Transportation Fuels Life-Cycle Analysis Using the GREET Model

Transcription

1 Transportation Fuels Life-Cycle Analysis Using the GREET Model Ignasi Palou Rivera Center for Transporta6on Research Energy Systems Division Argonne Na6onal Laboratory January 31, 2012

2 The GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transporta8on) Model Life cycle analysis is an integral part of evalua6on and pursuit of efficient vehicle technologies and new transporta6on fuels GREET LCA model development has been supported by US Department of Energy since 1995 GREET and its documents are available at hpp://greet.es.anl.gov/ The most recent version of GREET (GREET1_2011) was released in Oct There are more than 14,000 registered GREET users 2

3 The GREET Model Estimates Energy Use and Emissions of GHGs and Criteria Pollutants for Vehicle/Fuel Systems Energy use Total energy: fossil energy and renewable energy Fossil energy: petroleum, natural gas, and coal (they are es6mated separately) Renewable energy: biomass, nuclear energy, hydro power, wind power, and solar energy Greenhouse gases (GHGs) CO2, CH4, and N2O CO2e of the three (with their global warming poten6als) Criteria pollutants VOC, CO, NOx, PM10, PM2.5, and SOx They are es6mated separately for Total (emissions everywhere) Urban (a subset of the total) 3

4 The 2007 EISA and Low-Carbon Fuel Standard Development Require Life-Cycle Analysis for Fuels EISA requires LCAs to be conducted to determine if given fuel types meet mandated minimum GHG reduc6ons New ethanol produced from corn: 20% Cellulosic biofuels: 60% Biomass based diesel (e.g., biodiesel): 50% Other advanced biofuels (e.g., imported sugarcane ethanol, renewable diesel, CNG/LNG made from biogas): 50% EPA released a no6ce of proposed rulemaking (NPRM) in early May Low carbon fuel standard development efforts in EU, California, and other states require LCAs for biofuels Life cycle analysis includes All major GHGs (CO2, CH4, and N2O) Both produc6on and use of fuels Direct and indirect land use change impacts 4

5 Key LCA Issues System boundary Construc6on of infrastructure vs. opera6on stages of the complete life cycle Indirect effects primarily via market/pricing effects Technology choices for LCAs LCA comparison among pathway technologies Fuel produc6on: commercial ones vs. emerging ones s6ll at the R&D stage Vehicle technologies: performance equivalency Pathway defini6on: technology op6ons for pathway stages Exis6ng vs. emerging Environmental sustainability vs. economic viability Inter and intra pathway technology choices result in many op6ons; cherry picking results from singular dimension can result in erroneous conclusions Methods of addressing co products of transporta6on fuels Life cycle analysis methodologies APribu6onal LCA: GREET approach Consequen6al LCA 5

6 Life-Cycle Analysis System Boundary: Petroleum to Gasoline 6

7 Life-Cycle Analysis System Boundary: Corn to Ethanol CO 2 in the atmosphere Energy inputs for farming Fertilizer CO 2 via photosynthesis Carbon in kernels CO 2 emissions during fermentation Carbon in ethanol CO 2 emissions from ethanol combustion N 2 O emissions from soil and water streams DGS Direct land use change Indirect land use changes for other crops and in other regions Conventional Animal Feed Production 7

8 GREET Includes More Than 100 Fuel Produc8on Pathways from Various Energy Feedstocks Petroleum Conventional Oil Sands Natural Gas North American Shale Gas Non-North American Corn Sugarcane Soybeans Coke Oven Gas Petroleum Coke Nuclear Energy Gasoline Diesel Liquefied Petroleum Gas Residual Oil (to electricity) Jet Fuel Compressed Natural Gas Liquefied Natural Gas Liquefied Petroleum Gas Hydrogen Methanol Dimethyl Ether Fischer-Tropsch Diesel Fischer-Tropsch Jet Fuel Ethanol Butanol Ethanol Biodiesel Renewable Diesel Renewable Gasoline Renewable Jet Fuel Hydrogen Coal Cellulosic Biomass Switchgrass Fast Growing Trees Crop Residues Forest Residues Residual Oil Coal Natural Gas Biomass Other Renewables (hydro, wind, solar, geothermal) The yellow boxes contain the names of the feedstocks and the red boxes contain the names of the fuels that can be produced from each of those feedstocks. Renewable Natural Gas Landfill Gas Biogas from anaerobic digestion Algae Hydrogen Methanol Dimethyl Ether Fischer-Tropsch Diesel Fischer-Tropsch Jet Fuel Compressed Natural Gas Liquefied Natural Gas Hydrogen Methanol Dimethyl Ether Fischer-Tropsch Diesel Fischer-Tropsch Jet Fuel Ethanol Hydrogen Methanol Dimethyl Ether Fischer-Tropsch Diesel Fischer-Tropsch Jet Fuel Electricity Biodiesel Renewable Diesel Renewable Gasoline Renewable Jet Fuel 8

