FOR PUBLICATION



### UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT

H E L P I N G H A ND T O O L S ; R O B S I MP S ON , Petitioners
,

v

.

U.S. E N VI RONME

N TAL P RO T E C T I ON A GE N C Y ; G I N A M C C A

R T HY , in her capacity as Adm inistrator of the U.S. Environm ental Protection Agency; D E B O R AH J O R D A N , in her capacity as Director of the Air Division of U.S. Environm ental Protection Agency Region IX, Respondents
,

S I E R R A P A C I F I C I ND U S T R

I E S , I N C ., Respondent-Intervenor. No. 14-72553H E L P I N G H A ND T O O L S V

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C E N T E R F O R B I O L O GI C AL D I VE R S I TY , Petitioner
,

v

.

U.S. E N VI RONME

N TAL P RO T E C T I ON A GE N C Y ; G I N A M C C A

R T HY , in her official capacity as Adm inistrator of the United States Environm ental Protection Agency; J A R E D B LU ME NF E L D , in his official capacity as Regional Adm inistrator of Region 9 of the United States Environm ental Protection Agency; D EB O R AH J O R D A N , in her official capacity as Director of the Air Division of Region 9 of the United States Environm ental Protection Agency,

Respondents
,

S I E R R A P A C I F I C I ND U S T R

I E S , I N C ., Respondent-Intervenor. No. 14-72602

EPA No.EPA-R09-OAR2012-0634

ORDER AND AMENDED OPINION

On Petitions for Review of an Order of the United States Environm ental Protection Agency

Argued and Subm itted July 19, 2016 San Francisco, California

Filed September 2, 2016 Am ended Decem

b er 23, 2016H E L P I N G H A ND T O O L S V

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B efore: Susan P. Graber and Richard C. Tallm an, Circuit Judges, and Nancy G. Edm unds, * Senior District Judge.

Opinion by Judge Tallm an

SUMMARY * *

Environmental Law

The panel d enied a p etition for review of a decision of the United States Environm ental Protection Ag ency granting Sierra Pacific Industries
, Inc. a p revention of significant deterioration permi t for construction of a new biom assburning power plant at its lumber m ill in California.

The panel held that the EPA did not act arbitrarily o r capriciously in granting a prevention of significant deterioration perm it to Sierra Pacific.

Addr e s sing petitioner Helping Hands Tools’ claim s that the EPA was required to consider solar po we r an d a greater natural g as m ix as clean fuel control technologies in the best available control technology (“BACT”) analysis for pollutants subject to Clean Air Act regulation, the p anel held that because the EPA properly took the requisite h ard look at Sierra Pacific’s proposed design and th e key purpose o f

* Th e Honorable Nancy G

. E dm unds, Senior United States District Judge for the Eastern District of Michigan, sitting by designation.

** This sum

m ary constitutes no p art o f th e o p i n i on of the court. It h as been prepared by court staff for the convenience of the reader.H E L P I N G H A ND T O O L S V

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burning its own b iom ass waste, the EPA reasonably concluded that consideration o f solar or increased natural gas would disrupt that purpose and redefine the source.

Addressing petitioner Center for Biological Diversity ’s claim s raised in response to the supplem ental greenhouse gas BACT analysis, the panel deferred to the agency’s determ inati o n because EPA was largely relying on its o wn guidance, acting at the frontiers of science.

C OUNSEL

Kevin P

. Bundy (argued), San Francisco, California; Brendan R. Cumm ings, Joshu a Tr ee, C alifornia; Anna Moritz, W oodinville, W ashington; as and for Petitioner Center for Biological Diversity.

Andrew S. Kingdale (argued), Law Office of Andrew S. Kingdale, S an Francisco, California, f or Petitioners Helping Hand Tools and Robert Sim pson.

Dustin J. Magham far (argued) ; J ohn C

. Cruden, Assistant A t t o rn e y G e n e r a l ; E n v i r o n me n t a l D e f e n s e Se c t i o n , Environm ent & Natural Resources Division, W ashington, D.C.; Brian Doster, Mark Kataoka, Nora Green g l as s, and John Krallm an , United States EPA, Office of General Counsel, W ashington, D.C.; Kara Christenson, United States EPA, Region IX, Office of R egional Counsel, S an Francisco, California; for Respondents.

Joseph R. P alm o re (argued), Marc A. He arron, and Lena Hughes, Morrison & Foerster LLP, W ashington, D.C.;H E L P I N G H A ND T O O L S V

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W illiam M. Sloan, Morrison & Foerster LLP, San Francisco, California; for Respondent-Intervenor.

Rog e r R. Martella, Jr., Joel F. Visser, and Jam es R. W edeking, Sidley Austin LLP, W ashington, D.C., for Am ici Curiae Am erican W o o d Counsel and National Alliance o f Forest Owners.

ORDER

The o pinio n filed on Septem ber 2
, 2016, is am ended as follows:

1

. On page 28 of the slip opinion, “The environm ent al i m pact report (“EIR”) prepared by EPA

. . . ” is changed t o , “The environm ental im

pact r eport (“EIR”) prepared by a consultant for the Shasta County De p artm ent of Resource Managem ent . . .”

2

. On page 28 of the slip o pinion, “EPA therefo r e conducted the E IR a s s um i n g

. . .” is changed to, “The consultant therefore conducted the EIR assum ing . . .”

3. On page 30 of the slip opinion, “The Bioenergy BACT Guidance EPA applied to the g reenhouse gas em issions from Sierra Pacific’s new facilit y i s rational and thoroughly

c onsistent with EPA’s prior guidance” is changed to , “ Th e Bioenergy BACT Guid ance, as applied by EPA to the greenhouse g as em issions from Sierra Pacific’s new facility, is rational and is consistent with EPA’s prior practice.”

W ith the s e a mendm ents, the panel has voted to deny Center f or Biological Diversity’s petition for panel rehearing.H E L P I N G H A ND T O O L S V

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Judges Graber and Tallm an have voted to d e n y He lping Hand Tools’ p e t i tion for rehearing en banc and Judge Edm unds so recomm ends.

The fu l l c o urt has been advised of Helping Hand Tools’ petition for rehearing en banc and no judge has requested a vote o n whether to rehear the m atter en banc. Fed. R

. App. P. 35.

Th e petition f

or panel rehearing and the petition fo r reh e ar i n g en banc are D ENIED

. No f urther petitions for panel rehearing or rehearing en banc will be entertained.

IT IS SO ORDERED.

