Integrating life cycle assessment and forest modelling for environmental and economic assessment of forest based bioenergy in Norway

(1)

Philosophiae Doctor (PhD) Thesis 2015:11

Ellen Soldal

Integrating life cycle assessment and forest

modelling for environmental and economic assessment of forest based bioenergy

in Norway

Integrering av livsløpsanalyse og

skogmodellering for analyse av miljømessige og økonomiske konsekvenser av bruk av

skogbasert bioenergi i Norge

Norwegian University of Life Sciences

Faculty of Environmental Science and Technology Department of Ecology

and Natural Resource Management

(2)

(3)

Integrating life cycle assessment and forest modelling for environmental and economic assessment of forest

based bioenergy in Norway

Integrering av livsløpsanalyse og skogmodellering for analyse av miljømessige og økonomiske konsekvenser av bruk av skogbasert bioenergi i Norge

Philosophiae Doctor (PhD) Thesis Ellen Soldal

Department of Ecology and Natural Resource Management Faculty of Environmental Science and Technology

Norwegian University of Life Sciences Ås 2015

Thesis number 2015:11 ISSN 1894-6402 ISBN 978-82-575-1268-2

(4)

ii

PhD Supervisors Prof. Dr. Birger Solberg

Department of Ecology and Natural Resource Management (INA) Norwegian University of Life Sciences (NMBU)

Prof. Dr. Ole Jørgen Hanssen

Department of Ecology and Natural Resource Management (INA) Norwegian University of Life Sciences (NMBU)

and

Ostfold Research

PhD Evaluation Committee Prof. Dr. Margareta Linnéa Wihersaari Energy Technology, Åbo Akademi University P.O. Box 311, FIN-65101 Vasa, Finland

Prof. Dr. Bart Muys

Department of Earth and Environmental Sciences, University of Leuven (KU Leuven) Celestijnanlaan 200E, BE-4001 Leuven, Belgium

Prof. Dr. Hans Fredrik Hoen

Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences

P.O. Box 5003, N-1432 Ås, Norway

(5)

iii

Preface

ThisthesisisapartialfulfillmentoftherequirementsforthePhDdegreeattheDepartment ofEcologyandNaturalResourceManagement(INA)attheNorwegianUniversityofLife Sciences(NMBU).Togetherwithaprogramof formal courses and adissertation, it completestherequirementsforthedegreeofPhilosophiaeDoctor.Theprojectwasfunded bytheNorwegianResearchCouncilthroughthestrategicuniversityprogram:“Thefuture roleofbiomassenergyinNorway–aninterdisciplinarytechnological,economicand environmentalresearchprogram".

TheadvisorygrouphasconsistedofmainsupervisorProf.BirgerSolberg(INA)andProf.Ole JørgenHanssen(OstfoldResearchandINA).Iwanttothankthesupervisorsforalltheuseful academicguidance.Youhaveprovidedmeinsights,knowledgeandinspirationthatIhighly appreciate!

DuringmyPhD,IvisitedNTNUforcourses.IwouldliketothanProf.AndersStrømmanand colleaguesforincludingmeintheirinspiringworkenvironment.

IwanttoextendspecialthankstomycolleaguesEvenBergseng,PerKristianRørstadand ClaraValenteforgreatcooperation,advicesanddiscussions!Icouldnothavedonethis withoutyoursupport.ThankyoutoPerKristianandBeritLindstadforproofreading!

IwanttothankmycolleaguesatINAformakingmytimethereenjoyable,throughalleight years.ThankyoutomynewcolleaguesatØstfoldforskningforsupportandcooperation duringthefinalphaseofmyPhD.ThankyoutoØstfoldforskningforprovidingmefunding duringthelastperiod!

DuringmystayatNTNUmyparentshousedmeandmyfamily.Thankyouforthat,andfor alwaysbeingsupportive!Ialsoextendgratitudetomysiblings,Marte,MagnusandVegard, foryourencouragementthroughoutthiswork.

AspecialappreciationtoTerjeforlettingmeembarkuponthisworkand,notleast,for followingmethewholeway.Thankyouforallyoureffortsandpeptalks!

DearSara,Johanandallmyniecesandnephews!Thisworkisdedicatedtoyouwiththe hopethatitcanbeacontribution(howeversmall)tomaketheworldabetterplaceforyour generationandthosethatfollow.

EllenSoldal Moss,May2015

(6)

iv

(7)

v

Summary

Thereisagrowinginterestinbioenergy,bothnationallyandinternationally,duetothe increasingemissionsofgreenhousegases.TheNorwegianforestgrowingstockisincreasing andcanbeusedtoproducearangeofproductswhichcanreplacefossilresources.Carbon dioxide(CO2)isthemostimportantoftheanthropogenicgreenhousegasesandtheforest playsanimportantroleinthecarboncycle;potentiallyactingasbothsourceandsinkofCO2. Reflectionofincomingsolarradiation(albedo)is,togetherwithcarbonsequestration,one ofthemostimportantclimatemitigationfactorinborealforestthatcanbeinfluencedby forestmanagement.

Thisstudyexploresenvironmentalandeconomicconsequencesofbioenergyandother woodͲbasedproductsfromNorwegianforestresources.Lifecycleassessment(LCA)was appliedinordertomaptheenvironmentalimpactsofwooduse.TraditionalLCAlackstime andspaceconsiderations,andtheseareimportant,inparticularwhenassessingpotential environmentaleffectsofharvestanduseofborealforest.LCAwascombinedwithabioͲ economic forest management model (GAYAͲJ/LP) in an attempt to overcome these shortcomingsandobtainalinktoeconomicaspectsofforestmanagedforclimatechange mitigation.

Theresultsshowsthatuseofforestresourcescanprovideenvironmentalbenefitswhen replacingfossiland/orcarbonintensiveproducts.Theforestproductsprovidereduced emissionsofgreenhousegasescomparedwithotherproductsfillingthesamefunctions, dependingontheclimateneutralityassumptionofbiomassandhowitisused.Withregard tootherimpactcategories,likeozonedepletionpotential,acidificationpotentialand eutrophicationpotential,theresultsaremixed.Importantfactorsinanalysisofclimate change mitigation contribution identified are the climate neutrality assumption of bioenergy,theclimateeffectofchangingalbedo,substitutionandsequestrationand emissionsofbiogenicCO2.InaforestcaseͲstudyofatax/subsidysystemwheretheforest ownerwascreditedforpositiveclimatemitigationcontribution,itwasfoundthatthe harvest profile over time was influenced by albedo, substitution and carbon price assumptions,aswellasthechoiceofdiscountingtheclimatecontribution.

(10)

viii

Conservation of biological diversity was included through restrictions on the forest managementandharvestintheforestmodel.Ifthecarbonfluxintheforestwasassumed tobeneutral,anegativerelationshipbetweenforestclimatemitigationandconservationof biologicaldiversitywasidentified,asthewoodͲproductsprovidepotentialsavingsofGHG emissionscomparedtoalternativeproducts.However,whentheclimatemechanisms relatedtotheforestwereincluded,therelationshipbetweenbiodiversityandclimate change mitigation was both positive and negative, depending on assumptions on substitutionandalbedo.

ProposalsforimportantfutureresearcharepresentedinChapter6.

ThecombinationoftheforestbioͲeconomicmodelandLCAwasfoundtobeavaluabletool forassessmentofenvironmentalimpactsofharvestingborealforest.Themainbenefitsof thismethodareinclusionofeconomicaspectsandthepossibilitiesforlocaladaptionofthe forestmanagement.WhentheforestmodelandLCAarecombineditcanprovidepolicy makerswithsitespecificdatathatcancontributetoaclimatepolicythatisfoundedon importantlocalfactorsthatinfluencethemitigationpotentialoftheforest.

(11)

ix

Sammendrag

Interessenforbioenergierøkende,bådeiNorgeoginternasjonalt.Hovedgrunnenfor interessenerdeøkendeutslippeneavklimagasserogfryktenforklimaendringer.INorge økerståendebiomasse,ogskogbiomassenkanbrukestilåprodusereenrekkeprodukter somkanerstattefossileråstoff.

Karbondioksid(CO2)erdenviktigstemenneskeskapteklimagassenogskogenspillerenviktig rolleikarbonetskretsløp.SkogenkanværeenkildetilCO2ogdenkanabsorbereCO2 gjennomfotosyntesen.Refleksjonavsolinnstråling(albedo)er,vedsidenavCO2,enavde viktigste klimadriverne knyttet til boreal skog som kan påvirkes av skogbehandling.

Forvaltning av skogen påvirker økosystemtjenestene som skogen tilbyr. I tillegg til tømmerproduksjon,karbonopptakog–lagring,erdetmangeøkosystemtjenesterknyttettil borealskog,somforeksempelbiologiskmangfoldogrekreasjon,sommåtashensyntilved vurderingeravmiljøkonsekvenseravbrukavskogbiomasse.

Idenneavhandlingenanalyseresmiljømessigeogøkonomiskekonsekvenseravbioenergiog andreprodukterbasertpånorsktrevirke.Livsløpsanalyser(LCA)erbenyttetforåvurdere demiljømessigeeffekteneavbrukavtrevirke.TradisjonellLCAinkludereikkeforholdknyttet tiltidogsted,mendisseerviktige,spesieltnårmiljøkonsekvenseneavhøstingogbrukav trevirkeskalvurderes.Foråinkludereaspekteneknyttettiltidogstedsamtøkonomiske virkninger,bleLCAkombinertmedenbioͲøkonomiskskogmodell.

Alletreproduktenesomeranalysertidettearbeidetharlavereutslippavdrivhusgasserenn sammenlignbareproduktersomfyllersammefunksjon,avhengigavommanregnerbrukav biomassesomklimanøytralt.Forandremiljøkategorier–somforeksempelforsuring, ozonnedbrytingogeutrofiering,erresultateneblandetogmindreentydige.Vedanalyserav klimafotavtrykktilbioenergi,erfølgendefaktorerfunnetåværeviktige:forutsetningom klimanøytralitet,klimaeffektenavendretalbedo,substitusjon,ogopptakogutslippav biogentCO2.IetskatteͲ/avgiftssystemhvorskogeierenblebelønnetforpositivebidragtilå redusereklimaendringene,bleavvirkningentydeligpåvirketavantagelseromalbedo, substitusjonogdiskonteringsrente.

