The Department of Energy has hit out at the recent Coordinating Research Council study into damage caused by using E15 gasoline.
In its rebuttal, the DoE points out several flaws in the CRC's study, and says the Council failed to establish a proper control group to determine the statistical significance of the results.
In the study, the latest in a line looking into the effects of raising ethanol content from E10 to E15, the CRC claimed that over two years of testing E15 in vehicles made between 2001-2009, two of the eight vehicles tested suffered significant wear. Another would have failed an emissions test.
The DoE highlights several flaws from the CRC study, including:
- Only three of the eight engines were tested with straight gasoline, containing no ethanol. One of the engines that failed was running on this straight gasoline--not an ethanol mix.
- None of the engines were tested with E10 fuel--a blend that represents 90 percent of all the gasoline sold in the U.S.
- The CRC's test cycle was specifically designed as a stress test, and there was no previous data on how this test would affect engine components.
- The CRC's cylinder compression testing was measured using an arbitrary 10 percent "leakdown" figure, not used anywhere else in the industry.
- Many of the engines used by the CRC for the testing are already known to have durability issues, regardless of the fuel used.
In its rebuttal, the DoE also cites its own research using standard gasoline, E10, E15 and E20, on 86 vehicles, using an EPA-approved 120,000-mile test procedure.
During this testing, the DoE found no statistically significant loss of performance on any of the fuel blends, and using the CRC's "leakdown" figure for compression, found no correlation between loss of compression and the type of fuel used.
Results are still uncertain for cars built before 2001, so our advice would be to steer clear of higher ethanol blends on earlier vehicles.
However, the debate looks set to rumble on as far as using E15 in later models goes--this is unlikely to be the last you'll hear from either side of the debate.
You can read the DoE's full rebuttal here.