Opinion for the Court filed by Senior Circuit Judge EDWARDS.
Williams Gas Processing-Gulf Coast Co. (“WGP”) and Transcontinental Gas Pipe Line Corp. (“Transco”) petition for review *321 of two Federal Energy Regulatory Commission (“FERC” or “the Commission”) orders asserting jurisdiction over a natural gas pipeline off the coast of Louisiana. See Transcontinental Gas Pipe Line Corp., 111 F.E.R.C. ¶ 61,498 (2005) (“2005 Transco Rehearing Order”); Transcontinental Gas Pipe Line Corp., Ill F.E.R.C. ¶ 61,090 (2005) (“2005 Transco Jurisdictional Order”). Under the Natural Gas Act (“NGA” or “the Act”), 15 U.S.C. §§ 717-717z, FERC has jurisdiction over pipelines that “transport” natural gas, but not over those that “gather” it. But the Act does not define these terms, leaving FERC to create a test that will rationally and reliably distinguish between the two types of pipeline. FERC’s efforts to properly classify Transco’s pipeline are emblematic of its struggle to complete this task.
In 2001, FERC disclaimed jurisdiction over a 12.43 mile, 24-inch diameter pipeline in Transco’s Central Louisiana system lying downstream of the pipeline facilities of Jupiter Energy Corp. (“Jupiter”).
Transcontinental Gas Pipe Line Corp.,
96 F.E.R.C. ¶ 61,246 (2001)
(“2001 Transco Jurisdictional Order”), reh’g denied in relevant part, Transcontinental Gas Pipe Line Corp.,
97 F.E.R.C. ¶ 61,298 (2001)
(“2001 Transco Rehearing Order”).
This court upheld FERC’s 2001 orders as supported by substantial evidence and not arbitrary and capricious.
Williams Gas Processing-Gulf Coast Co. v. FERC,
In 2003, in a separate proceeding initiated by Jupiter, FERC determined that an 8-inch Jupiter pipeline feeding into the 24-inch Transco lateral serves a transportation function.
Jupiter Energy Corp.,
103 F.E.R.C. ¶ 61,184 (2003),
reh’g denied, Jupiter Energy Corp.,
105 F.E.R.C. ¶ 61,243 (2003)
(“2008 Jupiter Rehearing Order
”). The consequence of this ruling was that a jurisdictional pipeline (Jupiter) flowed into a non-jurisdictional pipeline (Transco). On review, the Fifth Circuit vacated and remanded, holding that the Commission’s decision was arbitrary and capricious because Jupiter’s transportation pipeline sat upstream of a Transco gathering pipeline.
Jupiter Energy Corp. v. FERC,
In 2004, before the Fifth Circuit’s Jupiter Appeal decision had been handed down, FERC issued an order requiring WGP and Transco to show cause why the agency’s 2001 Transco Jurisdictional Order should not be reversed as “anomalous” in light of the Jupiter orders. Transcontinental Gas Pipe Line Corp., 107 F.E.R.C. ¶ 61,122 (2004) (“Show Cause Order ”). Shortly after the Fifth Circuit vacated the Jupiter orders, FERC reversed its prior determination and held that the Transco lateral directly downstream of the Jupiter facility serves a transportation function. 2005 Transco Jurisdictional Order, 111 F.E.R.C. ¶ 61,090.
On June 28, 2005, FERC issued two decisions. First, in the case on remand from the Fifth Circuit, the Commission affirmed its jurisdictional determination in the Jupiter orders. Jupiter Energy Corp., 111 F.E.R.C. ¶ 61,497 (2005). Second, FERC denied the request for rehearing of its 2005 Transco Jurisdictional Order, on the grounds that the disputed 2001 orders were issued “on the basis of incomplete information,” and “no gas is collected along the length of Transco’s downstream line.” *322 2005 Transco Rehearing Order, 111 F.E.R.C. ¶ 61,498. The Jupiter orders are now pending review before the Fifth Circuit and the challenges to the Commission’s 2005 Transco Jurisdictional Order and 2005 Transco Rehearing Order are at the heart of the petition for review in this case.