Bevaringavbiologiskmangfoldblehensyntattgjennomrestriksjonerpåskogbehandlingen, inkludertavvirkning,iskogmodellen.Dersombiomassebleantattåværeklimanøytral,ble

(12)

x

detnødvendigåforetaenavveiningmellomulikemiljøhensyn,medbiologiskmangfoldog rekreasjonpådenenesidenogutslippsrelatertemiljøgevinsterpådenandresiden.Menda klimadriverneiskogenbleinkludert,fantvibådepositivtognegativtforholdmellom bevaringavbiologiskmangfoldogklimabidrag,avhengigavantagelseromalbedoog substitusjonavfossilprodukter.

Framtidigesentraleforskningsoppgavereridentifisertikapittel6.

Kombinasjonen av skogmodellen og livsløpsanalyser kan være et nyttig verktøy ved vurderingeravmiljøkonsekvenseneavavvirkningogbrukavnorsktrevirke.Hovedfordelene vedåkombinerebioͲøkonomiskmodelleringoglivsløpsanalysereratøkonomiskeaspekter blirinkludertianalysenogatanalysenekantilpasseslokalskogforvaltning.Dennemetoden kangipolitikereoglokaleforvalterestedspesifikkdatamedinformasjonomlokalefaktorer somerviktigeforklimatiltakikommunerogregioner.

(13)

xi

Listofpapers

ThisPhDthesisisbasedonthefollowingpapersreferredtobytheirromannumerals(IͲIV):

PaperI

Soldal,E.andSolbergB.2014.Environmentalimpactsandcostsofusingwoodfromboreal forestforclimatechangemitigation:areviewofrecentstudiesinScandinavia.Submitted February2015.

PaperII

SoldalE.2014.LifecycleassessmentofbioethanolusedforheavyͲdutytransportinNorway.

SubmittedSeptember2014,resubmittedafterrevisionMarch2015andMay2015(Journal ofCleanerProduction).

PaperIII

Soldal,E.,Valente,C.,Bergseng,E.,Modahl,I.andHanssen,O.J.2014.Combiningforest modelingandLCA:acasestudyofbiodiversityandlifecycleemissionsforforestproducts.

SubmittedSeptember2014.

PaperIV

Soldal,E.,Bergseng,E.,Rørstad,P.K.andSolberg,B.2015.Includingforestcarbon,albedo andproductsubstitutioninharvestdecisions–acasestudyforaforestmanagementunitin Norway.SubmittedMay2015.

(14)

(15)

1

1 Introduction

Humanshavealwaysdependedontheforest.Theforestprovidedtheearlyhuman settlementswithheat,food,fodderandmaterialsforhousing,toolsandweapons.Asthe humanpopulationhasgrownandourtechnologyhasdeveloped,theabilitytoexploitand influencetheforestsandotherecosystemshavestronglyincreased.AccordingtoRockstrom etal.(2009)humanactivitiesarenowthemaindriverofglobalenvironmentalchanges, climatechangebeingoneofthemostimportantenvironmentalchallengesoftoday.

ThereareseveralobservationsthatindicatethattheEarth’sclimateischanging:increased averagesurfacetemperature,increasedsealevelanddecreasingsnowandicecover (Cubaschetal.,2013).TheInternationalPanelonClimateChange(IPCC)wasestablishedin 1988inordertoprovideknowledgeabout“humanͲinducedclimatechange,itspotential impacts and options for adaption and mitigation” (UNEP & WMO, 2013). The first assessmentreportwaspublishedin1990anditplacedglobalclimatechangeontheagenda.

Sincethentheevidenceofachangingclimatehasbecomestrengthenedandinthefifth assessmentreport,theIPCCstatesthat“Itisextremelylikelythathumaninfluencehasbeen thedominantcauseoftheobservedwarmingsincethemidͲ20^thcentury”(IPCC,2013,p.

17).Thereishighconfidencethattheobservedclimatechangesaffectbothphysicaland biologicalsystems(IPCC,2013).ThehumaninfluencewhichtheIPCCpointstoasthe dominantcauseofclimatechange,isemissionsofgreenhousegases(GHG).Despitethe understandingoftherelationshipbetweenemissionsofGHGandclimatechange,and internationalagreementsonreductionofthese,theglobalemissionsofGHGareincreasing (Hartmannetal.,2013).

GHGcaptureradiativeheatthatisreflectedfromtheEarth’ssurface(Forsteretal.,2007,Le Treutetal.,2007).LifeonEarthdependsonthenaturalgreenhouseeffect,buttheincreased emissions of GHG after the industrial revolution have createdanimbalance in the concentrationofGHGintheatmospherecausingincreasedheatabsorption(Hartmannet al.,2013).

NotonlyaretheemissionsofGHGincreasing,thegrowthrateofemissionsisalsoincreasing.

TheUnitedNations(UN)hasdefineda2°Ctarget,whichaimsatkeepingtheglobalaverage temperatureincreasebelow2°C.AsubstantialcutinglobalGHGemissionsiscalledforin

(16)

2

ordertoincreasethelikelihoodofreachingthistarget.Intermsofradiativeforcingand anthropogenicemissions,carbondioxide(CO2)isthemostimportantGHG.In2011the atmosphericconcentrationofCO2was390.5ppm(Hartmannetal.,2013).

TheenergysectoristhelargestcontributortoGHGemissions(Andersonetal.,2008).The increasedconcentrationofCO2intheatmospherecanbedirectlylinkedtocombustionof fossilfuelthroughanalysesofisotopes,andburningoffossilfuelisfoundtobethemost importantcontributortohumaninducedclimatechange(Forsteretal.,2007,LeTreutetal., 2007,Blancoetal.,2014).Thus,aconsiderablechangeintheenergysectorisnecessary (Brandãoetal.,2013).ThekeydriversofglobalCO2emissionsare(Andersonetal.,2008):

x Carbonintensity(carbonreleasedperunitofenergyused):_{ா௡௘௥௚௬}^஼ை^మ

x Energyintensity(amountofenergyusedintheproductionofgoodsandservices):

ா௡௘௥௚௬

ீ஽௉

x Activitylevelpercapita::_{஼௔௣௜௧௔}^ீ஽௉

Reducingtheactivityleveliscontroversialasgovernmentswanteconomicgrowthand reducingpopulationgrowthisasensitivesubject.Reductionsofemissionscanthenbe obtainedbyincreasedenergyefficiencyand/orbyincreasingtheshareofrenewableenergy (Andersonetal.,2008,Brandãoetal.,2013,Cubaschetal.,2013).

Bioenergyisgloballythemostusedrenewableenergy,andIPCChaspointedtobioenergyas animportantpartofthemitigationstrategy.Thereispoliticalinterestinbioenergyglobally.

Norwayandmanyothercountrieshavepronouncedgoalsofincreasingtheshareof bioenergy,togetherwithotherrenewableenergysources(TheEuropeanParliament,2009, NorwegianMinistryofForeingAffairs,2011,NorwegianMinistryofEnvironment,2012, EuropeanCommission,2014).IPCChasdevelopedseveralscenariostodescribepotential waystodecreasethedependencyonfossilfuel.Bioenergyplaysanimportantroleinall thesescenarios,andtheypredictthatthebioenergyusewillshiftfromthetraditionalusein smallstovestomodernusefortransportation,heat,andcombinedheatandpower(Smith etal.,2014).

AtthesameastheNorwegiangovernmenthasastatedgoalofincreasingtheshareof bioenergy,NorwayisobligatedtoreducetheemissionsofGHGthroughtheKyotoprotocol.

(17)

3

Norwayhaslimitedsupplyofagriculturalwasteforbioenergyuseandthemainsourcefor bioenergyinNorwayiswoodfromforest.Becauseoflimitedpossibilitiesofincreasing bioenergyproductionfromforestindustryresiduesandwastewood,anincreasedbioenergy usewillmostlikelyhavetobebasedonprimaryforestproduction(Bergsengetal.,2013).

TheannualharvestofforestinNorwayhasforalongtimebeenabout10millm³,whichis lessthanhalfoftheannualincrement(Trømborgetal.,2011),sointhatperspectiveforest biomasshasthepotentialtocontributetoincreaseduseofbioenergy.

Thissynthesisaimsatsummarizingthebackgroundfortheresearchquestionsaskedandthe obtainedresultsinthefourresearchpapers.Thefourresearchpapersconstitutesthemain partsofthethesis.Thesynthesisisstructuredasfollows:InChapter2theobjectivesofthe studyandthemainresearchquestionsarepresented,followedinChapter3byareviewof backgroundliteratureandstateͲofͲtheartinrelevantfields.InChapter4,theoreticalbasis, methodsanddatafortheworkaredescribed.ThemainresultsarepresentedinChapter5.

Finally,inChapter6overalldiscussion,conclusionsandfutureresearchtasksarepresented.

ThefourpapersareincludedasAppendicesIͲIV.

2 Objectivesandresearchquestions

Theoverallobjectiveofthisthesisistoinvestigateenvironmentalandeconomicimpactsof usingNorwegianforestresourcesforbioenergy.ThisisdonebycombiningabioͲeconomic forestmodelwithlifecycleassessment(LCA).Themainemphasishasbeenonintegrating thesetwoapproachesinordertodevelopatool forbalancingandevaluatingdifferent forestmanagementobjectives,withparticularreferencetoeconomicresults,biodiversity andclimatechangecontributions.Incorporatingimpactsoffutureclimatechangeand changingatmosphericconcentrationsofCO2wasoutsidethescopeofthisthesis.

