WhatiftheDunedinEnergyCentreconvertedto

woodfuel?

AsummerprojectbyEllaOberschneiderSupervisedbyMichaelJack,PhysicsDepartment,

UniversityofOtago(michael.jack@otago.ac.nz)

DunedinEnergyCentre(DEC)

University

DunedinHeatCentre

Hospital

Cadbury

• Internationallydistrictheatingisregardedasasustainable,low-costmethodofsupplyingheat1

• NZ’slargestdistrictheatingplant(30MWcapacity)

• Supplies~60GWh/yearofheatto:• UniversityofOtago• DunedinHospital• Cadbury

• Burns13thousandtonnes ofcoalperyear• From2010to2016carriedouttrialsto

burnwoodfuelinsteadofcoal• Notechnicalconstraints!• Similarresultsfoundinternationally2

1http://www.ieabcc.nl/publications/IEA_Task32_DHS_Cost_Analysis.pdf;http://www.ieabcc.nl/publications/IEA_Task32_DHS_Status_Report.pdf2http://www.ieabcc.nl/publications/IEA_Bioenergy_T32_cofiring_2016.pdf

WhatiftheDECconvertedtowoodfuel?

• Aretheresufficientsuppliesofwood?• WhatwouldtheGreenhouseemissionreductionsbe?• Whatwouldtheimpactonthelocalenvironmentbe?• WhataretheeconomicconsequencesforDunedin?• Jobs?• Marketing?

Woodfuelavailability

Growingharvestvolumesplentifulsuppliesofresidueslongterm

Source:http://woodco.org.nz/images/stories/pdfs/woodscape/woodscaperegionalreportfinal2_web.pdf

Woodfuelavailability

Basedonhistoricplantings,morethanenoughsustainably-managedplantationwoodwasteavailableforfuelintheDunedinarea(estimatesincludeonlycost-effectivelandingsiterecovery)

Heatene

rgyprod

uctio

n(GWh)

Greenhousegasemissions

• TheDHCcurrentlyburns13thousandtonnes ofcoalperyear

• Combustingthiscoalreleases27thousandtonnes ofCO2peryear1 – 1/2oftheCO2 emissionsfromcoalinDunedin2

• Incontrast,woodfuelhaszeroCO2 emissions(aslongastreesarereplanted).AllCO2 isreabsorbedbygrowingtrees.

• Therearealsosmallamountslife-cycleemissionsassociatedwithbothcoalandwood(e.g.fromextraction,harvestingandtransport).

1Emissionfactorof2.08tCO2-e/tcoal,MfE2EECAEndUseDatabase

Localenvironmentalimpact

• Woodproduceslessparticulateemissions(P10).• Inpractice,particulateemissionsarerelativelyeasilycontrolledforlargemoderncoalandwoodheatplants(lesseasyforsmallboilersanddomesticfires)• Otherharmfulairemissionsaresignificantlyhigherforcoalthanwood• NO2 (30%greater)• SO2 (5xgreater)– difficulttocontrolincoalheatplant• heavymetals

• Ash:Coalproducesx10theashofwoodanditisnotcompostable

http://www.ieabcc.nl/publications/Nussbaumer_et_al_IEA_Report_PM10_Jan_2008.pdfhttp://file.dnr.wa.gov/publications/em_forest_biomass_and_air_emissions_factsheet_8.pdf

Economicimpact• Internationalstudiesfoundthatwoodfuelrequires4FTEforeveryFTEforcoal1.E.g.conversionofDECcouldpossiblyresultin~17additionaljobs1.

• Benefittolocaleconomy- nocoalminesinDunedinbutlocal plantationforests.

• MarketingDunedin’sCleanGreenImage• EnvironmentalstatusofNZworth>$900Mintourism

• InUS>60%ofstudentstakesustainabilityintoaccountwhenchoosingaUniversity2 – NZlikelytofollowsuit

• ClosertohomeaOtagoUniversityAssociationsurveyfound>70%ofstudentswanttheUniversitytoreduceinvestmentinfossilfuels

1http://www.sciencedirect.com/science/article/pii/S09619534971000582PrincetonReview2016CollegeHopes&WorriesSurveyReport

Lookingtothefuture

• DunedinEnergyCentre:50yearoldboilers–Opportunityfornewmodernwoodboilers(10yeartimeframe)

• OtagoUniversity - seekingtomovetowardscarbonneutralcampus– LargestopportunitytoreduceemissionsisfromDECmovingtowoodfuel• notechnicalbarrierstothishappeningtoday!

• Hospitalrebuild– Opportunitytocontinuewithlow-cost,sustainableheatsource(ifDECmovestowoodfuel)

• PossibilityofexpandingheatpipenetworktootherpartsofDunedin(e.g.centralcity)– mostcost-effective,sustainableheatingsolutionforlargeusers

Conceptualplanofcentralcitydistrictheatingscheme.

CourtesyofNevilleAuton

WhatiftheDECconvertedtowoodfuel?

• Aretheresufficientsuppliesofwood? Plentifulsuppliesofwoodfueldrivenbylong-termincreasesinharvestvolumes

• WhatwouldtheGreenhouseemissionreductionsbe?27thousandtonnesperyear- ½Dunedin’stotalemissionsfromcoal(inoneeasyhit!)

• Whatwouldtheimpactonthelocalenvironmentbe?Lessparticulates,lessNOX ,SOx andheavymetals.Large-scaleheatplantsminimalizeairemissions.

• WhataretheeconomicconsequencesforDunedin?• Jobs?Increaseinlocaljobsandbenefitstolocaleconomy• Marketing?Significantmarketingbenefits

CurrentHeatPlant-

Coal

CurrentHeatPlant– Wood

Fuel

2018NewModernHeatPlant–WoodFuel

ExpandedHeatNetwork

2023 2028

Apossiblefuture

UniversityandHospitalcommittowoodfuels

ExpansiontocentralcityHospitalrebuildfeatureswood-

fueleddistrictheating