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Clean Cities GREET Life cycle NG

The document discusses using Argonne National Laboratory's GREET model to estimate the benefits of alternative fuel vehicles through life-cycle analysis. It introduces the GREET model, which evaluates energy use and emissions from vehicle/fuel systems on a well-to-wheels basis. As an example of its use, recent research on greenhouse gas emissions from shale gas is mentioned. The document outlines how the GREET model separates energy use and estimates emissions, allowing life-cycle comparisons of different vehicle and fuel options.

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Using Argonne’s Modeling Software to Estimate Benefits of Alternative Fuel Vehicles Andy Burnham Clean Cities University Workforce Development Program Webinar August 8, 2012
Outline  Life-Cycle Analysis and GREET Model Introduction  Example of Current Life-Cycle Analysis Research – Shale gas greenhouse gas emissions  GREET Fleet Footprint Calculator Introduction 2
Life-Cycle Analysis and GREET Model Introduction 3
From the Department of Energy’s Perspective Transportation Sector: Dual Challenges, Dual Approaches  Challenges – Oil use (energy security) – Greenhouse gas emissions (climate change)  Approaches – Vehicle efficiency – New transportation fuels 4
U.S. Petroleum Production and Consumption 1970-2030 20 18 16 Million barrels per day Air Rail 14 U.S. Production Marine Off-Road 12 Heavy Trucks 10 8 Light Trucks 6 4 Cars 2 0 70 75 80 85 90 95 00 05 10 15 20 25 30 19 19 19 19 19 19 20 20 20 20 20 20 20 Sources: Transportation Energy Data Book: Edition 27 and projections from the Early Release Annual Energy Outlook 2009. 5
Highway Vehicles Contribute Significantly to U.S. Greenhouse Gas Emissions Heavy Duty Trucks & Buses Commercial 21% 19% Transportation 33% Air Light Duty 8% Residential 65% Water 22% 2% Rail 2% Industrial 26% Pipelines Other 2% 0% 2009 Fossil Fuel GHG Emissions by End-Use Sector 2009 Fossil Fuel GHG Emissions by Transportation Mode 2009 U.S. GHG emissions from fossil fuels = 5.2 Gt of CO2e (EPA 2011) 6
Life-Cycle Analysis for Vehicle/Fuel Systems Has Evolved in the Past 30 Years  Pursuing reductions in transportation petroleum use and GHG emissions requires for well-to-wheels (WTW) analyses  Pioneering WTW analyses began in 1980s – Early studies were motivated primarily by battery-powered EVs  Recent studies are motivated primarily by introduction of – New fuels such as cellulosic ethanol – New vehicle technologies such as plug-in hybrids 7
Life-Cycle Analysis of Vehicle and Fuel Systems in the GREET Model 8
The GREET Model Estimates Energy Use, GHGs, and Criteria Pollutants  Separates energy use into: – Total energy • Fossil energy • Renewable energy  Includes emissions of greenhouse gases – CO2, CH4, and N2O  Estimates emissions of six criteria air pollutants – VOC, CO, NOx, SOx, PM10, and PM2.5  The GREET model and its documents are available at Argonne’s website at http://greet.es.anl.gov/ 9
Taking the Results from GREET Can Provide Us with a Life-Cycle Comparison As an example, greenhouse gases are illustrated here 600 Pump to Wheels Well to Pump Vehicle Cycle 500 GHG Emissions (g/mi.) 400 300 200 100 0 ) ) e e n) e G ix cl cl cl (N or M hi hi hi (C S Ve Ve le Ve (U ic e rid as e cl eh e lin hi cl G yb lV o Ve hi al as H el Ve ur 5 C G E8 at ic el N tr Fu ec 2 El H 10
Example of Current Life-Cycle Analysis Research 11
Shale Gas Has Been Described as a Game Changing Resource, Which Could Permit Expanded NG Usage Source: EIA Annual Energy Outlook 2011 12
However Boom in Shale Gas Production Has Brought Attention to its Potential Environmental Impacts  Large-scale production made possible due to recent advancements – Horizontal drilling – Hydraulic fracturing  Environmental issues are beginning to be examined – Water quality – Water quantity – Local air pollution – Greenhouse gas emissions Source: EPA 13
EPA Has Recently Made Significant Changes to the Estimate of CH4 Emissions from the Natural Gas System Source: EPA – U.S. GHG Inventory Archive  Major changes include adding emissions from shale gas operations 14
