E15 and Higher Blends

Approved in 9 out of 10 Cars Today

Ethanol is the lowest cost, highest octane fuel additive available to gasoline refiners and marketers today.  Consumers will benefit from more competition and greater savings as E15 use expands. EPA has already approved the use of E15 for 9 out of 10 cars on the road today.  Auto makers provide full warranty coverage for E15 for more than 93% of 2019 vehicles being sold today.

In March, EPA proposed to provide the 1-psi RVP tolerance to E15.  EPA’s proposed regulatory fix would allow year-round sales of E15 in conventional gasoline markets for the first time, finally opening the marketplace more broadly to a fuel that provides consumers higher octane, lower cost, and reduced tailpipe emissions.  The RFA strongly supported EPA’s proposal allowing E15 to take advantage of the 1-psi RVP waiver.  RFA’s comments to EPA on the proposed rule are available here.

On May 31, 2019, the U.S. Environmental Protection Agency, at the direction of President Trump, issued a final rule allowing retailers to sell E15 year-round, which will provide American drivers with choice at the pump and access to cleaner fuels all year.

The Case for RVP Parity

The disparate treatment on volatility regulation between E10 and E15 or higher blends had been the single most important barrier to ethanol growth over the past 5 years.

Reid Vapor Pressure (RVP) is a measure of a fuel’s volatility, which is necessary for ignition. Fuels with low volatility are slow to ignite; fuels with a high volatility will ignite quickly. But increased volatility can mean increased evaporative emissions, and consequently the Environmental Protection Agency (EPA) has regulated gasoline volatility in the summer months since the mid-1980s, generally requiring gasoline to have no more than 9 psi RVP.

Ethanol itself has a very low volatility — ~2 psi RVP. But when mixed into gasoline at low levels (<10%), ethanol reacts with certain hydrocarbons to increase the RVP of the finished blend approximately 1 psi, or generally to about 10 psi RVP.

In order to accommodate increased ethanol use as an octane component and later as a means of reducing tailpipe emissions, EPA in 1989 provided a 1 psi RVP tolerance to gasoline blended with 9-10% ethanol. EPA did so for two reasons. First, the Agency realized that in the absence of a volatility waiver gasoline marketers intending to use ethanol would have to secure a specially tailored sub-RVP blendstock that was simply not available. Second, the Agency concluded after numerous air quality analyses that the exhaust emissions benefits of ethanol, including greater carbon monoxide and hydrocarbon reductions, outweighed the negligible impact of increased evaporative emissions attributable to the 1 psi waiver.

EPA limited its regulatory relief to up to 10% ethanol blends because at the time 10% ethanol was the only ethanol blend with a 211(f) fuel waiver allowing it to be sold commercially. In 2011, EPA granted a partial 211(f) fuel waiver for 15% ethanol, but failed to extend the volatility tolerance to the new fuel, greatly limiting its marketplace opportunities for the exact same reason 10% blends would have been limited – marketers were unable to secure a specially-tailored, sub-RVP blendstock.

The disparate treatment on volatility regulation between E10 and E15 or higher blends had been the single most important barrier to ethanol growth over the past 5 years.

Recent research taking into account changes in vehicle technology since the original RVP waiver was granted has demonstrated the reduced evaporative emissions from today’s automobiles and the increased oxygen content of higher ethanol blends provides even more air quality improvement than E10, and that emissions are reduced with higher ethanol blends.