OPINION

TALLMAN, Circuit Judge:

Helping Hand Tools (“Helping H and”) and Cen t er for Biological Diversity (“Center”) petition for review of a final decision of the United States Environm ental Protection Agency (“EPA”) granting Sierra Pacific Industries (“Sierra Pacific”) a prevention of significant deterioration (“PSD”)
p ermit for construction of a new biom ass-burn in g p o w er p lant at its lum ber m ill in California. Plaintiffs contend th a t EPA i s sued the PSD perm it in violation of the Clean Air Act
, 42 U .S. C. § § 7401–7671q. This is the first tim e we have reviewed EPA’s doctrine o f “redefining the source.” It also

ap p e ar s to be the first tim e that EPA’s fram ework for evaluating the best available control technolog y for greenhouse gas em issions f rom facilities burning biom assH E L P I N G H A ND T O O L S V

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fuels is considered by any circui t i n the United States. W e hold that EPA did not act arbit r ari ly or capriciously in granting a PSD p erm it to Sierra Pacifi c p ur suant to that fram ework.

I

Sierra Pacific owns and operates a lum ber m anufacturing facility in Anderson, California, situated at the northern end of the Central V alley in Shasta County. On March 29, 2010, Sierra Pacific filed an application for a PSD perm it with EPA in o rder to construct a new cogeneration 1 unit at its m ill. The

new un it wa s de s igned to burn b iom ass fuels 2 in a boiler to produce steam used to turn turbine b lades to ge n e r a t e 31

m egawatts of electricity and to h eat existing lum ber d ry k ilns. Fuel for the unit w ould com e prim arily from wood wastes from Sierr a Pa c i fic’s own lum ber m ills, as well as other readily availab le sources of agricultural and urban wood
wastes. The n ew boiler replaces a sm aller exi sting b oiler at the Anderson Faci l ity. The sm aller boiler could burn only 60,000 b one-dry tons (“BDT”) 3 of the 160,000 BDT of wood

was te the Anderson Facility annually produces. T h e new

1 Cogeneration units produce both electrical power and heat. S ee, e.g. , In re N. Mich. Univ. R ipley Heating Plant
, 14 E.A.D. 283, 285 ( E.A.B. 2009).

2 U s ed interchangeably with t he term s “bioenergy” and “biogenic, ” biom ass fuels include wood waste s u c h a s chips and bark from sawm i l l operations, forest residu e , a g ricultural residue, crops, grasses, standing trees, and waste fromlandfills or water treatm ent. 76 Fed. Reg. 43,490- 01, 43,493 (July 20, 2011).

3 A BDT i s 2,000 pounds of w o o d pu l p with a zero percent m oisture
content.H E L P I N G H A ND T O O L S V

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boiler has the increased capacity to burn up to 219,000 B DT of wood waste. Additionally, the boiler wi l l utilize natural
ga s fo r th e lim ited purpose of startup, shutdown, and flam e stabilization. 4

To understand the process by which Sierra Pacific sought approval by EPA to build the new b oiler and the res u lting litigation that ensued first re qui res an exam ination o f the statutory and regu lato ry f

ram e w o rk underlying the perm itting
process and then an exam ination of h ow EPA em ployed that process with Sierra Pacific’s particular perm it application.

A

The C lean Air Act establishes a com prehensive program for controlling and im

proving air quality. As part of this
program , 42 U.S.C. §§ 7470–7479 require new and m odified

m ajor em itting facilities, like Sierra Paci fi c ’s n ew boiler, to seek a PSD perm it p rior to construction. Id. § 7475(a). T h ese p ermits are required in geo g rap h ical reg io n s d esign ated
to m eet particular national am bient air quality standards. Id. § 7 4 71. C ritically, in o r d er t o obtain a PSD perm it, the applicant m

ust dem onstrate that the proposed facility utilizes the best available control technology (“BACT”) for ev ery polluta n t s u

bject to regulation b y the Clean Air A ct. Id. § 7475(a)(4). BACT is defined as

4 Flam e stabilization is necessary when optim al operations of the boiler

are upset by fue l variability, such as from burning wet wood waste fuel. At these tim es, the optim al com bustion of t

he wood waste is not occurring and natural gas is used to stabilize com bustion and to m axim ize efficiency by returning the boiler to desired high temperature operations.H E L P I N G H A ND T O O L S V

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an em ission lim itation based on the m aximum degree of reduction of e a c h pollutant subject
to regulation

. . . f

rom any m ajor em itting facility, wh ich [ E P A ]
, on a case-by-case basis,

. . . d eterm ines i s a chievable f or such facility through application o f production processes

a n d a v a i l a b l e m e t h o d s , s y s t e ms , a n d techniques, including fuel cleaning, clean fuels, or tr eatm ent or innovative fuel

com bustion techniqu es for control of each such pollutant.

Id. § 7479(3). In every case-by-case ana l y s is, EPA will consider “energy, environm ental, and econom ic im pacts and other costs.” Id.

In 1990, in th e absence of any clear guidance from Congress on how to evaluate BACT for a particular pollutant, EPA developed a five- st e p, “top-down” approach. See Env ironm ental P rotection A gency, New Source Review W orkshop Manual, Chapter B (1990) (hereinafter “ NSR Manual”). PSD perm it applicants m ust engage in this analysis for every regulat ed p ollutant with a significant

em issions increase. Id. at B.4.

Briefly, the top-down analysis b egins at Step 1 when the applicant lists all available c o ntrol technologies. Id. at B.5. Control technologies are those technologies that have “a practical potential for appl i c a tion to the em issions unit and the regulated p o llutant under evaluation.” Id. This list is

m eant to be com

prehensive and include all options applicable
to the particular pollutant even though the option m ay be elim inated in later steps. Id. at B.5–7. At St e p 2, the applicant elim inates any technically infeasible opti ons andH E L P I N G H A ND T O O L S V

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m ust clearly d o cum ent why the particular control option
cannot b e u sed. Id. at B.7. At Step 3, the applicant ranks the

rem aining control o ptions against eac h other in order o f overall effectiveness. Id. at B.7–8. Then, base d o n this ranking, at S tep 4
, the applicant evaluates each control option
to c o n sid er th e energy, environm ental, and eco n o m ic i m p acts. Id. at B.8. If the top candidate is unfavorable for any of these reasons, then the applicant evaluates the im pacts of the next available con trol option. Id. at B.8–9. The m ost effective control option that is not elim inated at Step 4 is then chosen as BACT at Step 5. Id. at B.9.