Scope of Argonne’s Natural Gas Life-Cycle Analysis  Developed GREET shale gas pathway – Updated CH4 leakage estimates for conventional NG, petroleum, and coal pathways  Focus of analysis was to estimate uncertainties and identify data gaps to provide insight to NG industry and government (Photographs by J. Veil) Natural Gas Transmission and Well Infrastructure Processing End Use Recovery Distribution 15
Key Issues Affecting Natural Gas Life-Cycle Results  Estimated Ultimate Recovery (EUR)  Shale Gas Well Completion Emissions  Conventional Gas Liquid Unloading Emissions  Global Warming Potential  End Use Efficiency 16
Periodic Well Emissions Must be Allocated Over Lifetime NG Production  Several key activities are estimated on a per-well basis – Lower the EUR, larger the impact  Shale gas EURs are highly uncertain as industry is in its infancy – Wide range for several plays  Conventional NG productivity is declining – Lower EUR than key shale plays Low EUR High EUR Estimate (Bcf) Estimate (Bcf) Barnett 1.4 3.0 Marcellus 1.4 5.2 Fayetteville 1.7 2.6 Haynesville 3.5 6.5 Shale Per-Well 1.6 5.3 Weighted Avg. Conventional Avg. 0.8 1.2 17
Shale Gas Completions CH4 Emissions Could Be Large, But Industry Data Says Much is Recovered  After hydraulic fracturing, a large volume of frac fluid & produced water return to the surface – Flowback water contains NG, which can be vented, flared, or captured  EPA estimates “uncontrolled” CH4 emissions – Data used by EPA to calculate emissions have significant questions  EPA then calculates amount of NG flared and captured by industry practices using NESHAP regulations and NG STAR reporting – Emissions were reduced by ~40% from 2005-2009 – Lack of transparency as data is highly aggregated 18
EPA’s Estimates Liquid Unloadings Account for Half of Uncontrolled CH4 Emissions From NG Production  Accumulation of fluids in wet NG wells can eventually stop production – Assumed to only occur in conventional wells (shale typically dry) – Removing liquids can be accomplished by several practices/technologies  Similar to issues with completion emissions, uncertainty arises from – Suitability of NG STAR data to calculate uncontrolled emissions – Lack of transparency regarding NG STAR reductions  Our examination found that liquid unloading emissions are potentially more significant than those from shale gas well completions 19
Global Warming Potential is a Simple Measure to Compare Radiative Effects of Different Gases  Need to choose a time-horizon when comparing emission impacts of different fuels – Especially important when comparing contributions of short-lived gases • CH4 has an atmospheric lifetime of ~12 years  IPCC recommends using a 100-year time-horizon when evaluating climate change mitigation policies  Other researchers have suggested a 20-year time-horizon should be examined – Effects of CH4 emissions are amplified  We use the 100-year time-horizon in our analyses – Also present 20-year for comparison to other studies 20
End-use Efficiency is a Key Factor for LCA Results  Compared to gasoline cars, NG cars have slightly lower fuel economy – Base case = 5% reduction • Weight penalty of CNG storage tanks • Power loss due to oxygen displacement – Use of direct injection and turbocharging can improve fuel economy and power  Compared to diesel transit buses, NG buses have moderately lower fuel economy – Base case = 15% reduction • Spark-ignited engines have low efficiency at low speeds – However NG spark-ignited engines have closed the gap on compression- ignition engines • Primarily due to emission control strategies implemented for diesels to meet 2010 regulations 21
CNGVs Using Fossil NG May Provide Small GHG Benefit, Improving Vehicle Efficiency Would Help  Interesting result - base-case shale gas emissions are lower than conventional NG – Values overlap so can’t say one is actually better than the other 22
