Respondents Brief — West Virginia, et al., Petitioners v. Environmental Protection Agency, et al.

Supreme Court briefJan 18, 2022

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Nos. 20-1530, 20-1531, 20-1778, and 20-1780

IN THE

Supreme Court of the United States

State of WEST VIRGINIA, et al.,

Petitioners,

ENVIRONMENTAL PROTECTION AGENCY, et al.,

Respondents.

THE NORTH AMERICAN COAL CORPORATION,

Petitioner,

ENVIRONMENTAL PROTECTION AGENCY, et al.,

Respondents.

WESTMORELAND MINING HOLDINGS LLC,

Petitioner,

ENVIRONMENTAL PROTECTION AGENCY, et al.,

Respondents.

State of NORTH DAKOTA,

Petitioner,

ENVIRONMENTAL PROTECTION AGENCY, et al.,

Respondents.

ON WRITS OF CERTIORARI TO THE

UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA CIRCUIT

BRIEF FOR STATE OF NEW YORK AND

OTHER STATE AND MUNICIPAL RESPONDENTS

MICHAEL J. MYERS

Senior Counsel

ANDREW G. FRANK

BRIAN M. LUSIGNAN

Assistant Attorneys General

LETITIA JAMES

Attorney General

State of New York

BARBARA D. UNDERWOOD*

Solicitor General

STEVEN C. WU

Deputy Solicitor General

MATTHEW W. GRIECO

Senior Assistant Solicitor General

28 Liberty Street

New York, New York 10005

(212) 416-8020

barbara.underwood@ag.ny.gov

*Counsel of Record

(Additional counsel listed on signature pages.)

QUESTION PRESENTED

Section 7411 of the Clean Air Act (42 U.S.C. § 7411)

provides that the Environmental Protection Agency

(EPA) shall select the “best system of emission reduction” that has been “adequately demonstrated” for

categories of stationary sources such as power plants,

after taking into account several enumerated criteria.

With respect to existing sources, EPA then promulgates regulations—known as emission guidelines—

reflecting “the degree of emission limitation achievable

through the application of the best system of emission

reduction,” and States use EPA’s guidelines to develop

state plans with source-specific performance standards. The question presented is:

Whether EPA, in determining the “best system of

emission reduction,” is forbidden from considering

measures that the agency judged could not apply “to

and at” an individual source standing alone—including

measures that have been widely adopted and proven to

significantly reduce emissions from sources.

TABLE OF CONTENTS

Page

Table of Authorities .......................................................ii

Introduction .................................................................... 1

Statement ....................................................................... 3

Summary of Argument ................................................ 15

Argument ...................................................................... 18

I. The ACE Rule Relied on an Erroneous

Interpretation of Section 7411. .......................... 19

A. The Text and Structure of Section 7411

Do Not Support the ACE Rule’s Narrow

Interpretation of “Best System of

Emission Reduction.” .................................... 19

B. The ACE Rule’s Statutory Interpretation

Improperly Constrained the States’

Compliance Choices. ..................................... 28

C. The ACE Rule’s “To and At the Source”

Interpretation Is Not Necessary to

Ensure Appropriate Limitations on

EPA’s Regulatory Authority......................... 33

II. This Case Does Not Present Concerns About

Major Questions or Non-Delegation.................. 38

A. EPA’s Consideration of Measures Beyond

Those That Can Be Implemented “To and

At” a Particular Source Does Not

Implicate Any Major Question. .................... 38

B. Section 7411 Does Not Raise NonDelegation Concerns. .................................... 47

Conclusion..................................................................... 49

iii

TABLE OF AUTHORITIES

Cases

Page(s)

Alabama Ass’n of Realtors v. Dep’t of Health &

Human Servs., 141 S. Ct. 2485 (2021) ............. 39,40

Alaska Dep’t of Envtl. Conservation v. EPA, 540

U.S. 461 (2004)................................................... 31,46

American Elec. Power Co. v. Connecticut, 564 U.S.

410 (2011) ........................................................ passim

Biden v. Missouri, No. 21A240, 2022 WL 120950

(U.S. Jan. 13, 2022) ................................................ 28

Bostock v. Clayton County, 140 S. Ct. 1731 (2020) .. 20,25

Carney v. Adams, 141 S. Ct. 493 (2020) ..................... 43

Department of Commerce v. New York, 139 S. Ct.

2551 (2019) .............................................................. 36

Department of Tax’n & Fin. of N.Y. v. Milhelm

Attea & Bros., 512 U.S. 61 (1994) .......................... 44

EPA v. EME Homer City Generation, L.P., 572

U.S. 489 (2014)................................................3,30-32

FDA v. Brown & Williamson Tobacco Corp., 529

U.S. 120 (2000)........................................................ 40

FERC v. Electric Power Supply Ass’n, 577 U.S.

260 (2016) ................................................................ 47

Gonzales v. Oregon, 546 U.S. 243 (2006) .................... 41

Gundy v. United States, 139 S. Ct. 2116 (2019) ......... 48

In re Murray Energy Corp., 788 F.3d 330 (D.C.

Cir. 2015) ................................................................. 36

Jama v. ICE, 543 U.S. 335 (2005) ............................... 21

Lehrfeld v. Richardson, 132 F.3d 1463 (D.C. Cir.

1998) ........................................................................ 24

Cases

Page(s)

Little Sisters of the Poor Saints Peter & Paul Home

v. Pennsylvania, 140 S. Ct. 2367 (2020) ........... 20,23

Massachusetts v. EPA, 549 U.S. 497 (2007) ............ 5,38

Michigan v. EPA, 576 U.S. 743 (2015)........................ 36

National Ass’n of Mfrs. v. Department of Defense,

138 S. Ct. 617 (2018) .............................................. 19

National Fed’n of Indep. Bus. v. Department of

Labor, OSHA, No. 21A244, 2022 WL 120952

(U.S. Jan. 13, 2022) ...........................................40-42

National Fed’n of Indep. Bus. v. Sebelius, 567 U.S.

519 (2012) ................................................................ 21

New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008) ...... 5

Rotkiske v. Klemm, 140 S. Ct. 355 (2019) ................... 20

SEC v. Chenery Corp., 332 U.S. 194 (1947)................ 37

Sierra Club v. Costle, 657 F.2d 298 (D.C. Cir. 1981).... 26

Touby v. United States, 500 U.S. 160 (1991) .............. 48

Train v. Natural Resources Defense Council, 421

U.S. 60 (1975) ..................................................... 30,46

Trump v. New York, 141 S. Ct. 530 (2020) ................. 42

Union Electric Co. v. EPA, 427 U.S. 246 (1976) ......... 29

Utility Air Reg. Grp. v. EPA, 573 U.S. 302

(2014) ............................................................... passim

Watson v. United States, 552 U.S. 74 (2007) .............. 24

West Virginia v. EPA, 577 U.S. 1126 (2016)............... 11

Whitman v. American Trucking Associations, 531

U.S. 457 (2001)........................................................ 48

Laws

Page(s)

Clean Air Amendments Act of 1977, Pub. L. No.

95-95, 91 Stat. 685 .................................................. 22

Clean Air Act Amendments of 1990, Pub. L. No.

101-549, 104 Stat. 2399 .......................................... 22

National Defense Authorization Act for Fiscal

Year 2012, Pub. L. 112-81, 125 Stat. 1298............ 21

42 U.S.C.

§ 7409....................................................................... 48

§ 7410.................................................................... 3,26

§ 7411............................................................... passim

§ 7412.................................................................. 14,20

§ 7416.................................................................... 4,29

§ 7479.................................................................. 20,46

§ 7491....................................................................... 20

§ 7607....................................................................... 36

§ 7651....................................................................... 27

§ 7651b..................................................................... 27

§ 7651f ..................................................................... 20

Cal. Code Regs § 95811 .................................................. 6

Wash. Rev. Code § 70A.65.005 et seq. .......................... 6

W.Va. Code § 22-5-18 ................................................... 27

Administrative Sources

Regulations

40 C.F.R.

§ 60.21a...................................................................... 4

§ 60.24a...................................................................... 4

30 Tex. Admin. Code § 101.300 ................................... 27

Administrative Sources

Page(s)

Federal Register (by date)

State Plans for the Control of Certain Pollutants

from Existing Facilities, 40 Fed. Reg. 53,340

(Nov. 17, 1975) .......................................................... 5

Emission Guidelines for Sulfuric Acid Mist, 42

Fed. Reg. 55,796 (Oct. 18, 1977) .............................. 4

Electric Utility Steam Generating Units, 70 Fed.

Reg. 28,606 (May 18, 2005) ...................................... 5

72 Fed. Reg. 46,161 (Aug. 17, 2007) ............................ 27

72 Fed. Reg. 72,978 (Dec. 26, 2007) ............................ 27

73 Fed. Reg. 3,194 (Jan. 17, 2008) .............................. 27

Endangerment and Cause or Contribute Findings

for Greenhouse Gases, 74 Fed. Reg. 66,496

(Dec. 15, 2009) ........................................................... 5

Carbon Pollution Emission Guidelines for Existing

Stationary Sources: Electric Utility Generating

Units, 80 Fed. Reg. 64,662 (Oct. 23, 2015) .............. 7

Standards of Performance for Greenhouse Gas

Emissions From New, Modified, and

Reconstructed Stationary Sources: Electric

Utility Generating Units, 80 Fed. Reg. 64,510

(Oct. 23, 2015) ........................................................... 7

Repeal of the Clean Power Plan, 84 Fed. Reg.

32,520 (July 8, 2019) .............................................. 11

Oil and Natural Gas Sector Climate Review, 86

Fed. Reg. 63,110 (Nov. 15, 2021) ........................... 35

EPA Publications

Environmental Protection Agency, Illustrative ACE

Scenario, State Emission Projections (2019),

https://www.epa.gov/sites/default/files/201906/illustrative_ace_scenario_0.zip ......................... 13

vii

Administrative Sources

Page(s)

EPA Publications (cont’d)

Environmental Protection Agency, Inventory of

U.S. Greenhouse Gas Emissions and Sinks:

1990-2019 (2021),

https://www.epa.gov/sites/default/files/202104/documents/us-ghg-inventory-2021-maintext.pdf?VersionId=uuA7i8WoMDBOc0M4ln8

WVXMgn1GkujvD .................................................... 6

Environmental Protection Agency, Regulatory

Impact Analysis for the Clean Power Plan

Final Rule (Oct. 23, 2015),

https://www3.epa.gov/ttnecas1/docs/ria/utilities

_ria_final-clean-power-plan-existingunits_2015-08.pdf ................................................... 11

Environmental Protection Agency, Regulatory

Impact Analysis for the Repeal of the Clean

Power Plan, and the Emission Guidelines for

Greenhouse Gas Emissions from Existing

Electric Utility Generating Units (2019),

https://www.epa.gov/sites/default/files/201906/documents/utilities_ria_final_cpp_repeal_an

d_ace_2019-06.pdf................................................... 13

Miscellaneous Authorities

Acadia Ctr., The Regional Greenhouse Gas

Initiative: 10 Years in Review (2019),

https://acadiacenter.org/wpcontent/uploads/2019/09/AcadiaCenter_RGGI_10-Years-in-Review_2019-0917.pdf ......................................................................... 6

viii

Miscellaneous Authorities

Page(s)

Facing Risks, EPA’s Counsel Defends ‘Bold’ ACE

Rule Legal Interpretation, Inside EPA (Aug. 2,

2019), https://insideepa.com/daily-news/facingrisks-epa-s-counsel-defends-bold-ace-rule-legalinterpretation .......................................................... 11

H.R. 17255, 91st Cong. (1970) ..................................... 22

Merriam-Webster Dictionary (online 2021) ................ 21

National Assoc. of Clean Air Agencies, State

Mercury Programs for Utilities (Dec. 4, 2007),

https://www.4cleanair.org/wpcontent/uploads/Documents/StateTable.pdf ......... 27

S. 4358, 91st Cong. (1970) ........................................... 22

U.S. Global Change Research Program, Fourth

National Climate Assessment (Rev. Mar. 2021),

https://nca2018.globalchange.gov/downloads/N

CA4_2018_FullReport.pdf ........................................ 6

Webster’s Third New International Dictionary of

the English Language Unabridged (1968) ............ 21

INTRODUCTION

To reduce harmful pollution from stationary

sources, Section 7411 of the Clean Air Act directs EPA

to study all means of emission reduction that have been

“adequately demonstrated” for categories of sources,

such as power plants, and to draw on that expert

analysis to determine the “best system of emission

reduction” for such sources. 42 U.S.C. § 7411(a)(1). For

existing sources, the best system informs EPA’s issuance of emission guidelines under which the States

then establish performance standards for individual

sources. Id. § 7411(d)(1).

