Congress’s Delegation of “Major Questions”: The Supreme Court’s Review of EPA’s Authority to Regulate Greenhouse Gas Emissions May Have Broad Impacts

Congress’s Delegation of “Major Questions”: The Supreme Court’s Review of EPA’s Authority to Regulate Greenhouse Gas Emissions May Have Broad Impacts

Legal Sidebari

Congress’s Delegation of “Major Questions”:
The Supreme Court’s Review of EPA’s
Authority to Regulate Greenhouse Gas
Emissions May Have Broad Impacts
December 7, 2021
The U.S. Supreme Court’s forthcoming ruling in West Virginia v. EPA will likely play a pivotal role in
how the U.S. Environmental Protection Agency (EPA) regulates greenhouse gas (GHG) emissions under
the Clean Air Act (CAA). On October 29, 2021, the Court agreed to review the scope of EPA’s authority
to regulate GHG emissions from existing coal-fired electric utility generating units, also known as power
plants. Legal battles over EPA’s authority to curb GHG emissions from power plants started before the
agency’s first rule, the Clean Power Plan (CPP), was finalized in August 2015.
The Supreme Court’s ruling in West Virginia v. EPA could have ramifications beyond the environmental
law context. The Court has been asked to address the extent that Congress may delegate to federal
agencies the authority to regulate matters that have significant economic and political impacts. A decision
to limit EPA’s authority could spark challenges to other agency regulations and to legislation that
delegates regulatory authority to the executive branch.
This Sidebar reviews the rulemaking and litigation history of EPA’s regulation of GHG emissions from
power plants, examines potential implications of the Supreme Court’s ruling, and discusses legislative
tools to address the legal issues raised in West Virginia v. EPA.
Background
EPA issued two rules limiting GHG emissions from existing power plants—the CPP and the Affordable
Clean Energy Rule (ACE Rule)—under CAA Section 111(d).
CAA Section 111 directs EPA to identify “air pollution which may reasonably be anticipated to endanger
public health or welfare”—known as the “endangerment finding”—and to list categories of stationary
sources that the EPA Administrator finds cause or contribute significantly to that pollution. Once EPA lists
a source category, Section 111(b) requires EPA to establish “standards of performance” for new and
modified sources (known as new source performance standards or NSPSs) within the listed category.
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After issuing NSPSs under CAA Section 111(b) for new or modified sources in that category, EPA
establishes emission guidelines for states to set a “standard of performance” for existing sources under
Section 111(d). Once EPA has set emission guidelines for existing sources, Section 111(d) requires states
to develop plans that establish standards of performance for existing sources in their jurisdiction.
In 2015, EPA finalized NSPSs for new or modified fossil fuel-fired power plants under Section 111(b) and
emission guidelines for existing power plants (the CPP) under Section 111(d).
In 2019, EPA repealed the CPP and, on the same day, issued the ACE Rule to replace it. See this CRS
Report for more background.
EPA’s Legal Interpretation of the “Best System of Emission Reduction”
Much of the legal debate surrounding the CPP and the ACE Rule centers on the scope of EPA’s authority
under CAA Section 111 to determine the “best system of emission reduction” (BSER) for existing power
plants. CAA Section 111(a) requires standards of performance to reflect the emissions reductions
achievable through “application” of the BSER. As explained in prior agency and court interpretations of
Section 111(a), EPA identifies and evaluates the ‘‘adequately demonstrated’’ systems of emission
reduction for a particular source category to determine which is the “best’’ and sets emission standards
based on that best system, ‘‘taking into account’’ ‘‘cost . . . nonair quality health and environmental
impact and energy requirements.’’ EPA also sets emission standards under Section 111(d) based on the
selected BSER.
In the CPP, EPA took a broad view of its Section 111 authority to identify the BSER for fossil fuel-fired
power plants. EPA determined that the BSER was a combination of three so-called “building blocks”:
(1) improving the heat rate (i.e., efficiency of energy generation) at coal-fired units, (2) shifting
generation to lower-emitting natural gas units, and (3) shifting generation from fossil fuel units to
renewable energy generation. EPA reasoned that the best “system” was one that applied to the “overall
source category,” because of the “unique characteristics of CO2 [carbon dioxide] pollution and the unique,
interconnected and interdependent manner in which affected [power plants] and other generating sources
operate within the electricity sector.”
In 2019, EPA adopted a narrower interpretation of its authority in the ACE Rule. EPA asserted that the
“application” of the BSER as referenced in CAA Section 111(a) “unambiguously limits the BSER to
those systems” that can be “applied” or “put into operation at a building, structure, facility, or
installation.” EPA claimed its revised interpretation in the ACE Rule is the “only permissible reading” of
EPA’s authority under Section 111: EPA must limit the BSER to source-specific measures and cannot
select as the BSER measures that apply to the source category as a whole or to entities entirely outside the
regulated source category. For the ACE Rule, EPA determined that the BSER was on-site heat rate
improvements (i.e., using less fuel per kilowatt-hour of electricity) and operating and maintenance
practices that reduce the CO2 emissions that a coal-fired power plant releases per unit of electricity it
generates.
Litigation History
EPA’s efforts to regulate GHG emissions from power plants under the CAA have faced numerous legal
challenges. In 2015, various states and stakeholders challenged, among other things, the scope of EPA’s
authority under CAA Section 111 to issue the CPP. These petitioners focused much of their argument on
EPA’s overall design of the CPP, alleging that EPA lacked authority under Section 111(d) to base
emissions guidelines on a system of emission reductions that is not applied directly at the source, such as
shifting generation away from fossil fuel units.