9 GREET Examines More Than 80 Vehicle/Fuel Systems Conventional Spark-Ignition Engine Vehicles Gasoline Compressed natural gas, liquefied natural gas, and liquefied petroleum gas Gaseous and liquid hydrogen Methanol and ethanol Spark-Ignition, Direct-Injection Engine Vehicles Gasoline Methanol and ethanol Compression-Ignition, Direct-Injection Engine Vehicles Diesel Fischer-Tropsch diesel Dimethyl ether Biodiesel Fuel Cell Vehicles On-board hydrogen storage Gaseous and liquid hydrogen from various sources On-board hydrocarbon reforming to hydrogen Battery-Powered Electric Vehicles Various electricity generation sources Hybrid Electric Vehicles (HEVs) Spark-ignition engines: Gasoline Compressed natural gas, liquefied natural gas, and liquefied petroleum gas Gaseous and liquid hydrogen Methanol and ethanol Compression-ignition engines Diesel Fischer-Tropsch diesel Dimethyl ether Biodiesel Plug-in Hybrid Electric Vehicles (PHEVs) Spark-ignition engines: Gasoline Compressed natural gas, liquefied natural gas, and liquefied petroleum gas Gaseous and liquid hydrogen Methanol and ethanol Compression-ignition engines Diesel Fischer-Tropsch diesel Dimethyl ether Biodiesel 9

10 The Suite of GREET Models GREET 1 Excel model: Fuel cycle (or WTW) modeling for light duty vehicles GREET GUI GUI: Graphic User Interface GREET SST SST: Stochas;c Simula;on Tool GREET APD APD: Algae Process Descrip;on GREET CCLUB CCLUB: Carbon Calculator for Land Use Change from Biofuels Produc;on GREET 2 Excel model: Vehicle cycle modeling for light duty vehicles 10

11 A Process is The Building Block of a Pathway in GREET A process employs technologies Technologies employ fuels and may produce emissions Product Pathway Energy is defined at process level Emissions are defined at technology level. Processes Technologies Fuels and Material Inputs 11

12 I. Fuels and Material Inputs: Product Fuels Biomass Pathway Processes Technologies Fuels and Material Inputs Proper6es: Hea6ng Value, C%, S%, etc. Electricity Nuclear Fer;lizers 12

13 II. Technologies (Combus;on) Emissions of species i [g] Emissions Factor (EF i ) = Unit of Fuel used [mmbtu] Product Pathway Processes Technologies Fuels and Material Inputs Emissions Important Notes: CO2 is calculated by balancing carbon in the fuel with carbon in emissions SOx may be calculated by balancing sulfur in fuel with sulfur in emissions (if no emissions control) EF for power genera6on technologies may be specified in [g/kwhe] Fuel Boilers Fuel Engines Fuel Turbines Fuel Tractors Fuel Trucks 13

14 II. Technologies (Light Duty Vehicles) Product Pathway Emissions of species i [g] Emissions Factor (EF i ) = Vehicle Miles Travelled [mi] Species vector include: Processes Technologies Fuels and Material Inputs CH4 and N2O VOC, CO, NOx, PM10, and PM2.5 Important Notes: CO2 is calculated by balancing carbon in the fuel with carbon in emissions SOx is calculated by balancing sulfur in fuel with sulfur in emissions Emission factors are independent of fuel economy The vehicle technology is a process by itself (PTW) Emissions Fuel VMT 14

15 III. Processes (The Building Blocks of Pathways) Emissions For Energy: Define output input rela6on (e.g., efficiency) Define Process Fuel Share For Emissions: Define Technology share for each process fuel Product Pathway Processes Process Fuel 1 Process Fuel 2 TECH. 1 TECH. 2 Main Product Technologies Fuels and Material Inputs Process Fuel 3 TECH. 3 Process 15

16 Example of Process Defini;on and Calcula;ons in GREET (a) Energy Accoun;ng: Define output input rela6on Efficiency (η) = 98% = energy in product/ all energy input Total Process Fuel used (TPF) = [(1/η) 1 ] x product_energy TPF = [(1/0.98) 1] x 1 mmbtu = 20,408 Btu = total process fuel to recover 1 mmbtu of crude Define Process Fuel Share 2% Residual Oil 15% Diesel 62% NG 21% Electricity Residual Oil (2%) TPF Diesel (15%) Natural Gas (62%) Electricity (21%) Crude Recovery (η=98%) Crude Residual oil = 0.02 x 20,408 = 408 Btu Diesel = 0.15 x 20,408 = 3,061 Btu etc. 16