WGP and Transco’s principal argument is that it was unlawful for FERC to reconsider its prior conclusion regarding Tran-sco’s pipeline segment lying downstream of the pipeline facilities of Jupiter. Petitioners argue, in particular, that “[t]he Commission’s lone finding and premise ... that the subject pipeline facility is not a ‘gathering’ facility solely because, purportedly, no gas was collected along that pipeline ... is contrary to the facts of record.” Petitioners’ Reply Br. at 2. Petitioners also contend that, because “the Commission ... previously decided these same facilities to be gathering in final, court-affirmed orders, the Commission is barred from re-deciding these same issues.” Id.
WGP and Transco are right in their observation that “[t]his is a classic case of an agency, both in its orders under review and its brief to this Court, failing to demonstrate that it has engaged in reasoned decisionmaking.”
Id.
They are wrong, however, in suggesting that FERC was without authority to reconsider its
2001 Transco Jurisdictional Order.
Indeed, petitioners’ counsel conceded at oral argument that it is within FERC’s authority to make jurisdictional determinations that rest on the premises that (1) there is one point on any given route where gathering stops and transportation begins, and (2) a transportation pipeline cannot feed into a gathering pipeline.
See
Recording of Oral Argument at 12:06. These two points were highlighted by the Fifth Circuit in the
Jupiter Appeal
decision.
In its briefs to this court, FERC argues that it revisited its 2001 Transco Jurisdictional Order to eliminate a “fundamental inconsistency” in its case law. Respondent’s Br. at 3, 13. The Commission could have stated as much in its 2005 orders and justified the policy shift, for an agency is free to change course in a regulatory regime provided that it offers a reasoned explanation for so doing and is not otherwise constrained by statutory limitations. We are forced to vacate the 2005 orders, however, because in those decisions, FERC neither explained its action as consistent with precedent nor justified it as a reasoned and permissible shift in policy. Although these orders ultimately may prove to be justified on the merits, they are presently wanting for lack of reasoned decisionmaking.
I. Baciíground
The Natural Gas Act grants FERC the power to regulate “the transportation [or ‘transmission’] of natural gas in interstate commerce” but not “the production or gathering of natural gas.” 15 U.S.C. § 717(b). Until fairly recently, companies sold gas under rates that encompassed both gathering and transportation services.
Lomak Petroleum, Inc. v. FERC,
Because the NGA does not define gathering and transportation, FERC is responsible for drawing the “not always clear” line between the two.
See ExxonMobil Gas Mktg. Co. v. FERC,
In
Farmland Industries, Inc.,
23 F.E.R.C. ¶ 61,063 (1983), FERC announced the “primary function test,” under which it considers six factors to determine the jurisdictional status of a pipeline: “(1) the pipelines’ length and diameter; (2) the central point in the field; (3) the facility’s geographic configuration or pattern; (4) the location of compressors and processing plants, particularly where the pipelines are located behind[,
i.e.
upstream of,] the [processing] plant; (5) the location of wells along all or part of the facilities; and (6) the line[s’] operating pressure.”
WGP-Transco I,
In response, FERC modified its primary function test to include “a sliding scale which will allow the use of gathering pipelines of increasing lengths and diameters in correlation to the distance from shore and the water depth of the offshore production area.”
Amerada Hess Corp.,
52 F.E.R.C. ¶ 61,268, at 61,988 (1990). It also announced that it would consider “nonphysical criteria such as the purpose, location and operation of the facility, the general business activity of the owner of the facility, and whether the jurisdictional determination is consistent with the objectives of the NGA . . . .”
Id.
at 61,987;
see Sea Robin Pipeline Co. v. FERC,
On remand, FERC revised the test. First, FERC concluded that the “behind-the-plant” factor should be given less .weight in the offshore context, because almost all offshore facilities are situated upstream of processing plants. Sea Robin Pipeline Co., 87 F.E.R.C. ¶ 61,384, at 62,425 (1999) (“Sea Robin II ”), reh’g denied, Sea Robin Pipeline Co., 92 F.E.R.C. ¶ 61,-072 (2000) (“Sea Robin II Rehearing Order”). FERC then replaced the “central point in the field” factor used in the onshore context with a “centralized aggregation” inquiry into whether “there exists a central location where gas is aggregated for further transportation to shore.” Id. FERC stated that its revised test would enable it to consistently discern the “point at which the collection or gathering of gas ends, and interstate transmission begins.” Id. at 62,427.