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Several judicial and regulatory actions prevented EPA from implementing the CPP before it was repealed.
Challengers of the CPP petitioned the Supreme Court to stay the implementation of the CPP. In a 5-4
decision, the Supreme Court granted the applications and stayed the CPP for the duration of the litigation.
The en banc (full) D.C. Circuit heard oral argument in September 2016 but, before deciding the case, it
granted EPA’s request to pause the litigation in 2017 to allow the agency to review and reconsider the
CPP as required under President Trump’s Executive Order 13783. In 2019, the D.C. Circuit dismissed the
litigation as moot after EPA finalized the ACE Rule and the repeal of the CPP.
Various states and stakeholders challenged the ACE Rule and CPP repeal in the D.C. Circuit. Several
legal issues raised in this litigation, including the scope of EPA’s authority and its interpretation of the
BSER under CAA Section 111, had also been central to the litigation challenging the CPP.
On January 19, 2021, a three-judge panel of the D.C. Circuit vacated the ACE Rule and the CPP repeal in
a split decision. In American Lung Association v. EPA, the majority held that CAA Section 111 does not
“constrain” EPA’s authority in determining the BSER to control methods that “apply physically ‘at’ and
‘to’ the individual source.” The majority concluded that the CAA’s text, structure, purpose, and legislative
history indicated that Congress conferred upon EPA “ample discretion” to determine the BSER.
The majority also rejected EPA’s argument that Congress would not have delegated to EPA a “major
question” of economic and political significance without a clear statement of its intent to do so. The
majority determined that Congress and the courts have “long” recognized EPA’s authority to regulation
GHG emissions from power plants under Section 111, leaving “no question” of “what the EPA may
regulate (greenhouse gas pollution), and whom it may target (power plants), and how (under Section
7411).” The majority also determined that Congress “expressly and indisputably” assigned and
constrained EPA’s role in determining the BSER.
The court’s opinion also addressed other challenges to EPA’s authority to regulate GHG emissions from
power plants under CAA Section 111, which were previously raised in the CPP litigation. The court
unanimously rejected the coal mine operators’ argument that EPA failed to make the “endangerment
finding” for regulating CO2 emissions from power plants. The court held that EPA made this finding when
promulgating the NSPSs for new or modified fossil fuel-fired power plants under Section 111(b) in 2015.
The majority also rejected the coal mine operators’ argument that the CAA prohibits EPA from regulating
CO2 emissions from power plants under Section 111(d) because power plants are a source category
regulated under Section 112 for mercury and other hazardous air pollutants (HAPs). The majority held
that EPA “correctly and consistently” interpreted Section 111(d) to authorize EPA to regulate both GHG
emissions under Section 111(d) and HAP emissions from the same sources under Section 112.
The court vacated the ACE Rule and the CPP repeal, but later granted EPA’s request not to reinstate the
CPP until EPA considers a new rulemaking action.
Judge Walker partly concurred and dissented from the court’s opinion. He argued that EPA was required
to repeal the CPP and that the ACE Rule was invalid because EPA has no authority to regulate fossil fuel-
fired power plants under CAA Section 111. Judge Walker agreed with the coal mine operators that Section
111 excludes from its scope any power plants regulated under Section 112. He also argued that EPA’s
exercise of authority in the CPP raises concerns about how and at what cost EPA should regulate power
plants—“major questions” that he claimed were not clearly delegated by Congress to EPA.
Supreme Court Review in West Virginia v. EPA
The Supreme Court granted and consolidated four petitions for certiorari, each seeking review of the D.C.
Circuit’s opinion in American Lung Association. The petitioners include a coalition of 19 states, the North
American Coal Corporation, Westmoreland Mining Holdings LLC, and North Dakota. In West Virginia v.
EPA, the petitioners question whether Congress authorized EPA to consider control measures that can be