EPA supplem ented the top-down approach as it ap p l ied
to greenhouse gases 5 in March 2 0 1 1 when it issued new guidance. 6 See Environm ental Protection Agency, PSD and Title V Perm itting Guidance for Greenhouse Gases (201 1 ) (hereinafter “GHG Perm itting Guidance”). At the sam e tim e, EPA issued m ore specific BACT guidance for carbon dioxide

em issions from facilities that u s e b i o m ass as a prim ary fuel

source. See Environm ental Protection Agency, Guidance for Determ ining Best Available Control Technology for Reducing Carbon Dioxide Em issions from Bioenergy

5 “Greenhouse gases” are considered a single p ollutant com p rised of the aggregate of carbon dioxide, nitrous o xide, m ethane, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.

6 Though t

he exte n t to wh i ch EPA can require particular facilities to

com p ly with BACT requirem ents for greenhouse gases has been heavily litigated, the Suprem e Court r ecently held that “EPA’s decision to require BACT for greenhouse gases em itted by sources otherwise subject t o PSD review is” perm i ssible. Util. Air R egulatory Grp. v. EPA
, 134 S

. Ct. 2427, 2448 (2014). The cogeneration p ower plant proposed by Sierra Pacific is such a facility and neither p arty d i s p u t e s EPA’s authority to regulate greenhouse gas em issions from that facility.H E L P I N G H A ND T O O L S V

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P r o d u c t i o n ( 2 0 1 1 ) ( h e r e i n a f t e r “ B i o e n e r g y B A C T Guidance”). The Bioenergy BACT Guidance describes h ow each step o f the five-step BACT analysis sh ould be approached when a facility proposes to use m o s t ly biom ass

as a fuel. Id. at 1 0 –11. It does not supersede prior guidance, id. at 4, and agencies m

ust still consider each PSD application on a case-by-case basis, id. at 5.

EPA p rom

ulgated a m ore particular BACT fram ework because carbon d ioxide em issions from biom ass fuels participate in the carbon cycle diffe re n tl y than other f uels, and biom ass fuel stocks replenish mo r e quickly than fossil fuel stocks. Id. at 6. Trees ar e a classic exam ple of this phenom enon in nature. The short regenerative t i me m eans that n ew g r o wing plant m atter, biom ass carbon stocks, can

ab sorb excess carbon dioxide from the atm osphere m ore quickly than fossil fuel carbon stoc k s

. Id. A dditionally, photosynthesis fr o m a well-m anaged biom ass carbon stock, such as a well-m anage d forest, can act as a carbon sink, thereby decreasing the net carbon diox i d e released from burning b iom ass a s fuels. Id. “Biogenic [carbon dioxide]

em issions are distinct from other regulated pollutants at bioenergy f

acilities because, unlike other pollutants and other [greenhouse gases], [carbon dioxide] em issions can participate directly in the global carbon cycle through photosynthesis.” Id. at 7. Therefore, EPA m o d ified the steps of the traditional BACT analysis in particular ways to account for the unique properties of biom ass.

Of particular relevance, at S tep 1, EPA notes that “it will be im portant to address the extent to which the BACT analysis f or [greenhouse gases] should include” an evaluation of other f uel typ es. Id. at 15. However, if utilization o f biom ass is the prim ary purpose o f the project, then the agencyH E L P I N G H A ND T O O L S V

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can rely on that purpose to determ ine that another fuel would redefine the p roject. Id. If a f acilit y relies prim arily on biom ass as fuel, the options at Step 1 “m ay be lim ited to (1) utilization of biom ass fuel alone, (2) energy efficiency im provem ents, and (3) carbon capture and sequestration.” Id.

Skipping to S tep 4, 7 the Bioenergy BACT Guidance notes that the traditional Step 4 analysis is “ an e nvironm ental,

econom ic, and energy im p acts analysis that includes both direct and indirect ( i.e.
, collateral) considerations.” Id. at 18. EPA em phasizes that indirect enviro n me ntal im pacts and benefits are b etter suited to analy s i s i n Step 4, id. at 21, and b urning different biom ass fuel stocks will not have a d ifferential im

pact on em issions at the facility b ut a t th e forest or region where the biom ass fuel is taken, id. at 22. 8

7 Steps 2 and 3 are conducted in the sam e m anner as p rom ulgated in the NSR Manual. Bioenergy BACT Guidance at 16–17.

8 T o illustrate the point, burning a dead tree that has fallen in the forest, instead o f a live tree, will have a different im pact o n the environm ent. Burning the dead tree releases the sam e am ount of carbon dioxide into the
atm osphere that would be released anyway as the tree decom posed. But the em i ssions occur faster and at the f acility, not i n the forest. Burning the live tree, which uses carbon dioxide for photosynthesis, rem oves a carbon dioxide absorbing source from the forest and also releases carbon dioxide

em issions at the facility. T he facility em its carbon dioxide in either case but the enviro nm ental i m pact at the forest—the benefit of rem oving a carbon dioxide em itting d ecom posing t ree o r t he harm in re m ov i n g a carbon dioxide absorbing live one—are an indirect re sult of burning biom ass fuel at the facility. However, a com parison of different biom ass fuel stocks, such as com

paring the effects of burni n g m i l l waste to the effects of burning a d e ad t ree, is a m

uch m ore technical endeavor t hat EPA is actively trying to calculate at present. Bioenergy BACT Guidance
at 23. The problem
, according to the agency, is the current inability o f the available science to quantify the tradeoff. I d. Where the agency is acting

on t he frontiers of developing science, our deference is at i ts highest l evel.H E L P I N G H A ND T O O L S V

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In holding that facilities like S ierra Pacific’s were subject
to PSD p erm it requirem ents for g r e e nhouse gas em issions, th e S u p rem e C o urt exp ressly refrained from deciding whether
to ap p rove o r endorse EPA’s current approach for determ ining BACT for g r e enhouse gases. Util. Air Regulatory Grp. v. EPA
, 134 S

. Ct. 2427, 2449 (2014). T o

our knowledge, no other court has evaluated EPA’s approach. W e exam ine it her e a s it was used to grant Sierra Pacific its PSD perm it.

B

E P A ’s co n s id eration of Sierra P acif ic’s p ermit ap p licatio n took p lace in two phases. During the first phase in Septem ber 2012, EPA proposed to issue a PSD perm it to Sierra Pacific tha t r e qu ired the use of add-on control technologies and inherently lo w er-emittin g co ntro l s as B A C T for the pollutants analyzed. EPA did not consider BACT for greenhouse gases because it was not th en required. 9 EPA accepted Sierra Pacific’s cap on n a tur a l gas use o f no m ore than 10% of the total fuel required, because it w as to be used only for lim ited purposes during startup, shutdown, and flam e stabilization.