In its order denying rehearing of
Sea Robin II,
FERC stated, “[T]he Commission does not agree that the fact of Sea Robin’s upstream interconnection with [a jurisdictional facility], by itself, compels a finding that the east leg of Sea Robin’s system is jurisdictional.”
Sea Robin II Rehearing Order,
92 F.E.R.C. ¶ 61,072, at 61,295. ExxonMobil sought review before this court arguing,
inter alia,
that “FERC’s jurisdictional ruling has created an utterly illogical situation, wherein gas is transported on a jurisdictional pipeline ... into a non-jurisdictional gathering leg of Sea Robin’s pipeline.”
ExxonMobil,
Such was the state of FERC’s primary function test when Transco asked FERC to authorize the spindown of its Central Louisiana system to WGP, and WGP in turn petitioned FERC for a declaratory order disclaiming jurisdiction over the facilities. After considering each factor of the revised primary function test, FERC found that a large central pipeline, “the spine,” serves a transportation function, while “6 to 24-inch offshore lateral lines connect at various locations into the spine and serve to collect gas from the surrounding production areas.”
2001 Transco Jurisdictional Order,
96 F.E.R.C. ¶ 61,246, at 61,976. FERC concluded that these lateral lines “serve to gather gas from production located in their vicinity.”
Id.
FERC denied rehearing with respect to the laterals’ classification, see
2001 Transco Rehearing Order,
97 F.E.R.C. ¶ 61,298, and we upheld the 2001 orders as supported by substantial evidence and not arbitrary and capricious,
see WGP-Transco I,
Before this court’s decision had issued in WGP-Transco I, FERC conducted a separate jurisdictional status proceeding covering Jupiter’s 8-inch line upstream of and feeding into one of the 24-inch Transco laterals. Jupiter Energy Corp., 103 *325 F.E.R.C. ¶ 61,184. Focusing heavily on the centralized aggregation point factor, FERC concluded that the Jupiter pipeline performs a transportation function. Id. at 61,713. Jupiter sought rehearing, arguing that the presence of Transco’s gathering lateral downstream of the Jupiter pipeline foreclosed a finding that the facility engages in transportation. 2003 Jupiter Rehearing Order, 105 F.E.R.C. ¶ 61,243. FERC concluded that its 2001 orders “cannot now be the basis for claiming that Jupiter’s facilities should also be declared to be gathering.” Id. at 62,286. In a footnote, FERC reversed the position it had taken in its Sea Robin II Rehearing Order and declared that “[t]he presence of upstream transmission facilities determines the classification of downstream facilities, not the opposite.” Id. at n. 8.
Seemingly uncomfortable with the muddle it had created — “[a] series of
gathering
pipelines” feeding into “a
transportation
pipeline (Jupiter’s 8-inch line), ... in turn feeding] into a
gathering
pipeline (the Transco line),”
Jupiter Appeal,
Before FERC could address the
Shoio Cause Order,
the Fifth Circuit vacated FERC’s Jupiter orders.
Jupiter Appeal,
Just a week after the Fifth Circuit vacated the Jupiter orders, FERC decided that WGP and Transco had failed to show cause sufficient to prevent reclassification of the 24-inch lateral. 2005 Transco Jurisdictional Order, 111 F.E.R.C. ¶ 61,090. In the “Background” section of its decision, FERC stated: (1) since it had not been aware that a transportation facility stood upstream of the lateral when it disclaimed jurisdiction over it in 2001, its determination “was made on the basis of incomplete information”; and (2) “[t]he presence of upstream transmission facilities determines the classification of downstream facilities, not the opposite.” Id. at 61,411. In the “Discussion” section of its decision, FERC based its conclusion that Transco’s 24-inch lateral actually serves a transportation function on one fact: unlike the gathering arms of the Sea Robin pipeline, “[n]o gas is collected along the Jupiter pipeline.” Id. at 61,413.
