Constellation Mystic Power v. FERC ( 2022 )


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  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued May 5, 2022                   Decided August 23, 2022
    No. 20-1343
    CONSTELLATION MYSTIC POWER, LLC,
    PETITIONER
    v.
    FEDERAL ENERGY REGULATORY COMMISSION,
    RESPONDENT
    BRAINTREE ELECTRIC LIGHT DEPARTMENT, ET AL.,
    INTERVENORS
    Consolidated with 20-1361, 20-1362, 20-1365, 20-1368,
    21-1067, 21-1070
    On Petitions for Review of Orders
    of the Federal Energy Regulatory Commission
    Matthew A. Fitzgerald argued the cause for petitioner
    Constellation Mystic Power, LLC. With him on the briefs were
    Noel H. Symons and Katlyn A. Farrell.
    Jeffrey A. Schwarz argued that cause for State petitioners.
    With him on the briefs were Seth A. Hollander, Assistant
    2
    Attorney General - Special Litigation, Office of the Attorney
    General for the State of Connecticut, Scott H. Strauss, Amber
    L. Martin Stone, Kirsten S. P. Rigney, Robert Snook, Assistant
    Attorney General - Environment, Office of the Attorney
    General for the State of Connecticut, Andrew Minikowski and
    Julie Datres, Staff Attorneys, Ashley M. Bond, Maura Healy,
    Attorney General, Office of the Attorney General for the
    Commonwealth of Massachusetts, Christina Belew, Assistant
    Attorney General, Jason Marshall, and Phyllis G. Kimmel.
    Scott H. Strauss, Jeffrey A. Schwarz, Amber L. Martin
    Stone, and John P. Coyle were on the briefs for intervenors
    Braintree Electric Light Department, et al. in support of State
    petitioners.
    Robert M. Kennedy and Carol J. Banta, Senior Attorneys,
    Federal Energy Regulatory Commission, argued the causes for
    respondent. With them on the brief were Matthew R.
    Christiansen, General Counsel, and Robert H. Solomon,
    Solicitor.
    John P. Coyle argued the cause for intervenors Braintree
    Electric Light Department, et al. in support of respondent.
    With him on the brief were Scott H. Strauss, Jeffrey A.
    Schwarz, and Amber L. Martin Stone.
    Michael J. Thompson, Ryan J. Collins, and Maria Gulluni
    were on the brief for intervenor ISO New England, Inc. in
    support of respondent.
    Before: SRINIVASAN, Chief Judge, HENDERSON and RAO,
    Circuit Judges.
    Opinion for the Court filed PER CURIAM.
    3
    PER CURIAM: In March 2018, Constellation Mystic Power,
    LLC (Mystic)—a subsidiary of Exelon Generation Company,
    LLC (ExGen), which itself is a subsidiary of Exelon
    Corporation (Exelon)1—announced its intention to retire the
    Mystic Generating Station (Mystic Station), a natural gas-fired
    generator serving the greater Boston metropolitan area, after
    the facility’s existing capacity obligations expired in May
    2022. The region’s independent system operator, ISO New
    England, concluded that Mystic Station’s loss would
    exacerbate anticipated stresses on the region’s electricity
    network during winter months and increase the risk of rolling
    blackouts. ISO New England also found that Mystic Station’s
    retirement risked the closure of its sole fuel source, the Everett
    Marine Terminal (Everett)—a liquified natural gas (LNG)
    import and regasification facility currently owned and operated
    by an ExGen subsidiary—adding to the risk of blackouts in the
    region.
    In light of these findings, ISO New England entered into a
    cost-of-service agreement with Mystic and ExGen to keep two
    of Mystic Station’s generating units, referred to as Mystic 8 and
    9, in service between June 2022 and May 2024. The parties
    filed the proposed agreement (Mystic Agreement) with the
    Federal Energy Regulatory Commission (Commission or
    FERC). The Commission ultimately approved the terms of the
    Mystic Agreement, albeit with significant modifications.
    1
    In February 2022, after the petitions for review here had been
    filed, Exelon consummated a spinoff transaction that placed
    ExGen—which was renamed Constellation Energy Generation,
    LLC—and Mystic under the corporate parentage of Constellation
    Energy Corporation. Despite this transaction, we will refer to
    Mystic’s parents as ExGen and Exelon, as the parties have done,
    unless context dictates otherwise.
    4
    At issue are six Commission orders related to its approval
    of the Mystic Agreement. See Constellation Mystic Power,
    LLC, 
    164 FERC ¶ 61,022
     (July 13, 2018) (July 2018 Order);
    Constellation Mystic Power, LLC, 
    165 FERC ¶ 61,267
     (Dec.
    20, 2018) (December 2018 Order); Constellation Mystic
    Power, LLC, 
    172 FERC ¶ 61,043
     (July 17, 2020) (First July
    2020 Rehearing Order); Constellation Mystic Power, LLC, 
    172 FERC ¶ 61,044
     (July 17, 2020) (Second July 2020 Rehearing
    Order); Constellation Mystic Power, LLC, 
    172 FERC ¶ 61,045
    (July 17, 2020) (Compliance Order); Constellation Mystic
    Power, LLC, 
    173 FERC ¶ 61,261
     (Dec. 21, 2020) (December
    2020 Rehearing Order). Two groups of petitioners now seek
    review of those orders: Mystic and a group of New England
    state regulators (State Petitioners).2 As detailed infra, we
    dismiss Mystic’s petition for review in part and deny it in part;
    we grant the State Petitioners’ petitions.
    I. BACKGROUND
    A. Statutory Background
    Section 201(b) of the Federal Power Act (FPA) grants the
    Commission jurisdiction of the transmission and wholesale
    sale of electric energy in interstate commerce. 
    16 U.S.C. § 824
    (b); see New York v. FERC, 
    535 U.S. 1
    , 6–7 (2002). The
    FPA provides that “[a]ll rates for or in connection with
    jurisdictional sales and transmission service are subject to
    review by FERC to ensure that the rates are just and reasonable
    2
    The State Petitioners include the Connecticut Public Utilities
    Regulatory Authority, the Connecticut Department of Energy and
    Environmental Protection, the Connecticut Office of Consumer
    Counsel (collectively, Connecticut Parties), the Attorney General of
    the Commonwealth of Massachusetts (Massachusetts AG) and the
    New England States Committee on Electricity, Inc. (States
    Committee).
    5
    and not unduly discriminatory or preferential.” New England
    Power Generators Ass’n v. FERC (NEPGA), 
    881 F.3d 202
    , 205
    (D.C. Cir. 2018)); see 16 U.S.C. §§ 824d(a), (e), 824e(a).
    Section 205 requires that all public utilities “file with the
    Commission . . . all rates and charges for any transmission or
    sale subject to the jurisdiction of the Commission,” 16 U.S.C.
    § 824d(c), with the utility bearing the burden to show that its
    proposed rate is lawful, id. § 824d(e). See NEPGA, 881 F.3d at
    205. If the Commission determines that a rate is “unjust,
    unreasonable, unduly discriminatory or preferential,” it must
    set aside the rate and replace it with one that is just and
    reasonable. 16 U.S.C. § 824e(a)–(b). A negatively affected
    party may challenge a Commission-approved rate by filing a
    complaint with the Agency, and it carries the burden of
    demonstrating that the rate is unjust or unreasonable. See id.
    § 824e(a)–(b). The reasonableness of a rate is assessed in light
    of the FPA’s goals of promoting reliable service at reasonable
    rates and developing plentiful energy supplies. See Consol.
    Edison Co. v. FERC, 
    510 F.3d 333
    , 342 (D.C. Cir. 2007); see
    also NAACP v. FPC, 
    425 U.S. 662
    , 669–70 (1976).
    B. The New England Electricity Market
    ISO New England is the independent system operator3 that
    operates the transmission facilities and administers the
    wholesale electricity markets across six states—Connecticut,
    Maine, Massachusetts, New Hampshire, Rhode Island and
    Vermont. The wholesale markets facilitate the sale of
    3
    Independent system operators result from the unbundling of
    transmission and generation services—which were historically
    handled by a single, vertically integrated utility—and serve to
    coordinate, control and monitor the electricity transmission facilities
    owned by its member utilities in order to ensure nondiscriminatory
    access to all electricity generators. See Midwest Indep. Transmission
    Sys. Operator, Inc. v. FERC, 
    388 F.3d 903
    , 906 (D.C. Cir. 2004).
    6
    electricity by generators to electric utilities and electricity
    traders before its eventual sale to end-use consumers. The rates
    charged by ISO New England for access to its transmission
    system and the rules governing the wholesale markets under its
    purview are set out in a grid-wide tariff.
    In addition to ensuring adequate supply to meet present-
    day electricity demands, ISO New England must also ensure
    sufficient supplies to meet future needs. This is accomplished
    via a forward-capacity market, in which load serving entities—
    i.e., the utilities delivering electricity to end users—purchase
    capacity, which “is not electricity itself but the ability to
    produce it when necessary,” from generators. Pub. Citizen, Inc.
    v. FERC, 
    839 F.3d 1165
    , 1167–68 (D.C. Cir. 2016) (quoting
    Conn. Dep’t of Pub. Util. Control v. FERC, 
    569 F.3d 477
    , 479
    (D.C. Cir. 2009)). The forward-capacity market is conducted
    via an auction held three years in advance of a particular
    capacity commitment period. Generators submit bids reflecting
    the lowest price they will accept before exiting the market.
    During the “descending clock” auction, the capacity price is
    steadily lowered, causing bidding generators to exit. Once the
    amount of capacity offered reaches ISO New England’s
    projected capacity requirement for the commitment period, the
    auction stops, and those generators remaining in the market are
    paid the clearing price, regardless of their initial bids. See
    generally 
    id.
     (explaining forward-capacity auction).
    Once a generator participates in a forward-capacity
    auction, it is automatically re-entered into every subsequent
    auction unless it affirmatively seeks to remove its capacity
    from the market for that commitment period or permanently,
    with the latter option constituting “retirement.” If a generator
    seeks to retire from the market, it must submit a Retirement De-
    List Bid eleven months before the auction corresponding to the
    period for which it intends to retire, which signals the
    7
    generator’s intent to exit the market if the clearing price falls
    below its bid price and gives ISO New England an opportunity
    to determine if the generator’s proposed retirement presents a
    service risk to the region. If ISO New England so concludes, it
    may ask the generator to remain in operation; if the generator
    accepts, it can then elect to receive either its initial bid price or
    a cost-of-service rate.
    C. Mystic 8 and 9
    Mystic 8 and 9 are combined-cycle natural gas-fired
    generating units with a combined summer capacity of about
    1,400 megawatts.4 The two units run on revaporized LNG
    imported via marine terminal, making them unique among
    other natural gas-fired units in the region, which run on vapor
    natural gas imported through regional pipelines.
