Since 2007, the Renewable Fuel Standard has required increasing levels of ethanol in gasoline blends sold in the U.S.
Most fuel stations across the United States no longer offer pure gasoline, with E10—a blend of 10 percent ethanol and 90 percent gasoline—prevailing.
After years of debate, the EPA has now announced it will study the possibility of reducing the amount of ethanol in the U.S. gasoline supply.
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Today, the total amount of ethanol-blended gasoline hovers around 19.28 billion gallons, but the EPA has proposed a reduction to 19.24 billion gallons earlier this year.
The agency could make further cuts, though the total amount of corn-based ethanol fuel is projected to remain the same at 15 billion gallons.
The EPA said several new factors may allow it to reduce ethanol levels and bypass the Renewable Fuel Standard, according to Hemmings Motor News.
Big square baler harvesting wheat straw for production of cellulosic ethanol
Those include inexpensive imports of renewable fuels, a low domestic supply of renewable fuel, and high costs associated with biodiesel and ethanol not based on corn.
The EPA could enact cuts on the premise of "severe economic harm," which the legislation presently stipulates. If the agency finds evidence that current ethanol-blend levels are hurting the economy, it may go ahead and adjust ethanol volumes.
Ten years ago, the law promoted ethanol as a budding renewable fuel, but supplies of ethanol generated from non-corn sources haven't materialized as envisioned.
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Cutting ethanol levels would slighly increase the consumption of fossil fuels, but it would also modify a decade-old policy designed on the premise that U.S. gasoline consumption would continue to rise indefinitely.
Instead, U.S. gasoline consumption peaked in 2007 and fell continuously for years thereafter, due to both the effects of the economic recession and then rising fuel-economy standards that took effect starting in 2012.
Flex-fuel vehicles that can run on E85 ethanol, especially larger and heavier trucks and SUVs, were Detroit's initial response to hopes that ethanol could displace gasoline.
Non-ethanol gasoline pump
Now, however, the world has moved from reducing the carbon footprint of liquid hydrocarbon fuels to eliminating them altogether—with the world's largest car market, China, now mulling the date after which sales of new vehicles with combustion engines will no longer be permitted.
Ethanol in gasoline is also considered damaging to older internal-combustion engines. Outboard motors, lawn mowers, chain saws, and other gasoline engines designed to run on pure gasoline haven't fared well on E10.
The EPA report takes pains to mention degraded fuel systems in older vehicles, which it suggests were caused by increased ethanol levels.
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The EPA said several years ago that E15 gasoline could damage older cars, and recommended vehicles built before 2000 should not use the fuel. Those vehicles now make up only a small portion of the U.S. fleet.
Gasoline with more than 10 percent ethanol remains scarce on the ground, however, in part because gas-station owners must install costly blender pumps to dispense it—and they see no market demand for it among drivers.
The EPA has opened a public comment period for input surrounding current ethanol levels in gasoline. The agency will submit its finalized ethanol-volume figures by November 30, 2017, for 2018.