17 Example of Process Defini;on and Calcula;ons in GREET (b) Emissions Accoun;ng: Define Technology share for each process fuel E i = Σ j Σ k EF i (j, k). PF(j). Share (j,k) Where: Residual Oil 100% Boiler Diesel 75% Engine, 25% Turbine NG 50% Boiler, 50% Engine Electricity Emissions free (at point of use) Residual Oil (408 Btu) E i = Total process emissions of pollutant i EF i (j, k) = Emissions Factor of pollutant i when fuel j is used in technology k Share (j,k) = Share of fuel j used in technology k Example: Diesel (3,061 Btu) Natural Gas (12,653 Btu) Electricity (4,286 Btu) E co = [EF CO,RO_Boiler x 1 x (EF CO,Diesel_Engine x EF CO,Diesel_Turbine x 0.25) Emissions Boiler 3,061 + (EF CO,NG_Boiler x EF CO,NG_Engine x 0.5) 12,653] % 25% Engine Turbine 50% 50% Boiler Engine Crude Recovery Crude 17

18 Example of Process + Upstream Emissions Upstream Process Crude Recovery Crude Transporta6on Crude Refining Fuel Transporta6on Residual Oil Diesel NG Recovery NG Processing NG Transporta6on Natural Gas Crude Recovery Crude Nuclear 21% Renewable 11% Oil 1% Gas 20% Electricity Coal 47% 18

19 Process Energy I/O Defini;on in GREET 1. Efficiency Power Plant Example: Electric energy (output) per fuel energy (input) 2. Yield EtOH Dry Mill Example: Gallons of Ethanol (output) per Bushel of Corn (input) 3. Energy intensity. Payload. Transporta;on distance Payload [ton] Energy Intensity [Btu/ton mi] Payload [ton] A Distance [mi] B 19

20 Three Categories of Process Emissions in GREET 1. Combus6on emissions (e.g., engines, boilers, turbines, etc.) 2. Non combus6on emissions (e.g., SMR, GTL, etc.) 3. Other emissions (from internally produced fuels) Process Fuel 1 Combus6on Process Fuel 2 Chemical Conversion internally produced fuel Main Product 20

21 Process Related Parameters in GREET Input / output rela6on (e.g., efficiency, yield, energy intensity, etc.) Co product amount (e.g., steam, electricity, etc.) Energy for carbon capture and sequestra6on (CCS) Market shares of feedstock or product (Petroleum/oil sands, CG/RFG, electricity genera6on mix, etc.) Technology shares (e.g., NG simple cycle / NG steam cycle / NG combined cycle, Dry mill / wet mill, etc.) 21

22 IV. Energy Accoun;ng Throughout A Pathway in GREET Product Pathway Processes Technologies feed fuel 1 Process 1 1 Process 2 1 Process 3 1 Vehicle Fuels and Material Inputs up feed Where: Σ i x i +up xi Σ j y j +up yj Σ k z k +up zk Traveling distance up feed is upstream energy needed to produce 1 unit of feed x, y, and z are energy in process fuels or input materials up x i is upstream energy needed to produce x i amount of fuel or material i 22

23 Process Co Products Handling Methodology in GREET Several methods are implemented in GREET: Displacement (of equivalent product) Alloca6on Energy based Mass based Market value based Hybrid 23

24 Co Product Methods: Benefits and Issues Displacement method Data intensive: need detailed understanding of the displaced product sector Dynamic results: fluctuate with economic and market modifica6ons Alloca6on methods: based on mass, energy, or market revenue Easy to use Frequent updates not required for mature industry, e.g. petroleum refineries Mass based alloca6on: not applicable for certain cases Energy based alloca6on: less accurate with non fuel co products Market revenue based alloca6on: subject to price varia6on Process energy use approach Requires detailed engineering analysis Must allocate upstream burdens based on mass, energy, or market revenue There is no consensus in policy and research arena on which method is the most appropriate; GREET offers several methods for users to select 24

25 Choice of Co-Product Methods Can Have Significant LCA Effects for Biofuels 80,000 D M E $ P D E $ D M E $ $ D M E H GHG Emissions (g/mmbtu). 40, ,000-80, ,000 Gasoline PTW WTP WTW Diesel E1 Corn Ethanol E2 E3 E4 E5 D: Displacement M: Mass based E: Energy Based Switchgrass to Ethanol E1 E2 E3 D1 Biodiesel D2 D3 D4 $: Market Value P: Process Purpose H: Hybrid Alloca6on D1 Renewable Diesel D2 D3 D4 D5 In Wang et al. (Energy Policy J., 2011) 25

