未来能源研究所-农业生物能源的政策前景（英）

ThePolicyLandscapeforAgriculturalBioenergy

IssueBrief24-03byEmilyJoiner,MichaelToman,andSuzanneRusso—May2024

KeyPoints

•Agricultural(ag)bioenergyhasreceivedfinancialandtechnicalsupportfromtheEnergyTitleof

theFarmBill,firstestablishedin2002.Atpresent,however,theprimarydriversofagbioenergy

areincentivesinfederalenergylegislation(the

RenewableFuelStandardorRFS)andCalifornia

legislationtoreducethegreenhousegasintensityoftransportationfuels(theLowCarbonFuel

StandardorLCFS),alongwithpoliciesadministeredbytheUSEnvironmentalProtectionAgency.

•TheRFScreatesrequirementsforincorporatingvariouscategoriesofrenewablesources,

includingagbiofuels,intoliquidtransportationfuels.Acomplexcreditprogrambasedonsalesofqualifyingrenewablesourcesfacilitatesthe

achievementofthoserequirements.Thethresholdsforqualifying(20,50,or60percentlowerestimatedlifecyclegreenhousegasintensity)arecoarse-

grainedandthuscoarselytargetedforprovidingincentivestoreducegreenhousegasintensity.

•TheLCFSalsousesacreditsystemtoachieve

targetedreductionsinlifecyclegreenhouse

gasintensityovertime.However,theemissions

intensitiesofqualifyingrenewablesourcesare

basedontechnologypathways,withcareful

assessmentsofactualemissionsthatprovide

incentivesforreducingactualemissionsintensity.Nevertheless,themeasurementofreductions

inemissionsintensityisonlyasgoodasthe

baselineusedforcomparison—aconcernthathasbeenexpressedoverthecalculationofnegativeemissionsintensityformanure-derivedbiogas.

•Thereisvigorousdebateabouttheoverall

reductioningreenhousegasesachievedwith

conventionalbioethanolmadefromcorn.Lower-

carbontechnologiesremaincostlytouseatscale.

Adverseenvironmentalimpactsalsocanarise

fromproducingbiofuels,someofwhichraise

environmentaljusticeconcerns.

1.Introduction

Bioenergyisenergyproducedfrombiologicfeedstocks

processedintoliquidfuel,orprocessheatorelectricity

fromcombustion.Variousrefiningorprocessing

techniquesgointoproducingbioenergy.Agricultural

bioenergy(agbioenergy)usesagriculturallyderived

feedstocks,eithercropsgrownexplicitlyfortheiruseasenergyorwasteby-productssuchasmanure.Biofuels

andbiogasarethetwomostcommonagbioenergyfuels.Renewablebiomassenergyfromforestryisanother

bioenergysource(WearandBartuska2020).However,ourfocusinthisissuebriefisonagbioenergyfromfarmsandranches.

CurrentagbioenergypolicyintheUnitedStatesreflectsseveralmotivations.Itcreatesafavorableregulatory

climateforproductionandsaleofadditionalproducts

fromtheagriculturalsector.Domesticbioenergy,

includingagbioenergy,isseenasimprovingthesecurityofUSenergysuppliesbyreducingimports—though

weraisequestionsaboutthatrationaleinSection5.A

thirdveryinfluentialmotivationisthepotentialforag

bioenergytoreducecarbonintensityandtotalemissionsofgreenhousegases(GHGs)intheUnitedStates.

Thisissuebriefprovidesabrieftypologyofbioenergyandthensummarizesanddiscusseskeyelementsinthenonagriculturalpolicylandscapethathaveexpanded

productionofagbioenergy.Italsohighlightssome

importantquestionsneedingfurtherconsideration.

Wefocusonatimeframeofroughlythenext5to10years,takinganagnosticviewhereonbiggerlonger-termissuessuchastheroleforagbioenergyvis-à-viselectricityindecarbonizinggroundtransportation1

2.TypesofBioenergy

Biofuelsincludebothethanolanddieselfuels.