The thesis focuses on boreal forest and forest products, and the literature review emphasizesScandinavialiteraturebecauseofsimilaritiesintreespecies,growthconditions, silvicultural and forest management. Harvested forest biomass is of varying quality, dimensionsandspecies,andseveralwoodͲbasedproductscompeteoverthesameresources.In theEuropeanbiomassmarket,bioenergyisstillacoͲproductorbyͲproductwithlow economicvalueanddoesnotactasadriverforharvest(EuropeanCommission,2014).

(18)

4

Consequently, analyses of the potential development of bioenergy based on forest resourcesmustbeseeninconnectionwithotherpotentialusagesofthewoodbiomass.

Climatechangeandlossofbiologicaldiversityareamongthemostimportantenvironmental challengesrelatedtoforestry,andbothareconsideredintheanalysis.Theenvironmental impactsofemissionsfromtheforestryvaluechainsareinvestigatedbylifecycleassessment.

BecauseLCAnormallydoesnotincludeeconomicimpactsnortheimpactsofharveston biologicaldiversity,thesetwofactorsareincludedbycombiningLCAwithabioͲeconomic forestmanagementmodel.

Thethesisisbasedonfourpapers.Inthefirstpaper,wehaveidentifiedknowledgegapsin theexistingscientificliteratureonenvironmentalimpacts,costsofprovidingwoodproducts andabatementcosts.Astheworkprogressed,themainresearchquestionswhichwere exploredintheremainingpapersemergedtobecomeasfollows:

x WhataretheenvironmentaleffectsofbiomassusedforavarietyofwoodͲbased productsinNorway,andwhatarethetradeͲoffsbetweenecosystemservicesand otherenvironmentalbenefitsprovidedbythewoodproducts?

x WhatistheeffectofincludingbiogenicCO2andalbedoontheestimatedclimate changemitigationpotentialofbioenergybasedonNorwegianforestresources?

x Howcanforestmanagementandbiomassusebeoptimizedforclimatechange mitigation?

x Whatarepotentialeffectsofbiodiversityconservationontheclimatechange mitigationcontributionfromforestry?

x Whatare thecoststradeͲoffsbetween biodiversity conservationand climate mitigation?

3 Background

Carboncycleandforests

CarbonisthefundamentforalllivingorganismsonEarth(Lawrence,2000)andCO2isthe mainatmosphericphaseofcarbon(Ciaisetal.,2013).In2010,60%oftheanthropogenic GHGemissionswereCO2(Cubaschetal.,2013).

(19)

5

Carbonisstoredinseveralreservoirs,andhumanactivityandnaturalprocessesleadto transportofcarbonbetweenthesereservoirs(Ciaisetal.,2013).Thenaturalfluxofcarbon betweenthelithosphere,biosphere,soil,oceanandatmosphereisreferredtoasthecarbon cycle(Figure1).Thecarboncyclecanbedividedintotwoparts,characterizedbydifferent turnoverrates.Thecontinuousnaturalfluxofcarbonbetweentheatmosphere,theocean andthebiospherethroughphotosynthesis,respiration,decompositionandoceansurface exchangeconstitutesthepartwitharelativelyfastturnͲover(fromafewyearstoafew thousandyears).Thepartofthecarboncyclethatincludesthecarbonstoredinthe lithospherehasslowreservoirturnover(>10,000years).Thenaturalfluxbetweenandwithin thefastandslowdomainsaremoreorlessinbalance,whiletheanthropogenicemissions ofCO2addstotheflux,creatinganimbalance(Denmanetal.,2007).

Figure1:Thecarboncyclewiththemainstoragecompartments(Pidwirny,2006)

Growingbiomassisanimportantpartofthecarboncycle.PlantsandtreessequesterCO2 fromtheatmosphereandstoreitascarboninbiomass.Thecarbonisoxidizedandreleased totheatmosphereagainasCO2whenthebiomassisdecomposedorcombusted.TheCO2 emittedthroughcombustionordecayofbiomassisreferredtoasbiogenicCO2.Becauseof thecarbonsequestrationandstorageabilityofbiomass,biogenicCO2emittedthroughthe combustionofbiomassisoftenexcludedfromenvironmentalassessments(TheEuropean Parliament,2009,Cherubinietal.,2011b,Bowyeretal.,2012).Thus,thetimespanbetween emissionsandsequestrationisignored(Cherubinietal.,2011b,Holtsmark,2012,Matthews etal.,2014).Thereareseveralstudiesthatfocusontheeffectofthetimingofcarbonflux betweentheatmosphere,biosphereandtechnosphere(seeforexampleCherubinietal.,

(20)

6

2011a,Cherubinietal.,2012a,Cherubinietal.,2012b,2013,Guestetal.,2013a,Guestet al.,2013b).

Cherubinietal.(2014)compareCO2frombioenergywithshortͲlivedGHG(SLGHG),finding thatthetemperatureresponseofbiogenicCO2isconstrainedbythemaximumemissions rateswhilethetemperature response oflongͲlived GHG(LLGHG),likefossil CO2,is proportionaltothecumulativeemissions.SomearguethatareductionintheSLGHGcan mitigateatemperatureincreaseintheshortterm,andthatshouldbethechosenstrategy inordertopreventtheclimatesystemtoreachatippingpoint(Bowermanetal.,2013).

Othersstressthatthemostimportantmeantoreducetheclimatechangeistoreducethe emissionsofLLGHG,especiallyfossilCO2(Bowermanetal.,2013,Shoemakeretal.,2013).

ThetemperatureresponsefromapulseemissionofbiogenicCO2ischaracterizedbyan initialwarmingfollowedbyacoolingeffectand,inthelongͲterm,thetemperatureresponse convergetowardszero,whilethetemperatureresponseofacorrespondingquantityoffossil CO2willbesustainedforcenturies(Cherubinietal.,2014).

Theforestsplayakeyroleinthecarboncycle.Therearefiveprimarycarbonpoolsinthe forest:abovegroundbiomass,belowgroundbiomass,deadwood,litterandsoil.Local conditionsliketypeofforestecosystem,siteclass,ageofforestandforestmanagement, includinglengthofrotation,arefactorsthatinfluencethefluxofcarbonbetweenthese poolsandtheatmosphere(NewellandVos,2012).Intheborealforestmostofthecarbon isstoredinthesoil(NewellandVos,2012).Thereareuncertaintiesinhowlargethecarbon soilpoolisandhowitisinfluencedbyharvest.deWitetal.(2006)estimatedaforestcarbon budgetfortheproductiveforestsinsoutheastNorwayfrom1971to2000andfoundthat thesoilcarbonincreasedby4.5%whiletheincreaseincarbonstorageinbiomasswas almost30%.

Theforestcancontributetomitigationofclimatechangeinseveralways.Mostimportant, theforestsequesterslargeamountsofCO2throughthephotosynthesis,anduntilthetreeis harvestedordies,thiscarbonisstoredinthewoodybiomassandlitter.Secondly,treescan replacefossilfuelsandotherenergyͲand/orcarbonͲintensiveproducts,andthereby reducingproductionrelatedemissionsofGHG.WhenwoodisbeingusedfornonͲenergy products,thecarbonisstoredinthetechnosphereuntiltheproductisdiscardedor

(21)

7

combusted(HoenandSolberg,1994,Guestetal.,2013a,Smithetal.,2014).Bioenergy usuallyhavehigheremissionsofCO2perenergyunitthanfossilfuels,butasmentioned,the biogenicCO2hasbeenconsideredtobeclimateneutral(Schlamadingeretal.,1997, Cherubinietal.,2011a).Regardlessoftheassumptionabouttheneutralityprinciple,the conversionefficiency(energyoutputperenergyinput)isimportantforthefinalresults (Schlamadingeretal.,1997).SubstitutionoffossilͲbasedproductsisacontinuousoption, whilestorageinsoil,biomassandtechnospherewill,atsomepoint,reachequilibrium (Schlamadingeretal.,1997,Gustavssonetal.,2010,Smithetal.,2014).

Forestbiomassisaversatilerawmaterialthathasseveralenergyapplications,likeheat, electricityandtransportationfuel.Inadditionitcanbeusedtoproduceconstruction material,paperandpackaging,fibersfortextilesandchemicals(HoenandSolberg,1994, Cherubini,2010,Erikssonetal.,2012,Rødsrudetal.,2012).Matthewsetal.(2014)expect thatwoodformaterials,fibersandchemicalswillincreaseinimportancethroughthe developmentofthenewbioͲeconomyanddecoupletheeconomyfromfossilfuel.

Forestbiomassisarenewablematerial,butalsoalimitedresource.Withmanypotential usesofwoodybiomass,thedevelopmentofbioenergybasedonforestresourcesincrease thecompetitionforfibers.Eventhoughthedemandforenergywoodisexpectedto increase,itwillnotlikelybecomethemaindriverofforestmanagementinthefuture.Wood suitableforhighͲvalueapplicationslikeconstructionmaterialwillhardlybeusedfor bioenergyinitially(TrømborgandSolberg,2010,Matthewsetal.,2014).Thedifferent applicationsofwoodcreatesdifferentcontributionstoclimatechangemitigation,andatoo narrowfocusonbioenergyasamitigationstrategycanleadtoanonͲoptimaluseofthe forestbiomass(Moiseyevetal.,2014).Whentheenvironmentalimpactsofbioenergyare assessed,theyneedtobecomparedwiththealternativefossilproductsthatcanbereplaced aswellaswithotherpotentialusesofthesamebiomass(Matthewsetal.,2014).

