This petition raises an important question concerning the authority of this court to review certain nonfinal administrative orders. At issue is a decision of the Federal Energy Regulatory Commission (FERC or Commission) to accept a rate filing by an electric power wholesaler under Section 205(d) of the Federal Power Act (the Act), 16 U.S.C. § 824d(d) (1976). 1 On December *237 29, 1978 intervenor Arizona Public Service Company filed a new schedule of wholesale electric rates with the Commission, estimated to increase its annual revenues by $10,-243,213. Petitioner Papago Tribal Utility Authority, a customer of intervenor, filed papers opposing the rate increase. 2 It claimed that the rate filing was unlawful on its face and should be rejected. Petitioner’s main arguments before the Commission were that intervenor improperly calculated its federal corporate income tax obligation according to the pre-1979 rate of 48 percent rather than the current rate of 46 percent; that intervenor’s three-year period for calculating peak demand charges should be reduced to one year; that intervenor’s regulatory expenses should be amortized over a two-year period instead of the proposed one-year period; that intervenor should bear the expense of certain low-cost sales to the Navajo Tribal Utility Authority; that intervenor’s proposed return on equity was excessive; and that intervenor overstated petitioner’s unit demand charge. 3
Intervenor responded to petitioner’s motion by acknowledging that the federal corporate income tax rate employed in the filing was misstated, and that the billing demand estimated for petitioner was excessive, because of certain changes in petitioner’s operations. It agreed to adjust its proposed rates to correct these errors. But it argued that the other issues raised by petitioner should be resolved after a hearing before the Commission. 4 By order of February 28,1979 the Commission accepted the proposed schedule for filing, suspended the new rates for the maximum five-month period, granted petitioner’s motion for summary disposition with respect to the corporate income tax rate issue, and denied the remainder of petitioner’s motion for summary disposition. 5
Petitioner moved for rehearing on the ground that intervenor’s rate filing contained patent defects requiring its rejection.
6
FERC denied this motion on April 30, 1979.
7
The Commission acknowledged that it has the authority to reject filings which are “ ‘patently . deficient in form or a substantive nullity’.” Joint Appendix (JA) 70
(citing Municipal Light Boards v. FPC,
*238 Petitioner thereafter filed this petition, seeking review of the February 28 order and the April 30 denial of a rehearing. It asserts that this court has jurisdiction under Section 313(b) of the Act, 16 U.S.C. § 8257 (1976). The first question we must resolve is whether FERC’s order accepting the filing, denying summary disposition, and setting the case for hearing is reviewable under this provision. Of course if material issues of fact formed the basis for petitioner’s challenge, we could not take jurisdiction, for the Commission has made no findings of fact for us to review. However, petitioner has alleged that the challenged rate filing contains patent defects requiring rejection on its face. We therefore must decide whether this court has jurisdiction under Section 313(b) to review orders denying motions for rejection of rate filings challenged on the ground of patent defects in form or content. 8
I
Section 313(b) provides: “Any party to a proceeding under this chapter aggrieved by an order issued by the Commission in such proceeding may obtain a review of such order in the United States court of appeals * * 16 U.S.C. § 8257(b) (1976). Since this provision is not limited on its face to final orders, it might be read as authorizing judicial review of interlocutory orders of any nature at any stage of an administrative proceeding. The courts have long held, however, that review under Section 313(b) is limited to orders of definitive impact, where judicial abstention would result in irreparable injury to a party.
Niagara Mohawk Power Corp. v. FPC,
Finality for the purpose of judicial review of administrative actions is not easy to define; yet the courts must be as precise as possible in defining reviewable orders. In this way we may prevent the delay that might otherwise occur if parties were induced to file petitions for review to find out whether given orders are reviewable. 9 When the courts intervene in the midst of agency proceedings, they often disrupt the administrative process and unnecessarily burden their dockets. We are therefore loath to do so. The best way to avoid this unfortunate drag on the administrative and judicial processes is to adhere to traditional principles of finality, and to define for the benefit of agencies and litigants what orders are subject to immediate judicial review.