Traditional,orconventional,ethanolreliesona

distillationoffoodstarchestofuel.Ethanolalsocan

bemadefrom

cellulosicfeedstocks

,whichresultsinaconsiderablylowerlifecycleGHGintensityrelativetoconventionalethanol.2Cellulosicfeedstockscan

begrownonlower-qualitylands,whichmayreduce

competitionbetweenfoodandfuelcropsonexistingagriculturallands,aswellasGHGemissionscomparedwiththeeffectsofmoreextensivelandusetoscaleupfoodcropsforethanolproduction.However,cellulosicethanolproductionremainslowbecauseofcontinuingtechnicalhurdles.

Alternativestopetroleum-deriveddieselfuelscanbe

madefromwasteoilsandgreasefromfoodpreparation,variousplant-basedoils,andanimalfats.

Biodiesel

isaproductmadefromthesesourcesthroughthechemicalprocessof

transesterification

.Limitedamountsof

biodieselcanbeblendedintopetroleum-baseddiesel

fuel.

Renewablediesel

ismadeviaprocessesthatyieldaproductfullyinterchangeablewithpetroleum-based

diesel.Bothfueltypesareagbiofuels,thoughraw

vegetableoilsandwasteproductsfromfoodpreparationarequitedifferentfeedstocks.Oilsextractedfrom

nonfoodenergycrops(e.g.,

jatropha

)canbeanothersourceofagbiofuels.

Biogas

isamixtureofmethane,CO2,andother

impuritiesresultingfromdecompositionofbiomassinalow-oxygenenvironment.Thisanaerobicdecompositionisfoundinlandfillsandsewagetreatmentplants,butthemainsourceofagbiogasisdecompositionoflivestockmanure.Ifthemanureiscollectedandplacedinabiogasdigester,theresultingbiogascanbecollectedandused.

Renewablenaturalgas

isbiogasprocessedtoremoveimpuritiesandisfullyinterchangeablewithconventional(fossil)naturalgasinvariousapplications,includingasatransportationfuel(compressednaturalgas).

3.FederalPolicyBackgroundforAgBioenergy

TheEnergyTitleoftheFarmBillwasestablishedin2002toaccelerateproductionofbiofuels,primarilycorn-basedethanol.ItisTitleIXinthecurrentFarmBill,theAgricultureImprovementActof2018(Pub.L.No.115-334).TitleIXsupports,amongothergoals,cultivationofbioenergyfeedstocks,technological

processesforbiofuelrefinement,andresearchandeducation(CRS2022).

TitleIXprogramstargetedatagbiofuelproduction

includeloanguaranteesandCommodityCredit

Corporationpaymentsforadvancedbiofuelproductionandpaymentsforbiomasscultivationandbioenergy

conversion.The2018FarmBillalsoestablishedthe

CarbonUtilizationandBiogasEducationProgramto

supporteducationonbiodieselandonfilteringmultiplesourcesofwasteintoasinglestreamofbiogas.Otherresearcheffortsfocusonstimulatingproductionofnewbiofuelsandotherbiomassderivatives.

CRS(2021b)showsthebiofuelfundingallocationovervariousyearsinwhichanenergytitlewasincludedinFarmBillauthorization.The2018FarmBillcontinuedatrendofprovidinglessmandatoryprogramfunding

1Wealsodonotdelveintothepossibleroleofagbioenergyinenergysourcesforaviationandmarinetransportorethanolderivedfromlow-carbonhydrogensources.

2Lifecycleanalysis(LCA)ofGHGsfrombioenergyincludesemissionsfromlandusechange(suchasforestclearing),agriculturalpractices(N2OandCH4emissions),andsoilcarbonsequestrationbenefitsfrombiofuelcropproduction.Italsoincludesemissionsassociatedwithtransportationoffeedstockstorefineriesforbiofuelproduction,andoperationoftherefiningfacilities(e.g.,

CO2releasedduringfeedstockfermentationtoproduceethanol).ThepropertiesofthemodelsunderlyingLCAresultsandthefundamentalassumptionsthesemodelsmakeareindispute.