Inadditiontothegasfluxresultingfrombiomassuse,changesinvegetationcanalsoinduce otherimpactsonlocalclimate,likealterationofthehydrologicalcycle,shelterandchanges inreflectionofsolarradiation,i.e.albedo(Solomonetal.,2007,Brightetal.,2011,Delucchi, 2011).TogetherwiththefluxofGHG,albedoisthemostimportanthumaninducedclimate changemechanism(Delucchi,2011).Especiallyinborealforestwithannualsnowcover,the albedoeffectcanhaveasignificantrolebecauseasnowͲcoveredclearcuttingreflectsmore

(22)

8

oftheincomingsolarradiationsthanadarkforestcover(Betts,2000,Bonan,2008,Sjølieet al.,2013a).Brightetal.(2011)investigatedhowthealbedoeffectcontributedtoclimate changeresultingfromharvestinNorway,andfoundthatduringthefirstdecadesthechange inalbedooffsetthenegativeclimaticeffectofcombustionofbiofuel.Cherubinietal.(2012a) analyzedtheeffectofchangesinalbedoafterharvest,andtheyfoundthatthecoolingeffect inNorwegianforestwasalmostaslargeasthewarmingeffectduetobiogenicCO2.

Cherubinietal.(2011a)arguedthateventhoughthesameamountofCO2isbeingemitted andsequesteredwhenusingbioenergy,thebiogenicCO2willstayintheatmospherefora significanttime,contributingtoclimatechange.TheylaunchedtheGWPbioindexinan attempttocapturetheglobalwarmingpotential(GWP)ofbiogenicCO2basedonthe atmosphericdecayofCO2andreͲgrowth.ThischaracterizationfactorforbiogenicCO2was furtherdevelopedbyincludingtheimpactofchangesinalbedofollowingaharvest(Bright etal.,2012,Cherubinietal.,2012a).

McKechnieetal.(2010)integratedforestcarbonmodelsandLCAinordertoassessthetotal emissionsofGHGincludingthecarbonfluxintheforest.Theyfoundthattheimpactsof forestdynamicsaresignificant,andthatthelocalfactorsthatinfluenceforestcarbon dynamicsshouldbeincluded.TheirstudyalsoreportsaninitialincreaseinGHGemissions fromthebioenergysystemscomparedtothefossilenergypathways,butthisincreaseis temporaryandaftersomedecades,thebioenergypathwaysgivesreducednetemissionsof GHG.

Repoetal.(2012)assesstheclimateimpactofusingharvestresiduesforbioenergy.They includebothacarbonbudgetfortheforestandemissionsassociatedwiththeproductionof bioenergy.Further,theycomparetheradiativeforcing(RF,inWatt/m²)asaresultofthese emissions,withtheRFduetofossilfuels. Alltheirbioenergyscenariosgivesmaller cumulativeRFcomparedtofossilfuels.

Kilpeläinenetal.(2011)developedamethodologyforcalculationofCO2emissionsand sequestrationsinforestbasedonanecosystemmodel,andincludedemissionsfromforest managementoperationsandcombustionofbioenergy.Underassumptionsaboutastable climate,theyfoundthatthenetemissionsofCO2fortraditionaltimberscenariowasͲ319g CO2/m²/year.Iftimberproductionwasintegratedwithbioenergyproduction(thinningand loggingresidue)netCO2emissionswereͲ110gCO2/m²/year.Theydidnotincludeavoided

(23)

9

emissionsthroughsubstitution,sothemaindifferencebetweenthesetworesultsisthe consumptionofwoodforenergy(220gCO2/m²/yearinthelatterscenariocomparedtozero gCO2/m²/yearinthefirst)(Kilpeläinenetal.,2011).Thismethodologywasusedby Kilpeläinenetal.(2012)tofindthenetfluxofCO2andtheconsequentradiativeforcing impactsofbioenergyproductionandutilizationunderFinnishborealconditions.Overatime frameof90years,theforestactedasbothsinkandsourceofcarbon,butthecumulative radiativeforcingwas19%lowerforbioenergythanforcoal(Kilpeläinenetal.,2012).Albedo wasnotincluded.

ThereareseveralotherexamplesofinclusionofbiogenicCO2inclimatechangemitigation analysisofbioenergyandMatthewsetal.(2014)havepublishedasubstantialliterature reviewonthistopic.

Otherforestecosystemservices

Inadditiontothepotentialcontributiontoclimatechangemitigation,theforestprovides manyotherservicesthatareimportant.Thetermecosystemservicesisusedasacollected termforallprovisioning,regulating,culturalandsupportingservicesthatnatureprovides forhumans(Reidetal.,2005).Ecosystemservicesprovidedbyborealforestsincludes provisioning of timber, game, bioenergy and fibers for cellulose and bioͲchemicals;

regulatingserviceswhichincludefloodcontrolanderosionprotection;supportingservices whichincludebiologicaldiversity,sustainmentofbiochemicalcycles,primaryproduction andresiliencetochange;culturalserviceswhichincluderecreation,healthandethicalvalues ofbiologicaldiversityconservation(LindhjemandMagnussen,2012).

Inadditiontoclimatechange,Rockstrometal.(2009)namelossofbiodiversityasoneofthe environmentalproblemsoftodaythathascrossedtheboundariesforasafeoperatingstage.

Thetermbiodiversityincludesvariabilitywithinandbetweenspeciesandvariabilityof ecosystems(SecretariatoftheConventiononBiologicalDiversity,2005).Throughthe ConventiononBiologicalDiversity(CBD,ratifiedin1992)andtheBernconvention(ratified in1986)Norwayhasobligationstoconservebiologicaldiversityandsecuresustainableuse ofbiologicalresources(NorwegianMinistryofEnvironment,2001).Loss,degenerationand fragmentingofhabitatandexcessiveharvesthavebeennamedtwoofthemostimportant humaninfluencesonbiodiversity(LierͲHansenetal.,2013).InNorway,about60%ofall terrestrialspeciesarelivinginorinproximityofforests(Direktoratetfornaturforvaltning,

(24)

10

2010).OftheRedlistedspeciesinNorway,40%isaffiliatedwithforestbiotopes.Oldforests haveahigherdensityofendangeredspeciesthanyoungforests,butbiodiversityalso dependsonadynamicdiversityofstandstructures(Artsdatabanken,2010,Oliveretal., 2013).Inadditiontosupportavarietyofspecies,adiversityofstandstructurescanalso increasetheforests’resiliencetocatastrophicevents(Oliveretal.,2013).

Landuseandlandusechange(LULUC)havebeenincludedinLCAindifferentways(Milài Canalsetal.,2007).SomestudiesincludeLULUCsimplyaslandoccupation(m²/year),while othershaveattemptedtoqualitativelyevaluateLULUCbyclassifyinglandareas(Antónet al.,2007).Suggestedindicatorsforimpactonbiodiversityincludespotentialdisappeared fractionofspecies,percentofthreatenedvascularplantspeciesinregionandredlisted species(MilàiCanalsetal.,2007).MilàiCanalsetal.(2007)suggestsaframeworkfor inclusionoflanduse(occupation)andlandusechange(transformation)inLCAbylinking LULUCimpactstobiodiversity,bioticproductionpotentialandecologicalsoilquality,while Michelsen(2008)proposedamethodologytoincludethebiodiversityaspectsinaccordance withthisframework.

Oliveretal.(2013)examinedtheCO2andfossilfuelssavingstogetherwithbiodiversity protectionthroughharvestandnonͲharvestscenarios.TheyfoundthatthegreatestCO2 savingswasachievedthroughsubstitutionofconcreteandsteel.Woodforenergyoffers smallersavings,andaccordingtothemonlyresidualwoodshouldbeusedforenergy(Oliver etal.,2013).ProtectingbiodiversityandmaximizingforestCO2sequestrationmaynotbe compatiblebecausebiodiversitydependsonavarietyofdifferentforestlandscapes(open landscape,denseforest,understoryforestandcomplexforest),whilethehighestamount ofCO2savingsareaccomplishedbykeepingallforestasunderstoryandcomplexforest structures(Oliveretal.,2013).

Theroleofforestmanagement

Howtheforestismanagedisessentialtotheservicesprovidedbytheforest,andinNorway managementofpublicandprivateforestsareregulatedbytheForestAct(Norwegian MinistryofAgricultureandFoodt,2005).ThroughtheForestAct,thegovernmentwantsto ensure that the forest owners take sufficient considerations to biological diversity,

(25)

11

landscape,recreationandculturalheritagewhenmanagingtheforest(HoenandSvendsrud, 2014).

Forestmanagementisanimportanttoolinordertopreservethedifferentqualitiesofthe forest,andforestmanagementinNorwayisgenerallycharacterizedbymultipurpose management,i.e.amanagementregimedesignedtoprovidearangeofproductsand services(Matthewsetal.,2014).Maintenanceofthedifferentecosystemservicesfromthe forestsrequireavarietyofmanagementstrategiesandinmanycasestherewillbeatradeͲ offbetweenatleastsomeofthevariousecosystemservices(LindhjemandMagnussen, 2012).AmongstmitigationoptionsforforestthatarementionedbySmithetal.(2014), forestmanagementisoneofthemostimportantforNorwegianforests.Lundmarketal.

(2014)claimthattheforestgrowthinSwedencanbeincreasedbymorethan50%by changesinforestmanagement.Inadditiontoincreasedforestyield,forestscanbemanaged inawaythatcanincreasethesequestrationofandthestorageofcarbon.Examplesof possiblemanagementoptionstoincreasecarbonsequestrationandstoragearehigher regenerationdensities,reducedthinning,forestfertilization,prolongedrotations,improved treeprovenances,andchoiceofspeciescombinations.Suchmanagementchangescangive reducedprovisionoftimberandwoodfibers,and/orlowerrecreationalvalueofforest.The tradeͲoffbetweenmaximizedbiomassharvestand maximizedbiomassstorageis an importantconsiderationwhenassessingforestmanagementmitigationstrategies(Hoen andSolberg,1994,Schlamadingeretal.,1997,Lundmarketal.,2014).Useoftimberis importantinthattradeͲoffsituation.HoenandSolberg(1994)wasafirstattemptto combine those factors for boreal forest in a consistent bioͲeconomic optimization frameworkinNorway.