This case concerns the scope of EPA’s authority to

determine the best system for reducing carbon dioxide

(CO2) emissions from existing power plants. Both the

power sector and the States have long relied on a broad

range of measures to cost-effectively reduce emissions

of harmful pollutants, including CO2, from sources on

the electric grid. But in the Affordable Clean Energy

(ACE) Rule, EPA concluded that certain of those measures were categorically disqualified from consideration

as part of the best system—no matter how effective or

“adequately demonstrated” they were—solely because

they involved the activities of more than one entity. The

Rule’s insistence that the unambiguous meaning of

“best system” in Section 7411(a)(1) was limited to

“measures that can be applied to and at the level of the

individual source” standing alone (J.A.1769) led it to

disregard widely adopted and proven measures of

reducing CO2 emissions, such as cap-and-trade

programs. And the Rule further concluded that this

unambiguous meaning not only restrained EPA, but

also barred States and sources from relying on such

measures to satisfy federal emission guidelines.

(J.A.1893-1894.)

The court of appeals rejected the ACE Rule’s

limitations on both EPA authority and state flexibility,

correctly finding that these limitations found no support

in the text or structure of Section 7411. Contrary to

petitioners’ arguments, nothing in the decision below

implicates this Court’s cases on “major questions” or

non-delegation. The lower court did not, as petitioners

contend, give EPA untrammeled authority to regulate

“any economic sector or almost any actor.” (West

Virginia (W.Va.) Br. 1.) Instead, it considered and

rejected only the specific “to and at the source” limitation that the ACE Rule found to be unambiguously

required by Section 7411.

Rather than focusing on the decision below or the

ACE Rule’s statutory interpretation, petitioners’ arguments about agency overreach instead criticize an

earlier rule, the Clean Power Plan, that EPA has said

it no longer intends to enforce; or speculate about the

impacts of future rules that EPA might adopt. These

arguments face serious jurisdictional defects, as the

United States and the Non-Governmental Organization and Trade Association (NGO) Respondents

correctly note. (NGO Resp. Br. 23-32.) In any event,

petitioners’ claim that the ACE Rule’s statutory interpretation is necessary to prevent EPA from overstepping its authority disregards important features of the

underlying statutory scheme. Congress has already

made the major policy choices to curb CO2 emissions

from existing power plants and to task EPA and the

States with distinct responsibilities in a multi-step

process to establish performance standards for such

sources. And Congress also enacted other constraints

on EPA’s discretion in Section 7411 and the Act that

would more directly prevent the dire consequences that

petitioners hypothesize, without resorting to the

atextual and ahistorical interpretation of “best system

of emission reduction” that the ACE Rule adopted.

STATEMENT

1. Section 7411 of the Clean Air Act is one of the

statute’s primary tools to address pollution from

stationary sources, including power plants. Section 7411

adopts distinct regulatory approaches for new sources

compared to existing sources. For new sources, Section

7411(b) authorizes EPA to directly set “standards of

performance” for categories of stationary sources to

curb their harmful emissions. 42 U.S.C. § 7411(b)(1)(A),

(B). The statute defines “standard of performance” as:

a standard for emissions of air pollutants

which reflects the degree of emission limitation achievable through the application

of the best system of emission reduction

which (taking into account the cost of

achieving such reduction and any nonair

quality health and environmental impact

and energy requirements) the Administrator determines has been adequately

demonstrated.

Id. § 7411(a)(1).

For existing sources in the same source categories,

Section 7411(d) uses a familiar cooperative-federalism

approach that is borrowed from the Section 7410

process for national ambient air quality standards. See

id. § 7411(d)(1) (cross-referencing 42 U.S.C. § 7410);

EPA v. EME Homer City Generation, L.P., 572 U.S.

489, 497-98 (2014). Instead of directly imposing

standards of performance on existing stationary

sources, EPA promulgates regulations—known as

emission guidelines—that contain EPA’s determination of “the degree of emission limitation achievable

through the application of the best system of emission

reduction.” 42 U.S.C. § 7411(a)(1) & (d)(1); 40 C.F.R.

§ 60.21a(e). “[I]n compliance with those guidelines and

subject to federal oversight, the States then issue

performance standards for stationary sources within

their jurisdiction.” American Elec. Power Co. v.

Connecticut, 564 U.S. 410, 424 (2011) (AEP).

Under Section 7411(d), States have considerable

flexibility in establishing performance standards for

individual sources so long as they curb overall pollution

to the levels provided in EPA’s guidelines. See 42

U.S.C. § 7416. For example, States need not require

sources to implement the system of emission reduction

that EPA has determined to be the “best.” States are

also permitted to consider site-specific factors, such as

a source’s remaining useful life or implementation

costs, in establishing a standard for a particular source.

See 40 C.F.R. § 60.24a(e). When EPA’s guidelines have

included emission limits that each source must

presumptively satisfy, see e.g., Emission Guidelines for

Sulfuric Acid Mist, 42 Fed. Reg. 55,796, 55,797 (Oct. 18,

1977), EPA has allowed state plans to rely on sitespecific factors “to deviate from [these] generally

applicable emission standards upon demonstration

that costs are ‘[u]nreasonable,’” among other reasons.

AEP, 564 U.S. at 427. In other instances, EPA has

established statewide emission limits and provided for

emissions averaging or trading programs that enable

States to take site-specific factors into consideration

when allocating responsibility for meeting the statewide targets. See, e.g., Electric Utility Steam Generat-

ing Units, 70 Fed. Reg. 28,606, 28,649-50 (May 18, 2005)

(mercury emissions from coal-fired power plants). 1

Although States have flexibility in establishing

standards for particular sources, EPA must ultimately

ensure that state plans are “satisfactory,” 42 U.S.C.

§ 7411(d)(2)—i.e., they “assure that meaningful controls

will be imposed,” State Plans for the Control of Certain

Pollutants from Existing Facilities, 40 Fed. Reg.

53,340, 53,343-44 (Nov. 17, 1975). If a State does not

submit a satisfactory plan, EPA must issue a federal

plan that directly imposes standards of performance on

the State’s existing sources. 42 U.S.C. § 7411(d)(2).

2. In response to this Court’s decision in Massachusetts v. EPA, 549 U.S. 497 (2007), EPA determined that

elevated atmospheric concentrations of six greenhouse

gases, including CO2, endanger public health and welfare. Endangerment and Cause or Contribute Findings

for Greenhouse Gases, 74 Fed. Reg. 66,496 (Dec. 15,

2009). These pollutants increase global average temperatures, cause sea levels to rise and coasts to erode;

produce more intense, frequent, and long-lasting heat

waves and wildfires; worsen smog; trigger longer and

more severe droughts; and generate more intense

storms and extreme weather events. Id. at 66,497-99.

EPA and other agencies have emphasized the need for

immediate efforts to reduce greenhouse-gas emissions

in order to avoid “substantial damages on the U.S.

economy, human health, and the environment,”

includeing “billions of dollars” of annual economic

1 The D.C. Circuit vacated this rule for reasons unrelated to

its emissions-trading program; specifically, it held that EPA had

unlawfully delisted mercury-emitting power plants under 42

U.S.C. § 7412. See New Jersey v. EPA, 517 F.3d 574, 582-84 (D.C.

Cir. 2008).

losses as well as “physical and ecological impacts” that

are “irreversible for thousands of years” or even

“permanent.” 2

Fossil-fuel-fired power plants (predominantly coaland gas-fired) emit about 25 percent of the nation’s

greenhouse gases, by far the highest emissions of any

sector of stationary sources. 3 (J.A.393-396, 1736 n.4.).

Despite the widespread recognition of the need for

limits on these emissions, existing power plants were

not subject to federal CO2 limits for many decades. In

the absence of federal limits, several States passed laws

to require existing power plants to reduce their CO2

emissions. For example, in 2009, ten northeastern

States launched the Regional Greenhouse Gas Initiative (RGGI), which caps the total amount of CO2

collectively emitted by covered power plants, requires

emitters to obtain emission allowances, and uses proceeds from auctioning allowances to invest in programs

that reduce electricity prices. Participating States have

reduced power-plant CO2 emissions by about 50 percent, while seeing electricity prices fall by 5.7 percent. 4

California and Washington use similar cap-and-trade

programs to limit CO2 emissions from electricity

generation and other sources. See 17 Cal. Code Regs

§ 95811; Wash. Rev. Code § 70A.65.005 et seq.

2 U.S. Global Change Research Program, Fourth National

Climate Assessment vol. 2, at 1347 (rev. Mar. 2021) (internet). (For

sources available on the internet, URLs are available in the table

of authorities. All websites were last visited on January 18, 2022.)

3 See EPA, Inventory of U.S. Greenhouse Gas Emissions and

Sinks: 1990-2019, at ES-27 (2021) (internet).

4 Acadia Ctr., The Regional Greenhouse Gas Initiative: 10

Years in Review p. 1 (2019) (internet).

In 2004, several of the State and Municipal

Respondents also brought a federal common-law

public-nuisance action seeking to impose CO2 limits on

some of the nation’s largest power plants. That lawsuit

culminated in this Court’s ruling in AEP that the Clean

Air Act had displaced any relevant federal common law

with respect to harms from power-plant CO2 emissions.

The Court held that Section 7411 “speaks directly to

emissions of carbon dioxide,” AEP, 564 U.S. at 424

(quotation marks omitted), and authorizes “limits on

emissions of carbon dioxide from domestic powerplants.” id. at 424-25 (quotation marks omitted). The

Court acknowledged that such regulation requires an

“informed assessment of competing interests,” including

economic consequences, and held that Congress had

“entrust[ed] such complex balancing to EPA in the first

instance, in combination with state regulators.” Id. at

427.

3. In 2015, EPA promulgated regulations under

Section 7411 that required new and existing fossil-fuelfired power plants to limit their CO2 emissions. See

Standards of Performance for Greenhouse Gas

Emissions From New, Modified, and Reconstructed

Stationary Sources: Electric Utility Generating Units,

80 Fed. Reg. 64,510 (Oct. 23, 2015) (new sources). The

Clean Power Plan was the Section 7411(d) rule for

existing sources. Carbon Pollution Emission Guidelines

for Existing Stationary Sources: Electric Utility

Generating Units, 80 Fed. Reg. 64,662 (Oct. 23, 2015)

(reproduced at J.A.273-1668.)