    Following the restructuring of the Massachusetts energy
    market in the 1990s, Mystic Station was acquired from the
    Boston Edison Company by Sithe Energies, Inc. in 1999. Sithe
    shortly thereafter began construction of Mystic 8 and 9, with
    the two units beginning commercial operation as merchant
    generators in 2003; according to Mystic, the two units were
    constructed at a cost of just under $1 billion. In 2002, ExGen
    acquired Sithe but subsequently ran into financial troubles in
    connection with the construction of Mystic 8 and 9. In May
    2004, ExGen reached a settlement with its lenders, transferring
    Mystic Station to a special purpose entity owned by a
    consortium of lenders in exchange for the cancellation of debts.
    4
    Mystic units 1 through 6 have been decommissioned, and the
    other units still in operation, Mystic 7 and Mystic Jet, are subject to
    Retirement De-List Bids but have not been designated as units
    necessary to meet reliability needs. None of these units is at issue
    here.
    8
    According to Mystic, as a result of this transaction, Mystic 8
    and 9 were valued at approximately $547 million.
    In 2010, after the special purpose entity declared
    bankruptcy, subsidiaries of Constellation Energy Group, Inc.
    purchased Mystic Station, as well as a separate natural gas-
    fired facility unrelated to the proceedings at issue, for $1.1
    billion. In 2012, Constellation Energy Group merged with
    Exelon. According to Mystic, as part of the merger, Mystic 8
    and 9 were independently appraised at $925 million. As a result
    of the merger, Mystic, which traces its parentage through
    ExGen to Exelon, became the owner of Mystic 8 and 9.
    D. The Everett Marine Terminal
    Everett, located on a property near Mystic Station, is
    Mystic 8 and 9’s sole source of revaporized LNG, making the
    two units “the only natural gas-fired units in the United States
    that are directly connected to an LNG import regasification
    facility.” Joint Appendix (J.A.) 7. Everett, the longest-
    operating LNG import terminal in the United States, has a
    storage capacity of 3.4 billion cubic feet and connects to, aside
    from Mystic 8 and 9, two outbound interstate pipeline facilities
    and a local gas company’s distribution facility.
    When the Commission proceedings began, Everett was
    owned by Distrigas of Massachusetts, LLC, a subsidiary of
    Engie Gas & LNG Holdings LLC, although Exelon was
    already in the process of purchasing the Everett facility.
    According to William Berg, an Exelon executive, the company
    determined that acquisition of Everett “was the best and most
    reliable option for Mystic to meet its existing capacity supply
    obligations through May 2022 without significant risk of non-
    performance.” J.A. 197. In late 2018, while the Commission’s
    proceedings were ongoing, Exelon finalized its purchase of
    9
    Everett, which is now owned by Constellation LNG, LLC,
    another subsidiary of ExGen.
    E. The Mystic Agreement
    In 2018, Mystic concluded that Mystic Station was no
    longer economically viable, notified ISO New England of its
    intent to retire when its existing capacity supply obligations
    expired in May 2022 and submitted the required Retirement
    De-List Bid. Following Mystic’s announcement, ISO New
    England analyzed the impact of Mystic 8 and 9’s retirements
    on the region’s fuel security during the winter months, when
    natural gas-fired power plants have difficulties obtaining the
    necessary fuel through the region’s limited pipeline network
    due to priority demands for heating. See Belmont Mun. Light
    Dep’t v. FERC, 
    38 F.4th 173
    , 180–81 (D.C. Cir. 2022)
    (discussing ISO New England’s fuel security analysis). ISO
    New England concluded that the loss of Mystic 8 and 9, given
    their unique reliance on imported LNG rather than vapor
    natural gas distributed through regional pipelines, would likely
    result in multiple days of “load shedding”—i.e., rolling
    blackouts—during the 2022 through 2024 capacity
    commitment periods. ISO New England further determined
    that Mystic 8 and 9’s retirements could affect the financial
    viability of Everett, whose retirement could further exacerbate
    the length and severity of load shedding events.
    In light of these findings, ISO New England sought to
    retain Mystic 8 and 9 for two years beyond their planned
    retirements. In May 2018, Mystic, acting pursuant to section
    205 of the FPA, filed with the Commission an agreement, the
    Mystic Agreement, among itself, Exelon and ISO New
    England that would provide Mystic cost-of-service
    compensation for the continued operation of Mystic 8 and 9
    from June 1, 2022, until May 31, 2024. We go into greater
    10
    detail infra as to several of the cost inputs comprising Mystic’s
    cost-of-service rate under the agreement but, in simplified
    terms, the rate is derived from four primary cost inputs: (1) a
    return on Mystic 8 and 9’s “rate base,” meaning the value of
    the facilities used to provide service to ratepayers less
    depreciation; (2) operation and maintenance expenses;
    (3) depreciation expenses; and (4) taxes.
    As part of its filing, Mystic attached a separate agreement
    between Mystic and Everett, referred to as the Everett
    Agreement. Per the Everett Agreement, over which the
    Commission disclaims jurisdiction, see Second July 2020
    Rehearing Order, at ¶ 43; FERC Br. 53, Mystic agreed to pay
    Everett a cost-based rate for the fuel used by Mystic 8 and 9
    alongside a monthly charge (Fuel Supply Charge) covering 100
    per cent of Everett’s fixed operating and maintenance costs as
    well as a return on investment tied to Everett’s rate base. As
    originally proposed, the Fuel Supply Charge would be offset
    by 50 per cent of the profits Everett earned on third-party sales
    over the course of the Everett Agreement.
    F. The Commission Proceedings
    This brings us to the Commission orders underlying this
    litigation. For clarity, rather than take the orders
    chronologically, we break up the orders according to the five
    disputed components of the Commission-approved Mystic
    Agreement.
    Mystic’s Rate Base: Under cost-of-service ratemaking
    principles, the starting point to calculate a generator’s return on
    capital is the generating facility’s rate base, or the value of the
    assets used to serve ratepayers. See NEPCO Mun. Rate Comm.
    v. FERC, 
    668 F.2d 1327
    , 1335 (D.C. Cir. 1981). Mystic
    initially proposed to set Mystic 8 and 9’s rate base according to
    the $925 million valuation it made in connection with the 2012
    11
    Constellation Energy Group-Exelon merger, before adding
    post-acquisition capital expenditures and subtracting
    depreciation. In its December 2018 Order, however, the
    Commission rejected Mystic’s approach as inconsistent with
    the Commission’s “original cost test,” which provides that a
    utility “may only earn a return on (and recovery of) the lesser
    of the net original cost of plant or, when plant assets change
    hands in arms-length transactions, the purchase price of the
    plant,” id. at ¶ 63; see infra Part III (explaining original cost
    test), and directed Mystic to reduce its valuation of Mystic 8
    and 9 to account for past sales of the units at prices lower than
    the 2012 valuation, see id. at ¶¶ 63–66.
    On rehearing, the Commission rejected Mystic’s claim
    that the original cost test, as applied by the Commission, was
    inappropriate to calculate its return on Mystic 8 and 9’s rate
    base, see generally Second July 2020 Rehearing Order, at
    ¶¶ 105–111, and on compliance, rejected Mystic’s proposed
    rate base calculation for failing to account for the 2004 $547
    million transfer in lieu of foreclosure, see Compliance Order,
    at ¶ 45.
    Mystic’s Capital Structure: Alongside its rate base, a
    generator’s return on capital under a cost-of-service model is
    derived from its overall rate of return, which is dependent upon
    its capital structure—i.e., the relative amounts of debt and
    equity. See NEPCO, 
    668 F.2d at 1335
    . Mystic initially
    proposed using the capital structure of its immediate parent,
    ExGen: 67.28 per cent equity and 32.72 per cent debt. See
    December 2018 Order, at ¶ 35. The Commission rejected this
    proposal, finding the proposed structure too equity-heavy
    relative to the industry, see 
    id.
     at ¶¶ 48–51, and instead directed
    Mystic to use the capital structure of ExGen’s parent, Exelon,
    which was 52.4 per cent debt and 47.6 per cent equity, id. at
    ¶ 52. After Mystic sought rehearing, the Commission
    12
    reaffirmed its determination, again citing the anomalous nature
    of ExGen’s capital structure relative to the industry. See
    Second July 2020 Rehearing Order, at ¶¶ 132–34.
    After the petitions for review had been filed but before oral
    argument, the Commission issued an additional order that,
    although not subject to review in this proceeding, is
    nevertheless relevant. In February 2022, Exelon consummated
    a spinoff transaction that placed ExGen and Mystic under the
    corporate parentage of Constellation Energy Corporation. See
    Constellation Mystic Power, LLC, 
    179 FERC ¶ 61,081
    , at ¶ 6
    (May 2, 2022) (May 2022 Order). As a result, Mystic amended
    the Mystic Agreement to reflect the changes in corporate
    structure and, as relevant here, argued that Exelon’s capital
    structure was no longer relevant—as Exelon no longer had any
    relationship with Mystic—and again requested to use ExGen’s
    capital structure. 
    Id. at ¶ 9
    . The Commission “agree[d] with
    Mystic that it would be inappropriate to continue basing its
    capital structure and cost of debt on those of Exelon
    Corporation,” 
    id. at ¶ 25
    , but further explained that Mystic had
    not yet shown ExGen’s capital structure to be just and
    reasonable, 
    id. at ¶ 24
    . The Commission accordingly set a
    hearing to determine the appropriate capital structure. 
    Id.
     at
    ¶¶ 24–25.
    Everett’s Costs: The Commission rejected Mystic’s
    proposal to recover 100 per cent of Everett’s fixed operating
    and maintenance costs via the Fuel Supply Charge, instead
    adopting its Trial Staff’s proposal that would allocate 91 per
    cent of Everett’s costs—the historical ratio of Everett’s vapor
    sales, as opposed to its LNG sales, to its total sales—and the
    Staff’s related revenue crediting mechanism, whereby Everett
    would retain up to 50 per cent of the margin on third-party
    forward sales, meaning those made at least three months in
    13
    advance.5 See December 2018 Order, at ¶¶ 133–35. The
    Commission also rejected Mystic’s proposal to include the
    Everett acquisition cost as part of Everett’s rate base, which is
    used to calculate the return-on-investment component of the
    Fuel Supply Charge. See 
    id.
     at ¶¶ 148–49.
    On rehearing, the Commission rejected Mystic’s
    arguments regarding the exclusion of Everett’s acquisition cost
    from its rate base. See Second July 2020 Rehearing Order, at
    ¶¶ 113, 118–20. Further, the Commission rejected arguments
    by the Massachusetts AG, one of the State Petitioners, that the
    Commission lacked jurisdiction to review and approve the
    inclusion of Everett’s fixed operating costs as a component of
    Mystic’s proposed cost-of-service rate, asserting that “[t]he
    Fuel Supply Charge is a component of Mystic’s cost-of-service
    rate and, as a result, is subject to Commission review and
    approval.” First July 2020 Rehearing Order, at ¶¶ 16–18, 26–
    31. Despite comments from several State Petitioners objecting
    to the Commission’s allocation of Everett-related costs, see
    Second July 2020 Rehearing Order, at ¶¶ 57–60, 62, the
    Commission reaffirmed the appropriateness of its 91 per cent
    allocation, see 
    id.
     at ¶¶ 64–65. In response to comments noting
    that vapor sales are made to parties other than Mystic, the
    Commission reasoned that those sales nevertheless benefit
    Mystic “by helping to manage Everett’s tank.” 