TherearealsotradeͲoffsbetweendifferentclimatechangemechanisms.Recentresearch suggestthatforestmanagementstrategiesforclimatechangemitigationshouldfocuson morethanjustGHGreduction,andthatthealbedoeffectcanbeamongthemostimportant factorstoconsiderinforestmanagement(Betts,2000,Gibbardetal.,2005,Balaetal.,2007, Bettsetal.,2007,Bonan,2008,Thompsonetal.,2009,SchwaigerandBird,2010,Aroraand Montenegro,2011,Sjølieetal.,2013a).Fromaclimatechangemitigationperspective, includingthealbedoeffectmayimplyshorterrotations,moremixedorbroadleavedforests

(26)

12

andlessafforestationthanwhatisoptimalwhenonlyconsideringcarbonsequestration (Brightetal.,2014,Sjølieetal.,2014).

TerͲMikaelianetal.(2013)simulatedfutureharvestscenariosinordertoassessthechange incarbonstockasaresultofchangingharvestlevelsinOntario.Intheiranalysis,theyfind thattheprojectedcarbonstock(inforestandharvestedproducts)convergetowithin2%

differenceby2100forallscenarios,andtheyconcludethatthesustainableharvestofboreal forestwillhaveasmalleffectonthecombinedforestandwoodproductslongͲtermcarbon stock (TerͲMikaelian et al., 2013). They do not include avoided emissions through substitutionoreffectofchangedalbedoafterharvest.

Pingoudetal.(2010)integratedforestmanagementandwoodproductsubstitutionina climatechangeperspective,andfoundthatthelargeststockofcarboninforestandproducts wasachievedbyincreasedrotationlengthandbasalarea.UseofsawlogsforlongͲlived productsinsteadofmoreenergyͲintenseproducts,followedbycascadingthematerialas bioenergyprovidedthelargestclimatebenefit(Pingoudetal.,2010).Cascadingofwoodis inlinewiththeindustrialecologyconcept,andtheenvironmentalandmaterialbenefitsof cascadingareconfirmedbyothers(e.g.DornburgandFaaij,2005,Gustavssonetal.,2006, McKechnieetal.,2010).

Cost

ThebioͲeconomicforestmodelGAYAͲJ/LPhasbeenusedtoanalyzeharvestandeconomic effectsofbiodiversityconservation(Hoenetal.,1998,Eidetal.,2002,Bergsengetal.,2011), as well as estimates of GHG balance and climate mitigation costs under different managementregimes(Hoen,1990,HoenandSolberg,1994,Solbergetal.,2008,Raymeret al.,2009).InSolbergetal.(2008)themodelwasusedtoquantifytradeͲoffsbetweenharvest income,climatemitigationandbiodiversityprotectionatforestpropertylevel.Raymeret al.(2009)foundthatmaximizingcarbonbenefitsbyforestmanagement,reducedthenet presentvalueoftheforestinHedemark(aNorwegianregion,13420km²)by21%.The correspondingcarbonbenefit,incl.substitutionbenefit,fromtheforestswas2.4millionton CO2Ͳequivalentsperyearonaverageover120years.

PaperIgivesanoverviewofcoststudiesinadditiontoenvironmentalassessments.Several analysesindicatethatbioenergyisnotcostcompetitivewithfossilenergy(seeforexample

(27)

13

HennigandGawor,2012,Bertrandetal.,2014,GerssenͲGondelachetal.,2014)whileothers foundthatbiomassbasedsystemshavelowercoststhanfossilreference(KaltandKranzl, 2011).GerssenͲGondelachetal.(2014)foundthatbioenergyforheatandpowergenerally hashigherinvestment,operationandmaintenancecoststhanfossilenergy.However,they expectedthepriceoffossilresourcestoincreaseinthefuturewhiletheproductioncostof bioenergyisexpectedtodecrease.Technologylearningwillincreasetheefficiencyof bioenergyproductionandthiswillleadtodecreasedcostandlessemissionsperenergyunit (GerssenͲGondelachetal.,2014).Accordingtothesamestudy,biomaterialsarealreadyable tocompeteonpricewithotherrawmaterials(GerssenͲGondelachetal.,2014).Several studiesfoundthatbioenergywillcontributetoreducedemissionsofGHG,andapriceon CO2canmakebioenergyprofitable(Bertrandetal.,2014).

Thecostofbioenergyisimportantfortheeffectofpolicyinstrumentsthataimatreduced GHGemissionsorincreaseduseofbioenergy.WhenEUandNorwaywanttoincreasethe useofrenewableenergy,thereductioninGHGemissionsisonlyoneofseveralgoals.In additiontheywanthigherenergysupplysecurityanddevelopmentofacompetitiveenergy sectorthat provides employment(Bentsenet al., 2014).Policyinstrumentsthatare designedtoreduceGHGemissionsortoshiftenergyproductionfromfossilfuelsto renewables,canhavedifferentresultsandcostͲeffectiveness(Schmidtetal.,2011).Policy instrumentsdesignedtoreducetheemissionsofGHG,likeCO2taxesandtheEUemissions tradingsystem(ETS),areexpectedtobethemostcostͲeffectivesolutionsbecausethe marketwillallowanefficientallocationofreductioneffortsamongtechnologies.Butthe emissionsreductioneffectdependsonavailablelowcarbontechnologies(Schmidtetal., 2011).DirectpromotionofselectedenergytechnologiesthroughfeedͲintariffs,required shareofbiofuelsandsubsidies,mayleadtodevelopmentofonlyapartoftheavailable technologies(Schmidtetal.,2011).

Locationofbiomasssupply,plantsforconversionandusersoftheenergyareimportant factorsforthecostofbioenergy,andthiscallsforspatialexplicitmodellingwhenanalyzing thecostofbioenergy(Schmidtetal.,2011).AccordingtoBergsengetal.(2013),thebiomass supplycostsinNorwayarerelativelystableforalargerangeofbiomassdemand;butwhen thedemandapproachesthesupplylimit,costswillincreaserapidly.Again,bioenergyis rarelythedriverofaforestbiomassvaluechain,andlikeenvironmentalanalysisbioenergy

(28)

14

concernshavetobeapartofmorecomprehensiveeconomicanalyses(SjølieandSolberg, 2011,Bergsengetal.,2013).

Biodiversityprotectionwillinmostcasesreduceincomefromtimberproductionforthe forest owner. Bergseng et al. (2011)analyzed the relationship between biodiversity conservationandthecostassociatedwiththeincreasedconservationefforts.Theyfound thatincreasedrestrictionsontheforestmanagementreducedthenetpresentvalueofthe forestby10Ͳ45%comparedtoacasewithnorestrictionsontheforesttreatment.Increased rotationlengthandminimumshareofoldͲgrowthforestwasconsideredtohavehighvalue forbiodiversity,andwerealsothemostcostlyforestmanagementoptions.Forthesame forestarea,Solbergetal.(2008)mappedthetradeͲoffsbetweentimberincome,biodiversity protection,andcarbonsequestration.

GHGabatementcostisthecostassociatedwithreducingtheemissionsofGHGbyshifting toanalternativesystem(HennigandGawor,2012).ItcanbecalculatedasthefractionA/B wereAistheadditionalcostassociatedwithproductionofbioenergyinsteadofusingfossil fuelsandBisthecorrespondingreductioninGHGemissionsbecausefossilfuelsarereplaced (SternerandFritsche,2011).ThisisalsoreferredtoascostͲeffectiveness.Manyresearchers havestudiedthis,andresultsofselectedstudiesdoneafter2003areshowninPaperI.

4 Methodology

Theoreticalbasis

Systemstheoryisthetheoreticalbasisfortheanalysis.Generalsystemstheorywasalready inthe1930sintroducedasaconceptbybiologistvonBertalanffyasthescientificbasisfora holisticexplorationofsystems(VonBertalanffy,1972).Asystemisacompositionof elementsandsubsystemsthatisseparatedfromthesurroundingsbyfulfillingacommon purpose,andasystemhassomecharacteristicsthataremorethanjustthesumofsingle elements(VonBertalanffy,1972,Dekkers,2015).Systemstheoryisbasedontherealization thatyouneedtounderstandtherelationshipbetweenthesystemelementsinorderto regulatethesystem(VonBertalanffy,1972).Inenvironmentalanalysis,thesystemtheoryis importantbecauseitdescribestheinteractionbetweenthesystemelementsandbetween thesystemanditsenvironment(BrattebøandKjelstrup,2011).

(29)

15

Theinclusionofallrelevantinteractionsareimportantalsoineconomicanalyses,butthere humanbehavior,humanwelfareandtheimportanceofhumaninteractionsandtheir influenceontheenvironmentareinfocus.Environmentaleconomicshasduringthelast halfcenturydevelopedtoincludealsoenvironmentalissuesineconomictheory(seefor exampleConrad(2010)foranoverview).However,forsimplicity,Ihaveinthisthesischosen systemstheoryastheoreticalbasis.

Duringthe1970’sand80’s,societygainedknowledgeofhowlargeinfluencehumanactivity hasontheenvironment,andthefieldofenvironmentalanalysisshiftedtowardsasystemsͲ thinkingapproach(Brattebøetal.,2011).InordertoavoidproblemͲshiftingandnonͲ optimalsolutions,itwascalledforamoreholisticproblemsolving.Thescientificcommunity sawtheneedforasystematictoolthatintegratedthematerialandenergyflowof productionsystemswiththeoutsideworld(Brattebøetal.,2011).

Anumberofanalyticaltoolshavebeendevelopedinordertosystematicallyexaminethe energyandmaterialflowsandtheimpactontheenvironment.Thesemethodsinclude materialflowanalysis(MFA),energyandexergyanalysis,environmentalriskassessment (ERA),lifecycleassessment(LCA),inputͲoutputanalysis(IOA),costbenefitanalysis(CBA), lifecyclecosting(LCC)andcombinationsofmethodslikeIOAͲLCAandLCAͲMFA(Baumann andTillman,2004,FinnvedenandMoberg,2005,Heijungsetal.,2011).

Methods

Thischapterdescribesthetwomainmethodsusedinthethesis.EachofPaperIͲIVhavea methodologicalsection,butthedescriptionthereisbynecessityrathershort,andtherefore enlargedinthefollowingsections.

