E15 analysis shows no issues with engine durability, maintenance

By Holly Jessen | October 14, 2013

A recently released National Renewable Energy Laboratory report concluded that there are no meaningful differences between E10 and E15 on engine durability, emissions and other categories. In addition, the 44-page report pointed out that the data does not support the conclusions of controversial Coordinating Research Council study that suggested that engines operating on E15 could experience engine failure.

Bob Dinneen, president and CEO of the Renewable Fuels Association, pointed out that the CRC study is the centerpiece in the petroleum industry’s fight against E15. Lawmakers have been given the false idea that the study is the only one conducted on E15. The NREL report exposes flaws in the methodology of the CRC study and others, which are often cited by the American Petroleum Institute. “It’s time for Big Oil to stop using actors to scare people about E15,” he said. “It’s time they start paying attention to the overwhelming data and real world experience demonstrating the efficacy of E15.”

The NREL study reviewed 43 studies on E15 use in vehicles model year 2001 and newer but did not include vehicles the U.S. EPA has not approved for using E15, such as pre-2001 vehicles as well as boats, snowmobiles, motorcycles and small off-road engines. The conclusion was that the data showed no evidence of deterioration in engine durability or maintenance issues for either E15 or E20 in comparison to straight gas and E10. (When that fuel was part of the testing.) Studies that examined materials compatibility testing showed no evidence that E15 causes increased metal corrosion or elastomer swell when compared to E10. And, emission studies revealed that engine control units can compensate adequately for the lower energy and higher oxygen content of E15.

The RFA, which sponsored the NREL study, pointed to flaws and gaps identified by NREL in some of the studies it reviewed for its analysis. For the CRC engine durability study that included a 10 percent leakdown failure criteria that has no scientific basis. That’s 50 percent below the lowest leakdown failure limit specified by the original equipment manufacturers, NREL said. The study also failed to use E10 as a control fuel, despite the fact that it’s currently the most commonly used fuel, leading to a presumption that failures were related to ethanol content when it could have been caused by other factors. Finally, the CRC study used assumed values, which demonstrated consistent bias, for vehicles that were not tested.

The Iowa Renewable Fuels Association, which recently released its own E15 testing data, also addressed the NREL report. “[It’s] the final nail in the coffin for Big Oil’s bogus E15 studies,” said Monte Shaw, IRFA executive director. “Big Oil has consistently pointed to two CRC studies as a basis to outrageously claim that E15 will cause engine damage and leave motorists in harm’s way. IRFA’s real world testing data combined with today’s NREL analysis proves Big Oil’s irresponsible statements on E15 cannot be trusted.”