    Id. at ¶ 64
    . But
    the Commission did decide to eliminate revenue crediting,
    finding that “proper cost allocation based on cost-causation
    principles obviate[d] the need” for the revenue crediting and
    5
    Under the revenue crediting mechanism, “the first 10 million
    MMBtus are credited 90 percent to Mystic (i.e., back to ratepayers)
    and 10 percent to Constellation LNG, revenue from the next 30
    million MMBtus are credited 80 percent to Mystic and 20 percent to
    Constellation LNG, and so on until all deliveries above 60 million
    MMBtus are credited 50/50 as initially proposed by Mystic.”
    December 2018 Order, at ¶ 134.
    14
    questioning its own jurisdiction to approve an incentive
    mechanism that “focuses directly on Everett’s conduct rather
    than Mystic’s.” 
    Id. at ¶ 66
    . The Connecticut Parties, a subset of
    the State Petitioners, sought rehearing on the elimination of
    revenue crediting, arguing that “unless or until Mystic’s share
    of Everett costs is reduced to correspond to its use of the
    facilities,” the Commission should “restore the crediting
    mechanism.” J.A. 1664. The Commission denied their request.
    On this issue, then-Commissioner (now Chairman) Glick
    dissented from all of the orders at issue, asserting that the
    Commission overstepped its jurisdictional boundaries by
    reviewing and approving recovery of Everett-related costs that,
    in his view, bore little relationship to Mystic’s jurisdictional
    rate. See, e.g., December 2018 Order (Glick, C., dissenting);
    First July 2020 Rehearing Order (Glick, C., dissenting).
    True-Up Mechanism: Recognizing that many of the
    components of Mystic’s cost-of-service rate were based, at
    least in part, on Mystic’s projections of future costs, the
    Commission directed Mystic to include a “true-up” mechanism
    in the Mystic Agreement, which would allow parties to
    reconcile cost projections with actual expenditures via
    surcharges and refunds as necessary. See July 2018 Order, at
    ¶ 20. Mystic initially proposed a true-up mechanism that would
    have applied only to specific subsets of rate inputs, see
    December 2018 Order, at ¶ 165, but the Commission rejected
    this approach, instead “direct[ing] that the true-up mechanism
    apply to the entire [Mystic] Agreement, with the exception of
    the [return on equity],” 
    id. at ¶ 177
    . The Commission
    emphasized that the true-up process included Mystic’s
    revenues. 
    Id. at ¶ 179
    . The Commission also noted that the
    reasonableness of tank congestion charges passed along to
    ratepayers “is more appropriately reviewed during the true-up
    process,” 
    id. at ¶ 164
    , but later determined that review of tank
    15
    congestion charges was “no longer required” given its
    elimination of the revenue crediting mechanism, see Second
    July 2020 Rehearing Order, at ¶ 73.
    Mystic sought rehearing on the breadth of the true-up
    mechanism as it applied to pre-2018 costs related to Mystic 8
    and 9 that, in Mystic’s view, had already been fully litigated.
    See Second July 2020 Rehearing Order, at ¶ 79. The
    Commission denied rehearing, finding that those historic
    numbers had not yet been fully litigated and were thus
    appropriately “subject to true-up.” 
    Id. at ¶ 86
    . Mystic also
    objected to the inclusion of revenues as part of the true-up
    process. 
    Id. at ¶ 80
    . The Commission agreed with this argument
    and “set aside” its earlier requirement that Mystic “true-up
    revenues.” 
    Id. at ¶ 88
    .
    The States Committee, another of the State Petitioners,
    sought clarification, or rehearing in the alternative, as to
    whether interested parties could still challenge the calculation
    of revenue credits despite the Commission’s decision to omit
    revenues from the true-up process. See J.A. 1716. As they see
    it, the Commission acknowledged their request, see December
    2020 Rehearing Order, at ¶ 25, but failed to address it
    adequately. See infra Part VI.B.1. With regard to the tank
    congestion charges, the States Committee also sought
    rehearing, arguing that if the costs of third-party sales are being
    passed on to ratepayers, ratepayers should have some
    mechanism to review and challenge the reasonableness of those
    sales, see J.A. 1712–13, arguments that the Commission
    addressed in its final rehearing order, see December 2020
    Rehearing Order, at ¶¶ 26–28.
    Clawback Provision: In its December 2018 Order, the
    Commission determined that the Mystic Agreement was not
    just and reasonable without a “clawback” provision—which
    16
    would require Mystic to reimburse ratepayers for certain
    capital and repair expenditures made over the course of the
    Mystic Agreement if Mystic 8 and 9 were to re-enter the New
    England energy market after the Agreement expires. See
    December 2018 Order, at ¶ 208. In essence, a clawback
    provision disincentivizes a generating facility from switching
    between cost-of-service and market-based rates so that
    ratepayers finance investments during the term of a cost-of-
    service agreement that benefit the facility beyond the term of
    the agreement. Id.; see also Midcontinent Indep. Sys. Operator,
    Inc., 
    161 FERC ¶ 61,059
    , at ¶ 55 (2017). The Commission
    accordingly directed Mystic to revise the Mystic Agreement to
    include a clawback provision. See December 2018 Order, at
    ¶ 208. The States Committee sought clarification as to whether
    the required clawback provision would apply to consumer-
    funded investments and repairs in connection with both Mystic
    8 and 9 and Everett. See J.A. 1374.
    On compliance, Mystic proposed a clawback provision
    applicable to certain repairs and capital expenditures made by
    Mystic. See J.A. 1506 (proposed clawback language);
    Compliance Order, at ¶ 16. The States Committee and
    Connecticut Parties protested the omission of Everett
    expenditures from Mystic’s proposed clawback provision,
    pointing to the affiliate relationship between Mystic and
    Everett. See J.A. 1509–11 (States Committee); J.A. 1512–15
    (Connecticut Parties).
    The Commission ultimately approved Mystic’s proposed
    clawback provision. See Compliance Order, at ¶ 25. In the
    Second July 2020 Rehearing Order, the Commission rejected
    the request that the provision encompass Everett’s costs, noting
    that neither Everett nor the Everett Agreement falls within the
    Commission’s jurisdiction and concluding that it “lack[ed]
    jurisdiction to require a clawback, true-up, and/or refund of
    17
    Everett’s costs.” See Second July 2020 Rehearing Order, at
    ¶ 43. The Commission further explained that, if Mystic 8 and 9
    retired while Everett remained in service, the Mystic
    Agreement would terminate, leaving “no rate within the
    jurisdiction of the Commission through which to order a
    refund.” 
    Id.
     In the Compliance Order, the Commission denied
    the States Committee’s and Connecticut Parties’ related
    protests, referring back to the Second July 2020 Rehearing
    Order. See Compliance Order, at ¶ 28. The Commission also
    denied the Connecticut Parties’ subsequent request for
    rehearing for the same reasons it outlined in the July 2020
    orders. See December 2020 Rehearing Order, at ¶ 39.
    G. Petitions for Review
    Mystic and the State Petitioners petitioned for review of
    the various Commission orders modifying and ultimately
    approving the Mystic Agreement. Mystic objects to the
    Commission’s application of the original cost test in
    determining Mystic 8 and 9’s rate base; the selection of
    Exelon’s capital structure instead of ExGen’s; the exclusion of
    Everett’s acquisition cost from the Fuel Supply Charge
    calculation; and the inclusion of Mystic 8 and 9’s rate base
    components as part of the true-up process. The State
    Petitioners, for their part, object to the Commission’s exercise
    of jurisdiction of and allocation of Everett’s costs as part of the
    Fuel Supply Charge; the exclusion of Everett’s costs from the
    clawback provision; the failure to address the request to allow
    revenue credit calculations to be reviewed during the true-up
    process; the confusion over who can review the reasonableness
    of tank congestion charges during that process; and the failure
    18
    to address the incentives created by the Mystic Agreement’s
    treatment of delayed capital projects.
    We dismiss Mystic’s petition for review in part and deny
    it in part, and we grant the State Petitioners’ petitions. The
    opinion proceeds as follows: In Part III, we hold that the
    Commission’s application of the original cost test to determine
    Mystic 8 and 9’s rate base was not arbitrary and capricious. In
    Part IV, we dismiss Mystic’s objection to the Commission’s
    selection of capital structure as moot in light of the
    Commission’s May 2022 Order. In Part V, we find that the
    Commission acted arbitrarily and capriciously in allocating
    Everett’s operating costs but otherwise acted lawfully in
    excluding Everett’s acquisition cost from the Fuel Supply
    Charge calculation. In Part VI, we conclude that the
    Commission properly included historical rate base components
    in the true-up mechanism but also find that the Commission
    failed to respond to the State Petitioners’ request for
    clarification as to whether interested parties may challenge the
    calculation of Mystic’s revenue credits and that the December
    2020 Rehearing Order created confusion over who can review
    the tank congestion charges during the true-up process. Finally,
    in Part VII, we hold that the Commission’s jurisdictional
    rationale for excluding costs related to Everett from the
    clawback process does not constitute reasoned decisionmaking
    and that the Commission failed to address related arguments
    raised by the State Petitioners.
    II. STANDARD OF REVIEW
    We begin by setting forth the standard of review common
    to all of the objections brought by the petitioners. This Court
    will set aside a Commission order found to be “arbitrary,
    capricious, an abuse of discretion, or otherwise not in
    accordance with law.” 
    5 U.S.C. § 706
    (2)(A); see Del. Div. of
    19
    Pub. Advoc. v. FERC, 
    3 F.4th 461
    , 465 (D.C. Cir. 2021). Our
    role is not to ascertain “whether a regulatory decision is the best
    one possible or even whether it is better than the alternatives.”
    FERC v. Elec. Power Supply Ass’n (EPSA), 
    577 U.S. 260
    , 292
    (2016). It is instead limited to ensuring the Commission can
    demonstrate that its decision is supported by substantial
    evidence in the record, see Emera Me. v. FERC, 
    854 F.3d 9
    , 22
    (D.C. Cir. 2017); see also 16 U.S.C. § 825l(b), and
    “articulate[s] a satisfactory explanation for its action including
    a rational connection between the facts found and the choice
    made,” Del. Div. of Pub. Advoc., 3 F.4th at 465 (quoting Motor
    Vehicle Mfrs. Ass’n of U.S., Inc. v. State Farm Mut. Auto. Ins.
    Co., 
    463 U.S. 29
    , 43 (1983)).
    Regarding ratemaking, the Commission is required to
    ensure that electricity rates are “just and reasonable.” 16 U.S.C.
    §§ 824d(a), 824e(a). “The statutory requirement that rates be
    ‘just and reasonable’ is obviously incapable of precise judicial
    definition,” and we accordingly grant the Commission “great
    deference . . . in its rate decisions.” Morgan Stanley Cap. Grp.
    Inc. v. Pub. Util. Dist. No. 1 of Snohomish Cnty., Wash., 
    554 U.S. 527
    , 532 (2008); see also EPSA, 577 U.S. at 295 (“The
    Commission, not this or any other court, regulates electricity
    rates.”). But deference does not mean carte blanche, and the
    Commission must at all times demonstrate the markers of
    “principled and reasoned decision[making] supported by the
    evidentiary record.” Emera Me., 854 F.3d at 22 (quoting S. Cal.