LifeCycleAssessment(LCA)isawellͲestablishedmethodforassessingtheenvironmental impactsofproduction,consumptionanddisposalofgoodsandservicesandisusedinthree ofthepapersinthisthesis.

TraditionalLCAdoesnotincludeanalysisofeffectsoflanduseandlandusechange(LULUC), i.e.whicheffectdoestheharvestofforestbiomasshaveonbiologicaldiversity,carbon storageandotherecosystemservices.InordertoovercometheweaknessofLCAinrelation tononͲemissionimpactsandtohaveastronglinktoeconomicimpacts,anintegrationof LCAandabioͲeconomicforestmodelisappliedinthisthesis.GAYA–J/LPisaforest

(30)

16

economicoptimizationmodelthatcanfindtheoptimaltreatmentofforeststands,given preͲspecifiedobjectivefunctionsandforestmanagementrestrictions.Basedongrowth models,naturalmortalitymodels,economicobjectivesandpreͲspecifiedalternativeforest managementoptions,GAYAͲJ/LPsimulatesthedevelopmentoftheforestforadefinedtime horizon(Hoen,1990,HoenandEid,1990,Raymeretal.,2009).LCAiscombinedwithGAYAͲ J/LPintwoofthefourthesispapers.

ȋȌ

LCAisanenvironmentalsystemsanalysistoolthatiswidelyappliedforinvestigationsof potentialimpactsofproductsorservices(BaumannandTillman,2004,KlöpfferandGrahl, 2014)thatemergedinthelate1980’sasaresponsetotheincreasingawarenessofthe human influence on the environment (Hanssen, 1999). LCA is a multiͲdisciplinary methodologythatanalyzestechnical,naturalandsocialsystems,andtheinterfacebetween thesesystems(BaumannandTillman,2004),asillustratedinFigure2.

Figure2:Illustrationofanalysisofenvironmentaleffectsofbioenergyincludinginteractionsbetweennaturalsystems, technicalsystemsandsocial/economicsystems.

LCAfacilitatesaquantitativeanalysisofpotentialenvironmentalimpactsacrossthelifecycle ofaproductorservice.Acompleteinventoryofallmaterialandenergyrequirementsfor production,useanddisposaloftheproductofinterestisgatheredandthepotential environmentalimpactresultingfromtheemissionsarecalculated.Thepotentialimpactsare relatedtoafunctionthatthetechnicalsystemdeliverstothesocialsystembasedon resources from the natural system (ISO, 2006b). The method provides a tool for understandingthemostimportantpotentialenvironmentalimpactsoftheproduction

(31)

17

system,andwhereintheproductionchaintheseimpactsoccur.Itisusedtocompare productalternatives,andasabasisforstrategicandpoliticaldecisionmaking(ISO,2006b).

Forexample,inanalyzingtheenvironmentalimpactsassociatedwithbioenergy,anessential questioniswhetherbiomassperformsbetterorworsethanalternativeproductsthat providethesamefunctionandwhatisthebestuseoftheavailablebiomass.LCAfacilitates thecomparisonbetweendifferentrawmaterialsanddifferentusesoftherawmaterial, usingthesamefunctionalunitaspointofreference.Matthewsetal.(2014)foundthatLCA isawellsuitedtoolforenvironmentalanalysisofwoodproducts,andaccordingtoAgostini etal.(2013)thereisapoliticalandscientificagreementthatLCAisanecessarymethodology forthesekindsofanalysis.

AnLCAstudyconsistsoffourstages:

1. Goalandscopedefinition(includinginformationonsystemboundaries,functional unitandallocation).

2. Inventoryanalysis(inputandoutputoftheproductsystem).

3. Impactassessment(theresultsoftheinventoryaretranslatedintocontributionsto relevantenvironmentalimpactcategories).

4. Interpretationoftheresults.

Thedefinedgoalformthefundamentforseveralimportantmethodologicalchoices.When thegoalandscopeoftheanalysisaredefined,themodellingprincipleanddecisioncontext oftheanalysisarealsodefined.InLCA,therearetwomodellingprinciples:attributionaland consequential(EuropeanCommissionͲJointResearchCentreͲInstituteforEnvironmentand Sustainability,2010b).Iwillgetbacktothoselater.

TherearethreearchetypaldecisioncontextsforLCA,illustratedinFigure3.Theproduction systemsanalyzedinthethesisarerelativelysmallandwillonlyhavesmallͲscaleimpactsin backgroundsystemsorothersystemsoftheeconomy.Ihavethereforeuseddecision contextA,whichisreferredtoas“MicroͲleveldecisionsupport”anditistypicallyusedfor products or production systems with smallͲscale market consequences (European CommissionͲJointResearchCentreͲInstituteforEnvironmentandSustainability,2010b).

(32)

18

Figure3:ThedecisioncontextofaLCAstudydependsonwhetherthestudywillbeusedtosupportdecisionsand,ifso, willthedecisionsleadtosmallͲorlargeͲscalechangesinbackgroundsystemorothersystemsFiguretakenfrom EuropeanCommissionͲJointResearchCentreͲInstituteforEnvironmentandSustainability(2010b).

Thesystemboundariesdefines whichprocessesthatbelongtothe analyzedsystem (EuropeanCommissionͲJointResearchCentreͲInstituteforEnvironmentandSustainability, 2011).Thesystemboundariesusedfortheanalysisinthethesisareillustratedschematically inFigure4,anddescribedindetailintheindividualpapers.ThetoppartofFigure4illustrates thesystemboundariesappliedinPaperII,IIIandIV,whilethebottompart(belowthe dashedline)illustrateshowthecarbonfluxinthenaturalsystemisincludedinPaperIIand IV.

Figure4:Illustrationofsystemboundariesusedinthreeofthefourthesispapers.ThefluxofCO2intheforestisbelow thedashedline.Thesolid,doubleͲsidedarrowsillustratethatthenetfluxofCO2Ͳequivalentsbetweentheforestvalue chainandtheforestmightpositiveornegative.Thedottedarrowsillustratethecarbonsequestration.

Theenvironmentalloadassociatedwithproductionanduseofaproductorserviceis distributedlinearlytoaunitofreference,asoͲcalledfunctionalunit(FU).TheFUcanbea unitofaproductorevenaserviceprovidedbytheproduct(ISO,2006b).Dependingonthe scopeoftheassessment,theFUcanberelatedtoinputintothesystemortooutputofthe system.Potentialenvironmentalimpactofwoodproductshastwopointsofdeparture.The productcanbecomparedtoanalternativeproductthatprovidesthesamefunctionor

(33)

19

service(output),oritcanbecomparedtoanotherproductthatisbasedonthesame resource(input)(Rivelaetal.,2006).Inthisthesis,Ihavemadeuseofbothofthose perspectives.InPaperII,Ihavecomparedbioethanolbasedonwoodybiomasswithfossil dieselusedforheavyͲdutytransport.Inthiscontext,itisinterestingtoanalyzethepotential environmentalimpactsofaserviceprovidedbytheproductionsystem.Therefore,inthis case,theFUwas1kmdrivenbyalorry.InPaperIII,Ihaveassessedthepotential environmentalimpactsoftheuseofaforestpropertyfordifferentwoodͲbasedproducts includingbiodiversityconservationmeasures.Thus,inPaperIIItheFUisonekm²of productiveforest.Ageographicalfunctionalunitwaschosentofacilitateanupscalingofthe analysistoalargerarea.

Whentheproductionprocessthatisbeinganalyzedproducemorethanoneproduct,the materialandenergyinputandoutputaswellasenvironmentalburdensneedtobeallocated between different coͲproducts (ISO, 2006b). There are many examples of such multifunctionalprocessesintheforestvaluechain:residuesfromproductionofconstruction materialarebeingusedforproductionofenergy,pulpandparticleboards,biorefineries producecellulose,bioethanolandbiochemicalatthesamesitewithmanyprocessesin common(Cherubinietal.,2011c).Thechoiceofallocationmethodhasbeenshowntobe importantforthefinalresult(Börjessonetal.,2010,Cherubinietal.,2011c,Kumaretal., 2012),anditisrecommendedtoavoidallocationwheneverpossible(BaumannandTillman, 2004).However,ifallocationisnecessary,therearetwomainmethods:systemexpansion andpartitioning.Whenusingsystemexpansion,theproductionprocessofinterestis creditedwithavoidedemissionsfromotherproductionpathwaysofthecoͲproducts(i.e.

emissionsfromproductionofcoͲproductsaresubtractedfromthetotalemissionsofthe multifunctionalprocess)(BaumannandTillman,2004,Cherubinietal.,2011c)Whenusing thepartitioningmethod,theemissionsfromthemultifunctionalprocessarebeingdivided amongsttheproductsbasedonforexamplemass,energycontentoreconomicvalue (Cherubinietal.,2011c).InthisthesisIhaveappliedmass(PapersIIandIII)andenergy partitioning(PaperIII).

ThesecondstepinLCAislifecycleinventoryanalysis(LCIA),i.e.themappingofallmaterial andenergyflowsrequiredforproductionandemissionsofsubstancesconnectedwiththese flows.Asmentioned,therearetwomainmodellingprincipleswhenthelifecycledatais

(34)

20

collected:attributionalandconsequential(EuropeanCommissionͲJointResearchCentreͲ InstituteforEnvironmentandSustainability,2011).“Attributional”modellingisusedwhen depictinganactualorforecastedspecificoraveragevaluechaininastatictechnosphere, while“Consequential”isusedtodepictgenericvalueͲchainswithexpectedchangesinthe foregroundandbackgroundsystem(adynamictechnosphere)(EuropeanCommissionͲJoint ResearchCentreͲInstituteforEnvironmentandSustainability,2010b).Inthisthesis,the investigatedsystemsareexistingsystems,andthereforeIhaveusedattributionalLCAinall papers.InPaperIIspecificdataarecollectedfortheforegroundsystems.InPaperIII,there isamixofgenericandspecificdatathataredescribedindetailinPaperIII.