After public comm ent, E PA i s s ued the PSD perm it, and Helping Hand petitioned the Envir o n me ntal Appeals Board (“the Board”) for review. On Ju ly 18, 2013, the Board

Baltimore Gas & El e c. Co. v. Nat. Res. Def. Council, Inc.
, 462 U .S. 87, 103 (1983).

9 At the tim e, EPA had issued a rule deferring regulation of biogenic

c arbon sources in order to exam ine the science behind biogenic carbon dioxide em i ssions from stationary sources like power plants. See Ctr. f or Biological D iversity v. EPA
, 722 F.3d 401, 407 (D.C. Cir. 2 013). The District of Colum

bia Circuit later vacated this rule. Id. at 412.H E L P I N G H A ND T O O L S V

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rem anded the PSD perm it to EPA for further p roceedings on

a single g round—that EPA had abused its discretion in not holding a public h earing. The Board held that EPA d i d n o t abuse its d iscretion in approving the perm it o n a ll other issues, two of which are relevant to the current petition before

us.

First, the B oard held that EPA did not abuse its discretion by declining to consider the inclusion of solar power as a fuel

source or a greater percentage of natural g as because it would im perm issibly redefine the source

. I n m aking this determ ination, the Board reviewed the adm inistrative record and determ ined that the p rim ary purpose of the project was to allow S ierra Pacific “to p ut to use the hundreds of thousands of bone-dry tons of wood waste the c o mp any h as in the Sh a sta County region, for the production of lum ber an d electricity.” The Boar d then held that “requiring [Sierra Pacific] to burn fewe r t o ns of wood waste so that it could generate solar power or burn m ore natural gas instead would plainly disrupt the project’s ‘basic business purpose’ of using

as m uch surpl u s bi o mass as possible” to get rid of the byproduct and t o generate steam to dry lum ber in kilns and produce electricity for use on site and for sale to the electrical grid.

Second, the Board held that EPA did not abuse its discretion in lim iting the m ix of fuel to 90% b iom ass and 10% natural gas. The B oard held that Sierra Pacific’s prudent

u se o f natural gas for startup, shutdown, and flame stabilization w as a valid reason to lim it the quantity of natural
gas used an d “ not evidence of a project design ‘derived for reasons of air quality perm itting.’”H E L P I N G H A ND T O O L S V

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The second phase of consideration occurred when, just a few days befo r e the Board’s decision, the District o f Colum bia Circuit v acated EPA’s rule deferri n g BACT d eterm inations for greenhouse gases em itted from facili t i e s like Sierra Pacific’s boiler. See Ctr. for Biological Diversity

v. EPA
, 722 F.3d 401, 412 (D.C. Cir. 2013). As a result, EPA conducted a supplem ental BACT analysis on S ierra Pacific’s

new biom ass fa cility. EPA considered public comm ents on the supplem ent al an aly sis, an d the Center contended that EPA could not consider the burning o f b iom ass fuel alone as a control option at Step 1 and should h ave directly com pared the environm ental im

p acts o f different biom ass fuel stocks at Step 1.

EPA n onetheless issued a final PSD perm it n o t i c e on April 25, 20 1 4

. The Center appealed to the Board and the Board dism iss e d fo r lack of jurisdiction because, in its July 2013 decision, the Board specifically stated that, pursuant to 40 C.F.R. § 124.19( l)(2)(iii), it would not require or accept an appeal after the re mand. Helping Hand and the Center then filed the petit i o ns fo r review now b efore us. Because all available adm inistrative rem edies h ave been exhausted, we have jurisdiction under 42 U.S.C. § 7607(b)(1). 1 0

1 0 Though not disputed by EPA, because this is the first tim e the case is before an Article III court, Helping Hand and th e C e n t er m ust establish standing. S

ee Sierra Club v. EPA
, 762 F.3d 9 71, 976 (9th Cir. 2014). W e

are satisfied that, through the declarat i on s o f its m em bers, both Helping Hand and t

he Center have assoc ia t i o n al standing to bring t he current petition. See i d. at 976–78 (discussing that “[a]n association has standing
to bring suit on behalf of its m em bers when its m em

bers would otherwise have standing to sue in their own right” and f urther discussing t

he factors dem o nstrating that the individual m em bers had standing t o pursue Clean Air Act claim s (internal quotation m arks om itted)).H E L P I N G H A ND T O O L S V

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II

EPA’s decision is reviewed under the Adm inistrative Pro c edur e Act and m ay be set aside only if it is “arbitrary,

c apricious, an abuse o f d iscretion, or otherwise not i n accordan c e wi th law.” 5 U .S.C. § 706(2)(A); see Alaska De p’t of Envtl. C

onservation v. EPA
, 540 U .S. 461, 4 9 6

– 9 7 (2004). EPA m

ust “ articulate[] a rational connection between
th e fa cts found and the choice m ade.” Sierra Club v. E PA
, 346 F.3d 9 55, 961 (9th Cir. 2003) (al teration in o riginal) (quoting Ariz. Cattle Growers’ Ass’n v. U.S. Fish & Wildlife
, 273 F.3d 1229, 1236 (9th Cir. 2001)).

“[W ]e do not sim

ply rev iew whether it was arbitrary o r capricious” fo r the Board to reject a p etitioner’s claim s that EPA clearly erred. Citizens for Clean A ir v. EPA
, 959 F.2d 839, 845–46 (9th Cir. 1 992). “Rather, we co n du ct a deferential review of the entire agency action,” including whether approval of the PSD perm it is based on a clearly erroneous finding of fact or conclusion of law. Id. at 846.

III

First, w e address the claim s raised b y Helping Hand that EPA was require d to consider solar p ower and a greater natural gas m ix as clean fuel control technologies in the BACT analysis. This is an issue of fi rs t i m p ression in our circuit, but o ur opinion is guided by well-reasoned d ecisions of the B oard and the Seventh Circuit. Because EPA properly took the requisite hard look at Sierra Pacific’s proposed design and the key purpose of burning its own biom ass waste,

we hold that EPA reasonably concluded that consideration o f solar o r increased natural gas would disrupt that purpose and redefine the source.H E L P I N G H A ND T O O L S V

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A

Though failur e to consider all available control alternatives in a BACT analysis constitutes clear error, EPA does not have to consider control alternatives th a t would “redefine the source.” S ee, e.g. , In re Des e r t Rock Energy Co.
, 14 E.A.D. 484, 526 (E.A.B. 2 0 09); see also NSR Manual
at B .13. In essence, a control alternative redefines the source if it requires a complete redesign of the facility. In a classic and sim p le exam ple, a coal-burning power plant n e ed not consider a nuclear fuel option as a “ c l ea n e r ” fuel because it would require a com

plete redesign of the co al-b u rn in g powerp lant. See Sierra Club v. E PA
, 499 F.3d 653, 655 (7th Cir. 2007). Considering control technologies is rarely so sim ple, however, and E PA e ngages in a two-step p rocess to determ ine whether a control technology will redefine the

source.