    Edison Co. v. FERC, 
    717 F.3d 177
    , 181 (D.C. Cir. 2013)).
    III. MYSTIC 8 AND 9’S RATE BASE
    Mystic first contends that the Commission erred by
    applying the original cost test to calculate the rate base for
    Mystic 8 and 9.
    20
    When calculating a cost-of-service rate for a facility
    devoted to public use, a generator must first establish what
    return it is permitted to recover on its capital. That is
    determined in part by the rate base, which represents a utility’s
    total investment in the facility. See FEDERAL ENERGY
    REGULATORY COMMISSION, COST-OF-SERVICE RATES
    MANUAL 8 (1999). We have explained that the Commission
    “may adopt any method of valuation for rate base purposes so
    long as the end result of the rate order cannot be said to be
    unjust or unreasonable.” NEPCO, 
    668 F.2d at 1333
     (cleaned
    up).
    To calculate the rate base, the Commission applies a set of
    accounting principles collectively known as the “original cost
    test.” The test begins with the “original cost” of a facility, such
    as the cost of construction, “to the person first devoting it to
    public service.” 18 C.F.R. pt. 101(23). The next step is
    calculating how much the facility has depreciated over time.
    The difference between the original cost and accumulated
    depreciation represents the facility’s depreciated original cost,
    or net book value. Net book value is a primary input for
    calculating the facility’s rate base. COST-OF-SERVICE RATES
    MANUAL, supra, at 8–9.
    Under the original cost test, the net book value may adjust
    after a facility is sold. If the sale price is below the net book
    value, that price becomes the new net book value, and the rate
    base will be lowered. Locust Ridge Gas Co., 
    29 FERC ¶ 61,052
    , at 61,114 (1984). If the sale price is higher than the
    net book value, the net book value (and thus the rate base)
    generally remains unchanged.6 In short, under the original cost
    6
    The Commission treats the amount of the purchase price
    above net book value as an “acquisition premium,” which does not
    increase the net book value or the rate base. Mo. Pub. Serv. Comm’n
    v. FERC, 
    783 F.3d 310
    , 313 (D.C. Cir. 2015). A utility paying a sale
    21
    test, the rate base decreases after a sale below net book value,
    yet generally cannot increase after a sale above net book value.
    Mystic’s parent company valued Mystic 8 and 9 as part of
    a merger in 2012 at around $925 million, and Mystic claims
    this “sale” price should determine its rate base. The
    Commission rejected that approach as inconsistent with the
    original cost test because, considering the units’ full purchase
    history, the rate base was in fact much lower. The Commission
    recognized that Mystic 8 and 9 were “first devoted to public
    service” in 2003 after being constructed for just under $1
    billion. See December 2018 Order, at ¶ 64. When the units were
    transferred in 2004 for approximately $547 million in lieu of
    foreclosure, that “sale” price fell below the units’ net book
    value. See Second July 2020 Rehearing Order, at ¶ 112. The
    net book value thus reset to $547 million, and under the original
    cost test, could not be increased to account for later sale prices
    above that amount, such as the $925 million merger valuation
    in 2012. See December 2018 Order, at ¶ 64; see also Second
    July 2020 Rehearing Order, at ¶ 105; Compliance Order, at
    ¶ 45. The Commission explained that the $547 million “sale”
    capped the units’ net book value, determining Mystic’s rate
    base going forward. See Second July 2020 Rehearing Order, at
    ¶ 112. This conclusion followed from a straightforward
    application of the original cost test as articulated in the
    Commission’s precedents.
    price above the seller’s net book value may be able to incorporate
    some of the acquisition premium into its rate base if it can “prove
    that benefits, equal to the excess acquisition costs and measurable in
    dollars, were conferred on its ratepayers.” Locust Ridge Gas Co., 29
    FERC at 61,114; see also Mo. Pub. Serv. Comm’n, 783 F.3d at 313
    (describing the Commission’s “two-part benefits exception test”).
    Mystic does not claim this exception applies.
    22
    Mystic maintains it was arbitrary and capricious to apply
    the original cost test to the circumstances here. Mystic first
    contends that using the original cost test was arbitrary because
    Mystic 8 and 9 previously functioned as merchant generators.
    According to Mystic, the original cost test should not apply to
    merchant generators that have converted to cost-of-service
    facilities because the economic calculus of selling a merchant
    generator differs from the calculus of selling a cost-of-service
    facility. While cost-of-service facilities are bought and sold
    with the original cost test in mind, Mystic claims merchant
    generators like Mystic 8 and 9 are bought and sold based on
    fair market value, which often does not track original cost.
    As the Commission explained, however, Mystic’s request
    for a merchant-generator exception to the original cost test is
    inconsistent with Commission precedent. For instance, the
    Commission has required a facility that previously operated as
    a merchant generator to apply original cost principles and
    explained that those principles apply to all cost-of-service
    facilities, “regardless of the rate treatment afforded the
    facilities” in the past. PacifiCorp, 
    124 FERC ¶ 61,046
    , at ¶¶ 7,
    10–11, 28–31 (2008). Likewise, the Commission in another
    decision concluded that the original cost test was “consistent”
    with past practice and “appropriate” for facilities converting
    from merchant generators to cost-of-service facilities, a
    situation almost identical to the facts presented here. PSEG
    Power Conn., LLC, 
    110 FERC ¶ 61,020
    , at ¶¶ 27, 30–31
    (2005). The Commission reasonably relied on its consistent
    precedent when applying the original cost test to Mystic 8 and
    9, even though those facilities were once merchant generators.
    See December 2018 Order, at ¶ 65.
    Furthermore, the Commission explained why Mystic’s
    argument rests on a mistaken assumption. Mystic presses for
    the Commission to create an exemption to the original cost test
    23
    for facilities that previously charged market-based rates
    because, it claims, original cost accounting principles are not
    considered during the sale of a merchant generator. But
    charging market rates as a merchant generator and using
    original cost accounting are not “mutually exclusive.” 
    Id. at ¶ 66
    ; Second July 2020 Rehearing Order, at ¶ 106. Instead, a
    facility could be a merchant generator and use original cost
    accounting principles, which would be taken into account
    during a sale. Given this possible overlap, it was reasonable for
    the Commission to decline making an exception to the original
    cost test for a facility that previously operated as a merchant
    generator.
    Mystic next argues it was unreasonable for FERC to apply
    the original cost test in this context because such an application
    would not serve the policy interests protected by the test. The
    original cost test was developed in part to prevent utilities from
    artificially inflating a facility’s purchase price, which would
    then increase the facility’s rate base and allow the utility to
    charge higher rates to the public. Mo. Pub. Serv. Comm’n v.
    FERC, 
    783 F.3d 310
    , 313 (D.C. Cir. 2015). Mystic argues that
    as a merchant generator it had no incentive to inflate the $925
    million valuation in 2012, and therefore there was no need to
    apply the original cost test. But the Commission set the original
    cost test as an across-the-board rule, not a calculation that
    applies only when certain policy concerns are present. See
    Second July 2020 Rehearing Order, at ¶ 105. Even when
    “[t]here is no allegation” that a utility “attempted to artificially
    inflate its rate base when it acquired” a facility, “the purpose of
    the [Commission]’s original cost accounting rules is to obviate
    the need for such allegations.” Mont. Power Co. v. FERC, 
    599 F.2d 295
    , 300 (9th Cir. 1979). Instead, these “rules provide an
    objective method of valuation without the need for independent
    assessment of the fair market value of individual acquisitions.”
    Id.; see also, e.g., PacifiCorp, 124 FERC at ¶¶ 11, 28–31
    24
    (applying the original cost test despite a utility arguing the “the
    policy concern” behind the original cost test “does not apply”).
    Mystic next argues it was arbitrary and capricious to apply
    the original cost test to merchant generators that convert to
    cost-of-service facilities because the fair market value of a
    merchant generator facility may rise or fall based on market
    forces, but the original cost test captures only the downward
    swings. This discrepancy, however, is the necessary and
    expected outcome of the original cost test. In an effort to
    protect ratepayers, the test was designed to ratchet down a
    facility’s net book value based on a facility’s lower sale price
    but prohibit ratcheting up the value based on a higher sale price.
    See Locust Ridge Gas Co., 29 FERC at 61,114. That design
    choice protects ratepayers from higher rates due to changes in
    ownership that do not increase the value of services provided.
    
    Id.
     A general rule “may produce unfortunate results in
    individual cases”; however, the possibility of such disparities
    does not “preclude the [Commission] from” adopting an
    objective and generally applicable accounting method. Mont.
    Power Co., 
    599 F.2d at 300
    . The Commission chose original
    cost accounting principles in part to “avoid the difficulties of
    more subjective methods of property valuation,” 
    id.,
     and we
    find that it applied that objective test here.
    Furthermore, the Commission declined to create an
    exception to its objective test because doing so would lead to
    unequal treatment between similarly situated electricity
    generators. The Commission determined it was unfair to allow
    a utility’s return to depend on its past accounting method,
    especially when a non-original cost method is not indicative of
    a facility’s actual cost and when actual cost is what lies at the
    heart of cost-of-service rates. See Second July 2020 Rehearing
    Order, at ¶ 107.
    25
    Mystic also maintains that Mystic 8 and 9 never would
    have been transferred in lieu of foreclosure in 2004 if the
    facilities had been charging cost-of-service rates, and therefore
    the 2004 valuation was an improper and unreliable input for
    calculating the rate base. The Commission reasonably rejected
    this argument, explaining that charging cost-of-service rates
    does not insulate facilities from financial distress or fire sales.
    Mystic’s assertions that the 2004 transfer would not have
    occurred were therefore speculative. See id. at ¶ 106. It was not
    unreasonable for the Commission to bypass such conjecture
    and instead rely on its objective test and the units’ actual
    purchase history.
    Because the Commission’s decision to apply original cost
    principles to Mystic 8 and 9 accorded with its precedent and
    was supported by reasoned explanation, Mystic’s petition
    cannot succeed on this ground.
    IV. MYSTIC’S CAPITAL STRUCTURE
    We next take up Mystic’s challenge to the capital structure
    adopted by the Commission for ratemaking purposes. Because
    the Commission’s subsequent order has mooted Mystic’s
    challenge, we dismiss the petition on this issue.7
    A case becomes moot if intervening events mean the
    court’s “decision will neither presently affect the parties’ rights
    nor have a more-than-speculative chance of affecting them in
    the future.” Clarke v. United States, 
    915 F.2d 699
    , 701 (D.C.
    Cir. 1990) (quotation marks and citation omitted). While no
    party contends that has happened here, we “have an
    7
    On August 12, 2022, Mystic notified the court it had reached
    a settlement in principle with the Commission on this issue. Because
    we find the issue moot, that settlement in principle has no bearing on
    our analysis.
    26
    ‘independent obligation’ to ensure that appeals before us are
    not moot.” Planned Parenthood of Wis., Inc. v. Azar, 
    942 F.3d 512
    , 516 (D.C. Cir. 2019) (citation omitted).
