pic pic
pic pic pic
Oil Seed Crops
Anaerobic Digestion
Fuel Quality
Laws and Incentives
Fuel Availability
Biofuel Projects
Climate Change
Reports WA
About Us

Fuel Quality

Washington State Biofuels Standards

Ensuring consumer’s have a high level of confidence in the fuel they purchase is a "top" priority for Washington State. Washington State Department of Agriculture (WSDA) Weights and Measures Division has developed a set of fuel quality and labeling rules for biodiesel and ethanol fuel. These rules were developed following an extensive outreach effort that involved consumers, industry, research groups and governmental agencies. The rules are based on national ASTM and NIST standards for fuel quality and product labeling and are posted at the WSDA website. The American Society of Testing and Materials (ASTM) is the recognized standard-setting body for fuels and additives in the United States. The National Institute of Standards and Technology (NIST) is the federal agency that develops and promotes measurement, standards, and technology. The Weights and Measures Division has also established a quality assurance and monitoring program which includes on-going field testing and field audits of biofuels sold in Washington.


Washington State biodiesel standards

Biodiesel is chemically referred to as a Fatty Acid Methyl Ester (FAME). It is produced by processing raw vegetable oil or animal fats through a chemical process called transesterification. The Washington State Department of Agriculture adoption of biodiesel regulation "by rule" became effective March 21, 2007. These standards can be found at WSDA’s Motor Fuel Standards website. The final rules are based on NIST Handbook 130 Uniform Engine Fuels, Petroleum Products, and Automotive Lubricants Regulation, with modifications to accommodate statutory requirements. For biodiesel (as well as fuel method of sale requirements), it is expected that NIST Handbook 130 will be adopted annually. WSDA has also incorporated biofuel sampling and testing into its existing Motor Fuel Quality Program. The program is sampling fuels throughout the distribution chain, from producer to retailer. The program goals are to assess the quality of fuels sold in Washington State, provide consumers with assurance of quality fuels, and establish consistent regulation for industry.

In addition to setting biodiesel quality standards, the WSDA has established labeling requirements for biodiesel pumps. Biodiesel must be labeled as follows:

  • Retail dispensers of biodiesel blends containing no less than 2% and no more than 5% biodiesel must be labeled “Contains up to 5% Biodiesel”.
  • Retail dispensers containing less than 2% biodiesel must not be labeled as dispensing biodiesel or biodiesel blends.
  • Biodiesel blends above 5% must be labeled with the volume percentage of biodiesel.
  • The label must be placed in the upper 50% of the dispenser front panel in a position clear and conspicuous from the drivers’ position.
  • The text on the label must be a type at least 1/2 inch in height and 1/16 inch in width with the capital letter “B” followed by the volume percentage of biodiesel and ending with the words “Biodiesel” or “Biodiesel Blend”, whichever is appropriate.

Biodiesel fuel quality

The National Biodiesel Board (NBB) maintains a fuel quality page on their website that provides useful information on the use and handling of biodiesel. Information on state fuel quality regulations, national ASTM and NIST standards and current industry actions on fuel quality can be viewed here. The National Renewable Energy Labs has also published a useful guidebook entitled Biodiesel Handling and Use Guidelines. This guidebook provides a comprehensive discussion of using biodiesel as a vehicle fuel and discusses biodiesel health and safety issues, as well as engine warranty concerns.

Locally, the Puget Sound Clean Air Agency (PSCAA) is conducting a study investigating biodiesel fuel quality issues, and has contracted with Washington State University and Imperium Fuels to complete this work. The study is focused on biodiesel use at Washington State Ferries.

Beyond local and state efforts to ensure quality fuel for consumers, the biodiesel industry as a whole is continually working to improve biodiesel standards to reflect real world operations and use. As of October, 2008 ASTM’s D02 Main Committee has approved a trio of ASTM specifications for biodiesel blends which should significantly bolster automaker support and consumer demand for biodiesel. The three changes are:

  • Changes to the existing B100 biodiesel blend stock specification (ASTM D6751) including a cold filtration test which should assure buyers that B100 won’t contain certain precipitates that can cause filter plugging in cold weather
  • Finished specifications to include up to 5% biodiesel (B5) in the conventional petrodiesel specification (ASTM D975)
  • A new specification for blends of between 6 percent biodiesel (B6) to 20 percent biodiesel (B20) for on and off road diesel.

The adoption of these new fuel quality standards is important, particularly the passage of a B20 fuel blend specification. Some companies, such as Chrysler LLC, had stated that the need for that specification was the single greatest hurdle preventing their full-scale acceptance of B20 use in their diesel vehicles. A copy of the current ASTM D6751-07be1 standards can be obtained at ASTM International.

