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Creating an Octane Blending Model for Gasoline Blends with Renewable Isobutanol

Company Name: Gevo, Inc.
Program Office: Bioenergy
Location: Englewood, CO
Email: Glenn Johnston, Executive Vice President;
Award Amount: $200,000
Project Term: 12 months
Project Status: Active
Participating Lab(s): National Renewable Energy Laboratory, Argonne National Laboratory


In an effort to diversify transportation fuel options, introduce new American-made renewables into the mix, and boost vehicle fuel economy, Gevo, Inc., is working to create next-generation biofuels that can augment or replace petrochemicals.

Isobutanol is a high-octane gasoline blendstock with approximately 30 percent greater energy content, lower water solubility, lower oxygen content and lower Reid vapor pressure (RVP) than ethanol. Compared to ethanol blends, isobutanol blends result in better gas mileage.

However, the effects of isobutanol on gasoline octane numbers is non-linear. A significant barrier for isobutanol's use in the marketplace is the lack of a predictive octane-blending model available to fuel refiners and blenders.

With the help of Argonne National Laboratory and the National Renewable Energy Laboratory, Gevo will develop a robust octane-blending model for isobutanol and gasoline, giving fuel refiners and blenders the tool they need to widely introduce isobutanol into the commercial fuel market.


No octane blending model currently exists for isobutanol and gasoline. A blending model exists for ethanol and gasoline; however, it cannot be applied to isobutanol blends due to significant differences in fuel properties between ethanol and


Developing such a model will allow the widespread introduction of isobutanol into the U.S. commercial fuel market for the first time. Compared to the biofuel in most common use today — ethanol — Isobutanol has approximately 30 percent greater energy content and lower oxygen content, and enables higher fuel economy.


Creation of a robust, predictive isobutanol-gasoline octane blending model will overcome a major obstacle to its use as a commercial fuel, leading to the possibility of widespread use and diversifying high-octane biofuels in the U.S. Expanding the manufacture and use of domestically produced isobutanol would create jobs and economic opportunities.

Because of higher energy content and lower oxygen content, isobutanol will result in better vehicle fuel economy compared to ethanol. It can also be blended at higher volumes before reaching the legislated oxygenate blend limit. This will save energy, reduce America's petroleum dependence and increase energy security.

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