    In the orders under review, the Commission adopted
    Exelon’s capital structure for ratemaking purposes. Mystic
    challenges that decision as arbitrary and capricious, contending
    that the Commission instead should have imputed the capital
    structure of Mystic’s immediate parent, ExGen. But after the
    petitions for review were filed in this case, the Commission
    revised its initial decision on this issue in response to
    intervening developments.
    On February 1, 2022, Exelon and a newly created holding
    company, Constellation Energy Corporation, consummated a
    spin-off transaction. May 2022 Order, at ¶¶ 6–7; supra Part I.F,
    at 12. As a result of that transaction, Mystic is no longer
    affiliated with or owned by Exelon. May 2022 Order, at ¶¶ 6–7.
    In light of that development, the Commission determined that
    “it would be inappropriate to continue basing [Mystic’s] capital
    structure and cost of debt on those of Exelon Corporation.” Id.
    at ¶ 25. The Commission therefore set aside its prior decision
    to use Exelon’s capital structure and set the matter for a new
    hearing. Id. at ¶¶ 25–26.
    The Commission, however, lacked jurisdiction to modify
    or vacate an order under judicial review without obtaining
    leave of the court. See 16 U.S.C. § 825l(b). The Commission
    thus sought the requisite leave to issue the May 2022 Order
    “[t]o the extent [it] constitutes a modification or vacatur of the
    capital structure ruling in the initial orders.” FERC Mot. for
    Leave 4. We granted the Commission’s motion. See Order
    Granting Mot. for Leave.
    Now that it has been issued with our authorization, the
    May 2022 Order effectively vacated the capital structure
    27
    rulings in the orders now under review. Mystic suggests that it
    nonetheless remains unclear whether the May 2022 Order,
    while vacating the decision to use Exelon’s capital structure as
    the basis for Mystic’s ratemaking, also vacated the decision not
    to use ExGen’s structure. Mystic, that is, seeks reassurance that
    the Commission remains free to base Mystic’s rate on ExGen’s
    structure.
    The May 2022 Order is clear on that issue: the entirety of
    the capital structure rulings have been vacated, including the
    Commission’s rejection of ExGen’s structure for ratemaking
    purposes. The order states that “Mystic’s proposal to use the
    capital structure of its immediate corporate parent . . . has not
    been shown to be just and reasonable and . . . the record would
    benefit from further information.” May 2022 Order, at ¶ 24.
    Although the Commission noted that Mystic’s proposed capital
    structure was more “equity-rich” than structures previously
    accepted, the Commission simply proceeded to set the capital
    structure issue for hearing without qualification. Id. at
    ¶¶ 25–26. And in oral argument before us, the Commission
    confirmed that the option to use ExGen’s structure remains
    open to the Commission in the new proceedings. Recording of
    Oral Arg. 29:03–29:51. The May 2022 Order thus fully vacated
    the capital structure rulings under review.
    Because the portion of the orders subject to Mystic’s
    challenge to the Commission’s capital structure decision has
    been vacated, we conclude that the challenge is moot. As we
    have previously explained, a “case is plainly moot” when “[t]he
    challenged orders of the Federal Energy Regulatory
    Commission were superseded by a subsequent FERC order,
    and while the challenged orders were in effect petitioners
    suffered no injury this court can redress.” Freeport-McMoRan
    Oil & Gas Co. v. FERC, 
    962 F.2d 45
    , 46 (D.C. Cir. 1992). In
    an analogous context, we noted that a court “can do nothing to
    28
    affect [a party’s] rights relative to . . . now-withdrawn”
    regulations, and we described challenges to such regulations as
    “classically moot.” Friends of Animals v. Bernhardt, 
    961 F.3d 1197
    , 1203 (D.C. Cir. 2020) (quoting Akiachak Native Cmty.
    v. U.S. Dep’t of the Interior, 
    827 F.3d 100
    , 106 (D.C. Cir.
    2016)).
    Here, we can grant Mystic no effective relief to redress an
    action that has already been vacated by the Commission itself.
    And Mystic suffered no injury from the Commission’s now-
    vacated ruling because a rate based on Exelon’s capital
    structure never took effect. If the Commission ultimately sets a
    capital structure in the new proceedings to which Mystic
    objects, Mystic may file a new petition for review to challenge
    that decision.
    We dismiss the petition on this issue as moot.
    V. RECOVERY OF EVERETT’S COSTS
    In the initially filed Mystic Agreement, Mystic proposed
    recovery of Mystic 8 and 9’s fuel costs through a cost-of-
    service rate charged by Everett. See July 2018 Order, at ¶¶ 21–
    22; see also J.A. 19–20. This rate would have included Mystic
    8 and 9’s variable fuel costs as well as a monthly Fuel Supply
    Charge encompassing all of Everett’s operating costs and a
    return on investment calculated from Everett’s rate base. See
    July 2018 Order, at ¶ 22. The Fuel Supply Charge was to be
    offset by 50 per cent of the profits Everett earned on third-party
    sales over the course of the Agreement. 
    Id.
    The Commission declined to approve recovery of the
    proposed Fuel Supply Charge, instead adopting, then
    modifying, an approach proposed by its Trial Staff. First, the
    Commission reduced the recovery of Everett’s operating costs
    to only those attributable to Everett’s sale of vapor natural
    29
    gas—91 per cent of Everett’s total operating costs. See
    December 2018 Order, at ¶ 133. Second, regarding the return-
    on-investment component of the Fuel Supply Charge, the
    Commission excluded the purchase price ExGen paid to
    acquire Everett from Everett’s rate base, finding that cost-
    causation principles did not support its inclusion. See 
    id.
     at
    ¶¶ 148–49. Third, the Commission adopted a sliding-scale
    revenue-crediting mechanism for Everett’s third-party sales
    that ultimately required greater revenue crediting than Mystic
    initially proposed, see 
    id.
     at ¶¶ 134–35, but later eliminated
    revenue crediting, citing a lack of necessity in light of its
    allocation of Everett’s costs and jurisdictional concerns, see
    Second July 2020 Rehearing Order, at ¶ 66.
    The State Petitioners bring two challenges, arguing that
    (1) the Commission lacked jurisdiction to regulate the rates
    charged by Everett and (2) the Commission’s decision to
    allocate 91 per cent of Everett’s operating costs to Mystic (and
    ultimately to ratepayers) was arbitrary and capricious. Mystic
    asserts that the Commission erred in excluding Everett’s
    purchase price from Everett’s rate base, arguing that the
    decision deviates from precedent and violates well-established
    ratemaking principles.
    As detailed infra, we conclude that the Commission did
    not exceed its statutory authority in reviewing and ordering
    recovery of Everett’s costs as part of Mystic’s cost-of-service
    rate. On the merits, we accept the State Petitioners’ challenges
    but reject Mystic’s.
    A. State Petitioners’ Arguments
    1.
    At the threshold, the State Petitioners raise an objection to
    the Commission’s jurisdiction with respect to Everett’s costs
    30
    and the Fuel Supply Charge. The Commission maintains that
    “[w]hether individual components of a cost-of-service rate,
    including fuel-related costs, are recoverable turns on whether
    they are just and reasonable, not whether the Commission has
    regulatory authority over all aspects of those rate components.”
    July 2018 Order, at ¶ 37; see FERC Br. 52–54. The State
    Petitioners contend, however, that the Commission’s
    jurisdiction of Mystic’s cost-of-service rate and incorporated
    Fuel Supply Charge “does not provide a jurisdictional basis for
    burdening New England ratepayers with Everett costs that are
    not fairly attributable to Mystic’s use of that facility.” State
    Pet’rs Br. 29. We reject their argument.
    Section 205 of the FPA delineates the Commission’s role
    to ensure that “rates and charges made, demanded, or received
    by any public utility for or in connection with” interstate
    wholesale electric sales as well as the “rules and regulations
    affecting or pertaining to such rates or charges” are just and
    reasonable and not unduly discriminatory or preferential. 16
    U.S.C. § 824d(a)–(b). Section 206 similarly instructs the
    Commission to affirmatively remediate any “rate [or] charge”
    or “any rule, regulation, practice, or contract affecting such rate
    [or] charge” found to be “unjust [or] unreasonable.” Id.
    § 824e(a). The State Petitioners do not seriously dispute that
    Mystic’s cost-of-service rate plainly falls within the ambit of
    the Commission’s authority under section 205, see State Pet’rs
    Br. 28–29 (“There is no dispute . . . that the Commission can
    review Mystic’s costs before permitting their inclusion in a
    jurisdictional rate.”), nor does the Commission claim authority
    over the rate Everett charges Mystic for its fuel, as outlined in
    the non-jurisdictional Everett Agreement, see FERC Br. 53; see
    also First July 2020 Rehearing Order, at ¶ 26; Second July
    2020 Rehearing Order, at ¶ 24.
    31
    The State Petitioners instead focus on the particular inputs
    of Mystic’s jurisdictional rate, arguing that the Commission
    lacks authority to permit recovery of Everett-related costs “not
    fairly attributable to Mystic’s use of that facility.” See State
    Pet’rs Br. 29. They principally rely on the United States
    Supreme Court’s decision in FERC v. Electric Power Supply
    Ass’n, 
    577 U.S. 260
     (2016), which held that the Commission’s
    authority under sections 205 and 206 to regulate rules and
    regulations “affecting” jurisdictional rates is limited to “rules
    or practices that ‘directly affect the [wholesale] rate.’” 
    Id. at 278
     (emphasis in original) (quoting Cal. Indep. Sys. Operator
    Corp. v. FERC, 
    372 F.3d 395
    , 403 (2004)). As the State
    Petitioners see it, the Commission cannot approve rate inputs
    that lack a sufficiently direct effect on wholesale rates, thereby
    proposing a sort of threshold inquiry applicable to rate inputs.
    See State Pet’rs Br. 28–29.
    But EPSA’s jurisdictional holding has little salience here.
    EPSA involved a Commission rule, Order No. 745, governing
    how energy market operators compensate suppliers of demand-
    response resources (i.e., those that alter a consumer’s energy
    consumption). See 577 U.S. at 272–75; see generally Demand
    Response Compensation in Organized Wholesale Energy
    Markets, 
    76 Fed. Reg. 16,658
     (Mar. 24, 2011). Accordingly,
    the Commission relied upon, and the Supreme Court
    interpreted, its jurisdiction of rules and regulations “affecting”
    wholesale rates. EPSA, 577 U.S. at 277–79; see also 16 U.S.C.
    §§ 824d(a), 824e(a). It was precisely because of the expansive
    meaning of “affecting,” which the Supreme Court observed
    “could extend FERC’s power to some surprising places,” that
    the Court found the need to limit its scope to those “rules or
    practices that ‘directly affect the wholesale rate.’” EPSA, 577
    U.S. at 277–78 (alteration accepted) (quoting Cal. Indep. Sys.
    Operator, 
    372 F.3d at 403
    ).