Our definition of finality under Section 313(b) begins with the statement of the Supreme Court in
FPC v. Metropolitan Edison Co., supra,
*239
967, that this provision relates to “orders of a definitive character dealing with the merits of a proceeding before the Commission and resulting from a hearing upon evidence and supported by findings appropriate to the case.” Ordinarily, an agency order is final for purposes of appellate review when it “imposes an obligation, denies a right, or fixes some legal relationship as a consummation of the administrative process[.]”
Cities Service Gas Co. v. FPC,
The ultimate test of reviewability is not to be found in an overrefined technique, but in the need of the review to protect from the irreparable injury threatened in the exceptional case by administrative rulings which attach legal consequences to action taken in advance of other hearings and adjudications that may follow, the results of which the regulations purport to control.
Columbia Broadcasting System, Inc. v. United States,
II
A
To determine whether the order under consideration in this case is final for purposes of judicial review, we must first place it in its proper context within the administrative process. Under the Federal Power Act a utility selling electricity subject to the jurisdiction of FERC must adhere to rates and terms of sale on file with the Commission. In order to change its rates or terms the utility must file a proposed change with the Commission 30 days before the change is to take effect.
10
The Commission may reject filings of proposed changes if the filings are grossly defective in form, or “so patently a nullity as a matter of substantive law, that administrative efficiency and justice are furthered by obviating any docket at the threshold rather than opening a futile docket.”
Municipal Light Boards v. FPC, supra,
The quintessential reviewable order under the Act is a final determination by the Commission concerning the justness and reasonableness of the rate filing.
11
Such a determination, generally made after a
*240
lengthy hearing during which all relevant legal and factual questions are aired, disposes of all significant disputed issues in the case on their merits and fixes the obligations of the parties. The decision to accept a rate filing, in contrast, is undeniably interlocutory. Acceptance of a filing decides nothing concerning the merits of the ease; it merely reserves the issues pending a hearing. The decision is quickly made, as the Act demands.
12
There is no time for a considered judgment concerning facts or law. We have described the order as taking a “first cut” at the materials presented to the Commission.
Municipal Light Boards
v.
FPC, supra,
Acceptance of a filing, coupled with scheduling of a hearing, is the
initiation
of an administrative proceeding; judicial review properly follows the
conclusion
of the proceeding. As we can see by the issues raised by petitioner in its motion to reject,
13
the same issues now posed for summary disposition will also constitute the principal issues in the full administrative hearing. Perhaps the Commission will resolve the claims of the parties and obviate any injury to them if we allow it to complete its proceedings. Thus we would be “deciding] hypothetical questions and wastpng] appellate resources by intervening at this stage.”
Green v. Dep’t of Commerce,
B
Only when parties face the prospect of irreparable injury, with no practical means of procuring effective relief after the close of the proceeding, might they be entitled to immediate review of a nonfinal order.
See Gardner v. Westinghouse Broadcasting Co.,
We do not deny that petitioner would
profit
if we were to order rejection of the rate filing at this point. It would receive the benefit of several additional years of electricity purchases at the former rate, even if intervenor’s costs have risen in the meantime. However, the purpose of the Commission’s authority to reject a rate filing is not to confer this type of undeserved benefit upon mtervenor’s wholesale customers, but to facilitate the orderly processes of the Commission.
See American Farm Lines v. Black Ball Freight Service,
C
The conclusion that orders denying motions for rejection of rate filings on the ground of patent defects are not reviewable under Section 313(b) also follows from the nature of the relationship between the regulatory agencies and the courts. Under a contrary rule the courts would be drawn into disputes properly subject to the discretion of the Commission.
