within their
jurisdiction. In fact, it is the ACE Rule’s unreasoned
barriers to certain compliance measures, like
generation shifting and biomass co-firing, that
The EPA now takes the position that natural gas co-firing
is not adequately demonstrated and that neither co-firing nor
carbon capture and storage is part of the best system of emission
reduction. See ACE Rule, 84 Fed. Reg. at 32,544–32,545, 32,549.
But those methods are amenable to implementation “to” and “at”
the source, in keeping with the EPA’s statutory view.
11
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hamstring the States. See supra Part II.A.3 (analyzing
ACE Rule, 84 Fed. Reg. at 32,555–32,556).
Finally, it seems doubtful that the volume of
litigation aimed at a regulation can reasonably bear on
its major-question status. The Supreme Court has
certainly never embraced that idea. For good reason.
A doctrine at the mercy of litigation stratagems, or the
mere existence of disagreements over which parties
find advantage in filing suit, cannot be an elucidating
or even logically relevant tool of statutory
interpretation.
In any event, the EPA offers no basis for concluding
that the best-system determination is what lit the
litigation fire. After all, the ACE Rule too has been
“subject to litigation” involving 43 States and all
manner of other interested parties, despite the Rule’s
jettisoning of generation shifting as part of the best
system of emission reduction. See Opinion Caption,
supra.
c. Regulating in the Electricity Sector
The ACE Rule’s last attempt to wrap the bestsystem determination in the major-question mantle
asserts that including generation shifting as part of
the best system of emission reduction lacks a “valid
limiting principle,” and that, by “shifting focus to the
entire grid[,]” it would “empower” the Agency “to order
the wholesale restructuring of any industrial sector[.]”
ACE Rule, 84 Fed. Reg. at 32,529. But that is entirely
wrong. The Clean Power Plan was aimed not at
regulating the grid, but squarely and solely at
controlling air pollution—a task at the heart of the
EPA’s mandate. Indeed, the EPA’s reasoning in the
ACE Rule defeats its own argument.
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The EPA suggests that counting generation shifting
among the tools for emission reduction risks
expanding the Agency’s regulatory sights too far,
because “any action affecting a generator’s operating
costs cou
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