Home - Background: Fuel Types - E85
Ethanol, or grain alcohol, is produced by fermenting biomass, commonly corn (though other, lower-value feedstocks have been tested in an effort to reduce costs, like brewery waste and cheese-factory effluent--blecch!). It is thus inherently a renewable resource, and contributes nothing in itself to greenhouse-gas loading of the atmosphere (and with efficient modern farming techniques, there's still an improvement even when you add in the petroleum-based fuel burned to plow the fields, make the fertilizer, etc.). As an alternative motor vehicle fuel, it is usually blended in a mixture of 85% ethanol, 15% unleaded gasoline, whence E85. (It is also used in up to 10% blends with gasoline (gasohol) to oxygenate the gasoline, and this mixture can be used by most modern gasoline vehicles.)
E85 is, in many ways, like M85, the other alcohol fuel made with methanol instead of ethanol blended with 15% gasoline. There is no national distribution network on the scale of those for gasoline, diesel, and natural gas; however...
...there are starting to be a fair number of E85 outlets, mostly in the Midwest (where the crops from which ethanol is made are grown), and the changes needed to enable a gasoline station to handle E85 are even smaller than those necessary for M85. Elsewhere in the nation, E85 stations are rarer than M85 stations; in particular, I don't think there's a single one in California.
Ethanol, as noted above, is a renewable resource that contributes nothing in itself to global warming concerns. Like methanol, it can be blended with any amount of gasoline in the tank of a flex-fuel vehicle, which is what automakers are selling these days. In fact, starting with the 1999 model year, some automakers are making every one of certain vehicle models capable of using E85 in any mixture with gasoline, at no extra charge. Thus buyers will not have to do anything extra at all to have a vehicle capable of using an alternative fuel, though they will still have to find an E85 fueling station to take advantage of that capability.
The main disadvantage of E85 is the price of the fuel, even with the available subsidies. However, research is under way to enable the fermentation of lower-grade feedstocks (think of using not only the corn squeezin's but also the cob to make alcohol!), which should help a lot. Ethanol is somewhat corrosive, though less so than methanol, and concerns about vapor lock, cold starts, and flame visibility like those for methanol have led to the same standard blend of 85% alcohol with 15% gasoline.
new 11 July 1998, revised 10 April 1999