The Act makes no mention of either a power or a duty of the Commission to reject patently invalid rate filings. However, pursuant to its authority to issue regulations “necessary or appropriate to carry out the provisions of” the Act, Section 309 of the Act, 16 U.S.C. § 825h (1976), 17 FERC has promulgated 18 C.F.R. § 35.5 (1979):
The Secretary, pursuant to the Commission’s rules of practice and procedure and delegation of Commission authority, shall reject any material submitted for filing with the Commission which patently fails to substantially comply with the applicable requirements set forth in this Part, or the Commission’s rules of practice and procedure.
By means of this regulation the Commission has sought to ensure that rate filings submitted to it will contain sufficient information to enable it to “reach an informed and equitable decision as to the necessity for an investigation, hearing, and suspension, and to permit the Commission and parties in interest with [sic] meaningful opportunity to prepare for any proceeding.”
Municipal Light Boards v. FPC, supra,
By its terms the regulation quoted above employs a flexible standard of “substantial
*242
compliance,” which can best be judged by the Commission in the light of its own needs. The Commission possesses “broad powers to structure the proceedings before it.”
Louisiana Power & Light Co. v. FPC,
The Supreme Court has emphasized that the courts have no jurisdiction to review agency orders where such review would necessarily infringe on the statutory role of the agency. In
Arrow Transportation Co. v. Southern Railway Co.,
More recently, in
Southern Railway Co. v. Seaboard Allied Milling Corp.,
*243
The force of these Supreme Court holdings becomes evident when we consider the impact of nonreviewability on the parties to
Arrow Transportation
and
Southern Railway.
The decision to suspend rate filings may inflict a large and irreparable economic loss on the carrier. As the
Southern Railway
Court noted, “[T]he pre-effective suspension of a new rate has a greater and more immediate impact on carriers and shippers than does the initiation of an investigation whose outcome is inevitably in doubt.”
From Arrow Transportation and Southern Railway it follows a fortiori that the order presented for review in this case is nonreviewable. The decision whether to reject or to accept a rate filing is based on precisely the same information, and primarily the same considerations, that govern decisions to suspend or not to suspend, to investigate or not to investigate. The decision to accept a rate filing is a necessary adjunct to the unreviewable decision to suspend and investigate. It would make little sense to declare orders concerning suspension and investigation unreviewable if the courts may review the related order to accept a rate filing. A holding that we could assume jurisdiction in this case would, in effect, avoid the strictures of Arrow Transportation and Southern Railway on the nicest of distinctions.
Moreover, the considerations that led the Supreme Court to declare orders concerning suspension and investigation of rates nonreviewable also apply to this case. The order presented for review in this case is not a decision on the merits,
cf. Southern Railway Co. v. Seaboard Allied Milling Corp., supra,
Indeed, the considerations that underlay the decisions in Arrow Transportation and Southern Railway even more strongly militate against review of the order challenged in this case. Those orders were declared unreviewable despite the fact that the petitioners might suffer irreparable injury from them. In the case at bar petitioner’s interests may be fully vindicated upon review of the final order of the Commission.
We therefore conclude that orders accepting rate filings challenged on grounds of patent invalidity are nonreviewable, because immediate review of such orders would invade the province reserved to the discretion of the agency. 20
*244 D
The three considerations that lead us to conclude we lack jurisdiction to review this order — finality, irreparable injury, and interference with agency discretion — also explain why orders accepting rate filings challenged on
Sierra-Mobile
grounds
21
have been treated as reviewable. The
Sierra-Mobile
doctrine holds that a utility cannot file a revised rate schedule under Section 205(d) in contravention of its contractual obligations.
See generally Richmond Power & Light Co. v. FPC,
The Supreme Court 23 and this court 24 have treated orders deciding Sierra-Mobile claims as immediately reviewable under Section 313(b). At first blush, this may appear anomalous since such orders are a subcategory of orders accepting or rejecting *245 rate filings challenged on grounds of patent invalidity, which we here find unreviewable. However, Sierra-Mobile orders are sharply different from orders like that presented for review in this case in their finality, their irremediable consequences, and their relation to agency discretion.