First, “the perm it applicant initiates the process and

. . . defines the proposed facility’s end, object, aim o r purpose—that is the facility’s basic design.” In re Prairie State Generat ing Co.
, 13 E.A.D. 1
, 22 (E.A.B. 2006), aff’d sub nom Sierra C

lub
, 4 99 F.3d 653; accord Desert Rock
, 14 E.A.D. at 530; In re N. Mich. Univ. Ripley Heating Plant
, 14 E.A.D. 283, 301–02 (E.A.B. 2 009) (hereinafter “NMU”). The purpose m

ust be “objectively discernable.” Prairie State
, 13 E.A.D. at 2 2

. Additionally, the applicant’s proposed definition “m

ust be for reasons independent of air perm itting” and cannot be m oti v at e d b y cost savings or avoidance o f risks. Id. at 23 n.23; see also Desert R ock
, 14 E.A.D. at 530; NMU
, 14 E.A.D. at 302 n.28.

Second, EPA takes a “hard look” at the proposed definition to determ ine which design elem ents are inherent toH E L P I N G H A ND T O O L S V

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the applicant’s purpose and which elem e n ts can be changed
to reduce p o llutant em issions w ithout d isrupting the applicant’s basic business purpose. Desert Rock , 14 E.A.D.
at 530 (rem anding a perm it back to the agency because it failed to take a “hard look” when the agency de term ined a particular technology would redefine the source even though the applicant ha d considered the technology in its application); see also Prairie State
, 13 E.A.D. at 25 –26; NMU
, 14 E.A.D. at 302. This determ ination and “[r]efining [of] the statutory definition of ‘contr o l technology’

. . . to exclude redesign is the kind of j u d g em ent by an adm inistrativ e a gency to which a reviewing court should defer.” Sierra Club
, 499 F.3d a t 6 5 5. Our exam ination o f this two-step process for Sierra Pacific’s PSD perm it is guided sign i fi c an t ly by the reasoning of our sister circuit in Sierra Club in which it denied the petition arising from Prairie State

.

Wh en a fuel source is co-located with a facility, EPA need not consider in the BACT analysis fuel sources that are not readily a v ai l able, because it would redefine the source. Prairie State
, 13 E.A.D. at 2 8. In Prairie State
, Prairie State Generating Com

pany filed an application for a PSD p erm it with EPA to build a coal-burning electrical plant in southern Illinoi s

. I

d

. a t 4–5. The proposed facility was a “m inem outh” pl an t i n which the plant is located at the site of the coal m ine which f

uels it. Id. at 16. However, the m ine only
p ro duced h igh-sulfur coal, which em its m ore sulfur dioxide pollution than low-sulfur coal from other outlying m ines. Id

. at 15. EPA did not list low-sulfur coal as a control technology in S tep 1 of the BACT analysis, however, because low-sulfur coal would have to be shipped in by rail from long distances. Id. EPA explained that “it would be inconsistentH E L P I N G H A ND T O O L S V

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with the scope of the project to u se coal from other regions o f the country.” Id. at 16.

In m aking this determ ination, EPA noted that “the project that m ust be addressed when evaluating BACT is the project for which an application has been subm itted

. ” Id. In this instance, the construction of a “m ine-m outh” plant. Id. EPA found that “use of a p articular coal supp l y i s an inherent aspect o f the proposed project.” Id. EPA broadly considered alternative coal supplies but rejected a m ore detailed analysis because it was beyond the scope of the project. Id. at 18.

The ultim ate dispute before the B oard lay in determ ining how to define the basic purpo s e of the p roject and whether Prairie St a t e co uld include use of coal from a particular

source as part of that purpose. Id. at 2 1

– 2 2

. “ The p erm it issuer m ust be m indful that BACT, in m ost cases, should not be applied to regulate the applicant’s objective or purpose for the proposed f

acility.” I

d. a t 2 3. The Board specifically rejected petitioners’ assertion that the facility’s business
purpose m

ust be viewed broadly as the producti on o f electricity from coal b ecause “we have frequently recognized that an electric generating facility’s p urpose m ay b e m ore narrowly defined.” Id. a t 2 5

. The Board held that, in d efi ni n g the scope of a project, EPA could consider if a parti cu l ar fuel source was an inherent part of the project design. See id. (“It h as also been long-standing EPA policy tha t c e rt ain fuel choices are integral to the electric power g enerating station’s basic design.” (citing NSR Manual at B.13)).

A d d itio n ally
, th e B o ard rejected the petitioners’ argum ent that a purpos e that includes a particular fuel source “would allow a perm it applicant to avoid all BACT review byH E L P I N G H A ND T O O L S V

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including its preferred fuel

. . . and hide behind the claim that requiring anything different would unlawfully ‘redefine’ the proposed source.” Id. at 27. Because Prairie Stat e could narrowly define its purpose as burning a particular fuel
source, EPA needed only to review the facility proposed, and that m eant reviewing a facility that burned co-localized highsulfur coal. The Board exam ined EPA’s review of the proposed facility and was satisfied that EPA had taken a hard look at whether further e mi s sions reductions were possible. Id. Therefore, the Board concluded, EPA did not err when it “determ ined that consideration of low-sulfur coal, because it necessarily involves a fuel source other th an th e co-located

m ine, would require Prairie State to redefine the fundam ental
p urpose or basic design of its proposed Facility” and, a s a result, EPA properly rejected low-sulfur fuel from Step 1 o f the BACT analysis. Id. at 28.

In denying the p e tition arising out of Prairie State
, the Seventh Ci r c uit noted that the Board and EPA were stru ggling to draw the line between where “control technology ends and redesign o f the ‘proposed facility’ begins.” S

ierra C lub
, 4 99 F .3d at 655. The court n oted that if EPA had to consider all clean fuels, it would be required to consider a nuclear plant rather than a coal-fired one, and it

was clearly n ot require d t o d o that. See id. (“That approach would invite a litigati on strategy that would m ake seeking a perm it for a new power plant a S is yp h ean labor, for there would always be one m ore o ption to consider.”). Because it

was not as clear cut, the Seventh Circuit characterized its case

as lying on the b orderline between contr o l technology and redesign. Id. at 656.