InthethirdstepofanLCA,thelifecycleimpactassessment,thesubstanceemissionsthat havebeenquantifiedintheinventoryprocessaretranslatedintoenvironmentalimpact indicatorresults.Duringthisstagetheemissionsarefirstassignedtotherelevantimpact categoriesaccordingtothesubstances’abilitytocontributeinthespecificimpactcategories (EuropeanCommissionͲJointResearchCentreͲInstituteforEnvironmentandSustainability, 2010a)TheimpactsofaproductcanbeassessedonthemidpointlevelorendͲpointlevel (Figure5).EndͲpointcategoriesareburdenedwithhigheruncertaintythanmidpointimpact categories.Theimpactcategoriesshouldreflectissuesofdirectenvironmentalimportance, andexamplesofmidpointimpactcategoriesincludeclimatechange,ozonedepletion, eutrophicationandecotoxicity.Examplesofendpointdamagesincludedamagetohuman health,damagetoecosystemdiversityandresourceavailability(Goedkoopetal.,2009).In thisthesis,IhavenotanalyzeddamagesatendͲpointlevel.

Figure5:Emissionsofsubstanceshaveimpactsindifferentdefinedimpactcategories,andtheimpactismodelledbased onsomeenvironmentalmechanisms.Thefurthertotherightwemoveintheprocess,thelargertheuncertainty.

Thenextstepoftheimpactassessmentischaracterization(EuropeanCommissionͲJoint Research Centre Ͳ Institutefor Environment andSustainability, 2010a). Emissions of

(35)

21

differentsubstanceswiththesametypeofenvironmentaleffectareconverted into equivalentsbasedonenvironmentalmechanisms(Figure5)(ISO,2006a).Therehavebeen developedseveralmethodsforimpactassessment.InPaperII,ReCiPe(Goedkoopetal., 2009)wasused,andinPaperIIICMLͲIAbaselinev3.00wasused.Inaddition,PaperII containsacomparisonofdifferentcharacterizationfactorsforbiogenicCO2andtheeffect ofchangeinsolarradiationreflectionbytheEarthsurfacefollowingaharvest(Table1).For globalwarmingpotential(GWP)theunitisCO2Ͳequivalents,andIPCCusuallygivetheGWP overthreetimehorizons;20,100and500years,andtheyarereferredtoasGWP20,GWP100 andGWP500,respectively.ThecharacterizationfactorforfossilCO2is1(Solomonetal., 2007).ThecharacterizationfactorforbiogenicCO2,GWPbio,waslaunchedbyCherubiniet al.(2011a)inordertoincludethetemporalincreaseinatmosphericconcentrationofCO2 followingcombustionofbioenergy.InBrightetal.(2012),andCherubinietal.(2012a) GWPbiowasfurtherdevelopedtoincludetheeffectofchangeinreflectionofsolarradiation (albedo)followingharvestatNorthernlatitudes.

Table1:DifferentcharacterizationfactorsforbiogenicCO2andalbedo(CO2Ͳeq.)usedinPaperII.

Method GWP100 GWP100 NetGWP100

BiogenicCO2 Albedo (BiogenicCO2+albedo)

GWP=1 1 Ͳ 1

GWP=0 0 Ͳ 0

GWPbio 0.62 Ͳ0.42 0.2 GWPbioincl.forestresidue 0.51 Ͳ0.38 0.12

InPaperIIandIII,severalimpactcategoriesareincluded:globalwarmingpotential(GWP), acidification potential (AP), eutrophication potential (EP), photochemical oxidation formationpotential(POFP)andozonedepletionpotential(ODP).Theseimpactsarethe mostcommonenvironmentalimpactcategoriesassessedintheforestfuelsupplychains (see e.g. Berg and Lindholm 2005 and CherubiniandStrømman 2011). Inaddition, particulatematterformationpotential(PMFP)wasincludedinPaperII,asthisisimportant whenassessingtransportationfuelusedindenselypopulatedareas.

AlimitationofLCAisthatitismainlyconstructedtoassessthepotentialimpactsofemissions andthatitlacksthetimedimension(ISO,2006b,Michelsen,2008).Productionofaproduct orservicecanalsohaveenvironmentaleffectsthatarenotrelatedtoemissions,andthatis particularlytrueforbiomassbasedvaluechainsthatcanhavelargeimpactsonlanduseand biodiversity(MilàiCanalsetal.,2007,Michelsen,2008).Still,areviewofLCAsonbioenergy

(36)

22

byCherubiniandStrømman(2011)revealedthatonly9%ofthestudiesincludedlanduse impactintheirassessmentandnoneincludedassessmentofthepotentialimpactson biodiversity.

ǦȀ

Inordertoovercomesomeoftheissuesregardingspaceandtimementionedaboveandto includeeconomiceffects,LCAisherecombinedwithaforesteconomicmodel,GAYAͲJ/LP, intwoofthethesispapers(IIIandIV).GAYAͲJ/LPisalongͲtermbioͲeconomicforest managementoptimizationmodelthatconsistsoftwoparts;aforeststandmodel(GAYA) andanoptimizationpart(J/LP).ItwasdevelopedandusedforthefirsttimeforNorwayin Hoen(1990),andlaterappliedinseveralstudieslikeHoenandEid(1990),HoenandSolberg (1994),Eidetal.(2002),Raymer(2005),Raymeretal.(2005),Solbergetal.(2008),Bergseng etal.(2011).GAYAͲJ/LPcombinesbiologicalandeconomicalaspectsofforestmanagement inordertofindoptimalforestmanagementsolutions,assumingexogenouslydetermined objectivefunction,costs,prices,constraintsandforestgrowthparameters.

Thesimulationpartofthemodel(GAYA)simulatesnumerouspossibledevelopmentpaths fortheforestbasedontheinitialstateoftheforest,obtainedbyforestinventory.The simulationsarebasedonbasalmeandiameter,meanheightweightedbybasalareaand numberoftrees,andgrowthisestimatedona5yearbasis(Hoenetal.,1998,Raymeretal., 2009).Simulationoftheforestusesthefunctionsfordiameterincrement,heightandnatural mortalityasdocumentedinHoenetal.(1998).Inadditiontopossiblebiologicalconstraints regardinggrowthandmortality,thedevelopmentoftheforeststandisinfluencedby constraintsthatexcludeforestmanagementalternativeswhichareclearlyunrealistic.Thus, GAYAsimulatesallrealisticstandtreatmentsandthecorrespondingdevelopmentsofthe foreststands,basedontheexͲantespecifiedbiologicalandmanagementrestrictions(Hoen etal.,1998,Raymeretal.,2009).

TheoutputfromGAYAisinputtothelinearprogramming,J/LP.Thispartofthemodel optimizesthemanagementoftheforeststandsandselectstheoptimalsetoftreatment optionsamongthenumerousalternativesthatissimulatedbyGAYA.Theoptimalsolution isfound,giventheobjectivefunction.Theobjectivefunctioncanberelatedtotheeconomy fortheforestowner(netpresentvalue),harvestvolumesorqualities(shareofsawnͲand pulpwood,keepingharvestatcertainlevels),standingstockafterharvest,ortospecified

(37)

23

forestmanagementoptionswithrespecttoregeneration,finalfellingandthinning(Hoen andEid,1990).Inthisthesistheobjectivefunctionismaximizationofthenetpresentvalue (NPV).

InPaperIIIandIV,GAYAͲJ/LPiscombinedwithLCA(Figure6).Thefiguregivesaschematic illustrationoftheintegrationbetweenGAYAͲJ/LPandLCAandimportantbuildingblocksin thedifferentparts.GAYAͲJ/LPfindstheoptimalforestmanagement,giventhemanagement restrictionsandobjectivefunction.Theresultingharvestisusedinforestryvaluechainsthat aremodelledintheLCAsoftware,SimaPro(PRéConsultants2013).InPaperIII,GAYAͲJ/LP andLCAarecombinedinordertofindenvironmentalimpactsofbiomassusefromaforest propertyinØstfold,Norway.InPaperIV,GAYAͲJ/LPandLCAarecombinedinorderto evaluatepotentialclimatechangecontributionofthesameforestasinPaperIII.Theresults fromPaperIIIareusedtocalculatethenetGHGemissionsfromproductionandsubstitution ofwoodͲproducts(kgCO2Ͳeq./m³)whichareusedasinputtoGAYAͲJ/LPinPaperIV(Figure 6).Inaddition,thecarbonfluxandalbedochangeintheforestfollowingharvestareincluded intheanalysisoftheharvestandforestclimateimpacts.

GAYAJ/LPuseempiricaldatainordertopredict futureforestsituations,whileLCAuse empiricaldatatodescribethecurrentsituation.LCAisstaticintimewhileGAYAͲJ/LPmodels developmentovertime.Thiscombinationprovidessomechallengeswhenthetwoare integrated.Inthisthesis,thishasbeentackledintwodifferentways.InPaperIII,the simulationoutputfromGAYAͲJ/LParesummarizedovertwodifferenttimehorizonsand usedasinputtoLCA(drymatter/km²).InPaperIV,theoutputfromLCA(kgCO2Ͳeq./m³)are oneofseveralinputstoGAYAͲJ/LP.Inthiscase,wehavetestedtheeffectofdiscountingthe climate effectsalongsidewithtimberprofit. LCAis ausefultool for assessment of environmentalimpactsrelatedtoemissionswhileGAYAͲJ/LPprovidesamodelforinclusion ofenvironmentalimpactsrelatedtolanduse.GAYAͲJ/LPkeepstrackofcarbonwhileLCA supplementtheanalysiswithothersubstances.

(38)

24

Figure6StructureoftheintegrationofGAYAJ/LPandLCA.Thearrowsindicateinformationflow.

InPaperIII,threemanagementscenariosaredefinedinGAYAͲJ/LPandtheobjective functionistomaximizethenetpresentvalueoftheforest.Twooftheforestmanagement scenariosthatformthebasisfortheanalysiscontainrestrictionsontheforesttreatmentin ordertopreservebiologicaldiversity,culturalheritagesitesandrecreationalvalues,while onescenariodoesnothaveanyrestrictionsonthetreatment.Thelatterisusedasa reference.