    32
    Unlike EPSA, this case does not involve rules affecting
    wholesale rates, but rather a wholesale rate itself—Mystic’s
    proposed cost-of-service rate—which is not similarly qualified
    by “affecting” language. Granted, section 205 references “rates
    and charges . . . for or in connection with the transmission or
    sale of electric energy subject to the jurisdiction of the
    Commission,” 16 U.S.C. § 824d(a) (emphasis added), and the
    Supreme Court in EPSA noted that phrases such as “affecting”
    and “in connection with” could “assum[e] near-infinite
    breadth” if unconstrained, see 577 U.S. at 278 (citing N.Y. State
    Conf. of Blue Cross & Blue Shield Plans v. Travelers Ins. Co.,
    
    514 U.S. 645
    , 655 (1995), and Maracich v. Spears, 
    570 U.S. 48
    , 59–60 (2013)). But Mystic’s proposed rate is plainly “for,”
    not merely “in connection with,” the transmission or sale of
    electricity, see J.A. 1 (“The Agreement provides cost-of-
    service compensation to Mystic for continued operation of . . .
    Mystic 8 and 9 . . . .”), and the State Petitioners have not given
    us reason to think otherwise. Thus, there is little question of the
    Commission’s jurisdiction of Mystic’s rate pursuant to section
    205 of the FPA.
    Moreover, as to individual rate inputs, our case law affirms
    that the reasonableness of an input is not a jurisdictional issue.
    The Commission maintains, and the State Petitioners do not
    appear to contest, that “[c]ost-of-service rates routinely include
    costs that are outside the Commission’s regulatory authority,
    such as fuel supplies, labor costs, and taxes.” FERC Br. 53; see
    also First July 2020 Rehearing Order, at ¶¶ 28, 30. Our
    precedent indicates that the key constraint on the
    Commission’s authority to order recovery of such cost inputs
    is the just-and-reasonable standard and cost-causation
    principles, not a threshold jurisdictional issue. For example, in
    BP West Coast Products, LLC v. FERC, 
    374 F.3d 1263
     (D.C.
    Cir. 2004) (per curiam), the Commission determined, and we
    affirmed, that it would have been inequitable for a pipeline to
    33
    recover certain civil litigation costs that “lack[] the requisite
    nexus to the provision of . . . service.” 
    Id.
     at 1294–95; see also
    
    id.
     at 1296–97 (“The salient criterion . . . for the recovery of
    legal expenditures by regulated entities is whether the
    underlying activity being defended in the litigation serves the
    interests of ratepayers.”). Similarly, in Grand Council of Crees
    (of Quebec) v. FERC, 
    198 F.3d 950
     (D.C. Cir. 2000), we
    determined that environmental costs associated with
    developing and operating a generating facility whose rates
    were subject to Commission jurisdiction under sections 205
    and 206 of the FPA could be deemed recoverable—subject, of
    course, to “the Commission’s normal rate calculation”—even
    though the Commission refused to consider the underlying
    environmental issues in section 205 proceedings. 
    Id. at 957
    .
    In our view, the State Petitioners’ argument boils down to
    a question of cost attribution and allocation, see State Pet’rs Br.
    29 (“[T]he [Mystic] Agreement does not provide a
    jurisdictional basis for burdening New England ratepayers
    with Everett costs that are not fairly attributable to Mystic’s use
    of that facility.” (emphases added)), which sounds in justness
    and reasonableness, not jurisdiction. See Old Dominion Elec.
    Coop. v. FERC, 
    898 F.3d 1254
    , 1255 (D.C. Cir. 2018) (“For
    decades, the Commission and the courts have understood [the
    FPA’s just-and-reasonable] requirement to incorporate a cost-
    causation principle.” (internal quotation marks omitted)). The
    cost of fuel purchased from Everett is plainly an input into
    Mystic’s cost of service. See, e.g., Delmarva Power & Light
    Co., 
    24 FERC ¶ 61,199
    , at 61,460 (1983) (concluding disposal
    costs of spent nuclear fuel were “an appropriate cost-of-service
    item”); Pub. Serv. Co. of N.H., 
    6 FERC ¶ 61,299
    , at 61,714–15
    (1979) (considering effect of coal supply contract on utility’s
    fuel expenses). The State Petitioners do not appear to dispute
    the Commission’s reasonable conclusion that “third-party
    suppliers can and do recover [operating] costs through their
    34
    sales because their business would not be sustainable if they
    did not.” First July 2020 Rehearing Order, at ¶ 30. Thus, to the
    extent the State Petitioners contest whether particular Everett
    operating costs are properly recoverable under cost-of-service
    ratemaking, that is a matter of cost causation. See infra Part
    V.A.2.
    At bottom, the State Petitioners have not given us reason
    to doubt the Commission’s statutory authority to review and
    order recovery of discrete portions of Everett’s costs. We
    therefore reject their jurisdictional argument and move to the
    issue of justness and reasonableness, where we find their
    arguments more persuasive.
    2.
    The State Petitioners contend that the Commission’s
    decision to allocate 91 per cent of Everett’s operating costs—
    or, put another way, all operating costs associated with
    Everett’s vapor gas sales—to Mystic (and, by extension,
    ratepayers) runs counter to longstanding cost-causation
    principles and is therefore arbitrary and capricious. We agree.
    Cost-causation principles “require[] that ‘all approved
    rates reflect to some degree the costs actually caused by the
    customer who must pay them.’” Black Oak Energy, LLC v.
    FERC, 
    725 F.3d 230
    , 237 (D.C. Cir. 2013) (quoting E. Ky.
    Power Coop., Inc. v. FERC, 
    489 F.3d 1299
    , 1303 (D.C. Cir.
    2007)). The Commission accordingly set out to allocate
    Everett’s operating costs pursuant to cost-causation principles.
    See December 2018 Order, at ¶ 133 (“[P]rinciples of fairness
    and cost causation require that New England ratepayers and
    those third-party customers should share [Everett’s] costs.”).
    Although we are generally “obliged to defer to [the
    Commission’s] technical ratemaking expertise,” deference is
    warranted only “[s]o long as its decision is reached by reasoned
    35
    decisionmaking and supported by substantial evidence.” Ala.
    Power Co. v. FERC, 
    993 F.2d 1557
    , 1560 (D.C. Cir. 1993); see
    also Del. Div. of Pub. Advoc., 3 F.4th at 465. Here, the
    Commission failed to meet its required burden for two reasons.
    First, the Commission failed to provide an adequate
    rationale for allocating all of Everett’s vapor-related operating
    costs to Mystic, despite the Commission’s express
    acknowledgment, based on record evidence, that at least some
    portion of Everett’s vapor sales is attributable to customers
    other than Mystic. See Second July 2020 Rehearing Order, at
    ¶ 64 (“We acknowledge that some vapor sales are made to third
    parties . . . .”); FERC Br. 63 (acknowledging same); see also
    J.A. 1253 (Connecticut Parties contending that “[e]ven when
    Mystic is operating at full capacity . . . , Everett is able to
    supply the Algonquin and Tennessee Gas pipelines an
    additional 465,000 MMBtu/day or more—nearly double the
    quantity consumed by Mystic”). On its face, then, allocating all
    vapor-related operating costs to Mystic appears to run contrary
    to rational cost causation. See Pa. Elec. Co. v. FERC, 
    11 F.3d 207
    , 211 (D.C. Cir. 1993) (“Utility customers should normally
    be charged rates that fairly track the costs for which they are
    responsible.”).
    The only rationale the Commission cites in support of its
    allocation is that Everett’s third-party vapor sales “benefit
    Mystic by helping to manage Everett’s tank,” a benefit the
    Commission describes as “not trivial.” Second July 2020
    Rehearing Order, at ¶ 64; see also December 2018 Order, at
    ¶¶ 155–56 (explaining Everett’s tank management practices).
    The Commission repeats this rationale before us, albeit without
    much additional elaboration. See FERC Br. 63. It makes no
    attempt, however, to explain how these tank-management
    benefits are sufficient to entirely offset Mystic’s apparent
    subsidization of vapor-related operating costs attributable to
    36
    third parties. Further, as both the State Petitioners and
    dissenting Commissioner Glick point out, any purported tank-
    management benefits “work[] both ways,” as all customers
    who purchase vapor gas stored in Everett’s tanks necessarily
    promote tank management by allowing the unloading and
    regasification of additional LNG. See State Pet’rs Br. 26
    (quoting J.A. 1253); Second July 2020 Rehearing Order (Glick,
    C., dissenting), at ¶ 8 n.19 (“What is never explained, however,
    is why third parties do not also benefit from ‘tank management’
    or why the Commission can so confidently conclude that all
    tank-related benefits go to and ought to be paid for by
    electricity customers.”). Ignoring such reciprocity of benefit
    runs contrary to the Commission’s mandate to ensure “burden
    is matched with benefit,” Old Dominion Elec. Coop., 898 F.3d
    at 1255 (quoting BNP Paribas Energy Trading GP v. FERC,
    
    743 F.3d 264
    , 268 (D.C. Cir. 2014)), and ignores party (as well
    as Commissioner) comments highlighting the flaw in its
    reasoning, see Pub. Serv. Comm’n of Ky. v. FERC, 
    397 F.3d 1004
    , 1008 (D.C. Cir. 2005) (“The Commission must . . .
    respond meaningfully to the arguments raised before it.”).
    Second, and relatedly, the Commission failed to justify the
    continuing validity of the 91 per cent cost allocation after
    eliminating the revenue crediting mechanism for Everett’s
    third-party sales. As noted previously, the Commission
    eliminated the sliding-scale revenue-crediting mechanism it
    had approved as part of its December 2018 Order, citing
    concerns that regulating Everett’s third-party sales may exceed
    its jurisdiction. See Second July 2020 Rehearing Order, at ¶ 66.
    Regardless of any perceived jurisdictional hurdles—on which
    we do not opine—the Commission failed to grapple with the
    cost-causation implications stemming from the elimination of
    revenue crediting. Despite allocating all of Everett’s vapor-
    related operating costs, the Commission expressly observed
    that Mystic is not the sole source causing Everett to incur those
    37
    costs, see id. at ¶ 64; see also FERC Br. 63, meaning that
    revenue crediting served as the sole means of offsetting
    payment of operating costs not reasonably attributable to
    Mystic, see December 2018 Order, at ¶ 134 (revenue crediting
    “allocates costs to third-party customers that do not benefit
    Mystic 8 and 9 at all”). In fact, in initially approving revenue
    crediting, the Commission explicitly noted the consequences of
    over-allocating costs while simultaneously eliminating
    crediting: “If costs are included but related revenue credits are
    excluded, then the resulting rate results in double recovery.”
    December 2018 Order, at ¶ 134 n.303; see also Minn. Mun.
    Power Agency, 
    68 FERC ¶ 61,060
    , at 61,205 n.3 (1994) (“If
    the utility excludes a firm customer from the cost allocation and
    simply credits the firm service revenues to the cost-of-service,
    other customers will subsidize the transaction if the revenues
    credited are less than the cost responsibility that should be
    allocated to that service.”). Yet in subsequent orders, the
    Commission failed to address these over-allocation concerns, a
    failure that does not evince reasoned decisionmaking.
