Ethanol, or ethyl alcohol, is the most practical renewable, not-from-petroleum pure gasoline substitute. It is commonly used in unleaded gasoline, usually as an oxygenate additive or blend, because ethanol burns cleaner than gasoline.

The most prominent ethanol fuel is E10, added to nearly all unleaded gasoline sold today. Coming on strong is E15, a larger blend of ethanol (85% unleaded gasoline, 15% ethanol) that yields a slightly higher octane and can be used in any vehicles produced since 2001. The E15 blend, often called Unleaded 88, is cheaper per gallon than typical unleaded gasoline blends. Its higher octane can reduce engine knock and produce greater overall efficiency and power. It also emits less carbon dioxide but may have a slightly lower fuel economy than standard unleaded gas.

E85, meanwhile, is unleaded gas and between 51% and 83% ethanol. It is used in flex-fuel cars and SUVs. An incentive for automakers to produce vehicles that run on E85 is that they dramatically boost the automaker's Corporate Average Fuel Economy (CAFE) ratings.

“For a dual-fuel model that achieves 15 miles per gallon operating on alcohol fuel and 25 mpg (miles per gallon) on the conventional fuel, the resulting CAFE (calculation) would be … 40 miles per gallon,” according to the National Highway Traffic Safety Administration (NHTSA). This effectively lowers average fuel economy requirements for other vehicles, allowing automakers to produce more large SUVs and trucks, which get poor fuel economy, even if the flex-fuel models never actually operate on ethanol.

“To build a lower-carbon future and meet our energy needs, we’ll need to explore and smartly deploy all of our options,” said Jake Comer, vice president of market development at biofuels association Growth Energy and former director of retail fuels at Casey’s General Stores Inc., Ankeny, Iowa. “The great thing about biofuels like ethanol is that we can expand their use now for the millions of cars on the road today that can immediately drive down tailpipe emissions.”

Ethanol can be used in 96% of vehicles already on the road today and reducing the auto fleet’s carbon footprint, Comer said. “No other fuel option can say all of those things.”

For convenience retailers who operate fuel pumps, the cost of converting to E15 can be much less expensive than converting to other fuel sources, Comer said. “If tanks and lines are compatible, the cost of conversion can range from only a few thousand dollars to maybe $20,000,” he said, adding there are many state and federal grants that can offset these costs in part or in whole.

About 3,000 c-stores and gas stations offer E15 today. Growth Energy is seeing E15 replace E10 as retailers notice that E15 has better margins and consumers want to buy it. “Iowa is moving to an E15 standard, and I expect that trend to spread,” Comer said.

“The great thing about biofuels like ethanol is that we can expand their use now for the millions of cars on the road today.”

Despite the increasing momentum of electric vehicles, the obituary for liquid fuels may be premature. Many retailers continue to believe that liquid fuels still have a place in the energy mix and still future.

“The electric-vehicle evolution has come so fast, and it has come guns ablazing. The challenge is what to do until we have adoption rates where we see registrations across the U.S. hit some sort of inflection point north of where it’s at today,” said Nathaniel Doddridge, vice president of fuels for Casey’s. “I don’t know if it’s when 10%, 15%, 20% of total cars on the road are EVs. We don’t know what the repercussions are to supply chains. We don’t know what the repercussions will be for natural resources. We just don’t know.”

“As that plays out, we’re still really reliant on the liquid fuel space, and I think that being really close to ethanol, biodiesel, some of those fuels will be really important as we as navigate through this shifting in energy.”