Shale Gas and Conventional NG Summary  Estimates of CH4 leakage from NG have increased significantly  Shale gas completion emissions could be large in theory – However, industry reports that a significant amount is captured – Data is extremely limited and there is a lack of transparency • Several efforts underway to get better data  Conventional NG liquid unloadings are potentially a larger source than shale gas completions – Causes the greatest amount of uncertainty in our study  Shale and conventional NG may provide small GHG benefits for passenger cars and transit buses – NGV efficiency is a key factor for improvement 23
GREET Fleet Footprint Calculator Introduction 24
GREET Fleet Allows Users to Estimate Petroleum and Carbon Footprints  Starting in 1998, US DOE and EPA co-sponsored Argonne to develop a tool, AirCRED, to assist Clean Cities coalitions to estimate ozone precursor and carbon monoxide emission credits from AFVs – For use in State Implementation Plans (SIPs)  Now with the interest in measuring petroleum use and carbon/greenhouse gas emissions, Clean Cities sponsored Argonne to develop the GREET Fleet Footprint Calculator – Developed in Microsoft Excel and uses simple spreadsheet inputs – Results are on WTW basis  This tool was designed for: – On-road-medium and heavy-duty vehicles – Off-road equipment 25
GREET Fleet is Available for Download  Contains 12 fuel/vehicle types – Conventional: gasoline and diesel – Hybrid: diesel HEV – Alt. fuel: biodiesel (B20 and B100), ethanol (E85), CNG, LNG, LPG, electricity, gaseous and liquid hydrogen • Additional simulation options include: – Corn vs. cellulosic ethanol – North American NG vs. Non North American NG vs. Landfill Gas – Electricity mix (% coming from coal, natural gas, nuclear, etc.) – Several hydrogen production pathways  GREET Fleet is based off the current public version of GREET  You can find GREET Fleet and its user manual at: http://greet.es.anl.gov/fleet_footprint_calculator 26
GREET Fleet Tutorial Comparing On-Road Vehicle Technologies for Potential Acquisitions 27
GREET Fleet Tutorial – Comparing On-Road Vehicle Technologies for Potential Acquisitions  First step: choose how to calculate footprint on ‘On-road fleet sheet’ – Choose “Option 1” to calculate using fleet size, VMT & fuel economy 1. Method to Calculate On-Road Fleet's Petroleum Energy Use and GHG Footprint 1 1 - Fleet size, vehicle miles traveled, and fuel economy 2 - Fuel use (skip to question 5)  Second step: enter the amount of vehicles – In this demo we will compare diesel transit buses to: diesel hybrid, B20, & CNG 2. The Number of Each Type of Vehicle in On-Road Fleet Compressed Diesel Biodiesel Biodiesel Ethanol Natural Gas Gasoline Diesel HEV (B20) (B100) (E85) (CNG) School Bus 0 0 0 0 0 0 0 Transit Bus 0 20 20 20 0 0 20 Shuttle/Paratransit Bus 0 0 0 0 0 0 0 Waste Hauler 0 0 0 0 0 0 0 Street Sweeper 0 0 0 0 0 0 0 Delivery Step Van 0 0 0 0 0 0 0 Transport/Freight Truck 0 0 0 0 0 0 0 Medium/Heavy Duty Pickup Truck 0 0 0 0 0 0 0 Maintenance Utility Vehicle 0 0 0 0 0 0 0 Other 0 0 0 0 0 0 0 Note: Several fuels to the right of CNG are not shown for clarity in this presentation 28
GREET Fleet Tutorial – Comparing On-Road Vehicle Technologies for Potential Acquisitions  Third step: enter the annual mileage 3. The Average Annual Vehicle Miles Traveled by Each Vehicle Type Diesel Gasoline Diesel HEV B20 B100 E85 CNG School Bus 30,000 30,000 30,000 30,000 30,000 30,000 30,000 Transit Bus 30,000 50,000 50,000 50,000 30,000 30,000 50,000 Shuttle/Paratransit Bus 30,000 30,000 30,000 30,000 30,000 30,000 30,000 Waste Hauler 23,400 23,400 23,400 23,400 23,400 23,400 23,400 Street Sweeper 12,600 12,600 12,600 12,600 12,600 12,600 12,600 Delivery Step Van 16,500 16,500 16,500 16,500 16,500 16,500 16,500 Transport/Freight Truck 80,000 80,000 80,000 80,000 80,000 80,000 80,000 Medium/Heavy Duty Pickup Truck 11,400 11,400 11,400 11,400 11,400 11,400 11,400 Maintenance Utility Vehicle 5,000 5,000 5,000 5,000 5,000 5,000 5,000 Other 30,000 30,000 30,000 30,000 30,000 30,000 30,000  Fourth step: enter the fuel economy 4. The Average Fuel Economy for Each Vehicle Type in the On-Road Fleet (miles per gasoline gallon equivalent) Diesel Gasoline Diesel HEV B20 B100 E85 CNG School Bus 6.0 7.0 8.5 7.0 7.0 6.0 6.0 Transit Bus 2.5 3.0 3.8 3.0 3.0 2.5 2.5 Shuttle/Paratransit Bus 7.0 8.0 10.0 8.0 8.0 7.0 7.0 Waste Hauler 2.0 2.5 3.0 2.5 2.5 2.0 2.0 Street Sweeper 3.0 4.0 5.0 4.0 4.0 3.0 3.0 Delivery Step Van 12.0 15.0 18.5 15.0 15.0 12.0 12.0 Transport/Freight Truck 5.0 6.0 7.5 6.0 6.0 5.0 5.0 Medium/Heavy Duty Pickup Truck 9.0 11.0 13.5 11.0 11.0 9.0 9.0 Maintenance Utility Vehicle 20.0 25.0 31.0 25.0 25.0 20.0 20.0 Other 2.5 3.0 3.8 3.0 3.0 2.5 2.5 Note: Several fuels to the right of CNG are not shown for clarity in this presentation 29