In the Clean Power Plan, EPA began by

considering which systems of reducing CO2 emissions

were “adequately demonstrated” for power plants in

light of the unique characteristics of CO2 as a pollutant

and the unique features of the power sector. EPA found

that CO2 cannot be removed at the smokestack as

easily as other pollutants like sulfur dioxide, and that,

unlike those pollutants, CO2 principally causes global

impacts regardless of where it is originally emitted.

(J.A.397-401, 565-566.)

With respect to the nature of the power sector, EPA

considered different types of measures that power

plants could use to reduce their CO2 emissions. For

measures that reduce individual power plants’ CO2

emission rates, EPA determined that heat-rate

improvements (i.e., increasing the efficiency of generating electricity) were adequately demonstrated and costeffective and thus should be part of the “best” system;

however, they would “lead to only small emission

reductions for the source category.” (J.A.577). EPA

found that more substantial reductions were available

from familiar approaches that power plants and state

regulators had long relied on to reduce CO2 or other

emissions. Those approaches relied on the uniquely

interconnected nature of the electric grid and the

concomitant ability of power companies to costeffectively shift generation to less-polluting sources.

(J.A.578). Such “generation shifting” occurs as a matter

of the routine operation of the electric grid, allowing the

grid to satisfy demand while meeting “technical,

environmental, and other constraints.” (J.A.567.) EPA

found that, due to falling prices for cleaner energy and

the increasing costs of aging coal-fired plants, the

power sector was already moving toward cleaner

sources, and it expected those trends to continue.

(J.A.352, 420-428, 894, 941-42.)

EPA identified several specific measures that the

power sector had used for decades to substitute cleaner

generation for higher-emitting generation. For example, power companies often have a mixed portfolio of

fossil-fueled and renewable generation resources, and

routinely shift generation among these resources for

environmental and economic reasons. (J.A.567, 898899, 937-938.) As a result, a substantial degree of generation shifting could be accomplished within an owner’s

fleet, without involving any third parties. (See, e.g.,

J.A.898.) Power companies also regularly used contractual and state-created mechanisms, including “welldeveloped” renewable energy credit markets, to substitute generation from one unit for another, such as the

replacement of fossil-fueled generation with renewable

energy. (J.A.901, 942-944; see also J.A.902-903 (noting

that similar crediting approach could work for gas-fired

units).) States had relied on such measures to costeffectively reduce CO2 emissions from existing power

plants, including in cap-and-trade programs like RGGI

(J.A.568), or to provide sources with compliance flexibility under state renewable portfolio standards, which

require that a certain percentage of electricity be

generated using renewable energy (J.A.425, 934-944).

And EPA too had used emissions trading programs

under the Clean Air Act to reduce other pollutants from

the power sector. (J.A.430-439.)

Based on this evidence, EPA determined that the

best system for reducing CO2 emissions from existing

power plants consisted of three “building blocks”:

(1) improving heat rates at coal-fired power plants;

(2) substituting generation from existing natural gas

power plants for generation from existing coal-fired

power plants; and (3) substituting generation from new

zero-emitting renewable energy sources for generation

from existing fossil-fuel-fired plants. (J.A.657.)

EPA considered including other measures in the

best system, such as carbon capture and storage, or cofiring coal-fired power plants with natural gas.

Although EPA found that these measures were feasible

and cost-effective and could potentially achieve significant emission reductions, it ultimately did not include

them because it found that they would be more expensive than the generation-shifting measures that power

companies were already utilizing. (J.A.578.) Indeed,

power companies made clear their preference to meet

emission limits by shifting generation to lower- or zeroemitting sources because doing so would be cheaper

than—yet still as effective as—these other measures.

(J.A.578, 603 n.380.)

EPA then quantified the degree of emission

limitation achievable under its determination of the

best system for two subcategories of power plants—

steam units (primarily coal-fired) and gas-fired

combustion turbines—based on historical trends in

heat-rate improvements (J.A.867) and projections

about the capacity of gas plants and new renewable

generation (J.A.890-891, 958). In determining these

emission reductions, EPA used conservative estimates

and built in significant compliance “headroom” to ease

power plants’ ability to achieve state performance

standards. (J.A.300, 531, 643.) To provide States with

flexibility in designing state plans, EPA then issued

state-specific emission goals for 2030. (J.A.1008-1012.)

EPA expressly allowed States to consider site-specific

factors, such as remaining useful life, to vary the

emission rates of individual plants, provided that the

overall state goals were met. (J.A.1240-1256.)

EPA predicted that the Plan would achieve

relatively modest CO2 emission reductions when fully

implemented in 2030: a 32 percent reduction below

2005 levels and a 16 percent reduction from forecasted

2020 levels. (J.A.1489-1490.) The agency also estimated that coal-fired power plants would continue to

provide a significant share of the country’s electricity

generation—27.4 percent, a decrease of 5.4 percentage

points over ten years as compared to the status quo. 5

By way of comparison, EPA noted that coal’s share of

electricity generation had decreased by more than 5.4

percent during the past decade, even without any

federal CO2 regulations. (J.A.843-844.)

Various parties sought review of the Clean Power

Plan in the D.C. Circuit, which denied a stay. See West

Virginia v. EPA, No. 15-1363 (Jan. 21, 2016) (consolidated cases). Several petitioners then filed stay applications with this Court. Application for Stay, West

Virginia v. EPA, No. 15A773 (Jan. 26, 2016). West

Virginia asserted that a stay was necessary to prevent

the States from “suffer[ing] immense sovereign and

financial harms as a direct result of the Plan.” Id. at

39-40. This Court granted the applications. See West

Virginia v. EPA, 577 U.S. 1126 (2016).

4. In 2019, following a change in presidential

administrations, EPA issued the ACE Rule, which

repealed and replaced the Clean Power Plan. Repeal of

the Clean Power Plan, 84 Fed. Reg. 32,520 (July 8,

2019) (reproduced at J.A.1725-2030). 6 In repealing the

Clean Power Plan, EPA made what its general counsel

referred to as a “bold” “strategic choice” to construe

Section 7411 as unambiguously precluding the Plan. 7

The ACE Rule thus relied on the view that the Clean

5 EPA, Regulatory Impact Analysis for the Clean Power Plan

Final Rule 3-27 (Oct. 23, 2015) (internet).

6 After the finalization of the ACE Rule, the D.C. Circuit

dismissed the earlier challenges to the Clean Power Plan. West

Virginia v. EPA, No. 15-1363 (Sept. 17, 2019), CADC doc. 1809652.

7 Facing Risks, EPA’s Counsel Defends ‘Bold’ ACE Rule Legal

Interpretation, Inside EPA (Aug. 2, 2019) (internet).

Air Act limited the best system of emission reduction to

“measures that can be applied to and at the level of the

individual source.” (J.A.1769.) EPA concluded that its

new interpretation precluded the agency from relying

on certain measures that States and power companies

had already been implementing to reduce CO2 emissions based on power plants’ unique interconnection on

the electric grid. Accordingly, the ACE Rule limited the

best system for coal-fired power plants to a handful of

minor efficiency (heat-rate) improvements. (J.A.18001825.) With respect to gas-fired power plants, EPA

found that it could not identify any best system at all.

(J.A.1791-1792.)

Rather than providing States with benchmark

emission limitations, the ACE Rule instead presented

States with a list of heat-rate improvements to be

evaluated along with an expected—but nonbinding—

range of outcomes. (J.A.1803-1809.) Abandoning EPA’s

long-held support for state flexibility, the ACE Rule

also expressly prohibited States and sources from

complying with EPA’s guidelines by using emissions

averaging or trading programs because these measures

“would undermine the EPA’s determination of the [best

system] in this rule.” (J.A.1895-1901.)

In analyzing the effect of repealing the Clean

Power Plan, EPA did not find that the repeal would

avert “immense sovereign and financial harms,” as

several of the petitioning States had previously claimed.

Application for Stay at 39-40, West Virginia v. EPA.

Instead, the agency found that the repeal would save

zero costs. (J.A.1672.) That finding reflected the fact

that, even though the Plan never went into effect,

power plants had continued—and even accelerated—

reductions in CO2 emissions such that the sector would

meet the Plan’s emission-reduction goals for 2030

nearly a decade early. (J.A.1690-1693.) Moreover, EPA

found that implementing the ACE Rule would lower

power-sector CO2 emissions by less than one percent by

2030. 8 And in more than a dozen States, emissions

would increase compared to a baseline of no regulation

at all. 9

5. The State and Municipal Respondents, along

with several power companies and nongovernmental

organizations, challenged the ACE Rule in the D.C.

Circuit. See American Lung Ass’n v. EPA, No. 19-1140

(and consolidated cases). The court of appeals held that

the “ACE Rule must be vacated and remanded to the

EPA” because it rested “squarely on the erroneous legal

premise that the statutory text expressly foreclosed

consideration of measures other than those that apply

at and to the individual source.” (J.A.214.).

The court identified three textual flaws with EPA’s

stated rationale for repealing the Clean Power Plan.

First, the definition of the term “best system of

emission reduction” in Section 7411(a)(1) “announces

its own limitations,” which “simply do not include the

source-specific caveat that the EPA now interposes and

casts as unambiguous.” (J.A.106.) Second, there is no

basis for EPA’s assertion that the language of subsection (d)(1) concerning state performance standards for

individual sources “must be read upstream” into the

definition of the best system in (a)(1). (J.A.106-107.)

Third, even assuming subsections (a)(1) and (d)(1)

8 EPA, Regulatory Impact Analysis for the Repeal of the Clean

Power Plan, and the Emission Guidelines for Greenhouse Gas

Emissions from Existing Electric Utility Generating Units ES-6

(2019) (internet).

9 EPA, Illustrative ACE Scenario, State Emission Projections

(2019) (internet).

could be so combined, EPA had improperly made an

“unexplained replacement of the preposition ‘for’ in

‘standards of performance for any existing source’ [the

language in subsection (d)(1)] with the prepositions ‘at’

and ‘to,’” which do not appear in that phrase. (J.A.107.)

The court further rejected the ACE Rule’s prohibition

of certain compliance measures by States, such as emissions averaging and trading, because that prohibition

was tied to its “flawed interpretation of the statute as

unambiguously confined to measures taken ‘at’ individual plants.” (J.A.132-133.)

The court of appeals also rejected the argument

that its interpretation of “best system of emission

reduction” would allow EPA to resolve major questions

in a way that Congress did not intend. First, the court

noted that EPA’s regulation of CO2 emissions from

existing power plants was expressly authorized by

Section 7411(d) as interpreted by AEP. (J.A.137.)

Second, the court found that the Clean Power Plan’s

incorporation of “generation-shifting measures” was

neither radical nor transformative because such

“measures . . . are already widely in use by States and

power plants.” (J.A.145.) 10

EPA subsequently filed an unopposed motion with

the court of appeals to withhold issuance of the

mandate insofar as it would require reinstatement of

the Clean Power Plan. EPA explained that it was

beginning a new rulemaking to address CO2 emissions

10 Judge Walker concurred in part and dissented in part. He

would have held that the ACE Rule was invalid on the ground that

EPA’s regulation of hazardous air pollutants from power plants

under Section 7412 of the Act precludes the agency from limiting

power-plant CO2 emissions under Section 7411(d). (J.A.217, 233.)