ThethreescenariosinPaperIIIare:

1) Areferencescenario(REF):abasescenarioforcomparison;withoutrestrictionson forestmanagement.

2) AscenariorepresentingProgramfortheEndorsementofForestCertification(PEFC), withconstraintsonmanagementtopreservebiodiversity.Thisscenariorepresents the current certification regime for sustainable forestry in Norway and the

(39)

25

constraintsareanoperationalizationoftherestrictionsgivenbythecertification organization.TheNorwegianForestryLawof2005legallyauthorizesthePEFC(LOVͲ 2005Ͳ05Ͳ27Ͳ31).

3) Abiodiversityscenario(BD),characterizedbyconstraintsonforestmanagement withextensivecaretakentopreservebiologicaldiversityandmaintaintheforests’

recreationalvalue.TheconstraintsexceedthePEFCscenariowithexplicitlocal adaptationsasdefinedbythelocalauthoritiesasabasisforfurthermultipurpose planning of the area, which enabled inclusion of specific considerations like importantrecreationalareas.Themunicipalityassignedareastofourdifferent categoriesrangingfromnormalforestrywithnorestrictions(category1)tofull preservationofforest(i.e.noharvestatall,category4).Category2and3are gradientsbetweenthesetwoextremes.

Inthisthesis,casestudiesareusedtoassessthepotentialeconomicandenvironmental impactsofwoodbioenergy.Allthestudiesarelimitedtoborealconiferousforestdominated byNorwayspruce(Piceaabies(L.)Karst.)andScotspine(PinussylvestrisL.),withelements ofdeciduousspecies,likeBirch(Betula)(FAO,2001).InPaperII,productionofbioethanol fromlignocellulosicbiomassusedforheavyͲdutytransportisanalyzed.InPaperIIIandIV, theLCAis combined withaforestmodelthatworks withspecificspatialandtime dimensions.Fordemonstrationsonhowtheintegrationofthesetwocanwork,wechosea publiclyownedforestinFredrikstadmunicipality,southeastpartsofNorway,asfundament fortheanalysis.AccordingtoPullaetal.(2013),the“publicforest[…]playakeyrolein sustainingforestecosystems,ensuringbiodiversityprotection,mitigatingclimatechange, enhancingruraldevelopmentandsupplyingtimberandnonͲwoodgoodsandservices”.

GAYAͲJ/LPsimulatesharvestofdifferentspecies(spruce,pineandbirch),qualitiesand dimensions(sawnwood,pulpwoodandloggingresidue)thatformsthebasisfora comparisonbetweendifferentusesoftheharvest.Severalofthemodelledproduction technologieshaverestrictionsonwhatkindofbiomass(speciesanddimensions)theycan utilize.Thus,itwasnecessarytocreateaproductionmixthatdefinedtheshareofharvest allocatedtothedifferentvaluechains.PaperII,IIIandIVarethereforeanalysesbasedon local data, applying a bottomͲup perspective. Nabuurs et al. (2007) reported large

(40)

26

differencesinestimatesofpotentialclimatechangecontributionbyforest,dependingon theperspective(bottomͲupvs.topͲdown),andthatgenerally,bottomͲupstudieshaveless radicalestimates,moredetaileddataandbetterknowledgeaboutimportantassumptions.

5 Results

Inthischapter,resultsarepresentedthatcancontributetoanswertheresearchquestions askedinChapter2,basedontheanalysisinthefourpapers.

Environmentalassessment

WhataretheenvironmentaleffectsofbiomassuseforavarietyofwoodproductsinNorway, andisthereatradeͲoffbetweenecosystemservicesandotherenvironmentalbenefits providedbythewoodproducts?

Aqualitativeassessmentofbiomassproductscomparedtootherproductsthatprovidethe sameservice,showthatwithregardtoGWP,16of17woodproductsperformbetterthan thealternativeproduct(PaperI).Inotherimpactcategories,theresultsaremixed(PaperI, IIandIII).

Forbioethanolusedastransportationfuel,theanalysisshowthatfossildieselperforms better with regard to acidification potential (AD), eutrophication potential (EP) and particularmatterformation(PMFP).Thedifferencesbetweenthetwofuelsareintherange 3Ͳ11%.Intheimpactcategoriesphotochemicaloxidantformation(POFP),ozonedepletion (ODP)andglobalwarming(GWP),thebioethanolperformsbetterthanthefossildiesel.The savingsare19%,82%and80%,respectively(PaperII).

Whenthewoodybiomassisusedforarangeofproductsdescribedbyaproductmix,the emissionsfromtheprocessingofthewoodproductsaresmallerthantheemissionsrelated toproductionofalternativeproducts(replacement).Theproductsintheproductmixhave differentenvironmentalimpactsdepending on productionmethodsandreplacement products(PaperIII).Intwo(eutrophicationandozonedepletionpotential)ofthefiveimpact categoriesinvestigated,woodbasedpackaginghavelargervaluechainemissionsthanthe plasticpackagingitisreplacing,whileconstructionmaterialprovidesbenefitsinallimpact categoriesassessed.Formostoftheproductsandimpactcategories,theproductprocessing isthemostinfluentiallifecyclestage(PaperIII).Withregardtoglobalwarmingpotential,all productsintheassessmentprovideGHGsavingscomparedtothealternativeproducts,with

(41)

27

constructionmaterialandbiorefineryprovidingthelargestbenefits(PaperIII).Thesavings perm³ofharvestedwood,assumingaproductionmixwhichrepresentslocaluseofthe forest resources, varies between 568Ͳ614 kg CO2Ͳeq./m³, depending on the forest managementscenario(PaperIII).Thesavingsperkm²ofproductiveforestvarybetween 18.4Ͳ56.7tonCO2Ͳeq/km²/20yearsand91.4Ͳ275.5tonCO2Ͳeq/km²/100years(PaperIII).

Astheproductmixprovidesenvironmentalbenefitsinallimpactcategories,thereisatradeͲ offbetweenconservationofbiologicaldiversityandotherenvironmentalimpacts.The harvestislimitedbytheforestmanagementrestrictions,andinthebiodiversityͲscenario, the harvest is more than 60 % lower than in the other scenarios (Paper III). The environmentalimpactcharacterizationsfollowmoreorlessthesametrend(Table2).

Table2:Relativeharvestlevel,environmentalbenefitsandnetpresentvalue(NPV)(percentage)oftheforest managementscenarioswhentheproductmixisapplied.

Impactcategory REF PEFC BD

Harvest 100% 92% 33%

GWP 100% 95% 32%

ODP 100% 92% 37%

POFP 100% 98% 28%

AP 100% 98% 39%

EP 96% 100% 35%

NPV 100% 94% 52%

GWP=globalwarmingpotential,ODP=ozondepletionpotential,POFP=photochemical oxidantformationpotential,AP=acidificationpotential,EP=eutrophicationpotential.

Insomecases,therewillbeatradeͲoffbetweenlocalandglobalenvironmentalimpacts.

ThebioethanolinPaperIIperformsbetterthanfossildieselwithregardtotheglobally importantclimatechange,butworseregardingthelocal/regionalimportanteutrophication, acidificationandformationofparticles.

Forestclimatecontribution

WhatistheeffectofincludingbiogenicCO2andalbedoontheestimatedclimatechange mitigationpotentialofbioenergybasedonNorwegianforestresources?

When assessing the global warming potential of bioenergy, the climate neutrality assumptionisimportantastheemissionsofbiogenicCO2fromproductionanduseof bioethanoldominatestheemissionsofGHG(PaperII).IfbiogenicCO2isincludedintheGHG accounting,itconstitutes84%ofthetotalGHGemissionsinPaperII.Fermentingofsugar

(42)

28

andcombustionofethanolarethetwomostimportantsourcesofbiogenicCO2.The warmingeffectofbiogenicCO2andthecoolingeffectofchangedalbedohavebeenincluded intheanalysisofthebioethanolbytheGWPbio,acharacterizationfactorforbiogenicCO2 (Table1).Figure7illustratesthetotalemissionsofCO2Ͳeq./kmunderdifferentaccounting strategiesforbiogenicCO2.

IfthebiogenicCO2isassumedclimateneutral(i.e.GWP=0),thebioethanolprovides 80%loweremissionsofCO2Ͳequvalentsperkm(PaperII).Ifthebioenergyisnotcredited for sequestration of CO2 by growing biomass, and is assumed to have the same characterizationfactorasfossilCO2(i.e.GWP=1),thebioethanolusedforheavyͲduty transportproduce33%moreemissionsofCO2Ͳeq./kmthanfossildiesel.

WhenthewarmingeffectofbiogenicCO2andthecoolingeffectofalbedoisincluded (Figure7),thesavingsofCO2Ͳeq.forbioethanolis57%comparedtofossildiesel(PaperIII).

Ifloggingresiduesareincludedintheharvesting,boththewarmingeffectofbiogenicCO2 andthecoolingeffectofalbedoissmaller(i.e.closertozero)assumingthesameamountof bioenergyharvested.Thismeansthattheclimateeffectofbioenergyissmallerwhen harvestresiduesarecollected.ThesavingsofGHGemissionsperkmdrivenbybioethanol comparedtofossildieselis65%(PaperII).

Figure7:TotalamountofCO2Ͳeq.perkmdrivenbyatruckfueledbyfossildieselorbioethanol.Forthebioethanol, differentassumptionsabouttheclimateeffectofbiogenicCO2andalbedoareillustratedbyGWPvaluesbetweenzero andone.ThebluecolumnsrepresenttheemissionsofallGHGminusbiogenicCO2.GWPbiovaluesarefoundinTable1.

FR=forestresiduescollectedinaddition.

Ͳ1000 Ͳ500 0 500 1000 1500 2000

Fossildiesel GWP=1 GWPbio=0.2 GWPbio(FR)=0.13 GWP=0

kgCO2Ͳeq/km

GHG BioCO2 Albedo