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implemented beyond the specific emission source when determining the BSER and setting emission
standards under CAA Section 111(d). And if so, the petitioners ask, did Congress violate the Constitution
in delegating such regulatory authority to EPA?
The implications of the Supreme Court’s ruling in this case depend on the breadth of the Court’s decision.
The Supreme Court could decide the narrow question of whether CAA Section 111(d) compels EPA to
limit the BSER to those control measures that can be applied directly to the source. The Court could
define boundaries on what EPA may consider when determining the BSER for a category of emission
sources. Even if the Court’s ruling addressed only those questions, it would likely be considered a
significant decision in environmental law.
The case also has the potential to be a landmark decision in administrative law more generally, with
potential implications in a wide range of fields. The Supreme Court could use this case to address the
major questions doctrine and the nondelegation doctrine, each of which affects the relationship between
Congress and executive agencies.
First, the Supreme Court could use its ruling in West Virginia v. EPA to clarify the contours of the “major
questions” doctrine as it applies to agency rulemaking authority. That doctrine is derived from a series of
decisions that have limited executive agency authority on major economic and political policy issues. The
Court has explained that “Congress could not have intended to delegate a decision of such economic and
political significance to an agency” without a clear statement of its intention.
The major questions doctrine played a significant role in the Supreme Court’s two previous split decisions
reviewing EPA’s authority to regulate GHG emissions under the CAA. The majority in the Court’s 2007
decision in Massachusetts v. EPA held that EPA has the authority to regulate GHGs from motor vehicles
because GHGs qualify as an “air pollutant” under the CAA’s general definition. The majority rejected
EPA’s argument that it lacked authority to do so because Congress did not clearly delegate authority to
impose GHG emission limits that would have great “economic and political repercussions.” In contrast,
the Supreme Court found EPA’s interpretation of its own authority to be “unreasonable” under the major
questions doctrine in its 2014 ruling in Utility Air Regulatory Group v. EPA (UARG). In UARG, the
question was whether the CAA compels EPA to require an air permit for a “major emitting facility” based
the facility’s potential to emit “any regulated air pollutant,” including GHGs. The Court held, among
other things, that it would be unreasonable to interpret the CAA to require air permits for “tens of
thousands” of new and modified stationary sources—an “enormous and transformative expansion in
EPA’s regulatory authority without clear congressional authorization.”
The Court has not yet resolved issues in applying the “major questions” doctrine, such as what agency
actions are considered politically and economically significant to trigger the doctrine; what types of
“clear” congressional statement or “substantial guidance” are sufficient to support an agency’s authority
to regulate matters that “affect the entire national economy”; and what level of deference, if any, a court
should give to an agency’s statutory interpretation when the doctrine applies to agency rulemaking. The
petitioners’ arguments in West Virginia v. EPA provide the Court a vehicle to elaborate further upon the
doctrine, if it chooses.
Second, if the Supreme Court in West Virginia v. EPA rules that Congress delegated sufficiently broad
authority in Section 111(d) to allow EPA to regulate power plants as a sector, the Court may also examine
whether Congress’s delegation of such authority was constitutional under the nondelegation doctrine.
This doctrine is based on separation of powers principles and exists primarily to prevent Congress from
abdicating its core legislative function as established under Article I of the Constitution. In limiting
Congress’s power to delegate, the nondelegation doctrine seeks to ensure that legislative decisions are
made through a bicameral legislative process by the elected Members of Congress or governmental
officials subject to constitutional accountability.