That b orderline, defining the distinction b etween considering alternative fuels to be control technologies or toH E L P I N G H A ND T O O L S V

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redefine the facility, is a p roduct of EPA’s fram ework for evaluating BACT. T h e Seventh Circuit therefore h eld that “it

m akes sense to let the EPA, the autho r of the underlying distinction, draw it, within reason.” Id. at 655. In the f acility proposed in Sierra Club
, the court noted that, in isolation, the difference between low-sulfur and h igh-sulfur coal as a fuel

source is a difference in control technology. Id. at 657. B ut “the difference between a plant c o

- lo c ated with a coal m ine and a plant that o btains its coal from afar” is a di ffe rence in design. Id. T herefore, the S eventh Circuit upheld the BACT determ ination because E P A reasonably d rew t h e lin e b etween control technology and redefining the source. Id.

The reasoning of Prairie S tate and S ierra Club has been applied to subsequent cases f rom the Board. In N

MU
, relating to the construct ion of a power plant on a college

cam pus, the Board rem anded a PSD perm it back t o th e agency when it r ejected the assertion that considering a different proportion o f a coal and wood fuel m ix would im perm issibly redefine the so urce. 14 E.A.D. at 301–03. Particularly, the B oard n oted that NMU locked onto a particular fuel com

bination without any logic or data to justify the choice. Id. at 303; see also id. at 297 (“[A]lthough the record reflects that other coal

. . . will produce the lowest sulfur e m issions, [the agency] p roceeds without explaining why the s e s o urces are unavailable or not technologically feasible.”). Notably relevant to the current appeal, NMU did
not fully analyze the possibility of natural gas as a fuel source wh en the perm it application stated that it would be u s e d fo r boiler startup and as a backup fuel source. Id. at 2 9 7 n.17;

see also In re Cash Cre e k Ge neration LLC
, 2 009 W L 7513857 (E.P. A. 2009) (rem anding the perm it to the applicant b ecause the record was insufficient to ju s t i fy a determi n a t ion that an exclusive use of natural gas, aH E L P I N G H A ND T O O L S V

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secondary fuel for the p roject, w ould im perm issibly redefine the source).

B

Adopting the two-step analysis prom ulgated by the Board and approved b y the Seventh Circuit, we m ust now determ ine whether EPA erred in determ ining that using solar power or

a greater natural gas m ix in Sierra Pacific’s proposed f acility would im perm issibly redefine the source.

First, we loo k a t how Sierra Pacific itself defined its facili ty

. In its application d escription, Sierra Pacific expli c i tly stated that it intended to build a power plant “that would burn biom ass fuels in a b o i l er to produce steam that would be used to g enerate e l e c tr icity and to heat existing lum ber dry kilns at the facility.” Sierra Pacific then went on to define m ore particularly that its biom ass fuel source would

com e f rom the existing Sierra Pacific mi l l s , in-forest

m aterials from tim

berlands owned b y Si e rr a Pacific, and other readily available sources o f a g ricu ltural and urban wood
wastes. S ierra Pa cific would use n atural gas only for the lim ited p urposes of startup, shutdown, and flam e stabilization. Capped at 10%, S ierra Pacific estim at e d its annual u s ag e o f natural gas to be significantly below that lim it.

Next, we m

ust determ ine i f EPA took the appropriate “hard look” at how Sierra P acific defined the facility and whether EPA appropriately determi n e d that the burning o f biom ass was an inherent elem ent of the facility or whether it could be changed to reduce em issions. In the PSD p erm it issued by EPA, the project description stated that fuel for the
power plant wo u l d be g enerated on-site or received fromH E L P I N G H A ND T O O L S V

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other local sources to produce steam in the n ew facility. The
steam w as then to be used to dry lum ber and to power a steam turbine to g enerate electricity for use onsite or for sale to the northern California power grid.

Helping Hand argues that the Board im properly deferred to Sierra Pacific’s purpose of “burning biom ass ‘as m uch as possible’” and read “clean fuel s ” out of the Clean Air Act. Sierra Pacific’s purpose, according to Helping H and, is only
to generate steam f

or lum ber drying kilns and to m a ke electricity. However, Sierra Pacific’s purpose need n ot be so lim ited, see Prairie State
, 13 E.A.D. at 25, and Helping Hand concedes that “Sierra Pa c i fi c arguably can have a basic business purpose of ‘prim aril y’ b urning a dirtier fuel that is readily available to it.” Just as the P rairie State facility was co-located with its fuel source, a high-sulfur coal m ine, Sierra Pacific’s f

acility is co-located with its fuel source, waste from its lum ber m anufacturing operations. Therefore, EPA took a “hard look” at the record and how Sierra Pacific defined its facility and reaso n ab l y determ ined that use of a co-located fuel source was an inherent part of the facility’s design.

Having determ ined that biom ass fuel was an inherent part of the design, we finally exam ine whether the two proposed alternative clean fuels we re control alternatives that should have b e e n considered or would im perm issibly redefine the
source, keeping in m ind the deference EPA m ust be afforded in m aking such a de t erm ination. Like the petitioners in Sierra Club
, Helping Hand essentially argues that “if a plant is capable—with redesign—of b urning a cl ean fuel, it m ust undergo a ‘best available control tec hnology’ analysis.” 499 F

. 3d at 656. Requiring a solar com ponent just because it is a cleaner fuel than b iom ass is the sam e as requiring Sierra Pacific to consider the nuclear option. See id. Sierra PacificH E L P I N G H A ND T O O L S V

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and EPA are not required to take on the “Sisyphean” task o f

c o n s idering every possible clean fuel alternative. See id. at 655. Therefore, EPA properly dism issed solar as a c o ntrol technology.