26 Co-Product Displacement of Equivalent Product Emissions Emissions (Credits) Process Fuel 1 Process Fuel 2 Feed Process Important Notes: Main Product Co Product Displaced Product Main product carry the burden of all process energy and emissions Energy (Credits) Displacement of equivalent amount Feed (Credit) Co product does not carry any burden Displaced product is iden6cal or equivalent to co product If not iden6cal, a displacement ra6o may apply All life cycle energy and emissions of the displaced product are credited to main product For large co product/main product ra6o, credits may overwhelm main process emissions 26

27 Alloca;on of Process Energy and Emissions to Co Products Emissions Process Fuel 1 Process Fuel 2 Feed 1 x x 1 x x 1 x x 1 x x Important Notes: Process Main Product (1 x) Co Product (x) x is the ra6o of co product in all products by mass, energy, or market value Main product and co product carry energy and emissions burden based on their ra6os in the total products The main product and co product are equivalent (func6on at end use, quality, etc.) Same process efficiency applies to all products for energy alloca6on (implied) 27

28 Main Effort and Challenge of LCAs: Data, Data, Data General Data Sources for GREET Open literature: transparent but much varia6on in data quality Process modeling (such as Argonne s own ASPEN Plus and Autonomie simula6ons): some6me specula6ve for yet developed commercial technologies Companies and technology developers: osen proprietary and less transparent Engagement of the whole community (LCA prac66oners, researchers, developers, agencies, etc.) and data source transparency are cri6cal 28

29 Two Dis8nctly Different Uncertain8es in LCAs System uncertain6es LCA methodology inconsistency: apribu6onal vs. consequen6al System boundary selec6on: a moving target Treatment of co products These issues cause inconsistencies among LCA studies and results Technical uncertain6es related to data availability and quality Varia6on in input parameters and output results Stochas6c simula6on feature is incorporated in GREET Model and LCA analysis transparency can help advance understanding and consensus building 29

30 Sample GREET WTW Results for Selected Vehicle/Fuel Options: Fossil vs. GHGs From Wang et al. (forthcoming ) 30

31 Sample GREET WTW Results for Selected Vehicle/Fuel Options: Petroleum vs. GHGs From Wang et al. (forthcoming ) 31

32 GREET Team at Argonne 11 staff on LCA research and GREET development Dr. Michael Wang: group leader Mr. Andy Burnham: vehicle cycle analysis, and natural gas pathways, and GREET user help Dr. Corrie Clark: geothermal and shale gas process analysis and water resource/quality assessment Dr. Jennifer Dunn: biofuels, soil carbon, baperies, and GREET applica6ons Dr. Amgad Elgowainy: hydrogen fuel vehicles, plug in electric vehicles, GREET development Dr. Ed Frank: algae based biofuels, electric power genera6on systems Dr. Jeongwoo Han: renewable natural gas, pyrolysis, vehicle technologies, GREET development Ms. Marianne Mintz: renewable natural gas pathways Dr. Ignasi Palou Rivera: biofuels and petroleum fuels process modeling and LCA applica;ons Dr. John Sullivan: vehicle cycle analysis and geothermal and conven6onal power systems Dr. May Wu: biofuels and water resource/quality assessment Two post doctoral researchers on GREET LCA Four GREET.net programmers Other organiza6ons who help Argonne MassachusePs Ins6tute of Technology Purdue University University of Illinois at Chicago and at Urbana Champaign University of Michigan at Ann Arbor The Great Plains Ins6tute 32

33 Extra Slides 33

34 GREET Includes Many Biofuel Production Pathways Ethanol via fermenta6on from Corn Sugarcane Soybeans to Cellulosic biomass Biodiesel Crop residues Renewable diesel Dedicated Renewable gasoline energy crops Forest Renewable residues jet fuel Renewable natural gas from Landfill gas Anaerobic diges6on of animal wastes Corn to butanol Cellulosic biomass via gasifica6on to Fischer Tropsch diesel Fischer Tropsch jet fuel Cellulosic biomass via pyrolysis to Gasoline Diesel Algae to Biodiesel Renewable diesel Renewable gasoline Renewable jet fuel 34

