In the same HX reveal, GM announced a partnership w/ an ethanol company that has supposedly found a way to make ethanol out of pretty much anything - old tires, trash, etc, at a cost of around $1.00/gallon - so after taxes, markup of several parties, it's estimated at around $2.00 to the consumer/gallon -- we are of course several years away from this, though.
http://www.boston.com/business/techn...based_ethanol/