It sounds like a great idea to use corn as automotive fuel. In some ways it is a great idea…less pollution, less dependence on foreign oil, and it would be cheaper, right? It does sound great but it is not so simple. We are already using about 15% of our home grown corn crop as E85, that’s an 85% blend of ethanol to gas mixture, to power vehicles. To make this ethanol we have to grow corn, it’s not just putting a corn seed in some dirt and giving it a little water. Growing this corn is a very energy intense process we use farm equipment, usually diesel powered, to plant, fertilize, protect and harvest it. The nitrogen rich fertilizers sometimes drain into the water table causing harm. In 2007 there were around 93 million acres of corn planted most likely they were fertilized with nitrogen based fertilizers, some of that was bound to reach the streams and rivers. Converting this corn to ethanol is also another energy intensive process. It requires heat which usually comes from coal fired or another fossil fuel fired generator.
Another drawback to E85 is that it doesn’t contain as much energy as gasoline. A gallon of gasoline will take you 20-30 percent farther than a gallon of E85. The “net energy balance” of ethanol is being debated right now. A study from Cornell University states that it takes 1.3 gallons of fossil fuel derived gas to make 1 gallon of corn derived E85. Another study from UC Berkeley takes into consideration that not just E85 is made from the distillation of corn; other products such as corn oil are made during the process. Therefore “the net energy balance” is positive.
Another possible alternative is to get the ethanol from switchgrass. Switchgrass is a cellulosic tall prairie grass that farmers sometimes plant to maintain the integrity of their fields when they are not using them for crops. Whereas corn is almost a 1:1 ratio as far as energy input to energy output, switchgrass is 5:1. There is more promise with switchgrass than there is with corn. Time will tell as cellulosic processing plants are popping in the United States.