This Court did not grant certiorari on the Section 7412 issue.

from existing power plants, and therefore had no

intention of implementing the Clean Power Plan (or the

ACE Rule). The court granted EPA’s motion. (J.A.270272.) EPA’s rulemaking remains ongoing. See EPA

Status Report at ¶4 (Jan. 17, 2022), CADC. doc.

1930863.

SUMMARY OF ARGUMENT

I.A. The ACE Rule misinterpreted Section 7411 as

unambiguously limiting EPA’s choice of the “best

system of emission reduction” to “measures that can be

applied to and at the level of the individual source.”

(J.A.1769.) That limitation appears nowhere in the text

of Section 7411(a)(1). And Congress knew how to write

such a limitation, if it had intended to include one:

narrower language focusing EPA on specific types of

emission-reduction tools appears elsewhere in Section

7411 and the Act, but not in Section 7411(a)(1)’s

authorization for EPA to determine the best system.

The ACE Rule attempted to justify its “to and at the

source” interpretation by splicing together language

from Section 7411(a)(1) and (d)(1) and relying on

language in (d)(1) that it deemed to be focused on

“individual sources.” (J.A.1746-1747.) But these two

provisions govern distinct phases of the regulatory

process: (a)(1) directs EPA to determine the best system

of emission reduction for the source category, while

(d)(1) directs States to establish standards of performance for individual sources. Any source-specific language in (d)(1) thus describes the distinct role of the

States; it does not limit EPA’s threshold determination

of the best system.

The ACE Rule’s overly restrictive reading of “best

system of emission reduction” also disregarded

Congress’s repeated recognition in other statutory

provisions that measures such as cap-and-trade

programs, which involve multiple entities, can costeffectively reduce emissions from regulated sources.

State regulators and private industry have also relied

on such measures to reduce CO2 from power plants.

The broader phrase “system of emission reduction” is

sensibly read to include specific measures of emission

reduction that Congress, the States, and the power

sector have long recognized and implemented.

B. The ACE Rule was invalid for the independent

reason that it prohibited States and sources from

achieving EPA’s emission guidelines by using emissionreduction measures involving multiple entities. That

prohibition was inconsistent with the plain text of the

Act, which allows States and sources to use any measures they choose to reduce emissions so long as state

plans achieve at least the degree of emission reduction

set forth in EPA’s guidelines.

Disregarding this feature of the ACE Rule,

petitioners instead contend that it was the decision

below that violated the Act’s requirements for state

flexibility. But the court of appeals properly respected

Section 7411’s cooperative-federalism regime and the

state flexibility that Congress built into that process.

Petitioners’ complaint that the Clean Power Plan did

not leave the States with sufficient flexibility is both

incorrect and immaterial here because the Plan is not

the rule under review and will not be enforced by EPA

going forward.

C. The ACE Rule’s statutory interpretation is not

needed to ensure appropriate constraints on EPA’s

discretion in selecting the best system. Petitioners’

slippery-slope arguments ignore the fact that Section

7411 and the Act contain numerous other limitations

on EPA. Among those limitations is the requirement

that EPA select measures that are “adequately demonstrated,” taking into account the nature of both the

industry being regulated and the pollutant to be

controlled. EPA must also consider energy requirements and the cost of achieving pollution reductions—

limitations that more directly address petitioners’

concerns about unduly burdensome rules than the ACE

Rule’s atextual “to and at the source” limitation.

Petitioners are also wrong to suggest that the

decision below endorsed the Clean Power Plan in its

entirety. The court of appeals considered only the specific interpretation of “best system of emission reduction”

that the ACE Rule relied on as its exclusive rationale

to repeal the Plan. The court accordingly did not

review, let alone approve, other features of the Plan—

including, for example, its inclusion of nonemitting

facilities that are not regulated by the Act, or its reliance on new rather than existing renewable facilities

in setting the stringency of its emission guidelines. A

court could thus still consider the validity of these

features if they are adopted by EPA in its forthcoming

rule.

II. This case does not resemble those in which this

Court has found that an agency exceeded its core

regulatory mission and decided major questions that

Congress did not intend it to address. To the contrary,

as this Court has already held, Congress made the

major policy choices here to curb CO2 emissions from

existing power plants and to utilize a cooperative-

federalism framework with distinct roles for both EPA

and the States. These choices are incompatible with

petitioners’ assertion that Congress intended to reserve

for itself the complex and technical task of establishing

standards of performance for existing power plants.

Petitioners assert that EPA might make particular

choices in determining the best system of emission

reduction that would be so “transformative” as to raise

a major question outside of the agency’s authority to

resolve. But without any extant rule that concretely

affects petitioners, that concern is purely speculative.

Equally speculative is petitioners’ concern that EPA’s

forthcoming rule will unduly disrupt the federal-state

balance. Nothing in the decision below purports to

deviate from Section 7411’s familiar cooperativefederalism framework.

ARGUMENT

The court of appeals decided a “relatively discrete”

question about the validity of a statutory interpretation

that the ACE Rule had chosen as its sole basis for

repealing the Clean Power Plan. (J.A.102.) Specifically,

the Rule had construed the phrase “best system of

emission reduction” in Section 7411(a)(1) as being

unambiguously limited to “measures that can be

applied to and at the level of the individual source.”

(J.A.1796.) And it further found that this purportedly

unambiguous meaning not only constrained EPA’s

emission guidelines but also barred States and sources

from using compliance measures other than those that

apply “to and at” an individual source. (J.A.1893-1894.)

The court of appeals correctly rejected the ACE

Rule’s statutory interpretation. That narrow ruling did

not, as petitioners contend, leave EPA with “unfettered

discretion” (Westmoreland Mining Holdings (Westmoreland) Br. 43) to regulate “any producer in any

economic sector—or really any building owner” (W.Va.

Br. 23); indeed, the court acknowledged other textual

constraints on EPA’s determination of the best system.

The ruling similarly raises no concerns about improper

agency resolution of major questions or impermissible

legislative delegation in light of the many indications

in Section 7411 that Congress made the major policy

choices here—including the choice to regulate CO2 emissions from power plants, and the choice to employ a

cooperative-federalism regime under which EPA and

the States have distinct, well-defined responsibilities.

Assuming that this Court has jurisdiction (see NGO

Resp. Br. 23-32), it should affirm the judgment below.

The ACE Rule Relied on an Erroneous

Interpretation of Section 7411.

A. The Text and Structure of Section 7411

Do Not Support the ACE Rule’s Narrow

Interpretation of “Best System of

Emission Reduction.”

1. a. Any analysis of EPA’s authority under Section

7411 “begins with the statutory text.” National Ass’n of

Mfrs. v. Department of Defense, 138 S. Ct. 617, 631

(2018) (quotation marks omitted). The ACE Rule

repealed the Clean Power Plan on the sole theory that

Section 7411 unambiguously limits EPA’s determination of the “best system of emission reduction” to

“measures that can be applied to and at the level of the

individual source,” standing alone, and thus categorically precludes emission guidelines “premised on a

system of emission reduction that is implementable

only through the combined activities of sources or non-

sources.” (J.A.1747, 1769, 1784, 1796.) But no language

in Section 7411(a)(1) imposes this “to and at the source”

limitation on EPA’s selection of the best system. The

absence of such limiting language is meaningful. “It is

a fundamental principle of statutory interpretation that

absent provision[s] cannot be supplied by the courts.”

Rotkiske v. Klemm, 140 S. Ct. 355, 360-61 (2019) (quotation marks omitted). And that principle specifically

forbids courts from “imposing limits on an agency’s

discretion that are not supported by the text.” Little

Sisters of the Poor Saints Peter & Paul Home v.

Pennsylvania, 140 S. Ct. 2367, 2381 (2020).

The absence of any express “to and at the source”

limitation in Section 7411(a)(1) is particularly striking

because that provision explicitly constrains EPA’s

determination of the best system in other ways,

including by requiring that the best system be “adequately demonstrated.” See infra at 33-38. Congress

also knows how to narrow EPA’s focus to “more specific

categories of emission-reduction tools.” (J.A.120.)

Section 7411 itself does so in other provisions that refer

more narrowly to a “technological system” of emission

reduction. 42 U.S.C. § 7411(h) & (j) (emphasis added).

Similarly, other provisions of the Clean Air Act refer to

“retrofit technology” (i.e., updated equipment), id.

§ 7491(b)(2)(A), (g)(2); see also id. § 7651f(b)(2); to measures that “collect, capture or treat . . . pollutants when

released,” id. § 7412(d)(2)(C); or to specific measures

like “fuel cleaning, clean fuels, or treatment or innovative fuel combustion techniques,” id. § 7479(3). These

other provisions demonstrate that “Congress could have

taken a more parsimonious approach,” Bostock v.

Clayton County, 140 S. Ct. 1731, 1739 (2020), to EPA’s

selection of the “best system of emission reduction” in

Section 7411(a)(1). But Congress omitted any such

limitations. This Court “do[es] not lightly assume that

Congress has omitted from its adopted text requirements that it nonetheless intends to apply, and [its]

reluctance is even greater when Congress has shown

elsewhere in the same statute that it knows how to

make such a requirement manifest.” Jama v. ICE, 543

U.S. 335, 341 (2005); see also National Fed’n of Indep.

Bus. v. Sebelius, 567 U.S. 519, 544 (2012) (“Where

Congress uses certain language in one part of a statute

and different language in another, it is generally

presumed that Congress acts intentionally.”).

Instead, Section 7411(a)(1) refers simply to the

“best system of emission reduction.” Nothing about this

phrase supports the ACE Rule’s “to and at the source”

limitation. The ordinary meaning of “system” refers to

“a complex unity formed of many often diverse parts

subject to a common plan or serving a common purpose,”

Webster’s Third New International Dictionary of the

English Language Unabridged 2322 (1968); see also

Merriam-Webster Dictionary s.v. system (2021) (defining “system” as any “interdependent group of items”

that “serv[e] a common purpose”). What ties together

the components of a “system of emission reduction” is

that they are all measures that are directed toward the

shared objective of reducing emissions from regulated

sources—regardless of whether they take into account

actions by just one entity, or many. Cf., e.g., National

Defense Authorization Act for Fiscal Year 2012, Pub. L.

112-81, § 2841(b), 125 Stat. 1298, 1696 (requiring design

of a “health care system” consisting of multiple components, including a medical plan, contractor-provided

health services, and access to local healthcare assets).

Similarly, the phrase “emission reduction” does not

support the ACE Rule’s interpretation because there is

no dispute that measures implementable through the

combined activities of multiple entities can meaningfully reduce regulated sources’ emissions. Indeed, the

Rule admitted that the measures considered by the

Clean Power Plan—including measures that would

increase the relative production of lower-polluting

sources on the electric grid—could be “a workable policy

for achieving sector-wide carbon-intensity reduction

goals.” (J.A.1785.) That admission reflected the practical reality that States and power plants have extensive

experience with strategies involving multiple entities

as a cost-effective means of reducing CO2 emissions.

(J.A.568-569.) See supra at 8-9.

Congress’s decision not to include narrowing

language in Section 7411(a)(1) was a deliberate one.

Before enacting Section 7411 during the 1970 legislative session, both chambers considered language that

would have more specifically referred to the types of

control measures that EPA could consider in selecting

the best system of emission reduction. See S. 4358, 91st

Cong. § 6 (1970) (“the latest available control technology, processes, operating methods, or other alternatives”); H.R. 17255, 91st Cong. § 5 (1970) (requiring the

use of “available technology” for new sources only). But

Congress chose instead the broader phrase “best

system of emission reduction” for Section 7411(a)(1).