The Board noted, correctly, that consideration of a greater natur a l g as m ix w as a closer question. Sierra Pacific’s proposed project falls o n the borderline discussed in Sierra Club

. However, unlike the applicant in Sierra Club
, Sierra Pacific is not considering two fuel sources as control options:

one an off-site “clea n” fuel, one an on-site “dirty” fuel. In this instance, Sierra Pacific has access to two on-site fuel

source s: “clean” natural gas and “dirty” biom ass. Though this typically would suggest that Sierra Pacific m ust consider

a greater m ix of natural gas, even when an alternative fuel is available, it need not be considered at Step 1 if it disrupts the business p urpose. GHG Perm itting Guidance at 28 (“[G]reater utilization of a fuel that the ap p licant is already proposing to u se in som e aspect of the p roject design should be listed as an option in S tep 1 unless it can be dem onstrated that such an option would disrupt the applicant’ s b a sic business purpose f

or the proposed facility.”). H ere, a greater

use of natural gas would disrupt Sierra Pacific’s intent to burn the biom ass waste it produces from m ill operations. 1 1

Notably, unlike the fa c i lities in N MU and Cash Creek
, Si e rra P acific does not propose to use natural gas as a “seconda ry ” or b ackup fuel source but only for strictly lim ited purposes. And unlike the facilities in NMU and Cash Creek
, Sierra Pacific gave v alid reasons for im posing a 10%

11 This co n c l u sion is supported by evidence in the record t hat Sierra Pacific p ro du c e s m ore waste than could be consum ed by the proposed generator.H E L P I N G H A ND T O O L S V

. USEPA 25

cap: that its purpose was to burn as m uch of its own biom ass waste as possible, and that it expected to burn m uch less than 10% natural gas because it was being used for such a lim ited
purpose. Burning natural gas is therefore incidental to Sierra Pacific’s business purpose of using its on-site source o f biom ass as fuel for the new facility. Decl i n ing to consider greater use o f an incidental fuel is not arbitrary, capricious, o r an abuse of discretion. 1 2

Drawing the line b etween control technology and redefining the source is a technical determ ination to which a court should d efer to EPA, see Sierra Club
, 499 F.3d at 655, and there was sufficient justification in the record for EPA to determ ine that prim arily burning biom ass from Sierra Pacific’s own wood waste, a co-localized so urc e , was an inh erent aspect of the facility’s design. Requiring E P A and Sierra P acific to consider solar power, a com pletely different fuel source, or a g r ea t e r percentage of natural g as, an

12 Petitioners seize upon Sierra Pacific’s adm ission t hat it lim ited natural
gas to 10% to avoid th e n itrous o xide lim iting requirem ents of the New Source Perform ance Standards ( “NSPS”). See 40 C.F.R. § 6 0.44b(d). Lim iting natural gas to avoid a nitrous oxide em ission lim it is not a design decision “independent of air perm itting.” The Board erroneously held t hat

s uc h a self-im

p osed cap was acceptable because it was “ federally enforceable.” Deciding whether or not to im pose a cap o f 10% natural g as to avoid NSPS r equirem ents does not exclude consideration of greater utilization of natural gas in the BACT analysis. See NSR Manual at B.12 (“The only reason for com paring control o ptions to an NSPS i s to de t e rm i n e whether the control option w ould r esult in an em i ssions level less stringent than the NSPS.”). Though troubling, th i s e rror does not ultim ately underm ine th e key fact that Sierra Pacific’s basic business
purpose and f

acility design is to use a co-localized source of biom ass fuel, its own wood wastes, to generate steam and electricity fo r i ts m ill and l i m i t e d u s e of natural gas is i ncidental to that purpose. For that reason , any error in justifying the 10% cap is harm less.H E L P I N G H A ND T O O L S V

. USEPA 26

incidental fue l s o urce, would redefine the source. E P A did
not act arbitrarily o r capriciously and Helping Hand’s petition is denied.

IV

Next we addre s s th e claim s raised by the Center in
response to the supplem ental greenhouse gas BACT analysis. The Center contends that EPA could not consider burning o f bio ma ss fuel alone as a control option at Step 1 and that it erred in weighing the effects of different biom ass fuel stocks
at Step 4 ins t e a d o f directly com paring them at Step 1. Because EPA was largely relying on its own guidance, acting
at the frontiers o f sc i ence, we d efer to the agency’s determ ination. See Baltimo r e Gas & Elec. Co. v. Nat. Res. Def. Council, Inc. , 462 U.S. 87, 103 (1983).

A

W e review questions of statutory inter p retations of the Clean Air Act b y the two-step process of Chevron U.S.A. Inc.

v. Natural Resources Def e n s e Council
, Inc.
, 467 U.S. 837, 842–43 (198 4 ). See Vigil v. Leavitt
, 381 F.3d 826, 833–34 (9th Cir. 2 004). If Congress has not direc tly spoken to the precise issue, o r the statute is silent o r am biguous, the court

m ust determ ine if the agency’s constructi on is perm issible. Chevron
, 467 U.S. at 842–43. When Congress has n o t pro v id e d c lear guidance in a statute, an agency m ay fill the
gap and its construction is to be given “controlling weight unless

. . . arbitrary, capricious, o r m anifestly contrary to the statute.” I

d. at 844 (deferring to EPA’s interpretation o f “source” in the Clean Air Act); see also EPA v. EME Homer City Generation, L. P

. , 1 34 S. Ct. 1584, 1603–07 (2014)H E L P I N G H A ND T O O L S V

. USEPA 27

( deferring to EPA’s interpretation of “am ount” in the Go o d Neighbor Provision of the Clean Air Act).

“[T]he weight that we are to give an adm inistrative interpretation not intended by an agency to carry the g eneral force of law i s a function of that interpretation’s thoroughness, rational validity, and c o n sistency with p rior and subsequent pronouncem ents.” Wilderness Soc’y v. U .S. Fish & Wildlife Serv.
, 353 F.3d 1 051, 1 0 6 8 ( 9 th Cir. 2 003) ( en banc). However, when an agency is acting “within its

area o f special expertise, at the f rontiers of science,” the court should “ be at its m ost d eferential.” B a ltimore Gas & Elec. Co

. , 4 6 2 U.S. at 103; see also Nat’l Wildlife Fed’n v. U .S. Army Corps of Eng’rs
, 3 84 F.3d 1163, 1174 (9th Cir. 2 004) (“Where sc i entific and technical expertise is necessarily involved in agency d ecision-m aking,

. . . a reviewing court

m ust be highly deferential to the judgm ent of the agency.”).

What level o f deference we m ust show E P A’ s BACT guidance is uncle ar

. Th e p ublications are not intended to carry the force o f l aw because E PA m ust still analyze each application on a case-by-ca s e b asis. However, all the publications w ere p rom

ulgated by EPA in o r d e r to bring

m eaning to the BACT statute which Congress h as n ot defined

an y further than it d id in 42 U.S.C. § 7479(3). EPA
prom ulgated these p o l icies specifically to carry out Congress’s intent. W e need not resolve the issue here, however, because, as discussed below, under either standard EPA’s actions were neither arbitrary nor capricious.

