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E85 Quality Specifications and Market Surveys

Clean Cities Webinar

Teresa L. Alleman

April 20, 2010

NREL/PR-540-48534
National Renewable Energy Laboratory Innovation for Our Energy Future

Ethanol Properties

Good Gasoline Blending 

Properties:

– Blending Octane = 115

– Completely miscible with 

hydrocarbons

– GHG profile

Bad Gasoline Blending 

Properties:

– 30% lower volumetric energy 

content – an inconvenience

– Non-ideal vapor pressure 

bump

– Potential to partition into water

6.00

6.50

7.00

7.50

8.00

8.50

9.00

9.50

0 5 10 15 20 25 30 35

Vapor Pressure (psi)

Ethanol Concentration (Vol %)

 p 

ASTM Class AA, Regular

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ASTM Specifications for Ethanol Fuels

ASTM D4806: Standard Specification for Denatured Fuel Ethanol for 

Blending with Gasolines for Use as Automotive Spark-Ignition Engine Fuel

Anhydrous denatured ethanol

Ensures adequate purity for use in gasoline

ASTM D4814: Standard Specification for Automotive Spark-Ignition Engine 

Fuel

Performance based specification for gasoline

US EPA currently allows up to 10 volume percent ethanol in gasoline

Potentially could accommodate higher levels of ethanol if approved

ASTM D5798: Standard Specification for Fuel Ethanol (Ed75-Ed85) for 

Automotive Spark-Ignition Engines

Performance based specification for flexfuel vehicles

Currently being modified to require minimum 68% ethanol for all grades

Under development: Standard Practice for Blending Mid-Level Ethanol Fuel 

Blends For Flexible Fuel Vehicles With Automotive Spark-Ignition Engines

For blender pump fuels made using D4814 and D5798 compliant 

blendstocks

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D5798

Specifications are used to ensure fuel is “fit for purpose”

Protects consumers

Provides regulatory agencies a “gold standard” to enforce fuel quality

Gasoline and gasoline/ethanol blends are subdivided into 

classes based on geography and time of year

E85 has 3 distinct classes

Class 1: Warm ambient temperature

Class 2: Moderate ambient temperature

Class 3: Cold ambient temperatures

Shoulder seasons: In-between two other classes where either grade 

is acceptable (e.g. 3/2)

Main difference between classes is vapor pressure and ethanol 

content 

Not every state will require every class (most often Class 3 is 

omitted for warmer states or Class 2 for colder states)

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D5798 con’t

Why are the changes in vapor pressure and ethanol 

content necessary?

More gasoline in the blend provides better cold start 

performance (higher vapor pressure)

Lower vapor pressures help prevent handling problems in 

warmer months

Major parameter is vapor pressure, ethanol content will vary 

depending on vapor pressure requirements (ethanol has very low vapor 

pressure compared to gasoline)

ASTM Specifications are “living” documents and can 

change from year to year, fuel providers must stay informed 

on most recent changes and how it impacts local 

regulations

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Previous CRC E85 Quality Surveys

CRC E-79 (2006)

10 states sampled (IL, IN, IA, MI, MN, MO, NE, ND, SD, SC)

47 samples collected in Class 1, 1/2, 2, 2/3 volatility classes

Most samples failed to meet vapor pressure (too low)

CRC E-79-2 (2007)

15 states (CO, IL, IN, IA, MI, MN, MO, NE, NC, ND, OH, SC, 

SD, TX, WI)

55 samples collected (3 in Class 2, and 52 in Class 3)

In Class 2, samples did not meet vapor pressure (too high, 

67%) and ethanol content (too low, 67%

In Class 3, samples did not meet vapor pressure (too low, 58%) 

and ethanol content (too low, 15%)

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CRC E-85: E85 Survey

Project goal is to collect nationwide survey of E85 quality

Samples taken across US from public pumps

Cover all 3 volatility classes

Provide data to industry on E85 quality

Interest from CRC for designing future projects

Report unbiased assessment of E85 quality

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Property Tests

Property Method Notes

Ethanol/methanol D5501 All samples

Dissolved water D6304 All samples

Vapor pressure D5191 All samples

Sulfur D5453 All samples

Washed and 

unwashed gum

D381 All samples

pHe D6423 All samples

Inorganic chloride 

and sulfate

D7319 All samples

Appearance D5798 All samples

Distillation D86 Select samples

Density/API gravity D4052 Select samples

NACE corrosion TM0172-2001 Select samples

RON/MON D2699/D2700 Select samples

Peroxides D3703 Select samples

Oxidation stability D525 Select samples

Silver corrosion D4814 Annex Select samples

Property Class 1 Class 2 Class 3

Ethanol,

vol%

79-83 74-83 70-83

Vapor

Pressure, psi

5.5-8.5 7.0-9.5 9.5-12.0

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Survey Locations

3 rounds of sampling from all 5 PADDS – broad coverage of market

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Results Summary Table

D5798

Class

# of 

samples

Vapor Pressure Ethanol Content

Below 

minimum, 

%

Above

Maximum,

%

OnSpecification,

%

Below 

minimum, 

%

Above

Maximum,

%

OnSpecification,

%

1 (2008) 47 53.2 0 46.8 4.3 89.4 6.3

1 (2009) 10 90.0 0 10.0 10.0 10.0 80.0

1 

(All Data)

