# Presentation: 302091

## Well-to-Wheels Analysis of Vehicle/Fuel Systems

***Michael Wang***
***Center for Transportation Research***
***Argonne National Laboratory***
***Workshop on Modeling The Oil Transition***
***Washington, DC, April 20-21, 2006***

## Well-to-Wheels Analysis of Vehicle/Fuel Systems Covers Activities for Fuel Production and Vehicle Use

## WTW Analysis for Vehicle/Fuel Systems Has Been Evolved in the Past 20 Years

- Historically, evaluation of vehicle/fuel systems from wells to wheels (WTW) was called fuel-cycle analysis
- Pioneer transportation WTW analyses began in 1980s
- Early studies were motivated primarily by battery-powered EVs
- Recent studies are motivated primarily by introduction of new fuels
- Transportation WTW analyses have taken two general approaches
- Life-cycle analysis of consumer products
- Transportation fuel-cycle analysis
- Most transportation studies have followed the fuel-cycle analysis approach
- For transportation technologies, especially internal combustion engine technologies, the significant energy and emissions effects occur in
- The fuel usage stage
- The fuel production stage

**Notes:**
Other competition use WTW analysis and GREET

## The GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) Model Includes Energy and Emissions

**Since 1995, DOE has been supporting GREET model development at Argonne**
**The GREET model**
**Includes emissions of greenhouse gases**
*CO**2**, CH**4**, and N**2**O *
*VOC, CO, and NO**x** as optional GHGs*
**Estimates emissions of five criteria pollutants**
*Total and urban separately *
*VOC, CO, NO**x**, SO**x**,** **and**  **PM**10*
**Separates energy use into**
*All energy sources *
*Fossil fuels (petroleum, natural gas, and coal)*
*Petroleum*
**The GREET model and its documents are available at Argonne’s GREET website at *****http://www.greet.anl.gov***
***The new GREET version 1.7, together with its user manual, was released in November 2005***

## GREET Includes More Than 90 Fuel Production Pathways from Various Energy Feedstocks

## Petroleum Refining Is the Key Energy Conversion Step for Gasoline and Diesel

**WTP Efficiency (US):**
**    ****Gasoline 80%**
**    ****Diesel 82%**

## Key Issues for WTW Analysis of Petroleum Fuels

- Recovery and refining of unconventional crudes are more energy and emission intensive
- Canadian oil sands
- Venezuelan heavy, sour crude
- US shale oil
- Better quality for fuel products is demanded in the U.S.
- Gasoline sulfur content of 30 ppm or less
- On-road diesel sulfur content of 15 ppm or less
- Ethanol is replacing MTBE as a gasoline additive
- Energy and emission differences between ethanol and MTBE
- Production of gasoline blend stock for ethanol vs. MTBE
- LP simulations of petroleum refining indicate that lowered sulfur contents in gasoline and diesel have minimal effects on energy and emissions
- But, use of unconventional crudes could significantly deteriorate energy and emissions of gasoline and diesel

## WTP GHG Results Show That Oil Sands Operations Are Carbon-Intensive

## Production and Compression Are Key Steps for Gaseous H2 Production

**G.H2: gaseous H2**
**LNG: liquefied natural gas**
**NA: North American  **
**nNA: non-North American**
**NG: natural gas**

## Resource and Infrastructure IssuesResult in Many Potential H2 Pathways

- Key stages affect H2 WTW results
- H2 production
- H2 compression for gaseous H2
- H2 liquefaction for liquid H2
- Produced from natural gas via steam methane reforming (SMR) now, and in the foreseeable future
- Over 90% H2 is currently produced in this way worldwide
- Carbon emissions from H2 production plants
- Central or station SMR production
*Could reduce or avoid expensive distribution infrastructure *
*But production emissions move close to urban areas*
*Some amount of central SMR *CO2* emissions can be potentially sequestered*
- Energy and emission effects of electrolysis H2 depend on electricity sources
- Fossil fuel-based electricity has huge amount of CO2 emissions for H2 production
- Renewable electricity, such as hydro, wind, and solar, has zero CO2 emissions
- Gasification for H*2* production
- Coal: CO2 and criteria pollutant emissions, but CO2 can be potentially sequestered
- Biomass: criteria pollutant emissions
- Nuclear H2 has zero air emissions, but nuclear waste will continue to be an issue

