BOOCHEVER, Circuit Judge:
This case involves the applicability of the anti-pollution requirements of the Clean Air Act, section 111 (42 U.S.C. § 7411), and the regulations promulgated under that section. Sierra Pacific Power Company and Idaho Power Company appeal Environmental Protection Agency (EPA) decisions holding that Unit 2 of their coal-fired power plant must conform to the stringent anti-pollution regulations promulgated by the EPA in 1978. The power companies argue that they had “commenced construction” of Unit 2 prior to September 19, 1978, and are therefore exempt from proposed standards promulgated on that date. The EPA interpreted its regulations to require actual physical construction of or a binding construction contract for Unit 2, independent of Unit 1, prior to the relevant regulatory date, and refused to consider planning and design activity. Because the EPA did not abuse its discretion in so interpreting its regulations, we affirm.
FACTS
Sierra Pacific Power Company and Idaho Power Company (Sierra Pacific) are jointly constructing
a coal-fired electric power plant at North Valmy Station in Humboldt County, Nevada. The plant consists of two boilers (Unit 1 and Unit 2) which are located at the same site and share common equipment. In two separate decisions, the EPA determined that Sierra Pacific had not “commenced construction” on Unit 2 before September 19, 1978, the date the EPA proposed new, more restrictive regulations. The EPA therefore determined that Sierra Pacific would have to meet the more stringent air pollution equipment requirements contained in the proposed regulations. Unit 1 is exempt from the 1978 regulations because construction of that unit was commenced prior to September 19,1978. Sierra Pacific has appealed the Unit 2 EPA determinations directly to this court pursuant to 42 U.S.C. § 7607(b)(1).
A. Statutory and Regulation Background
In 1970, Congress extensively amended the Clean Air Act of 1955, for the first time enacting a comprehensive program to combat air pollution at both the state and federal level. Pub.L.No. 91-604, 84 Stat. 1676 (1970). Section 111 of the Act authorized the EPA to issue regulations for new stationary sources of air pollution, which would include such facilities as power plants. In 1971, the EPA issued “new source performance standards” for coal-fired power plants such as Sierra Pacific’s, requiring the use of either a high-grade
(low sulfur) type of coal, or the installation of flue gas desulfurization equipment, commonly called “scrubbers.”
36 Fed.Reg. 24876 (Dec. 23, 1971). Both units of Sierra Pacific’s proposed plant were originally designed to meet these requirements by burning high-grade coal, and did not contemplate scrubbers.
In 1977, Congress amended section 111 of the Clean Air Act and directed the EPA to issue regulations requiring new pollution sources to use the best adequately demonstrated technology available. Pub.L.No. 95-95 § 109, 91 Stat. 685 (1977).
See
H.R. Rep.No. 1175, 94th Cong., 2d Sess. 156-59 (1976). Section 111 now provides in part that “[a]ny new or modified fossil fuel fired stationary source which
commences construction
prior to the date of publication of the proposed revised standards shall not be required to comply with such revised standards.” 42 U.S.C. § 7411(b)(6) (emphasis added). On September 19, 1978, the EPA published the proposed revised standards,
which, in effect, required scrubbers on all coal-fired power plants above a certain size. 43 Fed.Reg. 42154
et seq.
(1978); 40 C.F.R. § 60.40a (1980). Because Sierra Pacific had entered into a binding construction contract for Unit 1 prior to September 19, 1978, this unit is exempt from the new regulations. The issue in this case is whether Sierra Pacific “commenced construction” on Unit 2 prior to September 19, 1978. If not, the company will be forced to install a scrubber on Unit 2.