ResourcesfortheFuture—ThePolicyLandscapeforAgriculturalBioenergy2

thanin2008.AsexplainedinSection3,themandatoryfundingreductioncoincidedwiththeintroduction

ofenergy-focusedlegislationthatledtosignificant

expansioninUSbiofuelproduction.TitleIXinthe2018FarmBillislargelyacomplementarypolicyfocusedonfundingresearchandeducation.

Onekeyenergy-relatedpolicyforstimulatingag

biofuelproductionistheRenewableFuelStandard

(RFS),establishedintheEnergyPolicyActof2005.

TheRFSsubsequentlywasexpandedintheEnergy

IndependenceandSecurityActof2007.TheRFS

systemisadministeredbytheUSEnvironmental

ProtectionAgency(EPA),whichalsosetsrequirementsforincorporationofethanolintomotorfuelstoimproveengineperformanceandreducetailpipeemissionsbypromotingmorecompletefuelcombustion.

TheRFSrequiresfuelsupplierstoprovideaminimumvolumeoftotalrenewablefuelsandofseveralspecificcategoriesofrenewablefuels.Therequirements

werespecifiedbystatutethrough2022,withrising

obligationsovertime.From2023onward,EPAhasset

thevolumerequirementsbybalancingvariousfactorslistedinthestatute(AFDC2024c;EPA2023;CRS2023).

Thecategoriesareconventionalrenewablefuels

(mostlycorn-basedethanol)andadvancedrenewablefuels,whichincludeassubcategoriesfuelsmadefromcellulosicfeedstocksandbiomass-baseddiesel.3Thespecifiedtypesofbiofuelsqualifyforinclusioninthesecategoriesonlyiftheymeetcertainlifecycleemissionsreductionthresholdscomparedwithconventional

petroleumfuel(gasolineordiesel).Thethresholdforconventionalrenewablefuelsisa20percentreduction,whereasthethresholdsforvariouscategoriesof

advancedrenewablefuelsare50or60percent.

Inpractice,ratherthaneachsupplierhavingtomeet

eachofthoseRenewableVolumeObligations(RVOs)initsownsales,therequirementsaremetthrough

asystemoftradablecredits.Suppliesofrenewable

fuelscoveredbytheRFSareassignedRenewable

IdentificationNumbers(RINs)whentheyaresoldintothefuelsmarket.ThesenumbersallowEPAtotrackthevolumesandcarbonintensities.FuelsuppliersthencanpurchasecertificatesbasedontheRINsasanindirectwayofmeetingtheirvolumetricobligationsbasedontheirownfuelsales.

Revenuesreceivedbyrenewablefuelsuppliersequal

thesumofpaymentsforthefuelsandpaymentsfortheRINcertificates.ThepricesofthecertificatesindicatetheindirectsubsidiesrequiredtodrawtheRFS-requiredvolumesofthecoveredrenewablefuelsintothe

market(AFDC2024c,2024d;CRS2023;Stock2015).4Therequirementsforconventionalethanolstopped

increasingin2015,asthedemandforethanolbecameconstrainedbyEPA’scurrentrequirementof10percentethanolblendingintomotorgasoline.Otheradvancedfuelshavesinceplayedalargerrole.

InadditiontotheRFS,theInflationReductionAct

of2022(IRA)containsnumerousproduction-and

infrastructure-relatedtaxbreaksforbiomass-based“cleanenergy”sources,includingbiogas(AFDC

2024b).5TheIRAexpandsaprevioustaxcredit

(knownas45Q)fortheuseofcarboncapture,

utilization,andstorage(CCUS).Thishasstrong

appealtocornethanolproducersbecausethecostofcapturingCO2fromethanolfermentationislow—animportantconsideration,sinceemissionsfromethanolfermentationareestimatedtobecloseto1percentoftotalUSCO2eemissions(Irwin2024).6

3Somerenewablenaturalgasfromfarm-basedmanurebiodigestersaswellaslandfillsandwastewatertreatmentplantsareincludedinthecellulosiccategory.