Similarly, from 1977 through 1990, Congress temporarily limited EPA’s choice of controls for new sources

to “the best technological system of continuous emission

reduction.” See Clean Air Amendments Act of 1977,

Pub. L. No. 95-95, § 109(c)(1)(A), 91 Stat. 685, 700;

Clean Air Act Amendments of 1990, Pub. L. No. 101549, § 403(a), 104 Stat. 2399, 2631. But at no time has

Congress imposed the same restriction on EPA’s choice

of systems for existing sources. Its decision not to do so

precluded EPA from engrafting such extratextual

limitations on the statute in the ACE Rule. See Little

Sisters of the Poor, 140 S. Ct. at 2380 (rejecting limits

on agency authority when “Congress could have limited

[the agency’s] discretion in any number of ways, but it

chose not to do so”).

b. The ACE Rule defended its “to and at the source”

interpretation by making a grammatical argument

centered on the word “application.” (See J.A.1744-1747.)

According to the Rule, the relevant phrase in Section

7411(a)(1)—“through the application of the best system

of emission reduction”—required EPA to identify an

“indirect object” to which the “best system” would be

applied. (J.A.1746.) The Rule then reasoned that a

different subsection—Section 7411(d)(1)—“provides

that the indirect object is the ‘existing source,’” based

on the latter subsection’s requirement that States

establish “standards of performance for any existing

source.” (J.A.1746.) The Rule concluded that this

splicing together of 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.”

(J.A.1746) (italics in original.)

For several independent reasons, the ACE Rule’s

reasoning is not persuasive, let alone unambiguously

compelled by the text. First, the Rule erred in assuming

that the phrase “application of the best system of

emission reduction” in Section 7411(a)(1) is grammatically incomplete in a way that requires the identification of an indirect object at all. As the court of appeals

correctly recognized, the noun “application” does not

require an indirect object but is instead a “nominalization” that “enables the drafter to leave certain

information unspecified—namely, who is acting and

where their action is directed.” (J.A.113-114.) In similar

contexts, where Congress chooses a grammatical

construction that allows for the omission of a part of

speech—for example, omitting the subject by using the

passive voice—that choice ordinarily reflects Congress’s

“agnosticism” about the part of speech that is not used;

it does not constitute a clear command to fill in the

missing part of speech in a specific way. See Watson v.

United States, 552 U.S. 74, 81 (2007); Lehrfeld v.

Richardson, 132 F.3d 1463, 1465-66 (D.C. Cir. 1998).

Second, even if a particular indirect object were

grammatically necessary, such an indirect object can

typically be inferred from context and does not require

an explicit textual reference. Here, as the court of

appeals observed, “other contextually appropriate

indirect objects” would include the source category or

the emissions themselves. (J.A.115.) Nothing required

EPA to identify a specific indirect object elsewhere in

Section 7411.

Third, the text of Section 7411(d) does not support

the ACE Rule’s grammatical claim that the “best system

of emission reduction” must be applied exclusively “to”

or “at” the source of emissions. The relevant language

in Section 7411(d)(1) references “standards of performance for any existing source for any air pollutant.” But

the Rule then departs from this text in two ways. For

one thing, although subsection (d)(1) uses “for any

existing source” to modify “standards of performance,”

the Rule instead uses it to modify subsection (a)(1)’s

“best system of emission reduction”—a phrase that is

only part of the definition of “standard of performance”

and thus cannot simply be substituted into subsection

(d)(1). (J.A.111.) In addition, although the language in

subsection (d)(1) uses the preposition “for,” the ACE

Rule concludes that the “best system of emission

reduction” must be “put into operation at a building,

structure, facility, or installation,” or applied “to the

designated facility.” (J.A.1746-1747 (second emphasis

added).) As the court of appeals observed, “[t]he word

Congress actually used—‘for’ the source—lacks the

site-specific connotation on which the [Rule’s] case

depends.” (J.A.116.) For example, a reservation system

“for” a hotel may be handled off-site as well as “at” the

hotel’s front desk. “[N]owhere in the ACE Rule does the

EPA explain this swap of one preposition for two

meaningfully more restrictive ones.” (J.A.117.) Thus,

the Rule’s interpretation of “best system of emission

reduction” in Section 7411(a)(1) depends on a reading

of the statute that is not consistent with “the words on

the page,” Bostock, 140 S. Ct. at 1738.

2. The ACE Rule’s narrow interpretation of “best

system of emission reduction” also conflicts with the

broader structure of Section 7411 and the Clean Air Act.

First, the Rule makes a fundamental mistake in

using language from Section 7411(d)(1) to limit EPA’s

determination of the best system in Section 7411(a)(1)

because the two provisions govern distinct phases of

the regulatory process. Subsection (a)(1) directs EPA to

“study all ‘adequately demonstrated’ means of emission

reduction” and then to draw on that analysis “to determine the ‘best’ system to reduce emissions” for the

source category. (J.A.108.) EPA’s determination of the

best system informs its emission guidelines, and those

guidelines in turn provide the criteria under which “the

States then issue performance standards for stationary

sources within their jurisdiction” pursuant to subsection (d)(1). AEP, 564 U.S. at 424.

In other words, EPA determines the best system

under subsection (a)(1) and issues emission guidelines

for the entire source category before States set perform-

ance standards for individual sources under subsection

(d)(1). Petitioners do not dispute that EPA’s threshold

determination of the best system at the start of this

process evaluates many of the other statutory factors—

including costs, health and environmental impacts, and

energy requirements—on a sector-wide as well as

individual-source level. (J.A.808.) See Sierra Club v.

Costle, 657 F.2d 298, 330 (D.C. Cir. 1981). It would be

anomalous if the same scope did not govern EPA’s

responsibility to identify the measures of emission

reduction that are “adequately demonstrated” for the

source category and thus should be considered for

inclusion in the best system. By contrast, the statutory

language in subsection (d)(1) identified by petitioners

as reflecting a “source-specific focus” (N. Am. Coal

Corp. (NACCO) Br. 33; see also id. 35-37) pertains to

the States’ establishment of standards of performance

for particular sources; it does not restrict EPA’s

threshold responsibility under Section 7411(a)(1) to

select the “best system of emission reduction.”

Second, the ACE Rule’s restrictive reading of “best

system of emission reduction” conflicts with the fact

that Congress has repeatedly recognized, in multiple

other statutory provisions, that measures can costeffectively reduce emissions through the activities of

multiple entities, including through cap-and-trade

programs. For example, in Section 7410 of the Act—a

statute whose cooperative-federalism scheme Section

7411 expressly references, see 42 U.S.C. § 7411(d)(1)—

Congress recognized that air quality could be improved

not only by “enforceable emission limitations” but also

by “other control measures” including, specifically,

“marketable permits, and auctions of emissions rights.”

Id. § 7410(a)(2)(A). Similarly, in Title IV of the Act,

Congress established a trading scheme as part of the

“emission limitation programs” to address acid rain, see

42 U.S.C. § 7651b(a)(1), and specifically found that this

“emission allocation and transfer system” provided a

way for sources to meet “prescribed emission limitations,” id. § 7651(b). Petitioners argue (W.Va. Br. 42)

that these other programs are inapposite because their

implementing statutes specifically mention trading,

but that argument ignores the explicit textual link

between Sections 7410 and 7411, as well as the fact

that Congress chose to use broader language in Section

7411—“system of emission reduction”—than in the

statutes that petitioners discuss. There is nothing

suggesting that Congress silently intended the phrase

“system of emission reduction” to exclude measures

that involve multiple entities, while elsewhere recognizing such measures to be effective methods for

reducing air pollution.

More broadly, States (including several of the

petitioners) have long relied on trading programs as

one tool to help reduce pollution, in both state-specific

schemes and regional programs such as RGGI. 11 See,

e.g., W.Va. Code § 22-5-18; 30 Tex. Admin. Code

§ 101.300 et seq. See also supra at 9. The power sector

likewise “has a long and well-established history” of

11 Indeed, every State that is a petitioner here previously

supported cap-and-trade programs as a means of emission reduction in connection with the Clean Air Mercury Rule, a Section 7411

rule. These States (except one, which accepted a federal plan)

informed EPA that they planned to participate in a national capand-trade program that EPA intended to establish. See, e.g., 73

Fed. Reg. 3,194 (Jan. 17, 2008) (Missouri); 72 Fed. Reg. 72,978

(Dec. 26, 2007) (Kansas); 72 Fed. Reg. 46,161 (Aug. 17, 2007)

(Louisiana); see also National Assoc. of Clean Air Agencies, State

Mercury Programs for Utilities (Dec. 4, 2007) (internet) (summary

table of state plan submissions).

engaging in multi-entity actions, including trading, “for

the purpose of reducing CO2 emissions—and certainly

always with the effect of reducing emissions.” (J.A.771772, 805-806; see Power Company Resp. Br. 35-41.)

This Court recently relied on similar examples of “preexisting state requirements” and industry experience

to uphold a COVID-19 vaccination rule by the Centers

for Medicare and Medicaid Services, pointing to

analogous vaccine policies by the States and publichealth sector as support for the federal agency’s

authority to do the same under its power to protect

“health and safety.” Biden v. Missouri, No. 21A240,

2022 WL 120950, at *3-4 (U.S. Jan. 13, 2022) (per

curiam). Here, too, the widespread state and industry

practice of reducing emissions through the actions of

multiple entities supports an interpretation of “best

system of emission reduction” that would include such

measures.

B. The ACE Rule’s Statutory Interpretation Improperly Constrained the States’

Compliance Choices.

1. The ACE Rule’s interpretation of Section 7411

was invalid for the additional reason that it forbade

States and sources alike from achieving EPA’s emission

guidelines by relying on commonly used methods of

emission reduction involving multiple entities—

including cap-and-trade programs—for no reason other

than that such methods “would be inconsistent with the

EPA’s interpretation of the [best system of emission

reduction] as limited to measures that apply at and to

an individual source and reduce emissions from that

source.” (J.A.1893; see also J.A.1914-1915.)

This constraint on state compliance measures finds

no support in the statutory text. (J.A.133.) Instead, it

conflicts with the cooperative-federalism regime that

Congress established for regulating existing sources.

Section 7411(d) empowers States in the first instance

to establish standards of performance for sources within

their jurisdictions. And Congress expressly provided

that “nothing in [the Act] shall preclude or deny the

right of any State . . . to adopt or enforce (1) any standard or limitation respecting emissions of air pollutants

or (2) any requirement respecting control or abatement

of air pollution,” so long as such standard, limitation,

or requirement is at least as stringent in curbing

emissions as one “in effect . . . under section 7411” of

the Act. 42 U.S.C. § 7416 (emphases added).

In other words, so long as States adopt plans under

Section 7411(d) that achieve emission reductions equal

to or greater than the minimum required by the

emission guidelines issued by EPA under Section

7411(a)(1), EPA has no lawful basis to interfere with

the manner in which state plans regulate sources

within their borders. See Union Electric Co. v. EPA, 427

U.S. 246, 264 (1976) (discussing Section 7410). In

particular, although EPA must identify a “best system

of emission reduction” in order to promulgate its

emission guidelines under Section 7411(a)(1), States

need not follow EPA’s choice of the best system if they

may achieve equal or greater emission reductions

through some other means. EPA’s “need to rewrite

clear provisions of the statute should have alerted EPA

that it had taken a wrong interpretive turn.” Utility Air

Reg. Grp. v. EPA, 573 U.S. 302, 328 (2014) (UARG).