B. History of Sierra Pacific’s Construction
Sierra Pacific initially began planning the North Valmy power plant in .1974. There is no dispute that the company planned to build both units from the very beginning. In 1975 its Board of Directors authorized construction of both units. On February 17, 1976, Sierra Pacific contracted with Babcock and Wilcox to purchase and construct the boiler for Unit 1. Sierra Pacific had an option for the purchase and construction of the Unit 2 boiler which it never exercised. Also in 1976, Sierra. Pacific prepared an environmental report which it filed with the State of Nevada. The company received certification from Nevada for the entire project in several stages in late 1976 and 1977. On December 19, 1977, it received a permit for physical, on-site construction of Unit 1 and some common facilities for both units from the Nevada Public Service Commission. Nevada Utility Environmental Protection Act, Nev.Rev.Stat. § 704.865. The state advised Sierra Pacific that it should apply for the Unit 2 permit after determination of the role Unit 2 was to play in the company’s overall load and supply program.
On April 4, 1978, the EPA issued a “prevention of significant deterioration” permit for the entire project as it was then planned, which did not include scrubbers. Issuance of such a permit merely indicates that the EPA believes the plant will not result in significant deterioration of the ambient air quality; the permit does not excuse compliance with the new source pollution standards of 40 C.F.R. Part 60.
On
September 12, 1978, Sierra Pacific appeared before the Nevada State Environmental Commission requesting a one-year extension on the expiration date for its Unit 2 construction certificate. A company representative, Mr. Saibini, told the Commission that “only preliminary design work has been done on the [Unit 2] boiler” because the company had been unable to enter into a binding contractual commitment. The request for an extension was granted, and the Unit 2 permit was finally issued on March 26,1979. Therefore, on September 18,1978, the last day to “commence construction,” the company had an on-site construction permit for Unit 1, but by its own statements was not ready to complete its application for a permit or begin actual construction on Unit 2. On April 11, 1979, Sierra Pacific contracted with the Foster Wheeler Company for the purchase of the Unit 2 boiler.
The company notified Region IX of the EPA that actual construction commenced on Unit 1 and some of the common facilities on September 11, 1978. At this time, then, approximately a week before the EPA proposed its new regulations, the company had received all necessary state air quality permits and its federal prevention of significant deterioration permit, and had begun design and engineering work for both units. Significantly though, the company had not yet entered into a boiler contract, received on-site construction permits, or begun actual construction on Unit 2. The company was aware that Unit 2 might be governed by the 1978 regulations, and therefore requested an EPA determination on the matter.
C. EPA Proceedings
On April 4, 1979, in response to Sierra Pacific’s request, the Nevada regional office of the EPA informed the company that Unit 2 was covered by the new regulations because the company had not entered into either a binding construction contract or a continuous program of construction. The company appealed this decision to EPA headquarters in Washington. Pending a final determination, Sierra Pacific officials met with the EPA and submitted cost information indicating its losses if the new source performance standards compliance was required. It hoped that this information would show a continuous program of construction. Sierra Pacific’s “lost investments” included: (1) design and engineering costs, (2) capital costs, (3) premium coal contracts, (4) environmental studies, and (5) costs incurred by delayed construction. These costs allegedly totaled over $35 million.
On August 24, 1979, the EPA issued a “final determination” requiring Sierra Pacific to comply with the 1978 regulations for Unit 2. This determination carefully analyzed each of the company’s claimed expenses and found that most of the costs were merely costs of compliance, and were not increased by any forced changes in its existing construction plans. In addition, the EPA found that some of the increased expense was de minimis in relation to the overall project cost. Due to confusion over the appropriate jurisdictional forum, Sierra Pacific challenged this determination in both the federal district and circuit courts.
On May 23, 1980, before any substantive action in either federal court, the EPA issued a revised determination which revoked and replaced the 1979 determination. Based on different grounds, the new determination reached the same result, namely that Sierra Pacific must comply with the new regulations for Unit 2. In the later opinion the EPA rejected use of the “lost investments” test. It stated that none of the lost investments were directly related to the “fabrication, erection, or installation” of the boiler for Unit 2, and therefore the investments were inappropriately considered in the first EPA determination. 40 C.F.R. § 60.2(g). The EPA interpreted its regulations to require either a contract or actual construction on the boiler unit itself, and therefore Sierra Pacific had not “commenced construction.”
Sierra Pacific has appealed the 1979 and the 1980 determinations directly to this court. Both appeals have been consolidated, and the parties have jointly agreed to dismiss the district court suit. The sole issue is whether the EPA abused its discretion in determining that Sierra Pacific had not commenced construction of Unit 2 prior to September 19, 1978.