First, a Sierra-Mobile order finally disposes of a substantive claim of right. When a seller of power subject to FERC jurisdiction files a rate change with the Commission, a purchaser that believes it is protected from an interim increase by the Sierra-Mobile doctrine will enter a motion to reject the rate filing. E. g., JA 11-14. At that time the Commission reaches a determination on the Sierra-Mobile issues. This decision is a purely legal question of contractual interpretation, unrelated to the factual and regulatory issues to be decided in the later hearing. The decision of the Commission at this point is effectively a final disposition of the purchaser’s contractual claim of right, for the Sierra-Mobile question will not ordinarily be at issue again in the later Section 205(e) hearing. 25 An immediate review of the Commission’s determination will not disrupt the continuing proceeding, nor will it raise the danger of multiple appellate proceedings concerning identical issues. Moreover, the reviewing court will have before it all information relevant to the Sierra-Mobile question: namely, the contract between the parties, the rate filing, and the Commission’s opinion.
Second, the injury to a purchaser of electric power from an erroneous order denying a Sierra-Mobile claim is quite different from the injury to such a purchaser from an erroneous decision to accept a patently invalid rate filing. The Sierra-Mobile petitioner will have been denied its contractual right to purchase electric power at the agreed-upon rate during the administrative process. Such a right, being interlocutory in nature, cannot be restored upon review of a final order. In contrast, a petitioner challenging an invalid rate filing on other grounds has no relevant interlocutory rights other than the right to proper procedures, 26 which can be vindicated upon appeal from the final order.
Third, the Commission has no discretion to accept a Section 205(e) rate filing that contravenes a private contract. The terms of such a contract can be altered only after a Section 206 proceeding. The Commission’s determination whether to grant a Sierra-Mobile motion to reject a rate filing is a purely legal matter of contractual interpretation. Thus by reviewing the Commission’s determination the court does not infringe upon the discretion of the agency.
Orders disposing of Sierra-Mobile claims are therefore immediately reviewable in the courts, and distinguishable from the order challenged in this case.
Ill
It has been the rule in this circuit for over 20 years that Section 19(b) of the Natural Gas Act, 15 U.S.C. § 717r (1976), and Section 313(b) of the Federal Power Act, which are identical, do not permit immediate judicial review of orders which do not reach the merits of a rate proceeding, but which “merely announce[] [the Commission’s] intention to embark on a hearing concerning the lawfulness of the rate[.]”
27
Texas Gas Corp. v. FPC, supra,
We agree with the Commission that the rules were promulgated for the purpose of providing the “necessary information” for the Commission “to reach an informed and equitable decision” on temporary authority applications. * * * The rules were not intended primarily to confer important procedural benefits upon individuals in the face of otherwise unfettered discretion * * *. Thus there is no reason to exempt this case from the general principle that “[i]t is always within the discretion of a court or an administrative agency to relax or modify its procedural rules adopted for the orderly transaction of business before it when in a given case the ends of justice require it. The action of either in such a case is not reviewable except upon a showing of substantial prejudice to the complaining party.” NLRB v. Monsanto Chemical Co.,205 F.2d 763 , 764. * * *
Id.
at 538-539,
Certain cases in this circuit, however, have introduced a degree of uncertainty into this important question of appellate jurisdiction. In
Papago Tribal Utility Authority v. FERC,
We recognize, however, that an agency has the power and in some cases the duty to reject a tariff that is demonstrably unlawful on its face. Thus, an agency will reject a tariff that conflicts with a statute, agency regulation or order, or with a rate fixed in a contract sanctioned by statute; similarly, a tariff will be rejected if it is unlawful without prior agency approval, and approval has not been obtained. In such cases the refusal of an agency to reject a tariff may be reviewed by the courts. * * *
(Footnote omitted.) However, a close examination of the opinions in these cases reveals that they were not intended to create a new and unwarranted exception to the final judgment rule of Section 313(b).