GREET Fleet Tutorial – Comparing On-Road Vehicle Technologies for Potential Acquisitions  Fifth step: adjust fuel production assumptions if needed 6. Fuel Production Assumptions Ethanol Feedstock Source 1 1 - Corn 2 - Switchgrass CNG Feedstock Source 1 1 - North American NG 2 - Non-North American NG LNG Feedstock Source 1 1 - North American NG 2 - Non-North American NG LPG Feedstock Source NG Petroleum 60% 40% Source of Electricity for On-Road Electric Vehicles and H2 Electrolysis 1 1 - Average U.S. Mix 2 - Average Northeast Mix 3 - Average California Mix 4 - User Defined (go to 'Specs' sheet) G.H2 Production Process 1 1 - Refueling Station SMR (On-site) 2 - Central Plant SMR (Off-site) 3 - Refueling Station Electrolysis (On-site) L.H2 Production Process 1 1 - Refueling Station SMR (On-site) 2 - Central Plant SMR (Off-site) 3 - Refueling Station Electrolysis (On-site) 30
GREET Fleet Tutorial – Comparing On-Road Vehicle Technologies for Potential Acquisitions  Final step: view petroleum and greenhouse gas results 7. Results of On-Road Fleet's Petroleum Usage (barrels) Diesel Vehicle Gasoline Diesel HEV B20 B100 E85 CNG Total School Bus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Transit Bus 0.0 7687.7 6069.3 6263.0 0.0 0.0 50.8 20070.8 Shuttle/Paratransit Bus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Waste Hauler 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Street Sweeper 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Delivery Step Van 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Transport/Freight Truck 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Medium/Heavy Duty Pickup Truck 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Maintenance Utility Vehicle 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Other 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Fuel Total 0.0 7,687.7 6,069.3 6,263.0 0.0 0.0 50.8 On-Road Fleet Total 20,070.8 barrels of oil 8. Results of On-Road Fleet's Greenhouse Gas Emissions (short tons CO2-equivalent) Diesel Vehicle Gasoline Diesel HEV B20 B100 E85 CNG Total School Bus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Transit Bus 0.0 4,186.1 3,304.8 3560.8 0.0 0.0 4014.0 15065.6 Shuttle/Paratransit Bus 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Waste Hauler 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Street Sweeper 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Delivery Step Van 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Transport/Freight Truck 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Medium/Heavy Duty Pickup Truck 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Maintenance Utility Vehicle 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Other 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Fuel Total 0.0 4,186.1 3,304.8 3,560.8 0.0 0.0 4,014.0 On-Road Fleet Total 15,065.6 short tons of GHG emissions Note: Several fuels to the right of CNG are not shown for clarity in this presentation 31
Final Thoughts  When examining your fleet’s petroleum and carbon footprint it is best to understand both the direct impacts from operating the vehicle and the indirect impacts that resulted from producing and transporting the fuel – The upstream (well-to-pump) activities can significantly affect a vehicle’s footprint, especially those that use alternative fuels  The thought of trying to account for all the issues that go into calculating a vehicle’s footprint may be overwhelming – However, there are easy-to-use yet robust tools that can help 32
Thank you!!! Argonne National Laboratory’s work is supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy For additional information contact: aburnham@anl.gov 33