Renewable Diesel

According to the Environmental Protection Agency’s Renewable Fuel Standard, renewable fuels are defined as motor vehicle fuels produced from plant or animal products or wastes. Within this definition, two distinct forms of diesel fuel are specified: biodiesel and renewable diesel. Each is defined according to the process by which it is produced. EPA defines renewable diesel as “…diesel fuel derived from biomass (as defined in section 45K(c)(3)) using a thermal depolymerization process which meets –(A) the registration requirements for fuels and fuel additives established by the Environmental Protection Agency under section 211 of the Clean Air Act (42 U.S.C. 7545), and (B) the requirements of the American Society of Testing and Materials D975 or D396.”

At this time, there is no universally accepted definition or technical standard that exists for renewable diesel. There are multiple technologies that produce a product that has been called “renewable diesel” fuel. While some of these technologies are in commercial production, others are still in the research and development phase, years away from producing commercially available product. The different technologies use widely different feedstocks, including wood biomass, slaughterhouse waste, tallow, and recycled or virgin vegetable oil.

One commonality of these fuels is that they are not biodiesel, which is defined in Washington State law as “the monoalkyl esters of long chain fatty acids derived from plant or animal matter that meet the registration requirements for fuels and fuel additives established by the federal environmental protection agency and standards established by the American society of testing and materials.” Biodiesel is produced via a reaction of vegetable oil or animal fat with an alcohol (usually methanol) and a catalyst. Biodiesel is chemically distinct from petroleum diesel and has a separate ASTM standard (D6751), which specifies the standard for biodiesel for use as a blend component with petroleum diesel. Biodiesel has passed the EPA Tier I and Tier II health-effects testing, and is registered with the EPA as a fuel additive.

Renewable diesel is produced through other chemical processes and is commonly referred to as non-esterified renewable diesel (NERD). The most advanced of these alternatives is produced through hydrotreating, a process which is being utilized in today’s petroleum refineries. During this process hydrogen replaces other atoms such as sulfur, oxygen and nitrogen and converts the oil’s triglyceride molecules into paraffinic hydrocarbons. While existing petroleum refineries could blend the renewable and petroleum fuels during the hydrotreating process to create a renewable diesel blend, stand alone facilities can produce 100 percent renewable diesel to be used directly or to be blended with petroleum diesel. Renewable diesel is considered substantially similar to conventional diesel and is expected to fall under the ASTM specifications for diesel fuel. The report “Renewable Diesel Technology” was completed for the Washington State Biofuels Committee and outlines the current state of renewable diesel technology in the US.

On September 23, 2008, the U.S. Senate voted to renew a one year extension for renewable energy tax credits worth $18 billion dollars. The legislation enacts a $1 per gallon credit for biodiesel production, but the “renewable diesel” made from waste fat, or tallow, would only be eligible for a 50 cent per gallon credit. Some renewable fuel manufacturers, such as ConocoPhillips, have suggested that without the full $1 per gallon credit for making “renewable diesel”, their proposed projects may not be economical.

Straight Vegetable Oil (SVO)

Straight vegetable oil (SVO), or pure plant oil (PPO), can be used as a fuel in diesel engines. However, it is more viscous (thicker) than diesel or biodiesel fuel, and typically requires preheating prior to combustion. Problems associated with SVO as a fuel include incomplete combustion and carbonization, which can result in pre-mature engine failure.

SVO use in the US has been limited. One of the major barriers to its use is that SVO is not registered as a “fuel” or “fuel additive” with the US Environmental Protection Agency (EPA) as per USC 42, Chapter 85, Subchapter II, Part A, Motor Vehicle Emission and Fuel Standards.

In short, EPA regulations require that in order for a fuel to enter commerce, it has to pass Tier I & II environmental and emissions testing, a very expensive undertaking. To date, no SVO products have completed this testing and received approval from EPA.

In addition, SVO operations require aftermarket conversion of the vehicle (typically the addition of a heat exchanger and some other fuel delivery system modifications). Aftermarket conversions fall under EPA regulation “Mobile Source Enforcement Memorandum 1A: Revised Tampering Enforcement Policy for Alternative Fuel Conversions”. This rule was passed to ensure that the modifications do not cause an increase in emissions compared to the baseline system and fuel. Unless the conversion equipment has been approved by EPA, converting a vehicle to SVO operations constitutes after-market tampering. No SVO conversion equipment manufacturer has received EPA certification at this time.


The Washington State Department of Agriculture’s adoption of ethanol regulations "by rule" became effective on March 21, 2007. The new rules are posted at the Department of Agriculture’s Motor Fuel Standards website. The final rules are based on NIST Handbook 130 Uniform Engine Fuels, Petroleum Products, and Automotive Lubricants Regulation, with modifications to accommodate statutory requirements. The ASTM standards for ethanol are:

  • Ethanol. - intended for blending with gasoline shall meet the most recent version of ASTM D 4806, "Standard Specification for Denatured Fuel Ethanol for Blending with Gasolines for Use as Automotive Spark-Ignition Engine Fuel."
  • E85 Fuel Ethanol. - shall meet the most recent version of ASTM D 5798, "Standard Specification for Fuel Ethanol (Ed75-Ed85) for Automotive Spark-Ignition Engines."