    To make matters worse, the Connecticut Parties, in their
    rehearing petition from the Second July 2020 Rehearing Order,
    pointed out the problem of eliminating revenue crediting
    without a corresponding adjustment to the initial cost
    allocation. See J.A. 1664 (“[The Second July 2020 Rehearing
    Order] wrongly set aside the December 2018 Order’s approval
    of a revenue-crediting mechanism necessitated by assigning
    Mystic a share of Everett costs far exceeding Mystic’s use of
    Everett facilities.”). Yet the Commission’s response was
    cursory at best, as it simply referred back to “the July 2020
    Orders,” December 2020 Rehearing Order, at ¶ 39 & n.94
    (citing Second July 2020 Rehearing Order, at ¶ 66), relying
    specifically on the similarly conclusionary statement that its
    “proper cost allocation based on cost-causation principles
    obviate[d] the need for . . . revenue crediting,” Second July
    38
    2020 Rehearing Order, at ¶ 66. As the preceding analysis
    makes clear, the Commission’s reliance on its purported
    achievement of “proper cost allocation” was unwarranted.
    This is not to say that revenue crediting was necessary to
    achieve a reasonable cost allocation. Rather, we find that its
    elimination materially altered the existing cost-allocation
    calculation, yet the Commission made no effort to address the
    implications of elimination aside from citations to cost-
    causation principles and sketchy assertions.
    In short, the Commission has failed to adequately justify
    its decision to allocate all of Everett’s vapor-related operating
    costs to Mystic (and, ultimately, ratepayers). We therefore
    grant the State Petitioners’ petitions on this issue.
    B. Mystic’s Arguments
    Mystic’s principal objection with respect to the recovery
    of Everett’s costs involves the Commission’s exclusion of the
    Everett purchase price from Everett’s rate base, which is used
    to calculate the return-on-investment component of the Fuel
    Supply Charge. As Mystic sees it, “[t]he Commission’s
    decision contradicts fundamental ratemaking principles and
    deviated from precedent without a principled rationale.”
    Mystic Br. 50. Mystic’s arguments on this issue are
    unpersuasive.
    In declining to include Everett’s acquisition price as part
    of Everett’s rate base, the Commission again relied on cost-
    causation principles. See December 2018 Order, at ¶¶ 148–49;
    Second July 2020 Rehearing Order, at ¶¶ 113, 118–20. As
    already noted, cost causation is premised upon the notion that
    “all approved rates reflect to some degree the costs actually
    caused by the customer who must pay them.” Black Oak
    Energy, 725 F.3d at 237 (quoting E. Ky. Power, 
    489 F.3d at
    39
    1303). In determining whether to include Everett’s acquisition
    price in the rate base calculation, the Commission relied in
    large part on William Berg, an Exelon executive, who testified
    that ExGen acquired Everett to satisfy pre-existing capacity
    obligations arising before the Mystic Agreement was set to take
    effect: “ExGen determined that acquisition of Everett was the
    best and most reliable option for Mystic to meet its existing
    capacity supply obligations through May 2022 without
    significant risk of non-performance.” J.A. 197 (emphasis
    added); see also December 2018 Order, at ¶ 148; Second July
    2020 Rehearing Order, at ¶ 118. The Commission therefore
    concluded that “the beneficiary of the purchase of Everett was
    ExGen,” not ratepayers, and the cost of that acquisition “should
    properly be recovered in the period prior to the [Mystic]
    Agreement (i.e., the period for which the purchase was initially
    made).” December 2018 Order, at ¶ 149; see also Second 2020
    Rehearing Order, at ¶ 118 (“Exelon was aware that, absent the
    Commission’s acceptance of the Mystic Agreement, Exelon
    would have had to absorb the cost of its purchase of Everett
    during the terms of its existing Capacity Supply Obligations.”).
    Mystic’s primary reply is that no precedent “suggest[s]
    that the subjective intent of the purchaser matters, or provides
    a reason to cut out the investment in the facility from a cost-of-
    service rate.” Mystic Br. 52. But the Commission focused on
    cost causation, not subjective intent. The Commission pointed
    to the Berg testimony to support its conclusion that ExGen’s
    acquisition of Everett was for the company’s—not
    ratepayers’—benefit. Mystic wants the Commission to ignore
    record evidence that goes directly to the question of cost
    causation—matching burden with benefit. See Old Dominion
    Elec. Coop., 898 F.3d at 1255. In fact, Mystic does not point to
    or provide any contrary evidence indicating that ExGen’s
    acquisition of Everett—as opposed to simply its continued
    40
    operation—provides ratepayers a benefit that would warrant
    the proposed burden.
    Mystic also argues that “a return on and of the investment
    made in purchasing a facility is part of the costs sunk to provide
    service to ratepayers and is recoverable in cost of service,”
    Mystic Br. 51, meaning that the Commission needed to
    articulate a “principled rationale” for departing from that
    established methodology, id. at 54 (quoting Williston Basin
    Interstate Pipeline Co. v. FERC, 
    165 F.3d 54
    , 65 (D.C. Cir.
    1999)). But in highlighting this supposed departure, Mystic
    confuses the matter by characterizing Everett—not Mystic 8
    and 9—as the facility providing service to ratepayers. To the
    extent that Everett contributes to Mystic 8 and 9’s provision of
    service, the Commission permitted recovery of “incremental
    capital expenditures” and the percentage of “Everett’s fixed
    operating costs . . . attributable to serving Mystic 8 and 9,”
    Second July 2020 Rehearing Order, at ¶ 118, a permissible
    outcome provided that the Commission hews more faithfully
    to cost-causation principles, see supra Part V.A.2. Mystic has
    not otherwise given a reason to find that its parent’s acquisition
    of Everett is providing service to ratepayers. For this reason,
    the two Commission decisions that Mystic cites in support are
    inapposite, as they involve sunk costs for cost-of-service
    facilities that were directly providing electric service to
    customers, not those facilities’ fuel suppliers. See PSEG
    Power, 110 FERC at ¶¶ 1, 30 (cost-based rates for generating
    plants); Mirant Kendall, LLC, 
    109 FERC ¶ 61,227
    , at ¶¶ 1, 6
    (2004) (same).
    In sum, we conclude that Mystic has not provided a
    sufficient basis to conclude that the Commission’s exclusion of
    Everett’s acquisition cost from Mystic’s cost-of-service rate
    was arbitrary and capricious and we therefore deny its petition
    on the issue.
    41
    VI. TRUE-UP MECHANISM
    A. Mystic’s Arguments
    Mystic challenges the scope of the “true-up” mechanism
    approved by the Commission. Cost-of-service rates are
    designed to pass along only those costs actually incurred by a
    utility. But with any cost-of-service rate, there is “inherent
    difficulty in projecting costs in advance.” December 2018
    Order, at ¶ 175 (cleaned up). A true-up mechanism allows
    ratepayers to seek an adjustment if the costs charged do not
    match the costs incurred. See 
    id. at ¶ 179
    . Mystic proposed a
    true-up mechanism that would allow interested parties to
    challenge only a subset of its costs. 
    Id. at ¶¶ 165, 178
    . The
    Commission rejected that proposal as unduly narrow and
    decided that “the true-up mechanism [shall] apply to the entire
    Agreement,” with one exception not relevant here. 
    Id. at ¶ 177
    .
    Mystic argues that the true-up is over-broad because it would
    allow interested parties to relitigate the pre-2018 costs that
    inform Mystic 8 and 9’s rate base. According to Mystic, the
    Commission had already approved these historic costs as just
    and reasonable when it accepted Mystic’s filings.8
    The Commission, however, has not yet determined
    whether the pre-2018 costs are just and reasonable. It reiterated
    throughout the proceedings that it “decline[d] to make
    findings” on Mystic’s historic costs, instead requiring Mystic
    to “adequately support” its historic costs “in the true-up
    8
    The Commission and Intervenors argue Mystic’s challenge is
    not ripe because the Commission has not determined the justness and
    reasonableness of Mystic’s historic costs. But Mystic does not
    challenge the Commission’s determination on the merits. Instead, it
    challenges the scope of the true-up mechanism, an issue properly
    before us because the Commission decided it below. See Second July
    2020 Rehearing Order, at ¶ 86.
    42
    process.” Compliance Order, at ¶ 47; see also December 2018
    Order, at ¶ 64; Second July 2020 Rehearing Order, at ¶ 86.
    When the Commission later accepted Mystic’s filings, it again
    specified that it had made no determination about whether
    those rates should be approved as just and reasonable:
    “acceptance . . . shall not be construed as constituting approval
    of the referenced filing or of any rate” in the filing. Acceptance
    of Compliance Filing, Constellation Mystic Power, LLC, Dkt.
    No. ER18-1639-009 (July 29, 2021).
    Mystic’s concern that the true-up mechanism will lead to
    relitigation of its historic costs is thus unfounded because those
    costs have not been evaluated in the first instance. We therefore
    deny Mystic’s petition on this issue.
    B. State Petitioners’ Arguments
    1.
    The State Petitioners allege that the Commission
    unreasonably failed to address the States Committee’s request
    for clarification about revenue credits.
    When an agency “d[oes] not respond to . . . arguments”
    that “do not appear frivolous on their face and could affect the
    [agency]’s ultimate disposition,” we remand for agency
    consideration. Frizelle v. Slater, 
    111 F.3d 172
    , 177 (D.C. Cir.
    1997). We do so because the “failure to respond meaningfully
    to objections raised by a party renders [the Commission’s]
    decision arbitrary and capricious.” PSEG Energy Res. & Trade
    LLC v. FERC, 
    665 F.3d 203
    , 208 (D.C. Cir. 2011) (cleaned up).
    The Commission determined that Mystic’s revenues
    would not be subject to true-up because the Mystic Agreement
    already contained a mechanism to “credit revenues Mystic
    earns against its annual fixed revenue requirement.” Second
    43
    July 2020 Rehearing Order, at ¶ 88. The States Committee
    sought clarification or rehearing of this finding, inquiring
    whether interested parties could challenge the calculation of
    these revenue credits during the true-up process. See December
    2020 Rehearing Order, at ¶ 25.
    The Commission does not claim that the States
    Committee’s request was frivolous or irrelevant; instead, the
    Commission maintains it responded to this request, pointing to
    a single paragraph. That paragraph, however, addresses a
    different issue, Everett’s tank congestion charges, and explains
    that “these costs may be reviewed in the true-up process.” 
    Id. at ¶ 27
     (emphasis added). In context, “these costs” refer to
    Everett’s tank congestion charges, not the States Committee’s
    request regarding the calculation of revenue credits. The
    Commission assures us that revenue discrepancies can be
    addressed during true-up proceedings. See FERC Br. 82. But
    the agency’s “explanation to this court cannot substitute for
    reasoned decisionmaking at the agency level.” Williams Gas
    Processing-Gulf Coast Co. v. FERC, 
    475 F.3d 319
    , 329 (D.C.
    Cir. 2006) (cleaned up).
    The failure to respond to the States Committee’s request
    was arbitrary and capricious. We thus grant the petition on this
    issue and remand for the Commission to consider the States
    Committee’s request in the first instance.
    2.
