# Presentation: 067905

## Life-Cycle Analysis Results of Vehicle/Fuel Systems with the GREET Model

***Michael Wang***
***Center for Transportation Research***
***Argonne National Laboratory***
***The Energy Modeling Forum on Climate Change ***
***Impacts and Integrated Assessment***
***Snowmass, CO, August 3, 2006***

## Life-Cycle 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 such as hydrogen and biofuels
- 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

## Life-Cycle Analysis of Vehicle/Fuel Systems Covers Both Fuel Cycle and Vehicle Cycle

***Life-Cycle Analysis of Vehicle/Fuel Systems Covers Both Fuel Cycle and Vehicle Cycle***

**Vehicle Cycle**
**(GREET 2 Series)**

**Fuel Cycle (Well-to-Wheels)**
**(GREET 1 Series)**

**Well to Pump**

**Pump to Wheels**

## WTW Analysis Is a Complete Energy/Emissions Comparison

- As an example, greenhouse gases are illustrated here

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

**Includes emissions of greenhouse gases**
- CO2, CH4, and N2O
- VOC, CO, and NOx as optional GHGs
**Estimates emissions of five criteria pollutants**
- Total and urban separately
- VOC, CO, NOx, SOx, and  PM10
**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 website at *****http://greet.anl.gov***
- There are more than 3,000 registered GREET users worldwide

## Calculation Logic for a GivenWTP Production Activity in GREET

***Calculation Logic for a Given******WTP Production Activity in GREET***

## Calculation Logic for a Given WTP Transportation Activity in GREET

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

## GREET Does Not Includes the Following Fuel Pathways Yet

- Petroleum pathways
- Venezuelan heavy, sour crude
- U.S. oil shale
- Bio-fuel pathways
- Sugarcane to ethanol
- Sugar beets to ethanol
- Municipal solid waste to ethanol
- Pyrolysis oil from biomass
- Biobutanol from sugars
- Hydrogen pathways
- Metal hydride hydrogen storage
- Chemical hydrogen storage
- Tube trailer hydrogen transportation
- Biological hydrogen production

## GREET Includes More Than 75 Vehicle/Fuel Systems

**Conventional Spark-Ignition Vehicles**
- •	Conventional gasoline, federal reformulated
- 	gasoline, California reformulated gasoline
- •	Compressed natural gas, liquefied natural
- 	gas, and liquefied petroleum gas
- •	Gaseous and liquid hydrogen
- •	Methanol and ethanol

**Compression-Ignition Direct-Injection Hybrid Electric Vehicles: Grid-Independent**
**and Connected**
- •	Conventional diesel, low sulfur diesel, dimethyl
- 	ether, Fischer-Tropsch diesel, and biodiesel

**Battery-Powered Electric Vehicles**
- •	U.S. generation mix
- •	California generation mix
- •	Northeast U.S. generation mix

**Fuel Cell Vehicles**
- •	Gaseous hydrogen, liquid hydrogen, methanol,
- 	federal reformulated gasoline, California
- 	reformulated gasoline, low sulfur diesel,
- 	ethanol, compressed natural gas, liquefied
- 	natural gas, liquefied petroleum gas,
- 	and naphtha

**Spark-Ignition Hybrid Electric Vehicles: Grid-Independent and Connected**
- •	Conventional gasoline, federal reformulated
- 	gasoline, California reformulated gasoline
- •	Compressed natural gas, liquefied natural
- 	gas, and liquefied petroleum gas
- •	Gaseous and liquid hydrogen
- •	Methanol and ethanol

**Compression-Ignition **
**Direct-Injection Vehicles**
- •	Conventional diesel, low sulfur diesel,
- 	dimethyl ether, Fischer-Tropsch
- 	diesel, and biodiesel

**Spark-Ignition Direct-Injection Vehicles**
- •	Conventional gasoline, federal reformulated
- 	gasoline, and California reformulated gasoline
- •	Methanol and ethanol

## WTW Results Are Affected by These Key Assumptions

- 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 Is Designed With Stochastic Simulations to Address Uncertainties