4Thisisahighlysimplifiedoverviewofwhatisinpracticeaverycomplexregulatorysystem.

5Amongthosemeasures,theIRAcontinuesexistingtaxincentivesforbiofuelsincludingbiodieselthrough2024,anditsetsupanewcleanfuelproductiontaxcredit(45Z)for2025(Pub.L.No.117-169).

6The45Qcreditisalsoapplicableforbioenergyoperationsthatrelyontheburningofbiomass,whichoftensharefeedstockswithadvancedbiofuels.

ResourcesfortheFuture—ThePolicyLandscapeforAgriculturalBioenergy3

4.TheCaliforniaLowCarbon

FuelStandard

Anotherimportantdriverofincreaseduseofag

biofuelsandotherrenewablefuelsintransportation

isCalifornia’sLowCarbonFuelStandard(LCFS),

whichbeganimplementationin2011asaresultofthe

GlobalWarmingSolutionsActof2006(Pub.L.No.

109-58,Pub.L.No.110-140,CAAB-32)andhasbeen

amendedseveraltimes,withanotherrevisionpending

for2024(CARB2024).7TheLCFSsetsanaverage

standardforthelifecyclecarbonintensityofallcoveredtransportationfuels,relativetoconventionalgasoline

anddiesel.BiofuelswithGHGemissionslowerthanthecompliancetargetforaparticularyeargeneratetradablecreditsthatcanbeusedbyotherfuelsourceswhose

carbonintensityexceedsthestandard(Yehetal.2021).Ethanol,biomass-deriveddiesel(biodiesel),andbiogashavebeenthethreegreatestgeneratorsofLCFScreditssince2011(Smith2024a).8TheLCFS,liketheRFS,hasincreasingcompliancetargetsfordecreasingtheGHGemissionsfromtransportationfuels.

Theuseoftradablecreditswithaperformancestandard(averageGHGintensity)intheLCFSillustratesan

interestingaspectofthisregulatoryapproach(Yehetal.2021).Thetradablecreditscreateacompetitiveincentiveamonglow-carbonfuelsupplierstoreducetheircarbonintensity,sincedoingsoincreasesthenumberofcreditstheirproductscanobtain.The

competitionisbasedondetailedscrutinybythe

regulatorofactuallifecycleemissionsforavariety

oftechnologypathwaysusedtosupplythefuelsto

avoidundercountingemissionsfromsomesources

whilefailingtofullyrecognizethelowlifecyclecarbonintensityofotherpathways.Forexample,ethanol

fermentingandrefiningcouldbemodifiedtoreduce

CO2.Oncethesystemwasfullyimplemented,with

creditsbenchmarkedtotheindependentassessmentsoflifecycleemissions,therewasasignificantreductioninlifecyclecarbonintensityforfuelsseekinga

competitiveadvantage.Theincentivefortechnologicalimprovementcontinuestorewardlow-carbonfuel

suppliersthatcanfindinnovativewaystolowertheircarbonintensity.9

TheLCFSincludesbiogas10Thelifecycleanalysis

methodologyspecifiedbytheCaliforniaAirResourcesBoard(CARB)calculatesthecarbonintensityofutilizedbiogasbasedonthecounterfactualofnocaptureofthemethaneemissionsfromdecompositionoftheanimalwastesusedtoproducethebiogas.Thisimpliesa

substantialnegativecarbonintensityforbiogas,whichmakesitvaluableintheLCFSforoffsettingtheimpactsofcarbon-intensivefueloptions11Thisisrelevant

becausecommerciallycollectedandtransported

biogasforuseasatransportationenergysourceis

costly.Althoughcattle-derivedbiogasaccountsfor

asignificantpercentageoftotalLCFScredits,its

contributiontothetransportationenergymixisminimal(Smith2024a,2024b).

7WhileotherLCFSprogramsexistinOregonandWashington,

California’sLCFS

hassetthepaceintermsofsizeandpolicyinnovation.