    The State Petitioners also argue that the Commission’s
    December 2020 Rehearing Order introduced an apparent
    contradiction that requires remand for further clarification. We
    agree. Ordinarily, “we will uphold an agency decision where
    the agency’s path may be reasonably discerned, even if the
    decision is of less than ideal clarity.” Epsilon Elecs., Inc. v. U.S.
    Dep’t of Treasury, 
    857 F.3d 913
    , 924 (D.C. Cir. 2017) (cleaned
    44
    up). But when an agency “fail[s] to provide an intelligible
    explanation” for its decision, it has “fail[ed] to engage in
    reasoned decisionmaking” and we remand for further
    explanation. FPL Energy Marcus Hook, L.P. v. FERC, 
    430 F.3d 441
    , 448 (D.C. Cir. 2005). An order with apparent
    contradictions as to a dispositive issue is not reasoned
    decisionmaking and requires remand for clarification.
    The Commission initially stated that Mystic need not file
    its general methodology for calculating tank congestion
    charges and that the reasonableness of those charges would be
    “reviewed during the true-up process.” December 2018 Order,
    at ¶ 164. In a subsequent decision, however, the Commission
    decided these costs no longer needed to be reviewed during the
    true-up process. Second July 2020 Rehearing Order, at ¶ 73.
    The States Committee sought clarification and rehearing to
    ensure that ratepayers could still challenge tank congestion
    costs, and in its last rehearing order, the Commission again
    changed course, granting the States Committee’s request and
    allowing such charges to be “reviewed in the true-up process.”
    December 2020 Rehearing Order, at ¶ 27. Immediately after
    this statement in the same order, however, the Commission
    explained that only ISO New England could “audit and ensure
    that the tank congestion charge is properly calculated.” Id. at
    ¶ 28. ISO New England does not represent ratepayers, but
    rather manages the grid.
    On its face, the Commission’s reasoning appears
    incongruous: it agreed with the States Committee that
    ratepayers could review tank congestion charges during true-
    up, yet limited review to only ISO New England. To resolve
    the inconsistency, we remand for clarification. See FPL Energy
    Marcus Hook, 
    430 F.3d at 448
    .
    45
    VII. CLAWBACK PROVISION
    A. Everett’s Costs
    We turn next to the State Petitioners’ challenge to the
    clawback mechanism in the Mystic Agreement. The State
    Petitioners contend that the Commission arbitrarily and
    capriciously excluded Everett’s costs from the clawback
    mechanism. We agree and accordingly grant the petition on this
    issue.
    The Commission’s cost-of-service ratemaking typically
    allows for the recovery of capital expenditures over the life of
    a facility. Clawback mechanisms address the unfairness that
    results if a generator switches from charging cost-of-service
    rates to charging market rates. In that event, customers under
    the cost-of-service regime cover capital expenditures and
    repair expenses that benefit a facility for years after the cost-
    of-service agreement ends. See December 2018 Order, at ¶ 210.
    The Commission has explained that it would be unfair to permit
    owners to recover capital expenditures and repair expenses
    “that provide significant benefits beyond the term of the . . .
    Agreement from . . . customers.” Midcontinent, 161 FERC at
    ¶ 55.
    Under the Mystic Agreement’s clawback mechanism, the
    costs of certain repair and capital expenditures attributable to
    Mystic 8 and/or 9 are refunded to ratepayers if the units return
    to the market after termination of the Agreement. See
    Compliance Order, at ¶ 25; J.A. 1506. The clawback
    mechanism, however, does not impose the same refund
    obligation as to Everett’s repair and capital expenditure costs.
    And the Commission rejected the States Committee’s and
    Connecticut Parties’ request that the clawback provision
    include Everett’s costs. See supra Part I.F, at 16–17.
    46
    In declining to include Everett’s costs in the clawback, the
    Commission reasoned that it “lack[ed] jurisdiction to require a
    clawback, true-up, and/or refund of Everett’s costs” because
    “the Everett Agreement is not on file with the Commission
    and . . . Everett is not a jurisdictional entity” (i.e., Everett is not
    subject to the Commission’s jurisdiction in relevant respects).
    Second July 2020 Rehearing Order, at ¶ 43. If the Mystic
    Agreement terminated but Everett remained in service, the
    Commission explained, “there would be no rate within the
    jurisdiction of the Commission through which to order a
    refund.” Id. The Commission rested entirely on that reasoning
    in rejecting subsequent requests for rehearing on this issue. See
    Compliance Order, at ¶ 28; December 2020 Rehearing Order,
    at ¶ 39.
    We conclude that the Commission arbitrarily and
    capriciously excluded Everett’s costs from the clawback. The
    Commission supported its decision solely by reference to its
    lack of jurisdiction over Everett. But in the same proceeding,
    the Commission also held that it could include Everett’s costs
    in Mystic’s rate notwithstanding its lack of jurisdiction over
    Everett. The Commission determined that “there is no bar to
    the Commission’s exercising jurisdiction to allow Mystic’s
    recovery of 100 percent of Everett’s fixed costs.” December
    2018 Order, at ¶ 133. It reasoned that Everett’s fixed operating
    costs are “a component of Mystic’s cost-of-service rate and, as
    a result, [are] subject to Commission review and approval.”
    Second July 2020 Rehearing Order, at ¶ 22.
    We find the Commission’s reasoning, without further
    explanation, to be internally inconsistent. The Commission
    acknowledges, and we agree, that it has jurisdiction to include
    Everett’s costs in Mystic’s rate in accordance with cost
    causation principles. See supra Part V.A.1. The Commission
    cannot in the same breath contend that it lacks jurisdiction to
    47
    refund a portion of those same costs to ratepayers. To be sure,
    the Commission does not claim authority over Everett itself or
    over the Everett Agreement. FERC Br. 53. But as we have
    already explained, that lack of jurisdiction did not prevent the
    Commission from including Everett’s costs in Mystic’s rate.
    See supra Part V.A.1. Lack of jurisdiction over Everett thus
    cannot prevent the Commission from ordering Mystic to refund
    a portion of those costs to ratepayers.
    The rest of the Commission’s reasoning does not resolve
    the seeming inconsistency. The Commission reasoned that if
    the clawback mechanism included Everett’s costs, the
    clawback “would not apply to payments that Mystic received
    under a jurisdictional rate, but rather would apply to payments
    that Everett received under the non-jurisdictional Everett
    Agreement.” Second July 2020 Rehearing Order, at ¶ 43. But
    the fuel supply costs paid by Mystic to Everett are also
    “received under the non-jurisdictional Everett Agreement,” id.,
    and the Commission saw fit to include 91 per cent of those
    costs in Mystic’s rate. Although we have determined that this
    allocation was arbitrary and capricious, see supra Part V.A.2,
    we have also concluded that the error in allocation was not a
    jurisdictional one, see supra Part V.A.1.
    The Commission further reasoned that it could not include
    Everett’s costs in the clawback because, once the Mystic
    Agreement terminates, “there would be no rate within the
    jurisdiction of the Commission through which to order a
    refund.” Second July 2020 Rehearing Order, at ¶ 43. That
    objection is also unpersuasive. Even as applied only to Mystic,
    the clawback contemplates a refund that will take place after
    expiration of the Agreement. The Mystic Agreement requires
    Mystic to make a true-up filing, reconciling estimated and
    actual costs, by April 1, 2025, after the expiration of the
    Agreement. The Agreement thus already requires Mystic to
    48
    engage in settlement of funds without a jurisdictional rate
    through which to order the refund. The Commission provides
    no reason that the same sort of settlement could not be used to
    refund Everett’s costs.
    We express no view on whether the Commission may
    come up with alternative reasons to exclude Everett’s costs
    from the clawback. But the reason the Commission did
    provide—its lack of jurisdiction over Everett—does not hold
    up to scrutiny. We accordingly conclude that the Commission’s
    “failure to provide an intelligible explanation . . . amounts to a
    failure to engage in reasoned decisionmaking,” FPL Energy
    Marcus Hook, 
    430 F.3d at 448
    , rendering its decision arbitrary
    and capricious.
    We grant the State Petitioners’ petition on this issue and
    vacate the clawback portions of the challenged orders.
    B. Capital Projects
    We next consider one additional argument related to the
    clawback provision. The State Petitioners contend that the
    Commission failed to address their argument that the Mystic
    Agreement will induce Mystic to delay capital projects into the
    term of the agreement. We agree and thus grant the petition on
    that issue.
    Recall that during the term of the cost-of-service
    agreement, Mystic will recover certain repair and capital
    expenditure costs from ratepayers. As previously discussed, the
    Mystic Agreement includes a clawback mechanism to refund
    ratepayers for such costs if Mystic stays in service past the term
    of the Agreement. In the December 2018 Order, the
    Commission also ordered Mystic to contractually agree not to
    “delay[] [capital expenditure] projects until the term of the
    Agreement that it would otherwise have undertaken sooner
    49
    with the purpose of recovering excessive costs from ratepayers
    under the Agreement.” December 2018 Order, at ¶ 174. In its
    Second July 2020 Rehearing Order, however, the Commission
    revised its decision. Rather than obligate Mystic to demonstrate
    that it had not delayed capital expenditure projects into the term
    of the Agreement, the Commission merely required Mystic to
    identify whether it had delayed any such projects and its
    reasons for doing so. Second July 2020 Rehearing Order, at ¶ 7.
    Seeking rehearing, the States Committee argued that the
    revised Agreement would permit Mystic to recover costs for
    capital projects that should have been completed before
    expiration of the Mystic Agreement. The States Committee
    pointed out that Mystic would have the incentive to delay those
    projects because it could recover the full cost of projects
    expensed during the term of the Agreement. To be sure, if
    Mystic stays in service past the term of the Agreement, those
    costs would be refunded through the clawback. But if Mystic
    retires from the market at the end of the Agreement, ratepayers
    will have covered the entire costs of delayed projects—
    potentially creating perverse incentives. The State Petitioners
    contend that while the Commission recited the States
    Committee’s argument in the December 2020 Order, the
    Commission entirely failed to respond to that argument. State
    Pet’rs Br. 43–44; see December 2020 Rehearing Order, at ¶ 32.
    The Commission counters that it did respond to the States
    Committee’s argument in the December 2020 Order. FERC
    Br. 80. But the portion of the order cited by the Commission
    mentions neither the challenged delay provision nor the
    incentives created by that provision. December 2020 Rehearing
    Order, at ¶¶ 30–31, 33. The Commission thus entirely failed to
    address the States Committee’s argument. And the
    Commission’s “‘failure to respond meaningfully’ to objections
    raised by a party renders its decision arbitrary and capricious.”
    50
    PSEG Energy Res. & Trade LLC, 665 F.3d at 208 (citation
    omitted).
    Accordingly, we grant the State Petitioners’ petition on
    this issue and vacate the portion of the orders under review
    relating to the challenged delay provision.
    VIII. CONCLUSION
    For the foregoing reasons, we dismiss Mystic’s petition for
    review in part and deny it in part, and we grant the State
    Petitioners’ petitions for review.
    So ordered.
    

Document Info

Docket Number: 20-1343

Filed Date: 8/23/2022

Precedential Status: Precedential

Modified Date: 8/23/2022

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