35 Electricity Generation Systems in GREET Coal: Steam Boiler and IGCC Coal mining and cleaning Coal transporta6on Power genera6on Natural Gas: Steam Boiler, Gas Turbine, and NGCC NG recovery and processing NG transmission Power genera6on Nuclear: Light Water Reactor Uranium mining Yellowcake conversion Enrichment Fuel rod fabrica6on Power genera6on Residual Oil: Steam Boiler Oil recovery and transporta6on Oil refining Residual oil transporta6on Power genera6on Biomass: Steam Boiler Biomass farming and harves6ng Biomass transporta6on Power genera6on Hydro Power Wind Power Solar Power via Photovoltaics Geothermal Power 35

36 Many Hydrogen Produc8on Pathways Are Included in GREET NA NG NNA NG NNA Flared Gas Landfill Gas Nuclear Energy Gaseous H2 Liquid H2 Gaseous H2 Liquid H2 Central Plant Produc6on: No C Sequestra6on C Sequestra6on Distributed Produc6on Central Plant Produc6on: HTGR H 2 O Splivng HTGR Electrolysis Distributed Produc6on: LWR Electrolysis HTGR Electrolysis Central Plant Produc6on: Standalone Steam Co Genera6on Electric Co Genera6on HTGR High temp. gas cooled reactors LWR light water reactors Biomass Gaseous H2 Liquid H2 Central Plant Produc6on: No C Sequestra6on C Sequestra6on Central Plant Produc6on: Standalone Electric Co Genera6on Coal Gaseous H2 Liquid H2 Central Plant Produc6on: No C Sequestra6on C Sequestra6on Central Plant Produc6on: Standalone Electric Co Genera6on Methanol Ethanol Gaseous H2 Liquid H2 Distributed Produc6on Solar Energy Gaseous H2 Liquid H2 Central Plant Produc6on via PV Electricity Gaseous H2 Liquid H2 Distributed Produc6on via Electrolysis Coke Oven Gas Pet Coke Gaseous H2 Liquid H2 Gaseous H2 Central Plant Produc6on Central Plant Produc6on: No C Sequestra6on C Sequestra6on Central Plant Produc6on: Standalone Electric Co Genera6on 36

37 Key Steps to Address GHG Emissions of Potential Land Use Changes by Large-Scale Biofuel Production Simula6ons of poten6al land use changes (in collabora6on with Purdue) Significant efforts have been made in the past three years to improve exis6ng computa6onal general equilibrium (CGE) models More efforts are being made to address addi6onal biomass feedstocks Carbon profiles of major land types (in collabora6on with UIC and UIUC) Both above ground biomass and soil carbon are being considered Of the available data sources, some are very detailed (e.g., the DAYCENT model) but others are very coarse (e.g., the IPCC data) There are mismatches between CGE simulated land types and land types in available carbon databases: satellite data with ground truthing

38 What Is New in GREET1_2011? Algae biofuel pathways, with the algae process descrip6on (APD) with detailed assump6ons of the key stages of the algae pathways Pyrolysis pathways from cellulosic biomass to renewable gasoline and diesel Shale gas pathway and updated natural gas pathways Renewable natural gas pathways from anaerobic diges6on of animal waste Jet fuel pathways, including opera6on of various classes of commercial aircrass Op6onal inclusion of energy uses and emissions associated with the construc6on of petroleum and natural gas wells, coal mines, and various electric power genera6on systems Geothermal power plant op6ons, including both opera6on and construc6on phases Updated petroleum recovery and refining efficiencies Updated farming assump6ons for corn stover, forest residue, switchgrass, sugarcane and soybean 38

39 Aviation Fuel Options in GREET1_2011 Fuels and Feedstocks Pyrolysis Oil Jet Fuel Crop Residues Forest Residues Dedicated Energy Crops Hydrotreated Renewable Jet Fuel Soybeans Palm Oil Rapeseeds Jatropha Camelina Algae Fischer Tropsch Jet Fuel North American Natural Gas Non North American Natural Gas Renewable Natural Gas Shale Gas Biomass via Gasifica;on Coal via Gasifica;on Coal/Biomass via Gasifica;on Aircrad Types Passenger Aircrad Single Aisle Small Twin Aisle Large Twin Aisle Large Quad Regional Jet Business Jet Freight Aircrad Single Aisle Small Twin Aisle Large Twin Aisle Large Quad LCA Func;onal Units Per MJ of fuel Per kg km Per passenger km (In collabora6on with MIT PARTNER) 39

40 Near Future GREET Upgrades and Updates An upgraded CCLUB for biofuel LUC GHG emissions Expansion on construc6on of fuels produc6on and distribu6on infrastructure An upgraded and updated GREET2 vehicle cycle version A detailed bapery LCA module Updated energy and emission profiles of key vehicle materials A detailed module on vehicle assembling, disposal, and recycling Alpha and beta tes6ng of GREET.net version Parallel development of GREET Excel and.net versions 40