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The Supreme Court has regularly upheld legislation that delegates authority to federal agencies. As
developed by the courts, the nondelegation doctrine requires that Congress lay out an “intelligible
principle” to guide and limit an agency’s discretion. The Court has held that a delegation is
“constitutionally sufficient if Congress clearly delineates the general policy, the public agency which is to
apply it, and the boundaries of this delegated authority.” In practice, this is a lenient standard. The
Supreme Court has only used the nondelegation doctrine to invalidate a delegation of authority to other
branches of government twice in 1935, and has rejected every nondelegation challenge thereafter,
including in a case regarding EPA’s authority to set national air quality standards under the CAA.
The Supreme Court’s 2019 decision in Gundy v. United States, however, signaled a potential shift in the
Court’s approach to reviewing delegations to governmental entities. Although a divided Court upheld the
delegation at issue, Justice Alito’s concurrence with the judgment indicated a willingness to reconsider
the “intelligible principle” standard. Also, Justice Gorsuch’s dissent, joined by Chief Justice Roberts and
Justice Thomas, argued for a more robust review of the authority Congress delegates to another branch of
government. Justice Kavanaugh, who did not participate in the Gundy decision, has stated that Justice
Gorsuch’s nondelegation analysis in his Gundy dissent “may warrant further consideration in future
cases.” These views of individual Justices suggest that the Court could further examine its approach to the
nondelegation doctrine in West Virginia v. EPA.
The Supreme Court has granted EPA’s request for an extension to file its brief until January 18, 2022 but
has not yet scheduled oral argument in West Virginia v. EPA. A ruling is expected by the end of the Court’s
2021-2022 term. Terms usually end in late June or early July.
Considerations for Congress
West Virginia v. EPA will be the third Supreme Court case in the last fifteen years reviewing the scope of
EPA’s authority to regulate GHG emissions under the CAA. Congress could consider proposing
legislation to clarify the scope of EPA’s authority under Section 111 in considering air pollution control
measures when determining the BSER. Congress could also address the question whether the CAA
prohibits EPA from imposing emission standards on power plants under CAA Section 111(d) because
their HAP emissions are regulated under Section 112—a question the D.C. Circuit considered, but that the
Supreme Court did not agree to review.
Congress could also conduct oversight over EPA’s rulemaking process to address GHG emissions from
power plants. It does not appear that EPA plans to wait for the Supreme Court to rule in West Virginia v.
EPA before moving forward. Following the grant of certiorari, EPA officials indicated that they intend to
“continue to advance new standards to ensure that all Americans are protected from the power plant
pollution that harms public health and our economy.” The agency has not announced a timeline for
developing a new rule; nor has it indicated whether it intends to take an approach similar to the CPP.
Some of President Biden’s executive orders and announcements issued in early 2021 on the
administration’s climate policy goals could shape how EPA regulates GHG emissions from power plants
in any new rule. For instance, the Biden Administration included the ACE Rule and the CPP repeal in a
fact sheet accompanying Executive Order 13990 that identified specific actions that agencies were
directed to review. International commitments, including from the 26th session of the Conference of the
Parties for the United Nations Framework Convention on Climate Change (COP26), may also affect
regulatory obligations to the extent emissions reductions the United States pledges to make are
implemented by imposing requirements on domestic power plants.
More broadly, the Supreme Court’s decision in West Virginia v. EPA could have far-reaching effects on
agency rulemaking authority and Congress’s efforts to delegate such authority to implement legislation.
The “major questions” and nondelegation doctrines are judicial tools used to reinforce the separation of
powers between the legislative and executive branches when interpreting statutes delegating authority to

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agencies. The Court’s ruling could guide agencies on interpreting their rulemaking authority and
Congress on limits on delegating such authority to agencies.
Members of Congress could consider participating in the litigation by submitting an amici curiae brief
expressing its views on these legal issues. Some Members of Congress filed amici curiae briefs in the
CPP and in the ACE Rule litigation.

Author Information

Linda Tsang
Kate R. Bowers
Legislative Attorney
Legislative Attorney

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff
to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of
Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of
information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role.
CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United
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