## Ethanol WTP Pathways Include Activities from Fertilizer to Ethanol at Stations

**Agro-Chemical Production**

**Corn Farming**

**Refueling Stations**

**Agro-Chemical Transport**

**Corn Transport**

**Transport, Storage, and **
**Distribution of Ethanol**

**Electricity **
**(Cellulosic Ethanol)**

**Woody Biomass Farming**

**Herbaceous Biomass Farming**

**Woody Biomass Transport**

**Herbaceous Biomass Transport**

**Animal Feed **
**(Corn Ethanol)**

**Ethanol Production**

**U.S. WTP Efficiency:  **
**    ****Corn-based EtOH 60%**
**    ****Cellulosic EtOH 41%**

## Key Issues for WTW Analysis of Bio-Ethanol

- Key stages affecting WTW GHG results
- Use of fertilizer in farms
- Nitrogen fertilizer
- Lime
- Energy use for farming
- Energy use of ethanol production
- Co-products
- Animal feeds for corn ethanol
- Electricity for cellulosic ethanol
- The debate on energy balance (energy in ethanol minus fossil energy used) is NOT meaningful, even though most studies concluded positive balance for corn ethanol
- Supply of corn ethanol may be limited relative to the U.S. transportation fuels market
- In 2005, of the 11.1 billion bushels of corn produced, 13% was used for producing ethanol
- In 2005, 4.2 billion gallons of ethanol was used, equivalent to 2.8 billion gallon of gasoline
- In 2004, the U.S. consumed 141 billion gallons of gasoline and 37 billion gallons of on-road diesel

## Most of the Recent Corn EtOH Studies Show a Positive Net Energy Balance

- Energy balance here is defined as Btu content a gallon of ethanol minus fossil energy used to produce a gallon of ethanol

## GREET Includes A Variety of Vehicle and Fuel Combinations

## Key Assumptions Affecting WTW Results

- WTP assumptions
- Energy efficiencies of fuel production activities
- GHG emissions of fuel production activities
- Emission factors of fuel combustion technologies
- PTW assumptions
- Fuel economy of vehicle technologies
- Tailpipe emissions of vehicle technologies
- Large uncertainties exist in key assumptions
- GREET is designed to conduct stochastic simulations
- Distribution functions are developed for key assumptions in GREET

## GREET Can Conduct Stochastic Simulations to Address Uncertainties

- Distribution-Based Inputs Generate Distribution-Based Outputs

## GREET Relies on A Variety of Data Sources

- Open literature
- Engineering analysis (such as ASPEN simulations for mass and energy balance)
- Stakeholder inputs (collaboration with the energy industry)
- The DOE H2A effort for H2 FCV WTW analysis

**Well-to-Pump Data Sources**

**Well-to-Pump Data Sources**

- Fuel economy
- Open literature
- Vehicle simulation with models such as the PSAT model
- Tailpipe emissions
- Open literature
- Emission testing results
- EPA MOBILE model
- CARB EMFAC model

## The PSAT Model Was Used to Estimate Fuel Economy for a 2010 Model-Year Midsize Car

- Values in RED are FreedomCAR 2010 Goals.

