Ethanol as an automotive energy resource is renewable fuel source works great at 10% content in the fuel tank in all cars, and can drive flexible fuel vehicles at 85% - known as E85. The latest issue of Consumer Reports shows a test of a flexible fuel vehicle, its mileage and the cost of operation.
The magazine's writers found that when a Chevrolet Tahoe - one of more than 5 million ffv's produced in the United States since the 1990s - runs in E85, it's mileage drops. That's because a gallon of ethanol has 75,670 British thermal units of energy versus 115,400 BTUs in gasoline. That nets out to about a 27% drop in miles per tank.
The magazine, whose cover shows "The Ethanol Myth" actually reports that at prices during its test, ethanol was higher than gasoline. A quick rise in demand had boosted ethanol prices above gasoline - based on energy available.
The magazine does report, however, that emissions tests of the Tahoe vehicle found a "significant decrease in smog-forming oxides of nitrogen" when using E85. That's an important pollution source from vehicle exhaust.
And the writers also point out that more feedstocks for ethanol - including cellulosic sources - are under research since only so much ethanol can be made from corn. They also note that while there's less energy per gallon there's a bigger picture to consider: ethanol is renewable.
A recent spate of ethanol stories have appeared in major car magazines and other publications as the U.S. public learns more about using renewable energy sources.
E85 - that 85% blend of gasoline and ethanol - is currently available from about 800 gasoline retail outlets and predominantly in the Upper Midwest. But the number is growing.