TECHNICAL SUPPORT DOCUMENT FOR 

ETHANOL FACILITIES: RULE FOR 

MANDATORY REPORTING OF GREENHOUSE 

GASES 

Climate Change Division 

Office of Atmospheric Programs 

U.S. Environmental Protection Agency 

June 14, 2010
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CONTENTS 

1. Industry Description...............................................................................................................3 

2. Total Emissions......................................................................................................................3 

3. Review of Existing Programs and Methodologies...................................................................3 

4. Types of Emissions Information to be Reported .....................................................................3 

5. Options for Reporting Threshold ............................................................................................4 

6. Options for Monitoring Methods............................................................................................5 

7. Options for Estimating Missing Data......................................................................................5 

8. QA/QC Requirements ............................................................................................................5 

9. References..............................................................................................................................5 
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1. Industry Description 

Ethanol is produced primarily for use as a fuel component, but is also used in industrial 

applications and in the manufacture of beverage alcohol. Ethanol can be produced from 

the fermentation of sugar, starch, grain, and cellulosic biomass feedstocks, or produced 

synthetically from ethylene or hydrogen and carbon monoxide. There are approximately 

170 ethanol refineries in the United States and its territories. 

The sources of GHG emissions at ethanol production facilities considered in the analysis 

for the proposed rule are stationary combustion, onsite landfills, and onsite wastewater 

treatment. 

Stationary combustion at ethanol facilities usually includes the combustion of either 

natural gas or coal in boilers. Many wet milling facilities use co-generation. 

Data are unavailable on landfilling at ethanol facilities, but it is believed that some of 

these facilities may have onsite landfills with significant GHG emissions. 

The wastewater generated at ethanol production facilities is handled in a variety of ways, 

with dry milling and wet milling facilities generally treating wastewaters differently. 

2. Total Emissions 

In 2007, CH4 emissions from wastewater treatment at ethanol production facilities were 

81,800 metric tons CO2 – equivalent (mtCO2e), less than 1% of total CH4 emissions. 

Energy-related CO2 emissions at ethanol production facilities were estimated to be 

18,570,000 mtCO2e. 

Estimates of total national emissions from landfills at ethanol facilities are unavailable. 

3. Review of Existing Programs and Methodologies 

For information on the review of existing programs and methodologies, please refer to 

the Technical Support Documents for general stationary fuel combustion, industrial 

landfills, and industrial wastewater treatment. 

4. Types of Emissions Information to be Reported 

For information on the types of emissions information to be reported, please refer to the 

Technical Support Documents for general stationary fuel combustion, industrial landfills, 

and industrial wastewater treatment. 
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5. Options for Reporting Threshold 

5.1 Source Emissions-based thresholds 

Ethanol production facilities are required to report under the rule if they exceed 25,000 

mtCO2e per year in combined emissions from all applicable source categories including 

stationary fuel combustion sources, industrial solid waste landfills, and industrial 

wastewater treatment. EPA estimated the number of ethanol production facilities that 

would be required to report GHG emissions based on emissions from industrial 

wastewater treatment and stationary combustion, only. EPA ignored emissions from 

industrial solid waste landfills at ethanol production facilities because it had no 

information. 

EPA estimated that there are 170 ethanol production facilities in the U.S. and estimated 

wastewater emissions for both wet and dry milling as shown in Table 1. For more 

information on wastewater treatment estimates, please see the Technical Support 

Document for Industrial Wastewater Treatment. 

EPA estimated that 4 ethanol production facilities would exceed a threshold of 25,000 

mtCO2e for wastewater treatment emissions alone. Wastewater treatment emissions at 

these 4 ethanol production facilities are estimated to be 21,681 mtCO2e. 

Table 1. Summary of Emissions Estimates for Industrial Wastewater Treatment at 

Ethanol Refineries 

Category

No. of 

Plants 

in the 

U.S. 

Estimated Plants with 

Anaerobic Treatment

*Estimated 

No. of Plants 

Required to 

Report

*Estimated No. 

of Reporting 

Plants with 

CH4 Recovery 

*Estimated 

Emissions Plants 

are Required to 

Report 

(mtCO2e) 

Ethanol- wet mill 25 33% have anaerobic 

treatment; of that, half have 

enough production to exceed 

the reporting threshold 

4 4 21,681 

Ethanol - dry mill 145 100% but none exceed 

reporting threshold 

0 0 0 

*These numbers represent facilities that are covered based on data available on 

wastewater treatment only. 

EPA also estimated emissions associated with stationary combustion sources, and 

estimated that 145 ethanol production facilities would exceed the threshold. Energyrelated CO2 emissions at these 145 ethanol production facilities are estimated to be 

18,243,000 mtCO2e. 
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5.2 Other threshold options 

EPA also considered a facility-level threshold for ethanol refineries. A limited data set 

on stationary combustion at ethanol refineries and emission factors from IPCC and the 

GHG Inventory was used to estimate the minimum number of facilities that would meet 

each of the facility-level thresholds examined (Graboski 2002). Data were unavailable to 

estimate emissions from landfills at ethanol refineries. 

Table 2. Threshold Analysis for Ethanol Production (including onsite wastewater 

treatment and stationary combustion) 

Emissions Covered Facilities Covered 

Threshold Level 

National 

Emissions 

mtCO2e 

Total 

Number 

of 

Facilities 

mtCO2e 

/year Percent Number Percent 

1,000 mtCO2e Not estimated 170 

Not 

estimated 

Not 

estimated >168 >99% 

10,000 mtCO2e Not estimated 170 

Not 

estimated 

Not 

estimated >155 >91% 

25,000 mtCO2e 18,348,000 170 

Not 

estimated 

Not 

estimated >143 >84% 

100,000 mtCO2e Not estimated 170 

Not 

estimated 

Not 

estimated >72 >42% 

6. Options for Monitoring Methods 

For information on monitoring methods, please refer to the Technical Support Documents 

for general stationary fuel combustion, industrial landfills, and industrial wastewater 

treatment. 

7. Options for Estimating Missing Data 

For information on options for estimating missing data, please refer to the Technical 

Support Documents for general stationary fuel combustion, industrial landfills, and 

industrial wastewater treatment. 

8. QA/QC Requirements 

For information on options for QA/QC requirements, please refer to the Technical 

Support Documents for general stationary fuel combustion, industrial landfills, and 

industrial wastewater treatment. 

9. References 

EPA. 2008. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006 (April 

2008) USEPA #430-R-08-005. 
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Graboski, M.S. 2002. “Fossil Energy Use in the Manufacture of Corn Ethanol”, Prepared 

for NCGA, August 2002. Available online at: 

http://www.ncga.com/ethanol/pdfs/energy_balance_report_final_R1.PDF. 

IPCC. 2006. IPCC Guidelines for National Greenhouse Gas Inventories: Wastewater 

Treatment and Discharge. IPCC (Volume 5 Waste, Chapter 6). Available online at: 

http://www.ipccnggip.iges.or.jp/public/2006gl/pdf/5_Volume5/V5_6_Ch6_Wastewater.pdf. 

RFA. 2006. Renewable Fuels Association (RFA). Historic U.S. fuel Ethanol Production. 

Available online at: http://www.ethanolrfa.org/industry/statistics/. Date Accessed: June 

2007.