California Air Resources Board

California Multimedia Evaluation of E11-E15 Gasoline-Ethanol Blends Tier I Report

Prepared by the Renewable Fuels Association and Growth Energy (June 2020)

The California Health and Safety Code (HSC 43830.8) requires that a multimedia evaluation (MME) be conducted and reviewed by the California Environmental Policy Council (CEPC) before specifications for new motor fuels can be adopted by the California Air Resources Board. The purpose of the MME is to develop information that will enable the CEPC to determine whether a new fuel specification would cause any significant adverse impacts to public health or the environment. Ethanol blended in California gasoline up to 15 percent by volume (E15) is currently undergoing the MME process.

Ethanol is a liquid alternative fuel that can be blended in California gasoline up to 10 percent by volume (E10), the maximum ethanol content allowed by California gasoline regulations (ethanol can also be blended up to 85 percent with gasoline as ethanol flex fuel (E85) for use in flex fuel vehicles). Ethanol is a renewable fuel with lower carbon intensity than petroleum-derived gasoline.  

The Tier I report is the first step in a three-tier process evaluating the cumulative health and ecological impacts from releases to air, surface water, groundwater and soil at all stages of the ethanol life-cycle: production, storage and distribution, and use. The risk posed by E15 in gasoline is assessed as a relative risk compared to E10 in California gasoline currently in use.  

As a part of the MME for E15, CARB contracted with the University of California at Riverside (UCR) Bourns College of Engineering – Center for Environmental Research and Technology (CE-CERT) to evaluate exhaust emissions from the use of California Reformulated Gasoline (CaRFG) that contains 15 volume percent ethanol (E15).  Two fuels (E10 and E15) were tested on twenty vehicles (2016 and newer gasoline-fueled) over triplicate Federal Test Procedure (FTP) cycles. The report is available at: Comparison of Exhaust Emissions Between E10 CaRFG and Splash Blended E15.