2. Petitioners largely ignore the ACE Rule’s explicit

and unprecedented constraint on state compliance measures. Instead, Petitioner North Dakota asserts that it

is the court of appeals’ decision, not the Rule, that somehow overrides state flexibility under Section 7411.

(North Dakota (N.D.) Br. 5.) But nothing in the decision

below disturbed Section 7411’s framework for regulating existing sources, which borrows the familiar

cooperative-federalism regime governing national ambient air quality standards under Section 7410. As this

Court has long recognized, this structure “plainly

charge[s]” EPA with the authority to issue binding

general guidelines, but then leaves to the States “the

process of determining and enforcing the specific,

source-by-source emission limitations which are

necessary if the [federal] standards [EPA] has set are

to be met.” Train v. Natural Resources Defense Council,

421 U.S. 60, 79 (1975). The court of appeals’ decision

preserves these roles by upholding EPA’s authority to

determine the best system of emission reduction while

rejecting the ACE Rule’s improper constraints on

States’ discretion to choose compliance measures that

achieve those federal guidelines. (J.A.98-100.)

To be sure, EPA’s emissions guidelines will

constrain state discretion to at least some degree. But

that effect is the intended result of the cooperativefederalism scheme. As this Court has previously

explained, in describing the analogous process for

national ambient air quality standards, “the statute

speaks without reservation” about the substantive

requirements that a State must address, and EPA has

a “statutory duty” to ensure that States comply with

these minimum requirements. EME Homer City, 572

U.S. 489 at 508-09. Indeed, Section 7411 expressly

authorizes EPA to review state plans to ensure that

they are “satisfactory,” 42 U.S.C. § 7411(d)(2)(A),

confirming that EPA has the authority to ensure that

minimum federal requirements are satisfied. And the

federal oversight role conferred by Section 7411 is

particularly important where a pollutant—such as

CO2—is “heedless of state boundaries” and thus inflicts

cross-state harms that States have limited power on

their own to curb. See EME Homer City, 572 U.S. at

496; see also Alaska Dep’t of Envtl. Conservation v.

EPA, 540 U.S. 461, 486 (2004). The court of appeals’

decision properly respects this essential federal role.

Some petitioners separately raise the fear that, in

practice, the court of appeals’ interpretation of “best

system of emission reduction” in Section 7411(a)(1) will

allow EPA to promulgate emission guidelines that

effectively leave the States with no discretion in setting

source-specific standards. (E.g., N.D. Br. 45; W.Va. Br.

29-30.) But the court of appeals’ reasoning does not lead

to any such inevitable interference with state authority. The court held only that EPA was permitted to

consider emission-reduction measures beyond those

that apply “to or at” an individual source; it did not hold

that EPA was required to adopt them, let alone that

EPA must employ those measures in such a manner

that the resulting federal guidelines would eliminate

state flexibility. (J.A.104, 161, 214.) Petitioners appear

to assume that any consideration by EPA of “outsidethe-fenceline measures” (W.Va. Br. 42) will necessarily

“tie the States’ hands” (N.D. Br. 36) in setting sourcespecific performance standards, but there is no such

inherent connection. To the contrary, multi-entity

measures like trading and averaging schemes are

widely acknowledged to reduce the costs of complying

with emission limits and thus to provide additional, not

fewer, options to States and regulated sources. 12

(J.A.430-439, 609-610.)

12 Petitioners are incorrect in arguing (W.Va. Br. 29) that the

Clean Power Plan violated Section 7411(d)(1) by preventing States

(continues on next page)

Petitioners’ complaint that the Clean Power Plan’s

emission targets were “reverse-engineered” to force the

States to facilitate “shifting generation” (W.Va. Br. 2930) is irrelevant to the issue before the Court because

the Clean Power Plan is not the rule under review and

will not be enforced by EPA. Given that EPA is in the

midst of considering a new rule for existing power

plants, it is at best premature to assume that the

agency will replicate the Clean Power Plan’s specific

approach in any future rulemaking. See EME Homer

City, 572 U.S. at 524 (recognizing that a “State may

bring a particularized, as-applied challenge” if EPA’s

guidelines in fact prove unduly restrictive).

Petitioners’ complaint is also wrong. The Clean

Power Plan provided States and sources with several

forms of “compliance headroom” and set emission

guidelines “not at the maximum possible degree of

stringency but at a reasonable degree of stringency.”

(J.A.531-532, 590, 597.) EPA identified numerous

methods of emission reduction besides increasing lowerpolluting generation that would have been “capable of

helping affected [sources] achieve compliance with

standards of performance” (J.A.706), including heatrate improvements; carbon capture and storage; fuelswitching to natural gas or biomass; waste-to-heat

energy conversion; demand-side energy efficiency; and

investments to reduce transmission and distribution

from considering a source’s “remaining useful life” in setting

source-specific performance standards. The relevant portion of the

Plan cited by petitioners said only that the statewide goals

established by the Plan’s emission guidelines could not be adjusted

based on “facility-specific factors,” including “remaining useful

life.” (J.A.1237, 1244-1246.) But States could consider such factors

in establishing performance standards for “each individual

existing source.” (J.A.1240-1244.)

losses. (J.A.703-715.) The Clean Power Plan thus

confirms that there is no inherent connection between

“outside-the-fenceline measures” (W.Va. Br. 42) and

undue restrictions on state flexibility.

C. The ACE Rule’s “To and At the Source”

Interpretation Is Not Necessary to

Ensure Appropriate Limitations on

EPA’s Regulatory Authority.

1. Petitioners repeatedly argue that, by rejecting

the ACE Rule’s “to and at the source” interpretation,

the court of appeals necessarily vested EPA with

“power to impose an indefinite series of transformative

measures on practically every industrial facility, office

building, community center, and home across the

Nation.” (Westmoreland Br. 29.) They are mistaken.

This argument depends on taking out of context the

court’s observation that Section 7411(a)(1) “impose[s]

no limits on the types of measures the EPA may

consider.” (J.A.108.) That statement was made to

explain that the phrase “best system of emission

reduction” does not limit EPA to considering only

measures that can be implemented “to and at the

source.” But the court elsewhere plainly and correctly

recognized that other “substantial and explicit constraints on the EPA’s selection of a best system of

emission reduction” would preclude the dire scenarios

posited by petitioners. (J.A.146.) Those textually

grounded constraints—none invoked by the Rule as a

basis to repeal the Clean Power Plan—provide ample

safeguards against the exercise of unconstrained power

conjured by petitioners. See UARG, 573 U.S. at 331

(identifying “important limitations” in the statute “that

may work to mitigate petitioners’ concerns about

‘unbounded’ regulatory authority”).

To begin with, as EPA acknowledged when it

issued the Clean Power Plan, the fact that States must

ultimately establish standards of performance “for

existing sources,” 42 U.S.C. § 7411(d)(1), imposes

“significant constraints on the types of measures that

may be included” (J.A.733-734). For example, the best

system must “assure emission reductions from the

affected sources” themselves, thus precluding EPA

from relying on measures that address CO2 pollution in

some other way, like “the planting of forests to

sequester CO2” (J.A.803) or requiring sources to

“invest[] in electric cars” (Westmoreland Br. 28; see

J.A.806-807). Likewise, the measures must be of a type

that regulated sources can implement (J.A.543, 804),

thus precluding measures such as demand-side regulations that “target[] consumer-oriented behavior”

(J.A.813-815) or prohibitions on the “import or export

of carbon-intensive goods” (W.Va. Br. 19). 13

Additional constraints come from Section 7411’s

direction that the best system of emission reduction be

“adequately demonstrated.” That requirement obligates

EPA to examine “the history of the effectiveness of the

controls or other measures, or other indications of their

effectiveness.” (J.A.804.) And proof of adequate demonstration must be tailored to “the nature of the regulated

industry and the nature of the pollutant” at issue

(J.A.804), thus precluding EPA from adopting a onesize-fits-all approach to all sectors under its juris13 West Virginia is wrong to claim that the decision below

“instructs EPA to consider demand-side (that is, consumerfocused) measures as an option.” (W.Va. Br. 19.) The footnote cited

by West Virginia (J.A.143 n.9) says no such thing. And in the next

footnote, the court of appeals correctly explained that States could

rely on demand-side measures to comply with EPA’s guidelines.

(J.A.144 n.10.)

diction. In the Clean Power Plan, for example, EPA

found that measures that reduced CO2 emissions

through the activities of multiple entities, rather than

from the actions of individual sources acting alone, were

effective at addressing the harms from CO2 because a

distinct feature of that pollutant was that it principally

caused global harms not dependent on the origin of the

pollution. (J.A.530-531, 565-566, 607-608.) Similarly,

EPA found that the measures it considered were

adequately demonstrated based on “characteristics

[that] are unique to the utility power sector” (J.A.805806), including the fungibility of electricity on the grid

and the industry’s extensive experience with (and

indeed preference for) trading schemes over technologies like carbon capture that would be “substantially

more expensive or substantially less effective at

reducing emissions.” (J.A.733.) Because these characteristics are not the same across pollutants and

industries, there is no basis for petitioners’ concern that

the Clean Power Plan’s approach would necessarily be

“adequately demonstrated” for non-greenhouse-gas

pollutants, or for non-utility sectors such as factories,

homes, or hospitals (W.Va. Br. 19; Westmoreland Br.

28; NACCO Br. 25-26). 14

Section 7411(a)(1) also identifies three specific

factors that EPA must consider in determining the best

14 Confirming this point, two months ago EPA issued proposed

rules under Section 7411 to limit emissions of methane—another

greenhouse gas—from new and existing oil and gas facilities. See

Oil and Natural Gas Sector Climate Review, 86 Fed. Reg. 63,110

(Nov. 15, 2021). Reflecting the differences between the electric grid

and oil and gas production, EPA determined that the best system

of emission reduction included technologies and measures that are

implemented at the level of each individual source, without

coordination with other sources. See id. at 63,121-22, tbl. 3.

system: the cost of achieving emission reductions,

nonair quality health and environmental impacts, and

energy requirements. EPA has interpreted these provisions to require consideration of cost and energy

requirements both on an individual source level and on

the sector level (J.A.808), and to preclude EPA from

imposing “unreasonable technological or financial burdens on industry” (J.A.140). Petitioners suggest that

these factors would not meaningfully limit EPA’s

discretion (e.g., W.Va. Br. 19), but that argument is

pure speculation: the court below said nothing that

would diminish the importance of these factors, and this

Court has previously recognized that cost considerations can constrain EPA’s regulatory decision-making,

see Michigan v. EPA, 576 U.S. 743, 753 (2015).

Finally, the Act authorizes courts to set aside any

Section 7411 regulation that is arbitrary and capricious, or that is an abuse of EPA’s discretion. See 42

U.S.C. § 7607(b)(1), (d)(9)(A). Arbitrary-and-capricious

review following promulgation of a specific rule and

based on a complete rulemaking record provides the

appropriate mechanism for testing whether EPA has

appropriately considered factors such as cost or energy

needs, or impacts such as the impairment of the electric

grid’s reliability. See In re Murray Energy Corp., 788

F.3d 330, 335 (D.C. Cir. 2015). Such review would also

provide the appropriate forum for petitioners’ concerns

(W.Va. Br. 8; Westmoreland Br. 14) that EPA may

regulate based on hidden, pretextual reasons outside of

its statutory authority—e.g., to shut down an industry

rather than to reduce emissions. See Department of

Commerce v. New York, 139 S. Ct. 2551, 2575-76 (2019).

