Industry officials say the results of a federal study prepared by the National Renewable Energy Laboratory (NREL) for the U.S. Dept. of Energy that looked at the effect ethanol blended gasoline as high as E15 and E20 has on small engines is inconclusive at best, leaves many questions unanswered and is primarily an indicator that much more research on higher ethanol blends in small engines is required.

“You can’t begin to approach the complexity of the small engine industry with the scope of this study,” says Kris Kiser, Outdoor Power Equipment Institute vice president of government affairs. “In our opinion, the study downplayed the challenges, and we’re very concerned with how they interpreted the data and wrote it up.”

The 136-page study, titled “Effects of Intermediate Ethanol Blends on Legacy Vehicles and Small Non-Road Engines, Report 1,” was released in October 2008 and is the first federal effort to gauge the impact that higher-level ethanol blends have on small engine operation. The study also looked at the effects of higher ethanol blends on legacy automobiles already on the road. PowerETblog recently covered the study’s results in a post, and a copy of the complete study can be downloaded here.

“A lot of people want this transition to be about automobiles,” Kiser says of the move toward more widespread use of higher ethanol blends in gasoline retailed throughout the country, adding that there are powerful political interests pushing to get more ethanol in the market. Kiser notes that many officials in the U.S. Dept. of Energy know that “moving small engines into mid-level ethanol blends will be extremely challenging with the 300 million legacy engines out there.”

According to Stihl Inc. national compliance director John Foster, “We found the study to be inconclusive, frankly, and too much of a ‘slam dunk’ with its conclusions.”

Kiser and Foster say the study overlooked many implications of higher level ethanol blends in small engines.“It’s obvious that anything higher than E10 (unblended) gasoline brings on a host of concerns, including enleanment, and heat issues in conjunction with catalytic converters—there are still a lot of unanswered questions,” Foster says. “Even the transition to E10 from a machine that has been running E0 can prove problematic during initial use.”

Both believe the study doesn’t accurately reflect real-world operating conditions. “They didn’t do anything related to evaporative emissions, there was no cold-start/warm-up testing, and we need more study on the effect on engine exhaust temps,” Kiser says.

To respond to the study, OPEI committees are currently preparing a formal letter of response that will be released by mid January, and the OPEI Technical Committee is currently working on testing protocols that better reflect actual operating conditions, more accurate “aging” process and cover other areas of concern.