We observe, first, that the above quoted dictum in the
Associated Press
case was written before the Supreme Court’s recent decision in
Southern Railway,
which reemphasized the importance of the nonreviewability doctrine in the context of nonfinal administrative orders. Moreover, though the quotation from
Associated Press
overstates the authority of the courts to review agency decisions to accept tariff filings, an examination of the cases cited in a footnote as illustrative of the quoted proposition,
Nor do
Municipal Light Boards, City of Groton,
or
Papago Tribal Utility Authority
require an assumption of jurisdiction in this case. In none of those cases does the court reverse a Commission decision to accept filing; indeed, it is difficult to imagine the circumstances in which the court would reverse such a decision under the closely “circumscribed” rule of appellate review espoused in those cases.
See, e.g., City of Groton v. FERC, supra,
The parties have not, however, focused on these questions, nor in the circumstances need we deal with them, for we are satisfied that on the merits petitioners’ case is deficient.
Id. The Papago Tribal Utility Authority case thus leaves open the issue we decide today. In view of Southern Railway, we consider it important to reaffirm our traditionally limited approach to reviewability of nonfinal agency orders. 32
IV
Because we find that there has been no reviewable final order in the Commission’s proceedings, we direct that the petition for review be
Dismissed.
Notes
. Section 205(d) of the Act, 16 U.S.C. § 824d(d) (1976), provides in relevant part:
*237 Unless the Commission otherwise orders, no change shall be made by any public utility in any such rate, charge, classification, or service, or in any rule, regulation, or contract relating thereto, except after thirty days’ notice to the Commission and to the public. Such notice shall be given by filing with the Commission and keeping open for public inspection new schedules stating plainly the change or changes to be made in the schedule or schedules then in force and the time when the change or changes will go into effect.
. See Protest, Petition to Intervene, Motion to Reject as to One Wholesale Customer, Motion for Partial Summary Disposition, Motion for Rejection as to All Wholesale Customers and Request for a Hearing and Suspension for Maximum Statutory Period, Joint Appendix (JA) 7.
. Petitioner also contended that intervenor could not unilaterally increase its rates under the terms of their contract. This contention— which raises issues sharply different both procedurally and substantively from those addressed in this opinion — was pressed by petitioner in a separate action, recently decided by this court.
Papago Tribal Utility Authority v. FERC,
. JA 29-31.
. See Order Accepting for Filing and Suspending Proposed Rate Increase, Providing for Hearing, Instituting Section 206 Investigation, Granting Motion for Summary Disposition in Part, Denying Motion to Reject, Denying Request for Waiver, and Establishing Procedures, JA 33.
. See Application for Rehearing, JA 46.
. See Order Denying Application for Rehearing, JA 69.
. In this case the order accepting intervenor’s tariff filing will be followed by a hearing under § 205(e) into the lawfulness of the new rates. We are not concerned in this case with orders that accept tariff filings and allow them to take effect without investigation or refund obligation. Such orders would present different questions of reviewability. With that limitation understood, we will use the phrases “order accepting a rate filing” and “order denying a motion to reject a rate filing” interchangeably for purposes of this opinion.
. The Supreme Court has held that the issue of
standing
for purposes of obtaining judicial review under the Act must be “determined by the specific circumstances of individual situations!)]”
United States ex rel. Chapman v. FPC,
. For good cause shown, FERC may permit changes in rates without the 30-day notice period. Section 205(d) of the Act, 16 U.S.C. § 824d(d) (1976).
. A party must file for rehearing pursuant to § 313(a) before it is permitted to file a petition for review pursuant to § 313(b). Technically, the Commission’s order denying such motion for rehearing is the final order.
See City of Vanceburg v. FERC,
. The Act indicates that the Commission’s decision to suspend and investigate the new rates is to be made “at once,” see § 205(e) of the Act, 16 U.S.C. § 824d(e) (1976). In this case one month elapsed between petitioner’s motion to reject and FERC’s denial of that motion.
