Is It Time to Try a Different Type of Gas?

You may have noticed new options popping up at the fuel station lately, in the form of different grades of gasoline fuel for their car. While "standard" and "premium" gas have been the typical choice for many years, more and more gas stations are offering some additional options. This includes two options that have higher fractions of  biofuel in their formulation:

• Unleaded88 - this is gasoline with 15% ethanol - it's often also called "E15" for that reason. It is usually less expensive than regular gas, and the pump is usually color coded blue.
• Flex Fuel - this is fuel that is mostly ethanol. The percentage of ethanol ranges from 51-83%. It is usually the least expensive option on a per-gallon basis, and the pump is usually color coded yellow.

While not every gas station has these new options available at the pump, an increasing number of gas stations are adding them to their lineup, giving drivers some new choices to make. And while price is not the only consideration when choosing a fuel, the recent period of high gasoline prices has prompted many of us to wonder if either Unleaded88 or Flex Fuel might be an option for their vehicle.

Can I Use Higher Percentage Ethanol Blends?

In general, every car in the US that has been manufactured since 2001 is approved to use Unleaded88. Older cars may have issues with Unleaded88 due to either the engine sensors and controls not being able to adjust optimally or due to older materials being used for hoses and gaskets that aren't compatible with the higher concentration of ethanol. Unleaded88 has a slightly higher octane rating than regular gas (that's good), but the total energy content per gallon is about 1.5% less (that's not as good).

Flex fuel, which is the commercial fuel with the highest percentage of ethanol, is only rated for use in vehicles that are "flex fuel" approved. Most flex fuel cars have a "flex fuel" symbol affixed to the back of the car (like the photo shown above), but you can check your owner's manual or contact the manufacturer to make sure. 

Does It Pay Off?

From an economics perspective, if Unleaded88 is more than 1.5% less expensive than regular gas, then you should be saving money by opting for Unleaded88. For example, if regular gas is $3.99 but Unleaded88 is $3.39, the Unleaded88 is only 3.39 / 3.99 = 0.85 or 85% as expensive. That means you'll be paying 15% less for fuel that has 1.5% less energy per gallon. However, the best way to confirm the savings is to try it out by measuring your car's mileage on a tank of Unleaded88 and comparing that to a tank of Regular in order to know for sure.

The lower price of Unleaded88 has been a source of considerable interest in Pennsylvania this year, with some stations selling out of the fuel at times because the number of people using it has risen faster than expected.

Similar to Unleaded88, the best way to know if it is a good deal for your vehicle is to measure the mileage from a tank of flex fuel, and compare that to the vehicles mileage when using regular gasoline.

When Should I Be Extra Careful?

Some people continue to be very concerned about the effect of fuel ethanol on engines. While long term storage of fuels with ethanol (such as in a lawn mower over the winter) should always include the use of fuel stabilizer additives, day-to-day use of Unleaded88 or Flex Fuel in approved vehicles doesn't appear to be causing issues. For those of us with classic cars or vehicles whose parts are not designed for modern fuels, it's probably worthwhile to consider opting for "ethanol free fuel", which is available at some gas stations but is more expensive than regular gas. We've also seen some examples of old engines running hotter with ethanol blends, necessitating adjustments to the fuel-air mix to keep it operating in the optimal range. It is interesting to note, though, that the Ford Model T was designed to run on gasoline or ethanol.

Is It Good For the Planet?

Are fuels with higher ethanol concentrations better for the ecosystem? This is a complex question, as it involves all of the steps from growing the biofuel crops through manufacturing the fuel and transporting it to the gas station, as well as its final use in your car. Many assumptions have to go into that analysis, and those assumptions can have big impacts on the results of the analysis. It will probably be several years before enough studies are carried out to allow us to make a reasonably balanced conclusion about this issue. In general, higher ethanol blends do appear to reduce harmful emissions from the exhaust of cars, and ethanol produced and used in the US is less greenhouse gas intensive than petroleum fuel. Ethanol is renewable, whereas petroleum gasoline is not.

For many people, the pros are outweighing the cons with respect to Unleaded88 and Flex Fuel. Ultimately, however, it's up to you to decide which type of fuel you'd rather use in your vehicle. As a summary, here are the key take-home points for this article:

• Unleaded88 (also called E15) fuel is approved for use in all US cars 2001 and newer.
• "Flex Fuel" is approved only for vehicles that are specifically rated to use high ethanol fuels.  
• The lower price of Unleaded88 often makes it a more cost effective option than regular gasoline.
• You get to choose which fuel you want to use.

If you'd like to learn more, you can read our extension article "Ethanol Fuel: Hero or Villain?".