I. STANDARD OF REVIEW
Sierra Pacific has not challenged the validity of the EPA regulations, and if they had we would be without jurisdiction to hear such a claim. 42 U.S.C. § 7607(b)(1). The question, then, is whether the EPA properly interpreted its regulations. Section 307 of the Clean Air Act sets forth the standard for review. We may overturn the EPA determination that Unit 2 is subject to the stricter pollution control regulations only if it was “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 42 U.S.C. § 7607(d)(9)(A).
See Citizens to Preserve Overton Park, Inc. v. Volpe,
401 U.S. 402, 416, 91 S.Ct. 814, 823, 28 L.Ed.2d 136 (1971);
Oljato Chapter of Navajo Tribe v. Train,
515 F.2d 654, 667 (D.C.Cir.1975). An appellate court will ordinarily give substantial deference to a contemporaneous agency interpretation of a statute it administers. When dealing with an interpretation of regulations the agency has itself promulgated, “deference is even more clearly in order.”
Udall v. Tallman,
380 U.S. 1, 16, 85 S.Ct. 792, 801, 13 L.Ed.2d 616 (1965).
We have held that the EPA’s interpretation of its regulations is entitled to great deference, even where, as here, it has overruled or questioned its own prior interpretations.
Montana Power Co. v. E. P. A.,
608 F.2d 334, 346-48 (9th Cir. 1979).
See Kenai Peninsula Borough v. State of Alaska,
612 F.2d 1210, 1214 n.8 (9th Cir. 1980). Therefore Sierra Pacific must overcome a strong presumption of validity to establish that the EPA incorrectly interpreted its regulations. We are not permitted to “substitute [our] judgment for that of the agency.”
Citizens to Preserve Overton Park,
401 U.S. at 416, 91 S.Ct. at 823;
Montana Power,
608 F.2d
at 344. We are nevertheless mindful of our obligation to make a “searching and careful” inquiry into the facts to determine the reasonableness of the EPA’s interpretation, under the standard of deference discussed above.
Citizens to Preserve Overton Park,
401 U.S. at 416, 91 S.Ct. at 823.
II. UNIT 2 AS A SEPARATE FACILITY
Section 111 of the Clean Air Act Amendments of 1977 exempts new stationary sources that have commenced construction prior to publication of the new proposed regulations, but the statute does not define the term “commenced construction.”
See
42 U.S.C. §§ 7411(a), (b)(6). The 1978 regulations define “construction” as: fabrication, erection, or installation of an affected facility.
40 C.F.R. § 60.2(g). With respect to a new source, “commenced” means that
an owner or operator has undertaken a continuous program of construction or modification
or
that an owner or operator has entered into a contractual obligation to undertake and complete, within a reasonable time, a continuous program of construction or modification.
40 C.F.R. § 60.2(i) (emphasis added). Unit 1 of Sierra Pacific’s plant meets the “contractual obligation” test of the regulation, and Sierra Pacific argues that Unit 2 meets the alternative “program of construction” test. The EPA, however, interpreted the word “program” in light of the physical emphasis in the definition of construction, and therefore found that Sierra Pacific had not commenced construction.
Initially we note that the EPA may properly analyze the state of construction on just one unit of a two-unit project. The statute and regulations apply to “any building, structure, facility, or installation which emits or may emit any air pollutant.” 42 U.S.C. § 7411(a)(3). The regulations further explain that “facilities” include
“[e]ach
fossil-fuel-fired steam generating unit,” 40 C.F.R. § 60.40(a)(1) (emphasis added), and define “unit” as a separate “furnace or boiler used in the process of burning fossil fuel ...” 40 C.F.R. § 60.41(a). Therefore the EPA must look to the Unit 2 boiler facility, by itself, in determining whether construction has commenced, and disregard the progress of construction on Unit 1, or on the facilities that will be shared by both units.