2. Petitioners also err in assuming that the decision

below endorsed the Clean Power Plan in its entirety

and the measures that it adopted to reduce power-plant

CO2 emissions. The court of appeals did no such thing.

It was reviewing not the Clean Power Plan itself, but

the ACE Rule’s repeal of that earlier regulation. And

because judicial review of agency action is limited to

“the grounds invoked by the agency,” SEC v. Chenery

Corp., 332 U.S. 194, 196 (1947), the court considered

only whether the Rule’s particular interpretation of

“best system of emission reduction”—the sole basis for

the Rule’s repeal of the Plan—was compelled by the

statute (J.A.102).

The court did not consider (because the ACE Rule

itself did not determine) whether any of the other

statutory constraints identified above might provide a

basis for repealing the Clean Power Plan. And the court

did not pass on the validity of other features of the

Clean Power Plan that made it unique compared to

prior power-plant or Section 7411(d) regulations. For

example, as some petitioners point out (NACCO Br. 8),

the Clean Power Plan was distinct in basing its best

system in part on increased generation from nonemitting facilities, like renewables, that are not regulated

under Section 7411, rather than limiting its scope to

sources within EPA’s regulatory jurisdiction. (J.A.657,

666-671.) In accordance with that choice, the Plan set

the stringency of its emission guidelines based in part

on “modeling projections” about the construction of new

renewable facilities—including “additional deployment

that would be motivated” by the Plan’s emission

standards (J.A.953)—rather than basing stringency

solely on the operations of existing sources. (J.A.946,

953-958.)

These features of the Plan are the appropriate

targets of petitioners’ repeated complaints that the

Plan would have required sources to “subsidize

competitors in the renewable-energy industry” (W.Va.

Br. 1) or compelled “States to shift from fossil fuel-fired

plants to new renewable resources” (Nat’l Mining Ass’n

Br. 43). But the court of appeals did not consider or

endorse these features of the Plan. Instead, it simply

rejected the ACE Rule’s broad conclusion that EPA

could not consider any measures that went beyond a

single source standing alone—including measures that

would have been limited to regulated industries, to

existing sources, or even to each individual operator’s

own portfolio of power plants. Nothing in the court’s

rejection of the Rule’s statutory interpretation would

preclude a future court from considering in the first

instance whether these other features are consistent

with EPA’s statutory authority, assuming that they are

part of a future rule.

II. This Case Does Not Present Concerns About

Major Questions or Non-Delegation.

A. EPA’s Consideration of Measures Beyond

Those That Can Be Implemented “To and

At” a Particular Source Does Not

Implicate Any Major Question.

1. Petitioners claim that EPA’s selection of the best

system of emission reduction in a future regulation

would “sidestep[] Congress to decide major questions

. . . that Congress ought to be the one to decide.”

(Westmoreland Br. 2.) But this argument ignores the

fact that Congress has already expressed its position on

“each critical element of the Agency’s regulatory

authority” relevant to this case. (J.A.136.) Congress

defined “air pollutant” in the Act in a manner that

encompassed CO2 emissions. Massachusetts, 549 U.S.

at 528-29. Congress empowered EPA to regulate “greenhouse gas emissions from fossil-fuel fired powerplants”

specifically. AEP, 564 U.S. at 425. And “Congress delegated to EPA the decision whether and how to regulate

carbon-dioxide emissions from powerplants.” Id. at 426

(emphasis added).

The Act also contains “clear Congressional

authorization,” UARG, 573 U.S. at 324, regarding who

should make the specific regulatory determination at

issue here: the selection of the best system of emission

reduction. Congress provided that the best system is

one that “the Administrator determines has been adequately demonstrated.” § 7411(a)(1) (emphasis added).

It chose to provide specific criteria for EPA to consider

in deciding on the best system, including cost, effectiveness, and energy requirements. See supra at 35-36.

And, for existing sources, Congress carved out an

important role for the States to issue source-specific

performance standards under EPA’s guidelines.

§ 7411(d)(1). Through these provisions, Congress made

clear that it was not reserving for itself the complex and

technical question of how best to reduce emissions of a

particular pollutant from a particular sector, but rather

was “entrust[ing] such complex balancing to EPA in the

first instance, in combination with state regulators,”

AEP, 564 U.S. at 427.

This case thus does not resemble those in which a

federal agency has acted outside of its assigned lane to

make decisions of “vast economic and political significance,” Alabama Ass’n of Realtors v. Dep’t of Health &

Human Servs., 141 S. Ct. 2485, 2489 (2021) (quotation

marks omitted), without any statutory basis to believe

that Congress intended to delegate such decisionmaking authority to it. In each of these cases, this

Court found that the agency had committed a category

error in deeming itself to have authority to regulate in

a particular area at all—such as the FDA’s assertion of

jurisdiction over tobacco, a substance that it had never

sought to regulate before, see FDA v. Brown &

Williamson Tobacco Corp., 529 U.S. 120, 160 (2000);

the Centers for Disease Control and Prevention’s

attempt to directly regulate “the landlord-tenant

relationship,” a domain outside its statutory authority

to “prevent[] the interstate spread of disease by identifying, isolating, and destroying the disease itself,”

Alabama Ass’n of Realtors, 141 S. Ct. at 2488-89; or the

Occupational Safety and Health Administration’s

recent attempt to issue “a general public health measure” rather than one tied more closely to the agency’s

express authority to regulate “‘occupational’ hazards

and the safety and health of ‘employees,’” National

Fed’n of Indep. Bus. v. Department of Labor, OSHA, No.

21A244, 2022 WL 120952, at *3 (U.S. Jan. 13, 2022)

(per curiam) (NFIB).

In these cases, the Court determined that the

agencies had made an error of kind, not just degree,

because they had strayed outside of the core regulatory

functions that Congress had assigned to them. This

Court thus did not rely solely on the impact of the rule

in question, but rather identified specific statutory

lines that Congress had drawn but the agencies had

disregarded. See, e.g., id. at *3-4 (describing “the text of

the agency’s Organic Act”); UARG, 573 U.S. at 325

(rejecting EPA’s decision to “rewrit[e] unambiguous

statutory terms”); Brown & Williamson, 529 U.S. at 141

(FDA’s regulation of tobacco would be “incompatible

with” other provisions). And this Court found that the

agencies, by exceeding their regulatory roles, had

removed an essential predicate for both congressional

delegation and judicial deference to agency action:

namely, the presumption that the agency is acting in a

field where it has unique experience and expertise that

neither Congress nor the judiciary shares. See NFIB,

2022 WL 120952, id. at *3 (noting that OSHA had acted

outside its “sphere of expertise”); cf. Gonzales v. Oregon,

546 U.S. 243, 269 (2006) (noting “Attorney General’s

lack of expertise in this area”). The agencies were thus

not just acting outside of their statutory authority, but

doing so in ways that this Court found undermined the

premise for delegating authority to them in the first

instance.

Here, by contrast, there is no dispute that Congress

has made the choice of what EPA may regulate (CO2

emissions), whom it may regulate (existing power

plants), and how it should do so (partnering with the

States to establish performance standards based on

EPA’s determination of the best system of emission

reduction). There is also no dispute that EPA has

experience and expertise in studying the harms of

greenhouse-gas pollution and evaluating the best

means of reducing that pollution from stationary

sources. See AEP, 564 U.S. at 428-29. And far from

being an “ancillary” or “marginal” provision (W.Va. Br.

i; NACCO Br. 1), Section 7411(d) is the “most relevant”

provision of a statute that “speaks directly” to

regulating CO2 emissions from existing power plants.

AEP, 564 U.S. at 424. Congress, not EPA, has thus

made the major policy choices here.

2. Petitioners thus cannot credibly argue that EPA

decides a major question outside of its delegated

authority whenever it regulates CO2 emissions from

existing power plants or determines the best system of

emission reduction for such sources. And their concern

that EPA might go too far in the future and resolve

“major questions” by issuing a “transformative” rule

(Westmoreland Br. 26; see also W.Va. Br. 19; NACCO

Br. 25-26) improperly depends on speculation about

“contingent future events that may not occur as

anticipated, or indeed may not occur at all.” Trump v.

New York, 141 S. Ct. 530, 535 (2020) (per curiam)

(quotation marks omitted).

Petitioners’ concerns are necessarily speculative

because, as the United States and NGO Respondents

point out (NGO Resp. Br. 23-32), no extant EPA rule

concretely affects them: EPA has already announced

that it will not implement the Clean Power Plan (see

supra at 14-15), and it is in the process of promulgating

a new rule in place of the vacated ACE Rule. There is

thus no EPA rule on the books that this Court can

consider to evaluate petitioners’ claims about practical

impacts on States and the power sector. But the details

matter when it comes to assessing whether a rule

exceeds an agency’s authority. This Court recently

confirmed as much when it stayed a broad COVID-19

rule issued by OSHA but acknowledged that narrower,

“targeted regulations” would be “plainly permissible.”

NFIB, 2022 WL 120952, at *4. Thus, until EPA completes its current rulemaking, it is entirely speculative

whether EPA will rely on “outside the fenceline”

measures at all—let alone in the particular way that

the Clean Power Plan did—or what the impact of its

selected measures may be on States and sources.

(W.Va. Br. 24-25.) It is also uncertain how EPA (or a

reviewing court) will apply the statutory constraints

discussed above (see Point I.C), including the requirement that the best system of emission reduction be

“adequately demonstrated” and the mandate that EPA

consider costs and “our Nation’s energy needs,” AEP,

564 U.S. at 427—constraints that would directly bear

on the impact of any Section 7411 rule. Given these

uncertainties, petitioners’ demand that this Court

prejudge hypothetical exercises of EPA’s rulemaking

authority seeks an advisory ruling of the type that this

Court has steadfastly refused to issue. See Carney v.

Adams, 141 S. Ct. 493, 498 (2020).

Perhaps to avoid this problem, petitioners appear

to assume that any power-plant regulation under

Section 7411(d) that goes beyond measures that can be

implemented “to and at” a single source will necessarily

have “vast economic and political significance,” UARG,

573 U.S. at 324 (quotation marks omitted). (See, e.g.,

Westmoreland Br. 26.) This assumption is unfounded,

as actual industry experience since the promulgation of

the Clean Power Plan confirms. Petitioners predicted

in 2016 filings to this Court that the Plan would inflict

“massive” economic harm if allowed to go into effect.

See Applicants’ Reply in Support of Application for

Immediate Stay at 28, West Virginia v. EPA (Feb. 9,

2016). But petitioners have been proven wrong. By

2019, industry-led trends toward low- and zeroemitting energy turned out to be so significant that,

even without the Clean Power Plan ever having come

into effect, the ACE Rule found that “there is likely to

be no difference between a world where the Clean

Power Plan is implemented and one where it is not.”

(J.A.1672-1673.)

In other words, the approach that the Clean Power

Plan adopted—and that petitioners so heavily criticize

here—would not have had the extreme effects on States

and industry that petitioners predicted. This experience rebuts petitioners’ assumption that dire impacts—

or major questions—are necessarily implicated by

EPA’s consideration of emission-reduction measures

that are not implemented “to and at” individual sources.

Claims of impact should be based on an actual rule and

a concrete record, rather than on speculative concerns

about what EPA might do in a future rulemaking.

Cf. Department of Tax’n & Fin. of N.Y. v. Milhelm Attea

& Bros., 512 U.S. 61, 69 (1994) (refusing to address

argument premised “on consequences that, while possible, are by no means predictable”).