B

Ultim ately, the Center’s concerns are not particular to the Sierra Pacific perm it but a ttack the Bioenergy BACTH E L P I N G H A ND T O O L S V

. USEPA 28

Guidance. The Bioenergy BACT Guidance bu il ds on the NSR Manual that EPA has used f or d ecades and proposes a

m ore detailed analysis for a particular pollutant—greenhouse
gas em issions from biom ass fuels—because the em issions from this particular fuel source have unique environm ental
consequences. N othing prohibits EPA from refining its topdown BACT approach for particular pollutants—particularly when the refinem ent is heavily dependent upon the agency’s

own scientific expertise. Following th e Bioenergy BACT Guidance is therefore thorough, rational, and consistent with EPA’s p rior practice. See Wi ld e rness Soc’y
, 353 F.3d at 1068. And as explained above, we m ust defer to EPA agency expertise and not distu r b th e analysis set forth in the Bioenergy BACT Guidance.

In particular, the Center contends that utilization o f biom ass fuel alone cannot b e considered a control technology for the b urning of biom ass fuel at S tep 1 of the BACT analysis because i t d oe s not “control” biom ass em issions. EPA argues, however, that the option is used as a baseline to which all other options are com pared and is not inconsistent with the traditional top-down approach. Moreover, EPA did
not ultim ately choose this option but selected other c o n trol technologies including: com bustion of specific biom ass fuel stocks; energy efficient design, operation, and m aintenance; and em ploying good com

b ustion p ractices and efficient operation as a cogeneration unit. In the end, EPA chose the

same control m easures as five other facilities. Providing a baseline in the BACT anal y s i s does not m ake the ultim ate determ ination arbitrary, capricious, or even unreasonable.

The Center f

urther argues that the effect of burn i n g different biom ass fuel stocks should be considered at Step 1 of the analysis. EPA does not disagree in theory. Bu t EPAH E L P I N G H A ND T O O L S V

. USEPA 29

currently lacks the scientific d ata at this tim e to m ake such a quantitative determ ination and is actively collecting the data
to d o in the future the type of analysis desired by the Center. See Bioenergy BACT Guidance at 23. F urtherm ore, because the sam e am o unt of carbon dioxide will be relea s ed a t the facility no m atter which biom ass f uel stock i s burned, any difference in environm ental con sequences is indirect. Id. at 22. Therefore, c o n s istent w ith the N SR Manual, these indirect environm ental im pacts and benefits are better suited to analysis in Step 4.

Acknowledging the differences in the environm ental i mp a ct o f different b iom ass fuel stocks, however, EPA responded to the Center’s comm ent b y clarifying th e fuel restrictions in the final p erm it. Notably, Sierra Pacific and EPA were particularly proactive in ensurin g the appropriate fuel restrictions were written into the PSD perm it. Sierra Pacific’s initia l ap p lication contem p lated the use of colocalized m ill waste as well as in-forest m aterials from Sierra Pacific’s tim

ber operations and other r e a dily available agricultural and urban wood wastes.

The environm ental impact report (“EIR”) prepared b y a consultant for the Shas t a Co unty Departm ent of Resource Managem ent n oted that there w ere d ifferent estim ates of the type of biom ass fuel blend Sierra Pacific p lanned on using, ranging from 100% m ill wastes to a b lend supplem enting m ill
wastes w ith b iom ass from forest-harvesting operations, forest-thinning op erations, agricultural waste f rom the Sacram ento Valley, and urban wo o d waste. T he consultant
th e refore conducted the EIR assum ing a “worst-case” scenario in which 35% o f the biom ass used was not colocalized with the facility. The supplem ental Statem ent of Basis and Am

b ient Air Quality Impact Report also assum edH E L P I N G H A ND T O O L S V

. USEPA 30

a biom ass fuel m ix of 75% mi l l residue and 25% in-forest residues, agricultural residues, and urban wood residues.

Based o n the EIR, EPA d rafted a PSD perm it restricting fuel to “clean cellulosic b iom ass” allowing Sierra Pacific to burn an extensive list of biom ass fuels at the facility. Sierra Pacific comm ented on the draft asking for more restrictive lim itations on the types of biom ass fuel it would be allowed
t o u s e in its facility because it was m ore consistent with th e original application. EPA adopted Sierra Pacific’s

m odifications in another draft o f the perm it, which was then further m odified in response to the Center’s com m ents.

Though it was n ot pr epared at the tim e to com pare the environm ental im

pacts of sawm ill residue versus other biom ass wast e s , EPA ensured that Sierra Pacific w ould not log tim b er solely for the purpose o f u sing it as bioma s s for the new facility

. EPA lim ited S ierra Pacific to only the particular b iom ass fuels readily available to the facility: m ill residues, untreated wood debris from urban areas such as pallets and crates, agricultural crops and residues, forest residues, and non-m erchantable forest b i o ma s s. The only
trees that can be burned in S ierra Pacific’s facility, therefore,

are those that would b e rem o v e d from the forest anyway as part o f Sierra Pacific’s ongoing forest m anagem ent and forest-thinning operations.

Tho u gh the Center argues that EPA is equipped to proceed with a quantitative analysis of d ifferent biom ass fuel stocks at Step 1, EPA says it cannot d o that based on the
current state of the science. Be c au se the agency is acting at the f rontiers of science, we m

ust defer. See Baltimore Gas & Elec.
, 4 62 U. S. a t 103. The Center does not clearly explain how EPA’s analysis here is not th o r o ugh, rational, andH E L P I N G H A ND T O O L S V

. USEPA 31

consistent with EPA’s prior guidance on BACT. Si erra Pacific i s re stricted to the form s of biom ass waste readily available to i t a nd cannot clear cut forests just to produce electricity for its lum

ber m ills. EPA did c onsider the environm ental im

pacts o f different biom ass fuel stock s , just
not in the m anner or the level of detail the C ent e r would prefer. Because we m

ust defer to EPA’s interpretation o f BACT and it s scientific expertise, EPA’s analysis is not arbitrary, capricious, o r an abuse of discretion, and we deny the Center’s petition.

V

Sierra Pacific’s applic a t ion went through an extensive
process to issue a reasoned PSD perm it for its new biom ass burning boiler. EPA p roperly defined the project and rejected

co ntro l tech

n o lo g ies th at red ef

in ed th e p ro

ject with thoughtful and rea s onable explanations. The Bioenergy BACT Guidance, as applied by EPA to the greenhouse gas em issions from Sierra Pacific’s new facility, is rational and is consistent with EPA’s prior practice. T h e gu idance relies extensively on the continually evolving analysis of the environm ental effect of differen t biom ass fuels in the ever-developing f ield o f clim ate-change science. It is not o ur place to interfere with EPA’s expertise when the record shows that its endeavors were reasonable.

Costs are awarded to Respondents.

The petitions for review are DENIED

.