57 60.0 0 40.0 5.3 66.7 28.0

2 26 61.5 7.7 30.8 3.8 38.5 57.7

3 40 87.5 0.4 12.1 12.0 5.0 83.0

All 123 73.1 0.7 26.2 7.5 35.7 56.8

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Results: Vapor Pressure

60% of Class 1 Summer time samples off spec on vapor pressure

87% of Class 3 Winter time samples off spec on vapor pressure

Primary reason cited by Marathon for cessation of E85 sales in Fall 2009

Summer 2008 Winter 2008-09

Class 1 DVPE, psi

Measured by D5191

2 3 4 5 6 7 8 9

Frequency

0

5

10

15

20

25

Mean Specification 

Limits

Class 3 DVPE, psi

D5191

4 6 8 10 12 14

Frequency

0

1

2

3

4

5

6

7

Mean

Specification 

Limits

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Results: Ethanol Content

81% of 2008 Class 1 samples off-spec on ethanol (high gasoline $)

10% of 2009 Class 1 samples off-spec on ethanol (gas. < ethanol $)

Summer 2008 Summer 2009

Ethanol content, vol%

D5501

50 60 70 80 90 100

Frequency

0

5

10

15

20

25

30

Mean

Specification 

Limits

Ethanol content, vol%

D5501

50 60 70 80 90 100

Frequency

0

1

2

3

4

5

6

7

Mean Specification 

Limits

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Class 2 and Class 3 Ethanol Content

Ethanol content, vol%

D5501

50 60 70 80 90 100

Frequency

0

2

4

6

8

10

Mean

Specification 

Limits

Ethanol content, vol%

D5501

50 60 70 80 90 100

Frequency

0

2

4

6

8

10

12

Mean

Specification 

Limits

Class 2 Class 3

Less significant problems with meeting ethanol limits 

when wider band of ethanol is allowed

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Results: Class 1 Vapor Pressure

Class 1 DVPE, psi

Measured by D5191

2 3 4 5 6 7 8 9

Frequency

0

5

10

15

20

25

Mean Specification 

Limits

Data was pooled for vapor pressure (statistically 

“allowed”) and showed the mean was well below 

the limit

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Class 2 and Class 3 Vapor Pressure

Class 2 DVPE, psi

D5191

3 4 5 6 7 8 9 10 11 12 13

Frequency

0

2

4

6

8

Mean

Specification 

Limits

Class 3 DVPE, psi

D5191

4 6 8 10 12 14

Frequency

0

1

2

3

4

5

6

7

Mean

Specification 

Limits

Both classes show problems with meeting vapor 

pressure minimums

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Other Properties

No significant failures for other properties (less than 5%)

Samples selected for additional tested showed quality was 

adequately met

Stability and corrosivity

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E-85 Project Summary

Samples were consistently off-specification for low volatility 

and excessive ethanol content

Failures on other specification properties were very low

Random re-sampling of Class 1 showed improvement in 

ethanol content, likely due to reduced cost of gasoline 

compared to first sampling period

Final report is published at:

http://www.crcao.org/publications/emissions/index.html

Another sample will be conducted this year (starting in 

summer 2010) to reassess E85 quality

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What is the future for ethanol in the US?

Will E85 continue to grow? Will more consumers select 

E85 for their FFVs or purchase FFVs with the intent of 

using E85?

How else could ethanol penetrate the US gasoline market?

Higher levels of ethanol in conventional gasoline are 

gaining popular support (i.e. blender pumps)

http://www.opisnet.com/e85/headlines.html

http://www.growthenergy.org/2009/e15/index.asp

http://www.byoethanol.com/

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Blender Pumps

A blender pump dispenses fuel for FFVs that is between 

conventional gasoline and E85

Typically, E20, E30, E50, and E85

Currently, geographically limited to Midwest 

IA, KS, MI, MN, MO, ND, NE, OH, SD, WI, CO

50% of blender pumps in MN and SD

Source: MN Departure of Commerce

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Ethanol Content

Samples show 

expected ethanol 

values, indicating 

good mixing 

practices

All other oxygenates 

were below 

detection limits

Sample ID

0 1 2 3 4 5 6 7 8 9 10

Ethanol content, vol%, D4815

0

10

20

30

40

50

E10

E20

E30

E50

Iowa South Dakota Minnesota

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Blender Pump Closing Remarks

Quick “snapshot” was taken of samples from blender pumps 

to assess quality of lower level ethanol FFV fuels

Pump labeling clearly shows “For Flex Fuel Vehicles”

Data shows samples are meeting the D4806 gasoline 

specification but not the D5798 E85 specification

In 2010, NREL and CRC will collaborate to conduct broader 

blender pump quality survey

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Questions?

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