This principle was made clear by the District of Columbia Circuit in a similar context. In
ASARCO Inc. v. E. P. A.,
578 F.2d 319 (D.C.Cir.1978), the court evaluated proposed EPA regulations defining a “stationary source” under 42 U.S.C. § 7411 as including, under some circumstances, a combination of facilities. Under this so-called “bubble concept,” an industry would be permitted to balance an increase in pollution from one source with a matching decrease in pollution from another source so long as the “net” pollution level from the “facility” remained the same. The court vacated the regulations and remanded to the EPA because the term “affected facility” is not synonymous with an entire plant. 578 F.2d at 323. The court held that the regulations must result in individual assessment for each energy producing unit.
In
Alabama Power Co. v. Costle,
636 F.2d 323, 395-98 (D.C.Cir.1979), the District of Columbia Circuit reaffirmed the
ASARCO
holding that the bubble concept was an improper regulatory application of the new source performance standards. The
Alabama Power
court held, however, that it was proper for the EPA to look to the entire facility before issuing a prevention of significant deterioration permit, because of the different purposes of these two EPA functions.
Id.
The
Alabama Power
court was also faced with a power company challenge to EPA prevention of significant deterioration regulations which in effect required a separate “commenced construction” date for each unit of a multi-boiler
power plant. 40 C.F.R. § 52.21(s)(2) (1978); 43 Fed.Reg. 26388, 26396 (1978). Relying on the EPA’s considerable discretion, the court found that the challenged regulatory standards were a reasonable interpretation of the Clean Air Act. 636 F.2d at 409-11.
Therefore, the EPA properly looked to the state of construction on Unit 2, independent of Sierra Pacific’s progress on Unit 1. Furthermore, the regulations make it clear that construction is to be interpreted with regard to the “facility” or boiler itself, not the related construction necessary for the entire project.
III. COMMENCEMENT OF CONSTRUCTION
The EPA’s 1980 determination in the instant case states that a power company can meet the regulatory test determining when construction is “commenced” by showing either: (1) a contractual obligation, or (2) a continuous program of construction.
Although the EPA might have adopted the company’s broad reading of the word “program” so as to include planning and design of a unit, failure to do so was not an abuse of discretion. The only court we are aware of that has considered this issue held that the EPA interpretation ignoring planning and preliminary purchases for a unit not yet under physical construction was a “reasonable interpretation.”
United States v. City of Painesviile,
431 F.Supp. 496, 500 n.5 (N.D.Ohio 1977),
aff’d,
644 F.2d 1186 (6th Cir. 1981). The EPA in the
Painesviile
case found that construction of a new boiler unit in a plant was only in the planning stages, and it interpreted 40 C.F.R. § 60.2(i) to require either a binding contract or actual construction. The district court, agreeing with the EPA, found that construction “had not progressed to the point that a change in its design would have required the facility already erected to be modified in order to insure that it could comply with the [new standards].” 431 F.Supp. at 501. The court further noted that had Congress intended the EPA to consider planning or design of a project, it would have used those terms instead of the word “construction.” 431 F.Supp. at 501 n.8.
The Sixth Circuit agreed that the EPA properly interpreted its own regulations, and affirmed the district court. At 1190. The appellate court also extensively discussed the congressional intent of Section 7411, and found that concern for the environment was a more important consideration than the costs borne by industry. At 1190-1193.
Citing only a dictionary as authority, Sierra Pacific contends that “program” of construction necessarily includes planning and design work. “Program” is not defined in the regulations.
See
40 C.F.R. § 60.2. It is reasonable, however, for the EPA to interpret “program of construction” in terms of the definition of construction: “fabrication, erection, or installation,” which suggests physical activity.
If the EPA adopted the power company’s broad construction of the word “program,” construction would have commenced in 1974 when Sierra Pacific first decided to build the plant. Under this approach, power companies could be building power plants well into the next decade under the technologically outdated 1971 regulations. The EPA approach of looking to physical construction on the boiler itself is not only a reasonable interpretation of the definitions in 40 C.F.R. §§ 60.2(g) and (i), but also provides a more workable test for determining the commencement of construction.
