Opinion for the court filed by SILBERMAN, Senior Circuit Judge.
These consolidated petitions for review are before us once again. The Maine Public Utilities Commission and the Attorneys General of Connecticut and Massachusetts, representing energy customers, challenged FERC’s approval of a settlement agreement that redesigned New England’s electricity capacity market. Although we rejected most of petitioners’ challenges, we granted their petition regarding the argument that the settlement agreement’s
Mobile-Sierra
provision — which requires FERC to adjudicate challenges to rates resulting from an auction procedure arising out of the settlement agreement under the
Mobile-Sierra
public interest standard — deprived non-settling parties of their rights under the Federal Power Act to challenge rates under the statute’s presumably more searching “just and reasonable” standard.
See Me. Pub. Utils. Comm’n v. FERC,
I
This case has characteristics of a chameleon; it has changed its colors — and its shape — at each stage of the proceedings. As we have previously explained, the basic dispute relates to New England’s electrical capacity market, in which an electricity provider purchases an option to buy electricity from a generator rather than purchasing the electricity directly. That market had been beset by problems, including a supply of capacity that was barely sufficient to meet the region’s demand, and FERC, electricity generators, electricity purchasers, and power customers engaged in several attempts to resolve those issues.
See Devon Power LLC,
The key feature of the settlement agreement is the Forward Capacity Market, which entails annual auctions that set the rates for electricity “capacity” (the option of buying a quantum of power). In these auctions, which are held three years in advance of when capacity is needed, electricity providers buy capacity at a standard rate, and must purchase enough capacity to maintain the reliability of the electricity grid.
See id.
As noted, the settlement agreement provided that challenges to the resulting auction rates— whether brought by a settling party, a non-settling party, or the Commission— would be “adjudicated under the highly-deferential
Mobile-Sierra
‘public interest’ standard rather than the usual ‘just and reasonable’ standard” of the Federal Power Act.
Me. Pub. Utils. Comm’n,
It should be noted that, at the outset of this litigation, it was common ground among all pax-ties that the normal statutory “just and reasonable” standard was a different standard than the “public interest” standard. This belief no doubt was shaped by the eponymous cases of the
Mobile-Sierra
doctrine, in which the Supreme Court addi’essed the Commission’s authority to modify rates set by contract. In
United Gas Pipe Line Co. v. Mobile Gas Service Corp.,
It appeared to us that application of the
Mobile-Sierra
doctrine was a form of estoppel,
i.e.,
a contracting party was not at liberty — short of extraordinary circumstances — to avoid its negotiated contract rate. And therefore we framed the
Mobile-Sie'iTa
issue in our px-evious opinion as whether “the Commission [may] approve a settlement agreement that applies the highly-deferential ‘public interest’ standard to rate challenges brought by non-contracting third parties.”
Me. Pub. Utils. Comm’n,
Then, before the Supreme Court, the ground shifted. Three months after we issued our original opinion in this case, the Supreme Court decided
Morgan Stanley Capital Group Inc. v. Public Utility District No. 1 of Snohomish County,
Following the Supreme Court’s lead, the parties presented arguments about whether Mobile-Sierra applied only to contract rates. Maine Public Utilities Commission and its allies, respondents before the Supreme Court, squarely contended for the first time (undoubtedly in light of Morgan Stanley) that the auction rates were not contract rates (a point that they had not specifically made before, except by adopting an argument in an intervenor’s brief). Petitioners before the Supreme Court, who had been intervenors defending the settlement agreement before us, now argued (again surely influenced by Morgan Stanley) that the rates were contract rates. And FERC, for its part, took a third position: the rates were not contract rates, yet it nevertheless had authority to approve the Mobile-Sierra clause as a matter of its discretion.
Relying on
Morgan Stanley,
the Supreme Court concluded that the
Mobile-Sierra
doctrine “is not limited to challenges to contract rates brought by contracting parties. It applies, as well, to challenges initiated by third parties.”
NRG Power Mktg., LLC,
*758
It is necessary to describe this jurisprudential Kabuki dance to deal both with a jurisdictional issue, as well as with the merits. The intervenors defending the settlement agreement (although not FERC) contend that we lack jurisdiction to consider petitioners’ argument that the auction rates are not contract rates to which
Mobile-Sierra
can apply because petitioners did not make that precise argument before FERC' — only intervenors opposing the settlement did. And our cases are quite clear that generally we do not have jurisdiction under the Federal Power Act to consider an argument not raised by a petitioner
before FERC;
an intervenor cannot fill the jurisdictional gap.
