EESI was dismayed to see the Trump Administration move to weaken passenger vehicle fuel efficiency standards in the proposed Safer Affordable Fuel-Efficient (SAFE) rule, as incremental and sustained gains in fuel efficiency are an important tool in reducing petroleum consumption and greenhouse gas emissions. While it is expected the proposed joint rule will face a protracted legal battle from California and environmental groups, it was also widely anticipated that vehicle manufacturers would struggle to meet ambitious miles per gallon (MPG) standards set forth in CAFE.

In comments led by the Clean Fuels Development Coalition, EESI joined the Governor’s Biofuels Coalition, the National Farmers Union, the Urban Air Initiative, and others, to urge the Trump Administration to recognize the full environmental, health, fuel efficiency and economic benefits of utilizing high-octane biofuels in the current and future passenger vehicle fleet in the proposed SAFE Vehicles Rule.  By recognizing and taking steps to introduce high-octane fuels, the Trump administration has perhaps inadvertently opened the door for a new pathway for increased fuel efficiency, as well.

As part of the Administration’s rewrite of the Corporate Average Fuel Economy (CAFE) standards, the Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) asked for comment on the question, “What is an ideal octane level for mass-market consumption balanced against cost and potential benefits?” Octane is a necessary component of gasoline that provides “anti-knock” properties. The “regular”, “mid-grade”, and “premium” labels on gasoline pumps are actually a measure of the gasoline’s octane content.  Using gasoline with a higher octane rating also enables more efficient engine design, allowing for increases in fuel efficiency.

Automotive manufacturers are expressing interest in raising the minimum octane level of the U.S. gasoline pool as a low-cost compliance option for increasing fuel efficiency. Until now, all MPG gains in the passenger vehicle fleet have been accomplished through engine and vehicle design, while the fuels we use to power our cars are largely unchanged over the last several decades.

A fuels and engine strategy is one that will yield the greatest fuel efficiency gains and GHG reductions, and must be seriously considered by automotive manufacturers and the administration, as well as other stakeholders. According to Oak Ridge National Laboratory, “…with the looming emphasis on unprecedented increases to fuel economy in the current CO2 age, it is hard to argue that the current stagnant fuel octane number can be sustainable over the long term. Therefore, increasing the fuel octane number offers significant motivation to achieve fuel economy and CO2 targets.”

This needed increase in octane can be accomplished in two ways: adding additional petroleum-based blending components (commonly called aromatics or the BTEX complex), or renewable biofuels, namely ethanol.  Ethanol is the superior choice for increasing octane -- from an environmental, health, and economic perspective. Conversely, BTEX is a highly toxic and more expensive petrochemical and will do nothing to reduce greenhouse gases.

In the comments to the proposed SAFE rule, EESI and co-signors focus on the benefits of E30 (30 percent ethanol and 70 percent gasoline) octane rating (RON) 98 – 100, as an ideal octane level, “to optimize light duty vehicle performance, fuel efficiency, and reduce harmful emissions and consumer costs.”  The comments also outline the steps the administration must take to remove regulatory barriers to national adaptation of a high octane, low carbon biofuel.

Specifically, the following benefits of broad adoption of an E30, 98 – 100 RON fuel were discussed:

  • Cost-savings to consumers (decreased gasoline prices, as ethanol is less expensive than gasoline aromatics), automakers (lower compliance costs) and the health care system (decreased amounts of air pollutants).
  • Public benefits are immediately available through adoption in the existing light-duty fleet, as well as increasing these benefits, through the adoption of highly efficient engines that require high-octane fuel over the coming decades,
  • The availability of ethanol at every fuel terminal and retail gasoline station,
  • Increasing the volume of ethanol in the gasoline supply will enable EPA to reduce mobile source air toxics (MSATs) to the “greatest achievable extent”,
  • Transitioning to E30 will complement, rather than compete with, the transition to electric vehicles (EVs), and
  • E30 98- 100 RON will allow refiners to reduce the volume of toxic BTEX in gasoline by up to 60 percent or more.

By transitioning to an E30 98 – 100 RON fuel, the United States could meet numerous legislative and social priorities, including reducing the carbon intensity of the light duty fleet and reducing toxic tailpipe emissions – especially in urban areas, meeting ambitious Renewable Fuel Standard targets, and reducing costs to consumers.


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