8TheLCFSoperatesontopoftheRFS,soenergysourcesthatearnrevenuefromLCFScreditsalsocanbenefitfromRINs.ThiscomplicatesassessmentoftheLCFS’simpacts.Generally,however,theresultisfurtherincreasesinincentivesforadvanced

biofuelproductionoverconventionalethanolbecausetheformeriscreditedwithloweremissionsundertheCaliforniastandardandtheRFS.

9Anappealingpoliticaleconomyaspectoftheperformancestandardisthatitcanreduceemissionsintensitythroughsupply-sideincentiveswithouttheincreasesinproductpricesthatwouldresultfromregulationsortaxmeasuresthatpenalizemorecarbon-intensivesources.Theflipsideisthattoreduceactualemissions,notjustemissionsintensity,policiestoshiftdemandstowardlower-carbonalternativesareessential.

10UnliketheLCFScreditsandRINsforbiofuels,whichareclaimedbyrefineries,biogascreditsareawardedtoagriculturalproducers,whoseanaerobicdigestersplaytheroleofmini-refineries.InadditiontoLCFScreditsandRINs,theCaliforniaDepartmentofFoodandAgricultureoffersgeneroussubsidiesforbiogasdigestersandothercapitalcosts(Smith2024a).

11Incontrast,methanecapturedfromlandfillsreceivesnocreditforavoidedemissions.

ResourcesfortheFuture—ThePolicyLandscapeforAgriculturalBioenergy4

OtherCaliforniapoliciesalsohaveimpactsonbiofuel

demandinthestate12California’smorestringent

vehicleemissionsstandardssupportadvancedbiofuelproduction(includingbiodiesel)throughtheClean

TransportationProgram(CARB2023;AFDC2024a).

California’sShort-LivedClimatePollutantReduction

Strategyseta2030statereductiongoalformethane

(whichhasashorterresidencetimefortrappingheat

intheatmosphere,hencethestrategy’sreferenceto

“short-lived”)andhasspurredreductionsthrough

theconversionofmanuremanagementsystemsto

anaerobicdigesters(CASB1383).TheCalifornia

DepartmentofFoodandAgriculturehasprovided

financialassistanceforthecapitalcostsofdigesters

(CARB2022).TheCaliforniaEnergyCommission’sCleanTransportationProgramhassupportedadvancesin

biomethaneandsubstitutesforgasolineanddiesel.

5.ImpactsoftheRFSand

CaliforniaLCFS

TheimpactoftheRFSontheproductionofcropethanolintheUnitedStateshasbeenprofound.From2008

to2016,therewasan8.7percentincreaseinUScorn

cultivationanda2.4percentincreaseinUScropland

production,accompanyinga60percentincreasein

gallonsofethanolproducedoverthesameperiod(Larketal.2022,5;EIA2024,193).However,theimpactonUSGHGemissionsandonotherenvironmentalconditionshasbeenandcontinuestobevigorouslydebated.ThefindingsbyLarketal.(2022)indicatethattheRFSmayhaveincreasedoverallGHGemissionsthrough2016

(whenconventionalethanolproductionleveledoff),

afteraccountingforlandconversiontoexpandcorn

output,increasedfertilizeruse,andincreasedintensityofsoilutilization.Inaddition,attimeswhenethanol

blendinghasdecreasedfuelprices(becausethepriceofgasolineisabovetheenergy-equivalentpriceof

ethanol),thelowerfuelpricewouldhavesomeupwardimpactonvehicledistancesmilestraveled(Huangetal.2013,7).

