E15 waiver expands fuel choice as summer prices rise

summer E15 – As oil and gas supplies tighten amid the conflict in Iran, pump prices climb just as many drivers head out over the Memorial Day weekend. In response, the EPA has moved to allow higher-ethanol E15 gasoline sales during summer months—an approach that could offe

For the third morning of a price spike. the story many drivers feel is the same: the trip is already planned. but the fuel bill keeps getting worse. With conflict in Iran strangling oil and gas supplies. prices at the pump have been rising—economic pain hitting hard when many hit the road over the Memorial Day weekend.

In March. the Environmental Protection Agency’s head Lee Zeldin announced he would grant a waiver to the ban on selling so-called E15 gasoline—fuel containing 15 percent ethanol—during the summer. The waiver went into effect on May 1 and was initially intended to last for 20 days. Zeldin has now signaled he will likely extend it through the summer, aiming to increase “fuel supply and consumer choice.”.

The move is not happening in a vacuum. In a shift from previous years. the House of Representatives passed a bill on May 13 to make year-round sales of E15 permanent. If the bill passes the Senate. E15 could become a standing part of summer fuel—at the same time critics warn it could also boost summer air pollution.

The argument over E15 is not only political. It also runs through the chemistry of what happens after fuel hits an engine.

Ethanol blended into gasoline is meant to change the exhaust. Most gasoline sold year-round in the U.S. contains 10 percent ethanol—a fuel made from fermented biomass, usually corn, instead of petroleum. Using ethanol in fuels dates back to the Clean Air Act Amendments of 1990 and the subsequent U.S. Renewable Fuel Standard established by the Energy Policy Act of 2005.

Ethanol contains more oxygen than gasoline. That means ethanol blends release fewer toxic carbon monoxide emissions from tailpipes. Ethanol also releases fewer nitrogen oxides, another set of tailpipe pollutants, compared with gasoline. When lawmakers pushed ethanol, they hoped it would have a smaller climate effect than gasoline. Holly Gibbs. a geographer at the University of Wisconsin–Madison who studies land use. says the premise was that replacing some petroleum with plant-based fuel would lower transportation emissions because the carbon released by burning ethanol was assumed to be partly offset by the corn absorbing CO₂ as it grows.

That hope, Gibbs adds, hasn’t panned out. The emissions picture changes when cornfields expand to supply the fuel.

Ethanol’s pull in the U.S. economy is tied directly to farming. About 40 percent of the U.S. corn crop is used for ethanol.

E15 is not the same as the standard mix. E15 fuel contains between 10.5 and 15 percent ethanol. In the U.S., it’s approved for use in all light-duty vehicles made in 2001 or later and for flexible fuel vehicles designed to run on blends of up to 83 percent ethanol.

It’s typically not sold during the summer, though. The reason is tied to air chemistry: burning ethanol releases volatile organic gases that react with sunlight and nitrogen oxides in the atmosphere to produce acetaldehyde. a major component of ground-level ozone. Ozone near the ground is a toxic gas that causes wheezing, coughing and asthma attacks, and it contributes to smog. Higher up in the stratosphere, ozone is protective against ultraviolet rays—but at the surface it’s the opposite.

The reaction is stronger in summer. Heat and sunlight speed up the processes that lead to ozone. The impact also depends on where the air already lacks reactive organic gases. Mark Jacobson. a Stanford University professor of civil and environmental engineering who has studied ethanol fuel pollution impacts. says the difference matters: most of the U.S. has fewer reactive organic gases already, while the Southeast has abundant vegetation that naturally releases reactive gases.

In places where baseline conditions keep reactive gases higher, the added ozone from E15 isn’t necessarily significant in summer. Jacobson says that could be the case for Atlanta. But in places like Los Angeles—where keeping reactive organic gases low is important for reducing smog—the increase tied to E15 could be more consequential. That’s why E15 sales are typically restricted in most of the U.S. during the summer months.

So what happens if the waivers widen the fuel availability now?. Farmers may see relief first. The waivers could bump up corn prices. which could help them make up for the financial hit from the increase in diesel and fertilizer prices stemming from the war in Iran. Carlisle Runge. a professor of applied economics and law at the University of Minnesota. says the Trump administration is under pressure to keep farmers’ support.

The practical side is smaller than the political stakes. About 3,000 gas stations, or 2 percent nationally, are equipped to dispense E15 gas, according to the EPA.

Even where the fuel is available, cost savings aren’t guaranteed to be the same everywhere. The cost effect of blending more ethanol into gasoline varies with the price of corn and the price of oil. Still. E15 is likely to sell for between five and 40 cents per gallon less than E10—regular gasoline with up to 10 percent ethanol—this summer. Drivers. however. may pay in fuel efficiency: ethanol has lower fuel efficiency than gasoline. meaning drivers may have to fill up more often. according to the American Consumer Institute.

When it comes to health effects during this summer’s waiver period, Jacobson expects limited impact. With the limited distribution of E15 stations and the relatively low ethanol concentration in E15, he says health effects from this summer’s waivers will likely be small.

The policy shift lands after several years of similar summer exceptions. E15 sales allowances have occurred every summer since 2022. The U.S. Renewable Fuel Standard for 2023 to 2025 also calls for an increasing proportion of biofuels—including ethanol—in gasoline. Advocates, often in the agricultural sector, have argued for up to 85 percent ethanol blends.

Supporters point to past emissions claims. An influential 2019 study from Argonne National Laboratory found that between 2005 and 2019. the use of corn ethanol reduced emissions by 544 million metric tons of CO2. a 23 percent reduction in the carbon intensity of fuel. Those results are hotly contested.

Gibbs has been part of a different conclusion. A 2022 study co-authored by Gibbs found that when researchers account for the effects of converting land into farmland for growing corn, corn-based ethanol fuel actually increases greenhouse gas emissions by 24 percent.

Runge adds that intensive land use needed to grow corn for ethanol has effects beyond climate. It influences water quality and fertilizer use.

For some researchers. that’s where the sustainability story breaks: alongside air pollution concerns. they argue ethanol isn’t as green as it’s sometimes made out to be. Jacobson’s work pushes the concern further when considering higher-ethanol proposals. He found that a move toward 85 percent ethanol gasoline would result in between 71 and 213 additional ozone-related deaths and 1. 200 additional emergency department visits for asthma in the U.S. each year.

“Both gasoline and ethanol are bad,” Jacobson says. “And the solution is really to go to electric vehicles.”

The waiver and the bill moving through Congress are now forcing an old debate into a new summer timeline: provide drivers with cheaper choice amid tight supplies. or restrict a fuel that can worsen ground-level ozone under the right conditions. The answer may change by season—but what’s at stake is constant.

E15 ethanol EPA waiver Lee Zeldin summer gasoline ozone air pollution ground-level ozone Memorial Day weekend Renewable Fuel Standard corn ethanol diesel and fertilizer prices corn prices electric vehicles