- Distribution-Based Inputs Generate Distribution-Based Outputs

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

## 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

## North America Has Relatively Little Conventional Oil But 30% of Unconventional Oil Reserves

***ANL Analyzed Energy and GHG Emissions of Recovering and Upgrading Oil Sands***

**Larsen, Wang, et al., 2005, “Might Canadian Oil Sands Promote Hydrogen Production for Transportation? Greenhouse Gas Emission Implications of Oil Sands Recovery and Upgrading,” *****World Resource Review*****, Vol. 17: 220-242.**

## The Pathway of Oil Sands to Gasoline and Diesel Requires A Large Amount of Steam and H2

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

## NG to FT Diesel Production Is Subject to Large Efficiency Losses

## Coal to FT Diesel Production Is Energy and Carbon Intensive

## Carbon Emissions Could Be a Major Concern for Coal to FT Diesel

- If coal-to-liquid (CTL) plant has an energy efficiency of 52%, CTL WTW CO2 emissions will be two times as much as those of petroleum diesel
- With carbon capture and storage, CTL WTW CO2 emissions will be about the same as those of petroleum diesel
- If CTL plant has an energy efficiency of 42%, CTL WTW CO2 emissions will be 2.3 times as much as those of petroleum diesel
- Integrated design of CTL plants to produce fuels and power will help improve plant efficiency

## Biomass to FT Diesel Production Could Result in Multiple Products

## GHG Reductions by FT Diesel from Three Feedstocks (XTLs)

**GHG is one of the criteria to compare XTLs**
**Feedstock resource availability and costs are important to consider as well**

## 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

## U.S., Brazil and China Are Major Ethanol Consuming Countries

***U.S.  ***
***Corn ethanol***
***No.1 consuming country with 4.2 billion gallons in 2005***
***Brazil***
***Sugarcane ethanol***
***No.2 consuming country with ~4 billion gallons in 2005***
***China ***
***Corn ethanol***
***No.3 consuming country with ~340 million gallons in 2005***

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

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

## 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

## Accurate Ethanol Energy Analysis Must Account for Increased Productivity in Farming Over Time

**Based on historical USDA data; results are 3-year moving averages**

***U.S. Corn Output Per Pound of Fertilizer ***
***Has Risen by 70% in The Past 35 Years***

## Improved Technology Has Reduced Energy Use and Operating Costs in Corn Ethanol Plants

- From Argonne’s discussions with ethanol plant designers, USDA data, and other reported data

## Accounting for Animal Feed Is a Critical Factor in Ethanol’s Lifecycle Analysis 

-   Argonne uses the displacement method, the most conservative approach.** **

## Energy Effects of Fuel Ethanol Depend on the Type of Energy Being Analyzed

***Energy Effects of Fuel Ethanol Depend ******on the Type of Energy Being Analyzed***

***Total Btu Spent for One Btu of Gasoline and Ethanol Available at Fuel Pumps***

- Total Energy

- Fossil Energy

- Petroleum Energy

## 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

## N2O and NOx Emissions from Nitrogen Fertilizer Are a Major Emission Source

- Argonne’s analysis shows that depending on soil type and condition, 1-3% of N in nitrogen fertilizer is converted into N in N2O
- On the well-to-wheels basis, N2O emissions from that conversion could account for _up to_ 25% of total GHG emissions from corn ethanol
- For economic reasons, N fertilizer use per bushel of corn has reduced in the U.S.; this has positive side effects on reducing environmental pollution and GHG emissions
- Also, application of lime results in non-trivial CO2 emissions for corn ethanol (throguh the process of converting lime stone [CaCO3] to lime [CaO])

## Corn EtOH Reduces GHGs by 15-26% While Cellulosic EtOH Yields 87% Reduction, on Per Gallon Basis of EtOH Used

***GHG Emission Reductions Per Gallon of Ethanol to Displace An Energy-Equivalent Amount of Gasoline ***

## Cellulosic Ethanol from Crop and Forest Residues Can Achieve Large GHG Reductions

## Opportunities and Challenges of Near Future U.S. Corn Ethanol Production

**Opportunities**
- Corn yield/acre will continue to increase, together with stabilized or reduced N fertilizer application
- Ethanol yield/bushel will continue to increase
- Energy use in ethanol plants may be reduced further through better engineering, integration of ethanol production and animal feedlots
- Gasification of biomass to provide process energy for ethanol plants
**Challenges**
- Switch from natural gas to coal in ethanol plants
- Potential use of marginal land for additional corn production