Some petitioners also argue that the Clean Power

Plan’s approach to emission reduction was flawed not

solely because of the sheer magnitude of its potential

impact, but also because it amounted to a form of

energy regulation that is automatically beyond EPA’s

purview. (Westmoreland Br. 5; W.Va. Br. 1.) Again, it

is pure speculation to assume that EPA’s forthcoming

rulemaking will follow the Clean Power Plan or be subject to a similar characterization. But petitioners’ arguments also wrongly assume that Congress intended to

forbid EPA from controlling pollution in a manner that

would have any significant impact on energy generation. To the contrary, because the power sector is well

understood to play a significant role in creating pollution, Congress was fully aware that EPA would have to

take energy into account in designing its emission regulations. For that reason, Section 7411(a)(1) expressly

requires EPA to consider “energy requirements” in

determining the best system of emission reduction, and

this Court observed that Congress intended for the

agency to consider “our Nation’s energy needs” in issuing emission guidelines under Section 7411(d), AEP,

564 U.S. at 427. EPA does not impermissibly decide “a

forbidden major question when [it] regulates as it was

told to do.” (J.A.153.) Indeed, it would be difficult or

even impossible for EPA to require meaningful pollution reductions from power plants if its regulations

could not in any way influence the manner in which

electricity is generated.

More broadly, petitioners’ view that EPA presumptively exceeds its authority whenever it issues signifi-

cant rules under Section 7411 disregards express

indications that Congress chose to have EPA consider

the costs of its regulations in the first instance, based

on “scientific, economic, and technological resources

[that] an agency can utilize,” but that neither Congress

nor the courts can easily marshal. AEP, 564 U.S. at

428. In Section 7411(a)(1), Congress instructed EPA to

determine the “best system of emission reduction” by,

among other things, “taking into account the cost of

achieving such reduction,” including both environmental and nonenvironmental impacts. Moreover, as this

Court has observed, Congress vested EPA with authority to regulate power-plant CO2 emissions because the

agency was best suited to evaluate what approaches to

emission reduction would be “practical, feasible and

economically viable.” AEP, 564 U.S. at 428-29. The

impact of a Section 7411 rule was thus a factor that

Congress wanted EPA to consider in the exercise of its

delegated expertise—not an independent, threshold

barrier to rulemaking in the first instance.

3. State Petitioners’ related argument that

Congress has not provided a “clear statement” authorizing EPA to alter the traditional federal-state balance

(W.Va. Br. 26-31) likewise provides no basis to reverse

the court of appeals’ decision. Again, that argument is

not properly presented because it is premature and

based on speculation about what EPA might do in a

future rulemaking. Under the status quo, there is no

EPA rule that has affected the federal-state balance at

all, let alone in a way that would require a “clear statement” from Congress.

In any event, as discussed (see supra at 29-33),

State Petitioners are wrong to characterize the decision

below as disturbing Section 7411’s cooperativefederalism scheme. The decision below faithfully

followed this Court’s past descriptions of the multistep

federal-state process in both AEP and its predecessors.

And this Court’s cases have recognized that Congress

has spoken clearly—both in Section 7411 and in the

analogous cooperative-federalism regime in Section

7410—by giving EPA the authority to determine “the

appropriate amount” of CO2 regulation and to decide

“how” to limit CO2 emissions to address climate change,

while reserving for the States the authority to issue

source-specific performance standards consistent with

federal guidelines. See AEP, 564 U.S. at 426-27; Train,

421 U.S. at 79-80.

North Dakota is mistaken in arguing (N.D. Br. 4047) that the court of appeals’ decision is inconsistent

with Alaska, 540 U.S. 461. The statutory provision at

issue in Alaska explicitly provided that it was up to the

state permitting authority to determine the best

available control technology (BACT) that is “achievable”

on “a case-by-case basis.” 42 U.S.C. § 7479(3). Section

7411, by contrast, tasks EPA in the first instance with

determining the best system of emission reduction that

it determines has been adequately demonstrated for a

source category. Id. § 7411(a)(1). Moreover, notwithstanding the clear primacy of States in determining

BACT under Section 7479, this Court rejected the

argument made by Alaska—and echoed by North

Dakota here—that the State “alone” made the BACT

determination. 540 U.S. at 488-89. To the contrary,

Section 7479 preserved a “vital role” for EPA to provide

“meaningful . . . oversight” regarding state determinations. Id. at 489, 491. This Court specifically recognized

that “an EPA surveillance role” was essential to

prevent both cross-border air pollution and “‘economicenvironmental blackmail’” in which regulated industries favor states with “more permissive” air-quality

regulation. Id. at 486 (quoting H.R. Rep. No. 95-294, at

134 (1977)). These concerns likewise apply to state

efforts to control greenhouse gas emissions from power

plants, including those that emanate from sources in

other States. (J.A.568-569.)

Finally, petitioners are incorrect that EPA is

barred from taking the nature of the power grid into

account on the ground that regulating electrical generation is a traditional state role. (W.Va. Br. 27.)

“[V]irtually any action” a federal agency takes with

respect to the power sector may affect electricity generation, but “[t]hat is of no legal consequence” provided

that the agency is regulating in its proper sphere.

FERC v. Electric Power Supply Ass’n, 577 U.S. 260, 281

(2016). A federal agency is not restrained from

regulating in an area where it has express delegated

authority simply because the consequences of its

regulation may affect areas of traditional state control.

Id. at 279-81. And this Court has made clear that

Section 7411(d) delegates to EPA, in combination with

the States, the authority to regulate CO2 emissions

from the power sector, despite the inevitable effects of

such pollution regulation on electricity generation.

AEP, 564 U.S. at 424. There is no indication that

Congress intended to undercut its own objectives by

allowing the inherent relationship between pollution

and electricity generation to disable EPA’s regulatory

authority.

B. Section 7411 Does Not Raise

Non-Delegation Concerns.

Finally, some petitioners suggest (W.Va. Br. 44-49;

Westmoreland Br. 41-44) that the court of appeals’

interpretation of Section 7411 would make that statute

an impermissible delegation of legislative authority to

EPA. This non-delegation argument rests on the illogical claim that the court of appeals’ rejection of one

atextual limitation on EPA somehow freed the agency

from all textual constraints on its determination of the

best system of emission reduction. The decision below

threatens no such slippery slope. Instead, as discussed

(see supra at 33-38), the court of appeals expressly

recognized the multiple other statutory criteria in

Section 7411(a)(1) that guide EPA’s determination.

(J.A.145.) These criteria “meaningfully constrain[]” the

[EPA’s] discretion and thus remove any non-delegation

concerns. See Touby v. United States, 500 U.S. 160, 166

(1991).

Petitioners dismiss the limitations in Section

7411(a)(1) as ineffectual (Westmoreland Br. 42-43), but

they ignore the fact that EPA has in fact relied on those

limitations to reject certain emission-reduction strategies, including in the Clean Power Plan itself (e.g.,

J.A.733-735). And the constraints in Section 7411(a)(1)

(including the “adequately demonstrated” requirement

and the need to consider costs, health and environmental impact, and energy requirements) are no less

directive than the language in Section 7409(b)(1)

(“requisite to protect the public health”) that this Court

upheld against a non-delegation challenge in Whitman

v. American Trucking Associations, 531 U.S. 457, 473,

475-76 (2001). In Section 7411, as in Section 7409,

“Congress has supplied an intelligible principle to

guide [EPA’s] use of discretion,” Gundy v. United

States, 139 S. Ct. 2116, 2123 (2019) (plurality op.).

CONCLUSION

The judgment of the court of appeals should be

affirmed.

Respectfully submitted,

LETITIA JAMES

Attorney General

State of New York

BARBARA D. UNDERWOOD*

Solicitor General

MICHAEL J. MYERS

STEVEN C. WU

Senior Counsel

Deputy Solicitor General

ANDREW G. FRANK

MATTHEW W. GRIECO

Senior Assistant

BRIAN M. LUSIGNAN

Assistant Attorneys General Solicitor General

barbara.underwood@ag.ny.gov

January 2022

* Counsel of Record

(Counsel listing continues on next page.)

ROB BONTA

Attorney General

State of California

1300 I St.

Sacramento, CA 95814

AARON M. FREY

Attorney General

State of Maine

6 State House Station

Augusta, ME 04333

PHIL J. WEISER

Attorney General

State of Colorado

1300 Broadway, 10th Fl.

Denver, CO 80203

BRIAN E. FROSH

Attorney General

State of Maryland

200 St. Paul Pl., 20th Fl.

Baltimore, MD 21202

WILLIAM TONG

Attorney General

State of Connecticut

165 Capitol Ave.

Hartford, CT 06106

MAURA HEALEY

Attorney General

Commonwealth of

Massachusetts

One Ashburton Pl.

Boston, MA 02108

KATHLEEN JENNINGS

Attorney General

State of Delaware

820 N. French St.

Wilmington, DE 19801

DANA NESSEL

Attorney General

State of Michigan

P.O. Box 30212

Lansing, MI 48934

HOLLY T. SHIKADA

Attorney General

State of Hawai‘i

425 Queen St.

Honolulu, HI 96813

KEITH ELLISON

Attorney General

State of Minnesota

445 Minnesota St., Ste. 1400

Saint Paul, MN 55155

KWAME RAOUL

Attorney General

State of Illinois

100 W. Randolph St.

Chicago, IL 60601

AARON D. FORD

Attorney General

State of Nevada

100 N. Carson St.

Carson City, NV 89701

ANDREW J. BRUCK

Acting Attorney General

State of New Jersey

25 Market St., 8th Fl.

Trenton, NJ 08625

THOMAS J. DONOVAN, JR.

Attorney General

State of Vermont

109 State St.

Montpelier, VT 05609

HECTOR H. BALDERAS

Attorney General

State of New Mexico

408 Galisteo St.

Santa Fe, NM 87501

ROBERT W. FERGUSON

Attorney General

State of Washington

800 Fifth Ave., Ste. 2000

Seattle, WA 98104

JOSHUA H. STEIN

Attorney General

State of North Carolina

114 W. Edenton St.

Raleigh, NC 27603

JOSHUA L. KAUL

Attorney General

State of Wisconsin

P.O. Box 7857

Madison, WI 53703

ELLEN F. ROSENBLUM

Attorney General

State of Oregon

1162 Court St. N.E.

Salem, OR 97301

KARL A. RACINE

Attorney General

District of Columbia

400 Sixth St., N.W.

Washington, DC 20001

JOSH SHAPIRO

TERESA TAYLOR TATE

Attorney General

City Attorney

Commonwealth of

City of Boulder

Pennsylvania

1777 Broadway

Strawberry Square, 16th Fl. Boulder, CO 80302

Harrisburg, PA 17120

PETER F. NERONHA

Attorney General

State of Rhode Island

150 S. Main St.

Providence, RI 02903

CELIA MEZA

Corporation Counsel

City of Chicago

2 N. LaSalle St., Ste. 580

Chicago, IL 60602

KRISTIN M. BRONSON

City Attorney

City and County of Denver

201 W. Colfax Ave.

Denver, CO 80202

DIANA P. CORTES

City Solicitor

City of Philadelphia

One Parkway Building

1515 Arch St., 16th Fl.

Philadelphia, PA 19102

MICHAEL N. FEUER

City Attorney

City of Los Angeles

200 N. Main St., 8th Fl.

Los Angeles, CA 90012

THOMAS F. PEPE

City Attorney

City of South Miami

1450 Madruga Ave., Ste. 311

Coral Gables, FL 33146

GEORGIA PESTANA

Corporation Counsel

City of New York

100 Church St.

New York, NY 10007

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.