On June 28, 2005, FERC issued two decisions. First, FERC affirmed its jurisdictional determination in the Jupiter orders. In so doing, FERC noted that, because Transco’s pipeline was being reclassified from gathering to transportation, “the inconsistency identified by the [Fifth Circuit] no longer exists.” Jupiter Energy Corp., 111 F.E.R.C. ¶ 61,497. Second, FERC denied Transco’s request for rehearing, offering two rationales in a five-paragraph decision: (1) the 2001 orders were issued “on the basis of incomplete information”; and (2) “no gas is collected along the length of Transco’s downstream line.” 2005 Transco Rehear *326 ing Order, 111 F.E.R.C. ¶ 61,498. FERC provided no other reasoning or factual support for its conclusion. WGP and Transeo now seek review in this court.
II. Analysis
A. Standard of Review
We must vacate FERC’s 2005 orders if they are arbitrary and capricious. 5 U.S.C. § 706(2)(A);
see ExxonMobil,
[a]n agency is free to discard precedents or practices it no longer believes correct. Indeed we expect that an[ ] agency may well change its past practices with advances in knowledge in its given field or as its relevant experience and expertise expands. If an agency decides to change course, however, we require it to supply a reasoned analysis indicating that prior policies and standards are being deliberately changed, not casually ignored.
Nuclear Energy Inst., Inc. v. EPA,
Arbitrary and capricious review “demands evidence of reasoned decision-making
at the agency level;
agency rationales developed for the first time during litigation do not serve as adequate substitutes.”
Kansas City v. HUD,
WGP and Transeo point out that in 2001 FERC applied each factor of its primary function test and concluded that Transco’s 24-inch lateral performs a gathering function; yet, in 2005, FERC reached the opposite conclusion, Petitioners’ Br. at 19-20, but without the requisite support for such a drastic change in course, id. at 18, 25. *327 The simple question here is whether FERC’s reclassification of the Transco lateral is justified either as consistent with precedent or as a considered departure therefrom. In other words, are the contested 2005 orders supported by reasoned decisionmaking?
B. FERC’s “Incomplete Information” Rationale Is Inadequate
FERC justified its 2005 orders in part by stating that its original decision was based on incomplete information. On this point, the Commission claims that it did not become aware that the Transco lateral sat downstream of a line properly classified as jurisdictional until after the 2001 proceedings. See 2005 Transco Rehearing Order, 111 F.E.R.C. ¶ 61,498, at 63,113; 2005 Transco Jurisdictional Order, 111 F.E.R.C. ¶ 61,090, at 61,411. But FERC never explained why the classification of the Jupiter facility is relevant to the jurisdictional status of the Transco lateral under existing precedent. The only statement approximating a clarification of the “incomplete information” rationale can be found in a blanket assertion contained in the “Background” section of the earlier of the two 2005 orders: FERC declared, “The presence of upstream transmission facilities determines the classification of downstream facilities, not the opposite.” 2005 Transco Jurisdictional Order, 111 F.E.R.C. ¶ 61,090, at 61,411.
But FERC simply cited the Jupiter footnote (where it had first stated the proposition without explanation). FERC made no attempt to square this new policy statement with its directly contradictory stance in
Sea Robin II Rehearing Order
and this court’s decision in
ExxonMobil.
In
Sea Robin II Rehearing Order,
FERC stated, “[T]he Commission does not agree that the fact of Sea Robin’s upstream interconnection with [a jurisdictional facility], by itself, compels a finding that the east leg of Sea Robin’s system is jurisdictional.” 92 F.E.R.C. ¶ 61,072, at 61,295. And in
Exx-onMobil,
FERC convinced this court to conclude that “the presence of an interconnection with an upstream jurisdictional facility [does not compel] a finding that the downstream facility is likewise jurisdictional.”
