Ethanol and Biodiesel: What You Need to Know

Ethanol is a renewable fuel made primarily by distilling grains such as corn, wheat, barley and other food crops. It is an alcohol that is mixed with gasoline when used in vehicles. Cars can run on a mix of 85% ethanol and 15% gasoline, but typically ethanol is only used as a fuel additive in smaller percentages.

There are positives of using ethanol as an alternative fuel source. It creates less pollution than regular gas and there is a growing infrastructure to produce it in mass quantities. But there are some negatives. It takes an entire acre of corn to create just 480 gallons of ethanol, which could lead to an issue with the nation’s food supply. Plus, ethanol produces just two-thirds the amount of energy that gasoline does, so you need to use more of it. But since ethanol fuels are cheaper at the pumps, any cost increase is negligible.

Ethanol by Grade:
• Low-Level Ethanol Blends, (E10 and under). Low-level ethanol blends are sold in every state. In fact, nearly half of U.S. gasoline now contains up to 10% ethanol (E10) to boost octane or meet air quality requirements.

• Intermediate Ethanol Blends, (E15-E30). Some fueling stations like Zarco‘s Green Energy Gateway currently use special fuel dispensers that can blend a variety of ethanol fuels by mixing E10 with E85. The resulting intermediate blends can be used legally in flexible fuel vehicles (FFVs), but not in standard vehicles. Commonly considered blends include E20 (20% ethanol, 80% gasoline) and E30 (30% ethanol, 70% gasoline).

• E85. This fuel blend of 85% ethanol and 15% gasoline is used exclusively to fuel E85-capable FFVs, which are available in a variety of models from U.S. and foreign automakers. E85 enables FFVs to operate normally under cold conditions. However, fueling a vehicle with pure ethanol (E100) creates problems during cold-weather operation. E85 has about 27% less energy per gallon than gasoline, but since E85 is priced lower than gasoline the cost per mile is comparable.

• Biodiesel: Made from oils like palm oil, soy oil and a variety of other vegetable oils, biodiesel can be used in newer models of both light-duty diesel and heavy-duty diesel vehicles. In fact, a car converted to use biodiesel can actually run on the grease drippings from a fryer if the drippings are filtered and heated. Blends are available anywhere from 2% biodiesel and 98% diesel all the way to 100% biodiesel.

Unlike with ethanol, the positive impact of biodiesels are often overlooked. Earlier this month, Maryland Gov. Martin O’Malley required all vehicles operated by the state to use a 5% blend of biodiesel wherever possible. The governor estimated that just a 5% biodiesel blend, statewide, would replace 180 million gallons of traditional diesel fuel, displace 1.4 metric tons of greenhouse gases and the reduced demand would save residents $20 at the pump. Plus, the fuel pollutes less than both ethanol and gasoline.


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