ThusthegreaterfocusintheRFSonadvancedbiofuelssince2015likelyisaplusforGHGmitigation.Thatviewisnotsharedbythosewhoemphasizethebenefitstotheagriculturalsectorandthecountryfromcrop-basedethanolundertheRFS13

WhiletheRFShassucceededincreatingincentivesforblendingagrowingquantityofagbiofuelsandother

renewablefuelsintoUSgasolineanddieselsupplies,

thedesignoftheprogramleadstoseveralinefficiencies.ChiefamongthemisthathavingRVOsforeachof

severalcoveredcategoriesofrenewablefuels,aswellasdifferencesintheenergycontentandlifecyclecarbonintensityofthefuels,leadstoawiderangeofRINpricesacrossrenewableenergytypes.Thereisnoreasonto

expectthatthesedifferentpricesinducecost-effectivereductionofGHGemissions,suchthatfuelblendswithlowerlifecycleCO2eemissionsarepricedbelowblendshavinghigherlifecycleemissions,forthesameamountofenergy.Thisisnotsurprisinginonesense,sincetheRFSwasnotdesignedtobeaGHGmitigationpolicy

perse;rather,itwasmeanttoprovideanincentive

forutilizationofvariousrenewablefuelsourcesfor

severalreasons.Nonetheless,otheralternativescan

inducegreatercost-effectivenessinGHGmitigation,asdiscussedinSection6.

AnothersourceofinefficiencyintheRFSisthecoarsenatureofthebinsforqualifyingfuels(20percent

lifecyclereductionversus50or60percentlifecycle

reduction).Focusinginsteadontheamountoflifecycleemissionsreductionperenergyunit(beit20percent,

somethinginbetweenlike35percent,orover60

percent),aswellasthecostofachievingthereductioninemissions,bettercorrelatesincentiveswithresults.An

12In2022,Californiapassedaregulationrequiringallnewvehiclesalestobeofzeroemissionsvehiclesby2035(CARB2023).Used

vehiclessalesandexistinginternalcombustionenginesarenotaffectedandthereforewillstillconsumetransportationfuels.

13WenotedinSection1thatamajorrationaleforsettinguptheRFSwasaperceptionthatfuelsourcesthatareproducedinthe

UnitedStatesratherthanimportedaremoresecure.Inpractice,however,themainconcernaroundenergysecurityhasbeenthevulnerabilityoftheUSeconomytopetroleummarketdisruptionsleadingtopriceshocks,sincetargetedembargoesofspecificcountriesareimpossiblegiventheintegratednatureoftheworldoilmarket.Whenthesehighlyintegratedmarketsexperienceadisruption(alossofsupply,asuddenweather-relatedincreaseindemand,orincreasedconcernaboutfuturedisruption),thepricesofallproductsrise,whethertheyareproduceddomesticallyorimported.Therelativelysmallamountofethanolusedforblendingimpliesthatitprovideslimitedprotectionfrompriceshocks(BohiandToman1995).

ResourcesfortheFuture—ThePolicyLandscapeforAgriculturalBioenergy5

additionalconcernisthatestimatesoflifecycleemissionsreductionsdonotadequatelyreflectdifferencesin

carbonintensityamongproductionprocesses.

ThereturnfromsalesofRINcertificatesoffersincentives

fortwotypesoftechnicalinnovationinthesupply

ofrenewablefuels:processinnovationandproduct

innovation.Processinnovationreduceslifecycle

emissionscomparedwiththosefromgasolineordieselusebycuttingemissionsfromproductionofthefuels.Productinnovationreducesthecostofsupplying

advancedrenewablefuelswithlowerlifecycleemissionsthanconventionalrenewablefuels.Theeffectofthe

RFSontheformertypeofinnovationislimitedbythecoarsenessofthebinsforqualifyingfuelsandthe

regulatoryspecificationoftheRVOstobeachieved.

TheRFSprobablyhashadsomepositiveeffect

onproductinnovation.However,cellulosicethanol

production—seenattheoutsetoftheRFSasthemostpromisingcategoryforfuturegrowthinbiofuels—

remainslowbecauseofcontinuingtechnicalhurdles.

Consequently,EPAhashadtoroutinelyexerciseits

authoritytowaivecellulosicfuelrequirementsundertheRFS.AmajorquestioniswhentechnologywilladvancesufficientlytomaketheachievementoftheclearGHGreduction(andotherenvironmental)benefitsfrom

cellulosicethanolproductioncommerciallypractical.