See, e.g., Platte River Whooping Crane Critical Habitat Maint. Trust v. FERC,
It would be rather anomalous at this point for us to hold that we lacked jurisdiction to consider the issues the Supreme Court has explicitly remanded to us. Moreover, given the shifts in the parties’ positions — including FERC’s — as well as the unanticipated change in the Supreme Court’s
Mobile-Sierra
jurisprudence, it might be thought overly technical to bar petitioners’ argument. But it is unnecessary to consider these factors. Intervenors, in asserting that petitioners did not raise the precise argument that the auction rates are not contract rates before FERC, are slicing the salami too thinly. After all, petitioners did argue before FERC that the
Mobile-Sierra
provision in the settlement agreement “deprives non-settling parties of their rights under Section 206 of the Federal Power Act,” an argument that applies whether or not the auction rates are regarded as contract rates.
2
Interestingly, FERC, when presented with intervenors’ more precise formulation that the auction rates were not contract rates, said “[w]e also reject [intervenors’] contention that market rules and tariffs are not contracts to which
Mobile-Sierra
can apply,” yet ambiguously also said that “tariffs have been held to be analogous to contracts.”
Devon Power LLC,
II
As we noted, the Supreme Court granted
certiorari
to determine whether the
Mobile-Sierra
public interest standard applied to a challenge to contract rates brought by a non-contracting party. And that issue was affected decisively by
Morgan Stanley,
which the Supreme Court decided after we issued our previous opin
*759
ion in this case. A freely-negotiated contract rate, the Court held in
Morgan Stanley,
was presumptive evidence that the rate was just and reasonable because it reflected market forces.
See Morgan Stanley,
We admit to being somewhat uncertain about the implications of the Supreme Court’s opinion in our case because although it states, following Morgan Stanley, that the public interest standard is merely an application of the just and reasonable standard, see id. at 700, its accurate description of Sierra makes clear that there an examination of the disputed rate under the just and reasonable standard would have led the Commission to overturn the rate, where adjudication under the public interest standard would not have, see id. at 699. It therefore appears that if the Mobile-Sierra doctrine is only an application of the just and reasonable standard — not a separate standard — it is true only at some theoretical level. Be that as it may, since the Supreme Court invigorated the Mobile-Sierra doctrine, and remanded for a determination whether the auction rates were protected against attack, either because they are freely-negotiated contract rates or because FERC has discretion to apply Mobile-Sierra to non-contract rates, it is obvious that the Court is of the view that the Mobile-Sierra public interest standard confers an advantage on a party claiming it applies.
Doctrinal difficulties aside, we turn to the questions the Supreme Court put to us: “[wjhether the rates at issue qualify as ‘contract rates,’ and, if not, whether FERC had discretion to treat them analogously.” Id. at 701. FERC’s counsel now concedes flatly that the auction rates are not contract rates, but rather closely resemble a conventional “cost based tariff rate” because during the Forward Capacity Market auction, a capacity buyer is simply assessed a standard market rate. Unlike a typical auction, then, the buyers do not agree to pay a seller a specific price set by a voluntary bid, so therefore no voluntary agreements develop. Nevertheless, FERC’s counsel argues that under the logic of Morgan Stanley, the Commission always has discretion to approve a clause that provides protection against an attack on these rates as unjust or unreasonable by imbuing them with the more difficult to challenge “public interest” cloak. 3 Exercising that discretion is appropriate here, FERC’s counsel believes, because the auction rates “share with freely negotiated contracts certain market based features that tend to assure just and reasonable rates.” Respondent’s Supplemental Brief at 13.
We cannot decide whether FERC’s counsel’s current position is reasonable under the APA because it is certainly obvious — whatever else is confusing about this case — that FERC never articulated
in its orders
a rationale for its discretion to approve a
Mobile-Sierra
clause outside the contract context, or an explanation for exercising that discretion here.
See Fed. Power Comm’n v. Texaco Inc.,
For the foregoing reasons, FERC’s orders approving the settlement agreement’s Mobile-Sierra provision are remanded for further proceedings.
So ordered.
Notes
. One of the most contentious issues in this case was the status of the "transition payments” paid to electricity generators to cover the three-year gap between the first auction and the time when the capacity purchased in that auction is provided.
See Me. Pub. Utils. Comm’n,
. For this reason, intervenors' alternative argument that petitioners waived their non-contract rate argument in their opening brief is without merit. In that brief, as before FERC, petitioners asserted that the settlement agreement deprives them of their statutory rights. See Petitioners’ Opening Brief at 51-54. We cannot imagine an argument would be specific enough to satisfy section 8257(b), yet not satisfy our prudential requirement that a party raise an argument in its opening brief.
. FERC’s brief rather confusingly refers to the public interest standard as a stricter standard.