Fuel FAQs

Find answers to commonly asked questions about Flex Fuel and Biodiesel. Printable PDF versions are also available for download.

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  • What is Flex Fuel E85?

    E85 is an ethanol-based, clean-burning alternative to petroleum gasoline. Derived today from fermented grains and sugars, it is formulated for use in Flex Fuel vehicles. Unlike petroleum, E85 is made from renewable resources like corn and next generation sources such as switchgrass and agricultural waste material. Using E85 not only decreases CO2 emissions by 21-28% (Argonne National Laboratory, GREET); it has also helped cut the consumption of crude oil by nearly one million barrels a day.

  • What is a Flex Fuel vehicle?

    A Flex Fuel E85 vehicle, or FFV, has an engine and fuel system designed to run on both petroleum gasoline and E85 ethanol. There are approximately 10 million Flex Fuel vehicles on US roads today. Nearly all vehicle manufacturers offer some models compatible with Flex Fuel E85 including Chrysler, Ford, GM, Jeep, Mazda, Mercedes Benz and Toyota. Automakers have pledged to make 50% of their vehicles Flex Fuel-compatible by 2012 if E85 refueling stations, like Propel’s, are widely available. For a list of Flex Fuel vehicles, visit our Vehicles page.

  • What is ethanol’s role in the U.S. Renewable Fuel Standard?

    The United States’ Renewable Fuels Standard (RFS) is a Federal plan to reduce America’s dependence on petroleum and set targets for the amount of renewable fuels in our nation’s fuel supply. The RFS requires that 36 billion gallons of renewable fuel, primarily ethanol, be blended into our transportation fuels by 2022. Of that, California’s market represents 3 billion gallons, nearly 10% of the entire mandate.

  • How big is the industry today?

    Currently, there are 200 ethanol plants in 26 states with nearly two dozen more under construction or expanding their capacity. The U.S. ethanol industry now has the capacity to produce an estimated 13 billion gallons of high-octane, clean-burning motor fuel per year and has created more than 500,000 American jobs.

  • Is ethanol better for the environment?

    Yes. Ethanol reduces tailpipe carbon monoxide emissions by 30%, reducing smog and air toxins, such as benzene, by 21%, and tailpipe particulate matter (PM) emissions by 50%. Ethanol is rapidly biodegradable in surface water, ground water and soil. If only five million Flex Fuel vehicles fill with E85 instead of gasoline, total carbon dioxide emissions are reduced by 20 million tons per year. Next-generation ethanol produced from cellulosic materials will offer even greater benefits with an 85% reduction in greenhouse gas emissions.

  • Doesn’t it take more energy to produce ethanol than is gained by using it?

    No. A June 2010 USDA study concluded that the current energy ratio for ethanol is about 2.3 BTUs of ethanol for 1 BTU of energy input. This means more than twice the energy comes out of ethanol than was put in to create it. These new findings reflect major increases in the productivity in corn production and the conversion of corn grain into ethanol – a trend that will only continue as advanced cellulosic ethanol comes online.

  • Are there economic benefits to ethanol?

    Yes. The US ethanol industry is creating jobs, reducing our dependence on foreign oil, and supporting the domestic economy. In late 2009, it was estimated that more than 500,000 American jobs are attributed to the ethanol industry—and that number is growing rapidly as plants are built or expanded.

Diesel HPR is a high performance renewable fuel that meets the ASTM D975 petroleum diesel fuel specification for use in all diesel engines. Diesel HPR contains no biodiesel.

Learn More About Diesel HPR.

  • Download Biodiesel FAQs (PDF)
    • What is biodiesel?

      Propel biodiesel is a clean-burning, domestically-produced fuel derived from 100% renewable resources like soybeans, canola and recycled fats and oils and is easily accessible in varying blends to drivers at Propel Clean Fuel Points. Better than pure petroleum diesel, biodiesel reduces harmful carbon emissions yet delivers superior performance.

    • What are the benefits to using biodiesel?

      Among the many benefits, biodiesel:

      • Reduces global warming by lowering environmentally harmful CO2 emissions by as much as 50%, carbon monoxide by 48% and particulate mater by 47% while containing zero sulfur
      • Lowers our dependence on foreign oil, increasing our national energy security
      • Supports local and regional farmers
      • Offers increased lubricity for enhanced performance and increased engine life


    • Do I need to convert my diesel vehicle to run Propel biodiesel?

      No, any diesel engine can use biodiesel without any conversion or modification to the vehicle. Propel offers biodiesel blends from B99 (99% biodiesel) to B5 (5% biodiesel, 95% petro-diesel).

    • Can I switch between Propel biodiesel and petro-diesel?

      Yes, diesel engines can switch back and forth between biodiesel and petro-diesel at any time, so you can fuel your vehicle with biodiesel or mix it with regular diesel in any ratio.

    • What is the difference between Propel’s biodiesel blends?

      Propel offers several blends of biodiesel, each named for the amount of biodiesel they contain. For example, B20 is a blend of 20% biodiesel and 80% petro-diesel; B99 is almost pure biodiesel; and B75, often used as a winter counterpart to B99 since it performs optimally even in cold temps, contains 75% biodiesel and 25% petro-diesel.

    • Does Propel biodiesel yield more energy than it takes to produce?

      Yes, Propel biodiesel provides more than twice the energy than is required for production, including the energy used to grow and produce the biodiesel and then transport and distribute that biodiesel to users.

    • Where does Propel’s feedstock come from?

      Propel only sources feedstock that meets our quality and price standards. Whenever possible, Propel partners with local producers to offer regionally grown and produced fuel at our Clean Fuel Points.

    • Can biodiesel void my manufacturer warranty?

      No, vehicle and engine manufacturer warranties apply to the specific products they manufacture. Fuel or fuel additives are not covered under a vehicle warranty. Under the Magnuson-Moss Warranty Act, if an engine experiences a malfunction due to parts and workmanship while under warranty, and it is not related to the fuel, it must be covered under the OEM’s warranty. Conversely, if it is determined that an engine malfunction is caused by the fuel used, it would become the responsibility of the fuel supplier to correct the problem. Under our Performance Guarantee, if Propel fuels are proven to be the cause of failure to any warranted fuel system, Propel will fix or replace the damaged material at no cost.

    • What vehicle manufacturers currently sell diesels?

      In the US, diesel passenger vehicles are available from Audi, BMW, Mercedes Benz and Volkswagen with a Chevrolet Cruze diesel offering slated for arrival in 2013. Diesel trucks and vans are available from Ford, Chevrolet, Dodge, GMC and Isuzu (for fleets), and the majority of commercial vehicles available today are diesel. Ford, Chevrolet, Dodge, Cummins and Isuzu all officially endorse biodiesel blends up to B20 (20% biodiesel) in engine models 2011 and newer.

    • Can biodiesel increase my engine’s life and performance?

      Yes. The lubricity in biodiesel is higher than petro-diesel – in fact, studies have shown a reduction in engine wear with biodiesel. Some biodiesel users find engine power and mileage to be the same, yet some customers have reported seeing even better mileage with biodiesel.

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