## Bio-EtOH, -FTD, -DME Produced from Two Processes

**M. Wu, Y. Wu, and M. Wang, 2006, “Energy and Emission Benefits of Alternative Transportation Liquid Fuels Derived from Switchgrass: a Fuel Life Cycle Analysis,” forthcoming in *****Journal of Biotechnology Progress*****.**

## Shares of Biofuels and Co-Products (Based on Energy Content) Vary for Different Cases

**Production Scenarios****	****Transportation Fuel****	****Power****	****            Others**
- EtOH/GTCC			79.6%		20.4%
- EtOH/Rankine			88.2%		11.9%
- Multi-Fuel 			89.9%		1.8%		8.3%
- EtOH/Protein/Rankine		83.2%		3.5%		13.3%
- DME/GTCC			44.7%		55.3%
- FTD/GTCC			36.8%		40.4%		22.9%

- Bio-EtOH has the largest amount of energy share in fuel products.
- Thermochemical process generates similar amount of energy between fuel and power.

## Energy Benefits of Biofuels Vary Among Different Production Cases

## GHG Benefits of Biomass Use Are from Production of Fuels and Power

**Grams of CO2 and GHGs Reductions Per Dry Ton of Biomass**

## A Group of Vehicle/Fuel Systems Was Analyzed

**A complete WTW evaluation, targeting energy use, GHGs (CO****2****, CH****4**** and N****2****O) and typical criteria air pollutants (VOC, NO****X**** and PM****10****), was conducted for MY2010 vehicles (midsize passenger car platform) at midpoint of lifetime mileage (2016).**

**Wu, Y., M. Wang, P. Sharer, and A. Rousseau, 2006, “Well-to-Wheels Results of Energy Use, Greenhouse Gas Emissions, and criteria Pollutant Emissions of Selected Vehicle/Fuel Systems,” SAE paper 2006-01-0377 **

## Fuel Economy of Vehicle Technologies Was Simulated with Argonne’s PSAT Model

**PSAT was used to estimate vehicle fuel economy for**
- MY2010 midsize passenger car as platform
- Baseline SI ICE was based on PSAT calibration of the EIA projections
- Advanced SI ICE and other advanced vehicle technologies were based on FreedomCAR goals
**PSAT results were adjusted to reflect on-road MPG**

**On-road Adjusted Fuel Economy (****55% UDDS and 45% HWY Cycle), mpgge**

## 2010 Model-Year Vehicles Were Assumed to Meet EPA Tier 2 Emission Standards

***Tier 2 Standards (PCs and LDTs, g/mi. for 120K miles)***

## Advanced Vehicle/Fuel Systems Could Achieve Moderate to Large Reductions in Energy Use 

**For WTW results, it is important to pay attention to both amount and type of energy use among vehicle/fuel technologies.**

**Notes:**
Now almost entirely mined; by 2030, expected to be 50/50 mined and in-situ

## NOX Emission Reductions by Advanced Vehicle/Fuel Systems Follow Similar Trends As for VOC Emissions, But WTP Stage Becomes a Dominant Source for Total NOx

***NO******X****** Emission Reductions by Advanced Vehicle/Fuel Systems Follow Similar Trends As for VOC Emissions, But WTP Stage Becomes a Dominant Source for Total NO****x*

**Notes:**
Now almost entirely mined; by 2030, expected to be 50/50 mined and in-situ

## PM10 Emissions Depend Heavily on Fuel Production Pathways

**Notes:**
Now almost entirely mined; by 2030, expected to be 50/50 mined and in-situ

## From ICEVs to HEVs and to FCVs, GHG Emissions Continue to Be Reduced

**Notes:**
Now almost entirely mined; by 2030, expected to be 50/50 mined and in-situ

## Outstanding Life-Cycle Analysis Issues

- Baseline crude for gasoline and diesel production
- Conventional crude vs. unconventional crude
- 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
- It is critical to maintain a consistent boundary for all fuels
- No silver-bullet fuel exists to solve all problems, trade-offs among impacts need to consider
- Energy security
- GHG emissions
- Urban air pollution
- Other environmental issues need to be addressed
- Water resource use and waste water discharge
- Land use, especially for biofuels