ThedesignandimplementationoftheCALCFSavoidedmanyoftheconcernswiththeRFS.Inparticular,the

specificationoftechnologypathwaysintheLCFShas

inducedconsiderableprocessinnovation(Yehetal.

2021).AnimportantpolicyquestioniswhatwouldcomefromimplementinganationalversionoftheLCFSto

replacetheRFS(CRS2021a;Huangetal.2013).Asnoted,however,biogasreceivesquitefavorabletreatmentin

theCALCFS,andtherearesignsthatthiswillcontinue(Smith2024b).Accordingly,alookatthecalculation

ofemissionsintensityfordifferentoptionsintheLCFSwouldbeusefultoensureitsenvironmentalintegrityandcost-effectiveness.Ultimately,policieswillbeneeded

tocurbdemandfortotaltransportationenergy(thus

supportingincreasedenergyefficiencyanddemandmanagement)andforhigher-GHG-intensityoptions.

6.OtherIssues

Soilcarbonsequestrationandcarbonstorageinplant

rootsaresignificantconsiderationsinminimizing

lifecycleGHGsofbiofuels,andtheyareamajorfactor

inclaimsthatsomebiofuelscanachievenetcarbon

negativitywithouttheintroductionofcarboncapture

andstoragetechnology(Kimetal.2023;Yangand

Tillman2020;Fieldetal.2020).JoinerandToman(2023)notethehighlevelofuncertaintyaboutthesefactors.

Agriculturalbioenergyfeedstocksdifferintheiryieldsandcapabilitiestoincreasesoilcarbonstorage,and

additionalagronomicresearchisneededtoexaminethetrade-offsamongtheseandotherfactors(Ellessetal.2023,58).

Therehasbeenalong-standingdebateoverhowmuchcornfarmersversusethanolprocessorsgainfromthe

existenceofpoliciessubsidizingconventionalethanol

productionandblendingintogasoline.Higherpricesofcornandothercommodityinputsincreasethevariablecostsofproductionforethanolrefinersbutprovide

economicgainstofarmers.AnalysisoftheRFShas

foundsignificantagriculturalsectorbenefitsfromthe

RFSattributabletoincreasesincornandsoybeanprices(Moschinietal.2017,1118).

Agriculturalbiofuelscanhave

adverseimpactson

theenvironment

.Atthefeedstock-growingstage,theadverseimpactscaninvolvereducedwaterqualityfromfertilizeruseandecosystemservicedamagesfromlandclearing.Inaddition,biorefineriescanproducelocalairpollutants.Becauseconventionalethanolproduction

hasledtoanincreaseincornoutputandtotalland

areadevotedtocorncultivation,theseconcernsaregreaterthaniffoodmarketshadbeentheonlydriverofcornsupply.Drinkingwatercontaminationandlocalairpollutionfrombiorefineriesraisequestionsabout

environmentaljustice

14

14Similarconcernsareraisedaboutlargeanimalfeedlotoperations(foraperspectiveonthis,seeGittelsonetal.2022).These

operationsmaypresentattractiveopportunitiesformanure-derivedbiogasproduction,thoughthisisacostlyenergysourcewhoseeconomicsuccessdependsonespeciallybeneficialpolicies.Theenvironmentalimpactsandnuisancesideeffectsalsoneedtobeconsidered,especiallyastheyaffectnearbydisadvantagedcommunities.

ResourcesfortheFuture—ThePolicyLandscapeforAgriculturalBioenergy6

Researchanddataondistributionalimpactsofbiofuel

productionandTitleIXfundingareinsufficient,makingitdifficulttoassessequitychallengesinaccessto

biofuelsproductionandrelevantTitleIXandotherpolicyresources(Ganetal.2019).Partofthedifficultyliesinaknowledgegapregardingpossibilitiesforengagingsmallandotherunderservedproducersinopportunitiesto

increaserevenueanddecreaseon-farmGHGreductionsthroughbiofuelfeedstockproductionanduseofbiofuels(JohnsonandButler2015;AdjoyiandKebede2017).Wecanobservegenerallythatcornandsoy,thepredominantfeeds