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November 13, 2017
To cut petroleum usage and reduce greenhouse gas emissions, fuel efficiency standards are set to rise significantly by 2025 under the Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) standards—jointly administered by the National Highway Traffic Safety Administration (NHTSA) and EPA. However, the automotive marketplace has changed significantly since the standards were written in 2009. Sustained low gas prices and the growing popularity of trucks and SUVs have led the auto industry to claim that it will be impossible to meet both 2025 and long-term efficiency standards without significant changes to the programs. Fortunately, there is another low-cost pathway available to regulators to preserve strong fuel efficiency standards and improve fuel quality. Research suggests that high-octane, low-carbon fuel is the lowest-cost compliance option for both consumers and the automotive industry.
Key to this discussion is an understanding that automakers are increasingly producing smaller, more efficient direct-injection, turbocharged engines. According to the Energy Information Administration, the production of these vehicles has increased from around 3 percent in model year 2009 to nearly 18 percent in model year 2014, and is expected to increase to over 80 percent of all light-duty vehicles sold in the United States by 2025. In producing these vehicles, automakers are creating additional demand for high-octane fuels, as higher amounts of octane are needed to prevent engine knock in these engines and produce efficiency gains. Premium gasoline is a high-octane fuel – whose octane can come from either a renewable, clean burning source – ethanol – or from aromatics, a petroleum derivative, which is toxic.
Dr. Robert McCormick, Principal Engineer, Fuels and Combustion Science Group, National Renewable Energy Lab (NREL)
Brian West, Group Leader, Fuels, Engines, and Emissions Research Group, Oak Ridge National Lab (ORNL)
Dean Drake, President, Defour Group, LLC
Andrew Varcoe, Partner, Boyden Gray & Associates
While not directly addressed at the briefing, the issue of gas station infrastructure compatibility with these fuels was raised. For more information on this issue please refer to these two publications:
Taking steps to reduce GHG and toxic emissions from the passenger vehicle fleet is critical. The U.S. transportation sector is responsible for 27 percent of greenhouse gas emissions as well as half of all toxic emissions in the United States. Numerous health studies have linked tailpipe exhaust to serious developmental and many chronic health conditions. While electric vehicles represent the greatest potential reduction in lifecycle and tailpipe emissions and will play an important role in decarbonizing the transportation sector, the internal combustion engine is likely to dominate vehicle sales for the next several decades. Therefore, it is important to ensure that fuel economy is addressed in these vehicles.
Higher-octane, low-carbon fuels enable greater engine efficiencies, thereby lowering GHG and toxic emissions and improving fuel economy. Automotive engineers have expressed interest in raising the octane level of gasoline, which would enable the design and sale of these more efficient engines, but the administration must act to enable a viable pathway for these fuels to enter the marketplace. A high-octane, low-carbon blend of 25 percent ethanol and 75 percent gasoline (E25), for example, would lead to fuel efficiency improvements between 5 and 10 percent, significantly reducing consumer fuel costs and harmful tailpipe emissions.