|  | Slow Technology | Fast Technology |
| --- | --- | --- |
| Body-in-White Mass (kg) | 988 | 889 |
| Specific Power (kW/kg) |  |  |
| Gasoline  Engine  | 0.8–1.6 | 1.0–1.8 |
| Diesel Engine | 0.60–0.72 | 0.80–0.90 |
| Fuel Cell System with Storage | 0.280 | 0.322 |
| Motor | 1.0 | 1.3 |
| Battery at 70% SOC | 0.74 | 1.11 |
| Peak Efficiency (%) |  |  |
| Gasoline Engine | 35 | 38 |
| Diesel Engine | 40.5 | 45 |
| Fuel Cell System | 55 | 60 |
| Gearbox | 96 | 97 |
| Final Drive | 97.5 | 97.5 |

## Fuel Economy Values of a 2010 Model-Year Midsize Car from PSAT Simulations

## GREET Takes These Steps to Estimate Vehicular Emissions

- Emissions of VOC, CO, NOx, CH4, and PM10
- Vehicle technologies are simulated with EPA’s MOBILE6.2 and CARB EMFAC by assuming their meeting of given tailpipe standards
- SOx emissions for each vehicle type are calculated from sulfur contained in fuels
- CO2 emissions for each vehicle type are estimated from carbon balance
- N2O emissions are based on limited testing results; CARB and EPA effort on vehicular N2O emission testing will greatly reduce tailpipe N2O uncertainties

## 2010 Model-Year Vehicles Are Assumed to Meet Stringent Tier 2 Emission Standards Tier 2 Standards (Fully in Effect in 2009, g/mi. for 120K miles)

**Assumptions for this analysis:**
**    ****Bin 3 for Gasoline cars; Bin 2 for gasoline hybrids **
**    ****Bin 4 for diesel cars; Bin 3 for diesel hybrids**
**    ****Bin 1 for H2 fuel-cell vehicles**

## H2 FCVs with Ethanol or Conventional Electricity May Increase WTW Total Energy, But ... 

***H2 FCVs with Ethanol or Conventional Electricity May Increase WTW Total Energy, But ... ***

- ICE and Hybrid

- FCV

- FC Hybrid

## Since H2 Is Produced from Non-Petroleum Sources, H2 FCVs Almost Eliminate Petroleum Use

***Since H2 Is Produced from Non-Petroleum Sources, H2 FCVs Almost Eliminate Petroleum Use***

- ICE and Hybrid

- FCV

- FC Hybrid

## Except for Average Electricity Options, H2 FCVs Achieve Large GHG Reductions

***Except for Average Electricity Options, ******H2 FCVs Achieve Large GHG Reductions***

- ICE and Hybrid

- FCV

- FC Hybrid

## H2 FCVs With Ethanol and Average Electricity Could Increase Total NOx Emissions, But ...

***H2 FCVs With Ethanol and Average Electricity Could Increase ***_**Total**_*** NOx Emissions, But ...***

- ICE and Hybrid

- FCV

- FC Hybrid

## H2 FCVs With NG, Ethanol, and Renewable Electricity Reduce Urban NOx Emissions

***H2 FCVs With NG, Ethanol, and Renewable Electricity Reduce ***_**Urban**_*** NOx Emissions***

- ICE and Hybrid

- FCV

- FC Hybrid

## On the Basis of Fuel Cycle and Vehicle Cycle, Advanced Vehicle Technologies Reduce GHG Emissions

## Outstanding WTW Analysis Issues

- Baseline crude for gasoline and diesel production
- Conventional crude vs. unconventional crude
- How to account petroleum Btus in petroleum use calculations?
- Technology advancement over time need to be considered
- Vehicle technologies for fuel economy and emissions
- Fuel requirements and production technologies
- Transparency should be emphasized in WTW analysis and results
- System boundary issues will continue to be debated
- WTW analysis includes operation-related activities, but usually does not include infrastructure-related activities such as building of petroleum refineries
- Definition of the boundary for a fuel is a moving target
- It is critical to maintain a consistent boundary for all fuels
- Absolute values vs. relative changes among vehicle/fuel systems: relative changes are more reliable
- No silver-bullet fuel exists to solve all problems, trade-offs among impacts are more realistic
- Energy security
- GHG emissions
- Urban air pollution