Summer Fuels and E15

NACS advocates for retailers to have the ability to sell E15 year-round.

Summer Fuels and E15

June 2023   minute read

By: Paige Anderson

It’s summertime at last! While most of us are thinking about barbecues, beaches and baseball, you might not know that our motor fuels system undergoes a complex transition between winter and summer. Not only are fuel retailers selling a different blend of gasoline, but fuel retailers are also unable to offer E15 to their customers.

In this month’s Inside Washington, we look at how this supply transition came about and key issues surrounding the ability—or in this case, inability—to sell certain fuels during the summer.

Key Figures


The number of states in which E15 is available.

1.02 billion

E15 sales in gallons in 2022, according to Renewable Fuels Association

Summer Blends Versus Winter Blends

By June 1, fuel retailers must sell gasoline with a lower volatility than gasoline sold in the winter. This fuel switch is a result of amendments to the Clean Air Act in 1990 enacted by Congress and implemented by EPA.

Summer-grade gasoline has a lower volatility than winter-grade gasoline to limit evaporative emissions that normally increase with warm weather and cause unhealthy ground-level ozone. Volatility is a measure of how easily a liquid will change into a vapor. For gasoline, it is measured by Reid vapor pressure (RVP). The higher the RVP, the more volatile the gasoline. Some areas of the country require cleaner reformulated gasoline (RFG), which must meet stricter limits on volatility.

Refiners and terminals must transition to summer blends of fuels by May 1.

In the summertime, gasoline has a greater chance of evaporating from a vehicle’s fuel system, which can produce smog and increase emissions. Thus, refiners produce gasoline blends that have a lower RVP. Winter-blend gasoline has a higher RVP, which means it evaporates more and allows gasoline to ignite more easily to start vehicles during cold temperatures.

For logistical reasons, the transition from winter blends of gasoline to summer blends of gasoline happens over the course of several months in the spring as temperatures rise. Refiners and terminals must transition to summer blends of fuels by May 1, and fuel retailers have to begin selling these fuels by June 1. This requirement lasts until September 15.

As one can imagine, facilitating lowering the RVP in fuels and handling the logistics of reducing winter-blend gasoline inventories can bring challenges. Hence, EPA does have waiver authority to provide flexibility in times of emergencies to allow winter blends to be extended past June 1 or brought into the fuels market before September 15, such as during hurricanes and other natural disasters. A waiver was also granted during COVID-19 in 2020 when the economy essentially shut down as the industry was transitioning to summer blends. NACS has worked with EPA and industry groups in advocating for these emergency waivers.

Minnesota, Wisconsin and Iowa lead the way in selling the most E15.


E15, gasoline blended with 10.5% to 15% ethanol, was approved by EPA in 2011 for use in light-duty conventional vehicles of model year 2001 and newer. This came about through a Clean Air Act waver request.

Vehicles prohibited from using E15 include motorcycles, vehicles with heavy-duty engines (e.g., school buses and delivery trucks), off-road vehicles, engines in off-road equipment (e.g., lawn mowers and chain saws) and cars older than model year 2001.

There is no mandate or requirement to sell E15, but many fuel retailers are selling E15 due to consumer demand and the ability to reduce costs of fuel for their customers. E15 is available in 31 states and at over 2,500 stations. As expected, the Midwestern states of Minnesota, Wisconsin and Iowa lead the way in selling the most E15. However, Texas, Florida, Pennsylvania and North Carolina fall right behind in the top ten states selling E15.

One challenge for fuel retailers who sell E15 or are considering selling E15 is that retailers are unable to sell E15 in the summer unless a one-pound RVP waiver is granted. While EPA originally approved year-round sales of E15 in 2019, a number of legal and regulatory battles have prevented this from happening. Currently, EPA must issue emergency fuel waivers each summer on an ad hoc basis, which it did last summer. NACS, working with other stakeholders, sent a letter in April to EPA, asking for such a waiver to allow for the sale of E15 this summer. The waiver was authorized later that month.

NACS supports this legislation and is working with the bill sponsors.

Lack of long-term certainty and the inability to sell E15 year-round continues to be an obstacle for fuel retailers. Legislation was introduced last year and reintroduced in March of this year to help resolve these issues.

The Consumer and Fuel Retailer Choice Act of 2023 was introduced in the Senate (S. 785) by Senators Deb Fischer (R-NE) and Amy Klobuchar (D-MN) and in the House (H.R. 1608) by Representatives Adrian Smith (R-NE) and Angie Craig (D-MN). The bill would enable year-round, nationwide sale of ethanol blends higher than 10% and permanently extend the RVP volatility waiver to ethanol blends above 10%. It also ensures uniformity and prevents a patchwork of regulations from disrupting the national fuel supply chain by nullifying pending governors’ petitions to remove the one-pound RVP waiver. NACS supports this legislation and is working with the bill sponsors and other industry groups to move this legislation forward. 

Paige Anderson

Paige Anderson

Paige Anderson is NACS director of government relations. She can be reached at [email protected].

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