# Presentation: 923151

## Energy and Greenhouse Gas Emissions Impacts of Fuel Ethanol 

***Michael Wang***
***Center for Transportation Research***
***Energy Systems Division***
***Argonne National Laboratory***
***NGCA Renewable Fuels Forum***
***The National Press Club***
***August 23, 2005***

## Argonne Has Conducted Life Cycle Analyses of Transportation Fuels for More Than 25 Years

- Its Center for Transportation Research has analyzed energy and emission effects of transportation fuels for DOE since 1980s
- With DOE support, Argonne began to develop the GREET model in 1995
- GREET is a life cycle model for transportation fuels and vehicle technologies
- It contains more than 85 transportation fuel pathways including four fuel ethanol pathways
- GREET is in the public domain; there are more than 2,000 registered users worldwide
- Since 1997, Argonne has used GREET to evaluate fuel ethanol’s energy and emission effects

## Argonne’s Thorough Evaluation of Fuel Ethanol Over the Past 8 Years Concludes:

- Energy balance value for fuel ethanol alone is not meaningful in evaluating its benefits
- Any type of fuel ethanol helps substantially reduce fossil energy and petroleum use, relative to petroleum gasoline
- Corn-based fuel ethanol achieves moderate reductions in GHG emissions
- Cellulosic ethanol can achieve much greater energy and GHG benefits
- This presentation summarizes GREET results of fuel ethanol

## Comparative Results Between Ethanol and Gasoline Are More Relevant to Policy Debate

## Even Though Electricity Has a Large Negative Net Energy Balance, There Is No Substitute for Its Main Uses

**Coal Mining**

**Coal**
**Transportation**

**NG**
**Processing**

**NG**
**Transmission**

**NG**
**Recovery**

**Coal**

**NG**

**Diesel Fuel**

**NG**

**Electricity**

**LPG, NGLs**

**NG**

**Electricity**

**Electricity Generation**

**Electricity Transmission**
**and Distribution (8% loss)**

**1 mm Btu of Electricity**
**at Wall Outlets**

**Uranium Ore Recovery**

**Petroleum Recovery**

**Uranium**

**Petroleum**

**Uranium Ore**
**Transportation**

**Petroleum**
**Transportation**

**Other**
**Petroleum**
**Products**

**Uranium Enrichment**

**Petroleum Refinery**

**Uranium Fuel Transportation**

**Residual Oil Transportation**

**U.S. Electricity Generation:**
**2.34 mm Btu Fossil Energy Input**
**for each 1.00 mm Btu Electricity Output**

## Energy in Different Fuels Can Have Very Different Qualities

## 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

- Source: from Argonne’s discussions with ethanol plant designers, recent USDA data, and other reported data.

## One-Third of Corn Kernel Mass Ends as Animal Feed (a Co-Product) in Ethanol Plants

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

-   Weight and energy methods are no longer used
-   Argonne uses the displacement method, the most conservative approach** **
-   Some studies do not consider co-products at all

## Cellulosic Ethanol Plants Will Be Significantly More Efficient than Corn Ethanol Plants

**Plants under intensive  R&D efforts are designed to use the unfermentable portion of biomass to generate steam and electricity.**

## 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

## Use of Ethanol to Replace Gasoline Results in Fossil Energy and Petroleum Reduction Benefits

***Change in Per-Mile Energy Use by Ethanol Blend to Displace Gasoline***

## Ethanol Blends, Especially E85 Made from Cellulosic Ethanol, Can Significantly Reduce GHG Emissions

***Reductions in Per-Mile GHG Emissions by Ethanol Blend to Displace Gasoline ***

## Corn EtOH Reduces GHGs by 18-29% While Cellulosic EtOH Yields 85-86% Reduction, on Per Gallon Basis of EtOH Used

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

## 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

## Energy Balance Results of Ethanol Depend Heavily on System Boundary Choices

## The Debate on Energy Balance Itself May Have Little Practical Meaning

- Though self evaluation of a fuel’s energy balance is easy to understand, to do so for a fuel in isolation could be arbitrary
- All Btus are not created equal. The energy sector has been converting low-value Btus into high-value Btus, _*with energy losses*_
- Society has not made energy choice decisions on the basis of energy balance values of individual energy products
- Issues of concern, such as petroleum consumption and GHG emissions, should be analyzed directly for fuel alternatives
- A complete, robust way of evaluating a fuel’s effects is to compare the fuel (e.g., ethanol) with those to be displaced (e.g., gasoline)

## Most Studies on GHG Emissions Show GHG Emission Reduction by Corn EtOH as Compared to Gasoline

## Conclusions

- Energy balance value for a given energy product alone is not meaningful in evaluating its benefit
- Any type of fuel ethanol helps substantially reduce fossil energy and petroleum use, relative to petroleum gasoline
- Corn-based fuel ethanol achieves moderate reductions in GHG emissions
- Cellulosic ethanol can achieve much greater energy and GHG benefits

## Thank You for Your Attention!

***For more information, ***
***please visit the GREET model website at http://greet.anl.gov***
***or contact Michael Wang at mqwang@anl.gov***