If you fill up at a gas station in the U.S. sometime this week, chances are you’ll be pumping gasoline blended with 10 percent ethanol by volume (E10). As the EIA reports, nearly all American gasoline is now E10, the result of nearly a decade of biofuel mandates that have required refiners to blend increasing amounts of ethanol into fuel:
Blends of petroleum-based gasoline with 10% ethanol, commonly referred to as E10, account for more than 95% of the fuel consumed in motor vehicles with gasoline engines. Ethanol-blended fuels are one pathway to compliance with elements of the federal renewable fuel standard (RFS). The total volume of ethanol blended into motor fuels used in the United States has continued to increase since 2010, albeit at a declining rate of growth. Meanwhile, the use of ethanol-free gasoline (E0) by fuel consumers has declined.
The near ubiquity of E10 matters, because many older car engines can’t run on higher ethanol blends, which effectively means we’re currently blending all the ethanol that’s possible to blend into the national fuel supply. This is the so-called “blend wall,” and it sets a very real limit to the biofuel boosting ambitions set out by the 2007 Renewable Fuel Standard (RFS). The RFS initially envisioned ratcheting up ethanol mandates year after year, but those quotas have had to be relaxed recently, partly because of the blend wall.
If we want to blend more ethanol, we’ll either need to consume more gasoline as a nation (cheap gas prices and the resulting spike in SUV sales may help here), or as the EIA details, we’ll need to start producing more higher ethanol blends that can only be used by newer cars:
With nearly all U.S. gasoline now being sold as E10, the only way to increase ethanol use in the motor vehicle fleet is to adopt fuel blends containing a higher volume of ethanol, such as E15 and E85. However, not all gasoline-powered vehicles can use these fuels. The U.S. Environmental Protection Agency (EPA) has issued a partial waiver allowing the use of E15 in model year 2001 and newer vehicles. Fuels marketed as E85, which contain between 51% and 83% ethanol by volume, can only be used in flex fuel vehicles. Recent EIA congressional testimony on the RFS program estimates that flex fuel vehicles make up about 7% (16.3 million) of the current on-road fleet of light-duty vehicles in the United States.
But the EIA concludes that sales of these higher ethanol blends “remain very limited because of a variety of economic, environmental, and distribution system challenges.” The blend wall is not so easily dismantled.
So we’re left with a system of mandates that’s now stymied by chemistry. Now seems as good a time as any to take stock of what the RFS has accomplished: it has raised global food prices, starving the world’s poor; it costs drivers billions at the pump every year; it’s killing wild bee populations; and it isn’t even green. Let’s end this boondoggle, the sooner the better.