Ethanol, E85, and Burning Your Food

In our modern day we are constantly being bombarded with the potential for new fuel alternatives that we can use to run our vehicles, or that we might soon be able to use to run whatever car or truck we might have in the future. One of the new technologies, or perhaps not so new is ethanol.

Ethanol works well as a fuel additive because it increases the octane rating of gasoline and it helps it to burn cleaner. When used as the primary component of the fuel, and not just an additive we usually refer to it as E85. This is a mix of 85% ethanol and 15% gasoline. Cars that are labeled “flex fuel” are capable of running on gasoline, E85, or any mixture of the two. These flex fuel vehicles are actually very common but most people who own them never run them on E85 and likely don’t even know that they can.

As an additive it’s great, as a fuel it leaves much to be desired. Ethanol takes so much energy to produce and provides so little energy in return that it is not very practical as a fuel. While it may be impossible to calculate the exact amount of energy return from E85 production, some experts say the return of energy with the production of E85 is actually negative.

Not everything about E85 is bad. The octane rating is somewhere in the neighborhood of 110 which is great. This makes it possible to produce a lot of power with E85 as a fuel. E85 is also completely renewable since it is derived from plant sources that are easy to cultivate. E85 burns very cleanly and produces fewer emissions than petroleum based fuels. If E85 is spilled or otherwise released into the environment it is much less harmful than most of the other fuels that we use.

The problem lies in the fact that E85 is not as energy dense as gasoline or diesel fuel. Because of this lack of energy things such as fuel economy suffer when running E85. Take the average midsize sedan that is flex fuel capable, with a V6 engine. Typically a car like this will be able to achieve a combined fuel economy rating of about 25 or 26 mpg. The exact same vehicle running on E85 will achieve about 14 or 15 mpg. Power output will feel the same but the engine will burn a lot more E85 to produce the same amount of power that the gasoline produces. The nationwide average price per gallon of E85 is currently $3.23 per gallon, while gasoline is $3.93. E85 is cheaper but not by much, and it’s certainly not worth the bad fuel economy. 

The FlexFuel badge found on the back of many cars. Most
people don't even know what it means.

Another problem with E85 is the feedstock that is most commonly used to produce it here in the U.S. is corn. This means that farmers who might otherwise grow corn that we eat, would instead grow corn for ethanol production. While the corn we eat is not exactly the same corn as that which is used in E85 production, the ground on which it is grown and other resources are the same. With ground and resources thusly diverted the amount of crops meant for human consumption goes down. Less food means more expensive food. And don’t forget, livestock eats corn as well, and if the cost of livestock feed goes up, the cost of food products derived from livestock also go up.

If we can get away from the idea of burning our food in our cars, we might be able to make something more useful of E85. One idea that is being developed is production of cellulosic ethanol. This is ethanol produced from things such as grasses and other plants that we do not eat, and that continually grow without the need for reseeding. Switch grass for example grows very well in many places around the country and can be used to produce E85. Switch grass grows very high very quickly and can be cut repeatedly without having to be replanted, kind of like your front lawn in the summer.