. See text at notes 2-3 supra.
. During oral argument the attorneys agreed that intervenor voluntarily ceased charging petitioner the new rate in late 1979, in response to this court’s action in Papago Tribal Utility Authority v. FERC, supra note 3. They could not *241 agree on whether the higher charges paid by petitioner prior to this action have yet been refunded to petitioner.
. This court has observed that the Commission’s power to order a refund of excessive charges “may be inadequate to protect the customer’s interest fully,”
Municipal Light Boards
v.
FPC,
. We do not imply that orders
rejecting
rate filings are not immediately reviewable. Such orders are. genuinely final orders, disposing of all the issues in the case, and have been uniformly treated as immediately reviewable by the courts.
E.g., FPC v. Texaco, Inc.,
.
See FPC v. Texaco, Inc., supra
note 16,
. For convenience we will hereafter cite to the older codification of the Interstate Commerce Act, 49 U.S.C. §§ 1-16 (1976), since the decisions we discuss predate the new codification.
. On this point the scheme of the Federal Power Act is nearly identical to that of the Interstate Commerce Act. This court has therefore held, on the strength of
Arrow Transportation Co. v. Southern R. Co.,
. If an order accepting a rate filing were clearly outside the bounds of FERC’s statutory authority, it would present different issues of reviewability. See
Trans Alaska Pipeline Rate Cases,
On a similar theory
Municipal Electric Utility Ass’n v. FPC,
.
See United Gas Pipe Line Co. v. Mobile Gas Service Corp.,
. A second effect of the
Sierra-Mobile
doctrine is that, in order to obtain an increase in the contractual rate, a seller must prove that the existing contractual rate is unjust or unreasonable under § 206(a). For example, the seller could prove that the rate “might impair the financial ability of the public utility to continue its service, cast upon other consumers an excessive burden, or be unduly discriminatory.”
FPC v. Sierra Pacific Power Co., supra
note 21,
.
United Gas Pipe Line Co. v. Memphis Light, Gas & Water Div., supra
note 22.
FPC v. Sierra Pacific Power Co., supra
note 21, arose on review of a final Commission decision.
United Gas Pipe Line Co. v. Mobile Gas Service Corp., supra
note 21, the procedural history of which is recounted in the appellate court’s opinion,
.
See, e. g„ Papago Tribal Utility Authority v. FERC, supra
note 3;
Appalachian Power Co. v. FPC,
. In the absence of intervening judicial review of the Sierra-Mobile order, the Commission presumably could reexamine the issue during the § 205(e) hearing, but there is no reason to expect that it would ordinarily do so.
. In this, we are abstracting somewhat from the facts of this case. In actuality, petitioner has also asserted a Sierra-Mobile right against intervenor. See note 3 supra. Such a right is, of course, interlocutory, see text at note 22 supra, and merits immediate judicial review if denied.
. Unless, of course, acceptance of the filing would irreparably violate some substantial independent right of a party. See Part II-B supra.
. See text at notes 19-20 supra.
. We also draw support from the Second Circuit’s ruling that denial of a motion to dismiss an FPC investigation is not reviewable under § 313(b),
Niagara Mohawk Power Corp. v. FPC, supra
note 20, and from the Tenth Circuit’s decision that an order instituting an investigation into the lawfulness of the rates and practices of a natural gas company is “in no proper sense a definitive order. Rather, it is a mere step in procedure.”
Canadian River Gas Co. v. FPC,
. Even if an agency violates a statutory duty, its order might not be immediately reviewable unless the order infringes a substantial interest of a party in a way which is not remediable upon review of final judgment. See Part II-B supra.
.
Municipal Light Boards
does discuss the reviewability of
suspension
orders.
. We observe that another panel of this court recently handed down a decision setting aside an FERC order that suspended an electric power rate filing for five months and remanding to the Commission for a statement of reasons for the length of the suspension period.
Connecticut Light & Power Co. v. FERC,