C. FERC’s Inconsistent Precedents and Changing Policg
FERC’s new assertion that a facility downstream of a jurisdictional pipeline must also be jurisdictional finds support in two interrelated principles which FERC once embraced but recently rejected: (1) there is one point along every route at which gathering ceases and transportation begins, and (2) a transportation facility cannot feed into a gathering facility.
In a 1996 Policy Statement, FERC announced, “[W]here gas is destined for interstate commerce, there is necessarily a point at which the gathering or collection of the gas ends, and interstate transportation begins.”
Gas Pipeline Facilities,
74 F.E.R.C. ¶ 61,222, at 61,757. In
Sea Robin I,
the Fifth Circuit treated this principle as a settled component of FERC policy: “The determinative question is when did gathering cease and transportation commence.”
FERC’s treatment of the second principle follows a similar course. In 1983, FERC stated, “[B]ecause the movement of gas through the Coronado system can be classified as intrastate pipeline ‘transportation,’ we cannot find the subsequent downstream movement of gas from that system to be exempt ‘gathering.’ ”
Galaxy Energies, Inc.,
24 F.E.R.C. ¶ 61,121, at 61,304 (1983). More recently, FERC declared, “[A] facility functionalized as gathering may not be located downstream of facilities functionalized as transmission.”
Trunkline Gas Co.,
70 F.E.R.C. ¶ 61,163, at 61,503 (1995);
see also Dauphin Island,
93 F.E.R.C. ¶ 61,198, at 61,652 (“[I]t would be incongruous for gas flowing on an upstream transportation line to be delivered into a downstream gathering line.”). But in 2002, FERC convinced this court to distinguish
Trunkline
as a case in which “the classification of the upstream system was in dispute,” and reject the “proposition that the presence of an interconnection with an upstream jurisdictional facility compels a finding that the downstream facility is likewise jurisdictional.”
Exxon-Mobil,
In
Jupiter Appeal,
the Fifth Circuit assumed that the first principle constituted FERC’s own tenet, and that the second principle necessarily flows from the first.
It would thus appear that FERC’s “incomplete information” rationale rests on its tacit adoption of these two principles and application of a new policy derived from them. Only if FERC views the principles as inviolate, does FERC’s “incomplete information” rationale begin to make sense.
D. The 2005 Orders Lack Reasoned De-cisionmaking
The problem with FERC’s “incomplete information” rationale is that it is not supported by any reasoned analysis
in the orders themselves.
Although we suspect that the orders may reflect an unstated endorsement of the two principles discussed above, we have no good basis upon which to rest this supposition. Arbitrary
*329
and capricious review strictly prohibits us from upholding agency action based only on our best guess as to what reasoning truly motivated it.
Columbia Gas Transmission Corp. v. FERC,
In order to rely on the two principles, FERC had to acknowledge the need to reconsider its precedent, announce its definitive adoption of the principles, and explain their impact on the existing primary function test. If FERC intended to adopt a new policy specifying that the classification of the downstream facility must yield where the principles demand corrective action, FERC was obliged to explain that extension of its case law as well.
See PG & E Gas,
In its briefs, FERC attempts to make the required showing, explaining that the Commission reversed the Transco lateral’s classification in order to eliminate a “fundamental inconsistency” in its case law. Respondent’s Br. at 3, 13. But counsel’s explanation to this court cannot substitute for “reasoned decisionmaking
at the agency level.” Kansas City,
This conclusion is dispositive. Although FERC rested its decision on both the “incomplete information” rationale and its finding that no gas is collected along either the Jupiter pipeline or the Transco lateral, it did so without according
*330
the two conclusions individual weight. “[W]hen an agency relies on multiple grounds for its decision, some of which are invalid,” we may only “sustain the decision [where] one is valid and the agency would clearly have acted on that ground even if the other were unavailable.”
Casino Airlines, Inc. v. Nat’l Transp. Safety Bd.,
III. Conclusion
For the reasons stated above, we vacate FERC’s 2005 orders and remand to the agency for further proceedings consistent with this opinion. We offer no judgment on the merits of FERC’s choice to reverse the Transco lateral’s jurisdictional determination. The decision on the merits must await reasoned decisionmaking from the Commission.