The American Society of Testing and Materials (ASTM) has developed ethanol fuel specifications ASTM D5798-99 Standard Specification for Fuel Ethanol for Automotive Spark-Ignition Engines to ensure proper starting, operation, and safety. The minimum commercial standards for ethanol fuel can be found in the Department of Energy publication- The Handbook for Handling, Storing, and Dispensing E85.

The majority of ethanol fuel consumed in Washington State is sold as E10, which is a blend of 10% ethanol and 90% gasoline. E10, or gasohol, is approved for use in all gasoline vehicles, and has been used for many years across the nation both to improve air quality and to increase gasoline’s performance. E10, and other low level blends, are classified as "substantially similar" to gasoline by the U.S. Environmental Protection Agency (EPA), meaning they can be used legally in any gasoline-powered vehicle.

E85 fuel, which is composed of 85% ethanol and 15% gasoline, is also an approved motor fuel by EPA and is sold in Washington State. However, unlike E10, E85 can only be used in Flexible Fueled Vehicles (FFVs). The Washington State Department of Agriculture has developed a set of guidelines for retailers interested in dispensing E85 fuel to Washington consumers. These guidelines are contained in the brochure E85 Dispenser Guidelines.

Any ethanol/gasoline blends between E10 (10% ethanol - 90% gasoline) and E85 (75% - 85% ethanol and 15% - 25% gasoline) fuel ethanol are prohibited from sale and are not permitted by federal law. Thus, ethanol/gasoline blends such as “E20,”“E30,” or other ratios are not permitted for sale at this time. However, significant studies (ORNL) are underway evaluating the use of mid-level ethanol blends. Early indications are that these blends may be suitable for use in conventional gasoline powered cars.

Small engine ethanol use

Two-stroke engines should experience little or no decrease in performance due to gasoline fuels containing up to 10-percent ethanol. However, ethanol is hygroscopic (it has an attraction for water) and will more readily mix with water than with gasoline. Therefore, marine users should make sure that their fuel tanks are free of water prior to fueling to minimize the possibility of phase separation and potential filter plugging or even engine damage. It is also best to maintain a full tank of fuel when the engine is not in use. This will reduce the void space above the fuel and will reduce the flow of air in and out of the tank with changes in temperature, thereby reducing condensation on the internal walls of the tank and limiting exposure of the ethanol in the fuel to humidity and condensation.

Ethanol blend fuels can also act as a solvent and may loosen rust and debris that might lay undisturbed in fuel systems. Loose debris can plug filters and interfere with engine operation. It is recommended that fuel filters be inspected regularly when first using an ethanol blend and that spare filters are readily available in case replacement is needed. Similarly, ethanol blends can be detrimental to some older plastic and rubber materials that might not be affected by gasoline alone. If an engine is a 1990 or older model, inspections of all fuel-system components are advised to identify any signs of leakage, softening, hardening, swelling or corrosion. If any sign of leakage or deterioration is observed, replacement of the affected components is necessary. For older engines it may be advisable to check with your engine manufacturer to determine component compatibility with ethanol blends.

Fiberglass tanks manufactured prior to 1991 may not be compatible with gasoline containing ethanol. It has been reported that, in the presence of ethanol, some resins may be drawn out of fiberglass and carried into the engine where severe damage could occur. If an older fiberglass tank is used, check with the manufacturer to determine if gasoline with ethanol can be safely used.

On-going Weights and Measures Issues

The WSDA Weights and Measures division is continuing to work on fuel quality, labeling and consumer education issues as biofuels are rolled out in response to the state Renewable Fuels Standard (RFS). In addition to setting fuel quality and labeling standards, WSDA is conducting field testing of biofuels. These tests help ensure that Washington State consumers are getting the highest quality fuel at the blend rate specified on the dispenser.

Some of the current WSDA Weights and Measures biofuel activities are noted below.

  • W&M began initial biofuels quality testing and label assessment in May 2007. Sampling/testing levels will continue to ramp up as methods/protocols are developed, biofuels locations identified, and inspectors become more experienced.
  • W&M began industry education and outreach efforts in the fall of 2007 to help ensure proper fuel dispenser labeling and the availability of high quality fuels.
  • Develop guidelines for E-85 pumps until there are pumps available that have the National Type Evaluation Program and UL certificates.

Additional Resources

WSDA Biofuels Standards Program
EPA- Renewable Fuels
National Biodiesel Board
National Ethanol Vehicle Coalition
U.S. Department of Energy Alternative Fuel Data Center
Biodiesel Handling and Use Guidelines
The Handbook for Handling, Storing and Dispensing E-85
Renewable Fuels Association
Boat U.S. Ethanol Fact Sheets
Renewable Diesel Technology Report

pic pic pic
Contact Us Webmaster