FAQunitemissionsFAQ单位排放.doc

FAQs- UNIT EMISSIONSInformation on the Data Sources Used to Obtain the Greenhouse Gas (GHG) Unit Emission FactorsThe data for each combination study region- waste management process obtained from facilities during the data collection survey and supplemented with literature data (See April 14, 2009 Interim Project Report) were used as input to RTIs MSW DST. RTIs MSW DST provided study region- waste management process- waste category specific GHG emission factors for the following processes: Collection Transportation for all modes, except ocean freighter. Franklin Associates, LTD. (1998) was used for ocean freighter. Compost preparation, excluding application Chipping and grinding, excluding application (emissions from tub grinders and rolling stock operation as obtain from the MSW DST were used) Recycling, separation and remanufacturing (excluding forest carbon sequestration) BTE (data were obtained only for combustion of biomass and energy recovery) WTE Landfill disposal (excluding carbon storage)RTIs MSW DST does not provide emission factors for N2O, only for CO2 and CH4, and RTI used the following data sources to obtain N2O emissions: Used IPCC (2006) and data collected during compost sampling for Brown et al. (2009) for compost preparation (excluding application) Used US.EPA (2006) and Franklin Associates, LTD. (1998) for WTE and BTE Used IPCC (2006) for AD, landfill disposal (leachate treatment and energy generation at landfills with energy recovery)N2O emissions from other processes (e.g., transportation) are less significant than CO2 emissions. When data were available from the sources consulted RTI considered those data and additional data sources were not consulted.RTI used additional data sources for other processes not included in the MSW DST as follows: Used data collected during compost sampling for Brown and Cotton (2009) for compost and mulch application emission burdens Used ROU (2006) for compost and mulch application energy burdens and for compost application energy offsets Used Brown and Cotton (2009) for compost application emission offsets Used US.EPA (2006), for recycling emissions offsets associated with forest carbon sequestration Used RTIs AD model (RTI, 2005) in combination with the data presented in the April 14, 2009 Interim Project Report for AD emissions and energy burdens and offsets Used Franklin Associates, LTD. (1998) for emissions burdens associated with using natural gas as supplemental fuel in BTE facilities Used CARB (2009) for energy and emission burdens associated with CNG production and Franklin Associates, LTD. (1998) for offsets associated with replacing natural gas with CNG as vehicle fuel. Used Staley and Barlaz (2009) for landfill emission offsets associated with carbon storageInformation on the Calculations Used to Obtain the By-Process Greenhouse Gas (GHG) Unit Emission Factors RTI calculated net emission factors for each waste management process according to the LCA boundaries defined in the April 14, 2009 Interim Project Report. Burdens and offsets were identified and factored in as presented in the following table.Waste Management ProcessProcess ComponentBurdens (A)Offsets (B)% Mass Flow to Different Activities (C) (1)Net Value CalculationCompost CollectionNAUser DefinedC = (A)Compost preparation- Windrow or ASPNAUser DefinedP = (A)Compost applicationVaries according to the waste category or User DefinedA = (A) - (B)Product (compost) transportationNAVaries according to the waste category or User DefinedPT = (A)Residuals transportationNAUser DefinedRT = (A)Residuals disposal at LF (1)User DefinedLF = (A) - (B)COMPOST NET GHG EMISSION OR ENERGY FACTOR (CNEMF)CNEMF = C + P + (C)*A + (C)*PT + (C)*RT + (C)*LFChipping and GrindingCollectionNAUser DefinedC = (A)Mulch preparationNAUser DefinedP = (A)Mulch applicationUser DefinedA = (A) - (B)Product (mulch) transportationNAUser DefinedPT = (A)Residuals transportationNAUser DefinedRT = (A)Residuals disposal at LF (1)User DefinedLF = (A) - (B)CHIPPING AND GRINDING NET GHG EMISSION OR ENERGY FACTOR (C&GNEMF)C&GNEMF = C + P + (C)*A + (C)*PT + (C)*RT + (C)*LFRecyclingCollectionNAUser DefinedC = (A)Separation at MRFNAUser DefinedS = (A)RemanufacturingUser DefinedR = (A) - (B)Product (recyclables) transportationNAUser DefinedPT = (A)Residuals transportationNAUser DefinedRT = (A)Residuals disposal at LF (1)User DefinedLF = (A) - (B)RECYCLING NET GHG EMISSION OR ENERGY FACTOR (RNEMF)RNEMF = C + S + (C)*R + (C)*PT + (C)*RT + (C)*LFAnaerobic DigestionCollectionNAUser DefinedC = (A)ADUser DefinedAD = (A) - (B)Leachate treatmentNAUser DefinedLT= (A)Leachate transportationNA (8)NANA Ltrans= (A)Compost preparation (2)NAUser DefinedP = (A)Compost applicationUser DefinedA = (A) - (B)Product (compost) transportationNAUser DefinedPT = (A)Residuals transportationNAUser DefinedRT = (A)Residuals disposal at LF (1)User DefinedLF = (A) - (B)AD NET GHG EMISSION OR ENERGY FACTOR (ADNEMF)ADNEMF = C + AD + (C)*LT + (C)*P + (C)*A + (C)*PT + (C)*RT + (C)*LFBiomass to-Energy (BTE)CollectionNAUser DefinedC = (A)BTEUser DefinedBTE = (A) - (B)Residuals transportationNAUser DefinedRT = (A)Residuals disposal at Ash LFNAUser DefinedLF = (A) BTE NET GHG EMISSION OR ENERGY FACTOR (BTENEMF)BTENEMF = C + BTE + (C)*RT + (C)*LFWaste to-Energy (WTE)CollectionNAUser DefinedC = (A)WTEUser DefinedWTE = (A) - (B)Ferrous separation at WTE facilityNAUser DefinedS = (A)Ferrous remanufacturingUser DefinedR = (A) - (B)Product (ferrous material) transportationNAUser DefinedPT = (A)Residuals transportationNAUser DefinedRT = (A)Residuals disposal at Ash LFNAUser DefinedLF = (A) WTE NET GHG EMISSION OR ENERGY FACTOR (WTENEMF)WTENEMF = C + WTE + (C)*S + (C)*R + (C)*PT + (C)*RT + (C)*LFLandfill (LF) DisposalCollectionNAUser DefinedC = (A)LF VentUser DefinedLFV = (A) - (B)LF FlareUser DefinedLFF = (A) - (B)LF Energy Recovery (ER)User DefinedLFER = (A) - (B)LF Compressed Natural Gas (CNG)User DefinedLFCNG = (A) - (B)Leachate treatmentNAUser DefinedLT= (A)Leachate transportationNAUser DefinedLtrans= (A)LF NET GHG EMISSION OR ENERGY FACTOR (LFNEMF)LFNEMF = C + LFV or LFF or LFER or LFCNG + (C)*LT + (C)*Ltrans(1) Values presented as percentage of incoming waste and according to information presented in the April 14, 2009 Interim Project Report.(2) Residuals disposal is assumed to happen at a landfill with flaring.NA: Not ApplicableGreenhouse gas (GHG) emission factors for LF CNG were estimated according to the following table:Waste Management ProcessProcess ComponentBurdens Data Sources (A)Offsets Data Sources (B)% Mass Flow to Different Activities (C) (1)Net Value CalculationLandfill (LF) Compressed Natural Gas (LF CNG)CollectionRTIs MSW DSTNA100%C = (A)LF CNGLandfill disposalRTIs MSW DST and IPCC (2006) (2)NA100%LF disposal = (A) Pathway for CNG including landfill gas (LFG) recovery, LFG pipeline transport, LFG cleanup and compression to natural gas (NG), gas transport, natural compression at refueling station, and fuel combustionCARB (2009)Franklin Associates, LTD. (1998) (3)Varies according to the LFG generation potential of the waste stream and the gas quality, i.e., CO2 vs. CH4. LFG generation potential was obtained from RTIs MSW DST and gas quality was assumed to be 50% CH4.Pathway for CNG = (A) - (B)Leachate treatmentRTIs MSW DST and IPCC (2006)NA5% (5)LT= (A)Leachate transportationRTIs MSW DSTNA5% (5)Ltrans= (A)LF NET GHG EMISSION OR ENERGY FACTOR (LFNEMF)LFNEMF = C + LF disposal + Pathway for CNG + (C)*LT + (C)*Ltrans(1) Values presented as percentage of incoming waste and according to information presented in the April 14, 2009 Interim Project Report.(2) Assumed to be the same as those estimated for a landfill with energy recovery (LF ER).(3) For offsets associated with replacing natural gas with CNG as vehicle fuelNA: Not ApplicableReferencesARI (Alternative Resources, Inc.). 2007. Los Angeles County Conversion Technology Evaluation Report- Phase II. Prepared for The County of Los Angeles, Department of Public Works. October.Brown, S. and Cotton, M. 2009. Benefits of compost use: Results of on-farm sampling. Report Prepared for the CIWMB (CA Integrated Waste Management Board).CARB (CA Air Resources Board). 2009. Detailed California-Modified GREET Pathway from Compressed Natural Gas (CNG) from Landfill Gas, Version 2.1. February 28.CARB (CA Air Resources Board). 2008. Local Government Operations Protocol.Franklin Associates, LTD. 1998. Energy Requirement and Environmental Emissions for Fuel Consu