Sierra Pacific finally contends that the congressional intent for excusing new sources under construction from the stricter pollution standards was to avoid excessive
economic waste from abandonment or alteration of a program of construction. The legislative history of the Clean Air Act of 1970 and of the 1977 amendments, however, does not discuss the purpose of the “commenced construction” language. Although it is reasonable to assume that Congress included this language to prevent economic waste there is nothing to indicate where Congress wanted the line between protection of the environment and costs to the regulated utility to be drawn.
The history of the Clean Air Act does indicate how important Congress believed it was to enhance air qualify by strictly regulating all new stationary sources of pollution. For this reason, the 1977 amendments require the use of the best adequately demonstrated technology rather than permit reliance on certain types of fuel such as low sulfur coal. H.R.Rep.No. 294, 95th Cong., 1st Sess. 11,
reprinted in
[1977] U.S.Code Cong. & Ad.News 1077, 1088.
In determining congressional intent the EPA was justified in balancing solicitude for industrial costs with strong statements of environmental concern contained in the Committee Reports.
See United States v. City of Painesville,
644 F.2d 1186 at 1191-1193 (6th Cir. 1981). Congress left to the EPA the final determination of which new sources were to be covered by the 1978 regulations, and Sierra Pacific has not shown that the EPA abused its discretion by drawing the line for determining the commencement of construction at the stage of physical “fabrication, erection, or installation” of a boiler unit, or when the power company can show a binding contract for boiler purchase.
IV. REJECTION OF THE LOST INVESTMENTS TEST
Sierra Pacific’s final contention is that the EPA improperly failed to consider evidence of lost investments. The EPA’s
1979 ruling creates the impression that when the magnitude of lost investments reaches large enough proportions it might justify grandfathering a construction project under the 1971 standards. In its 1980 ruling, the agency stated that the magnitude of lost investments was, by itself, irrelevant. Instead, a permit applicant would be required to show that lost investments fit into two narrow categories: either that money was spent on actual physical construction related to a particular unit, or that money would be lost from a forced breach of a construction contract.
In this case it was conceded that there was no contract for the construction of Unit 2.
The EPA also determined that all the
lost investments claimed by Sierra Pacific related to activities that were connected with other elements of the construction project, or related to planning activities. None related to actual physical construction of Unit 2. Because none of the investments fell into the appropriate categories, the agency concluded that Sierra Pacific’s lost investments claim failed to establish that the company had “commenced construction.”
Sierra Pacific has raised the additional problem that the EPA first requested information on lost investments, then applied that test, and later rejected it, after the company initiated federal litigation. The company contends that the EPA could not abandon the lost investments standard having once applied it in the 1979 determination.
In
Montana Power Co. v. E. P. A.,
608 F.2d 334 (9th Cir. 1979), this court upheld the EPA’s use of a “substantial loss” test.
The court, however, was only interpreting the “contractual obligation” test of the “commencement” definition. 40 C.F.R. § 52.21(b)(7);
Id.
at 345.
Montana Power
found that the EPA did not abuse its discretion by applying a “new and different rationale” to evaluate the progress of construction, even though similarly situated power plant projects were evaluated under a different test.
Id.
at 348-49. We made it very clear that substantial deference is given to the EPA in interpreting its own regulations. The EPA is not strictly bound by its earlier interpretations, even though they may be “apparently inconsistent,”
id.
at 346, and the EPA is “free to make reasonable changes” in interpretation.
Id.
at 348. Therefore, even though Sierra Pacific may have initially been misled by what test the EPA would apply, the EPA did not abuse its discretion in changing its reasoning.
It was perhaps unwise for the EPA to issue a second determination with conflicting reasoning, particularly after commencement of federal litigation, but it did not amount to an abuse of discretion. Sierra Pacific suffered no demonstrable harm; the result reached in each case was the same. Therefore, we hold that the 1980 determination effectively “revoked and replaced” the 1979 determination. The rationale utilized in the 1980 determination was a reasonable interpretation of 40 C.F.R. Part 60, and therefore the 1980 determination is
AFFIRMED.