Tom Wallace, GM Global Vehicle Chief Engineer for Performance Vehicles, explained on the GM FastLane Blog that "the Green Challenge was a 'race within a race' during the 1,000-mile endurance event." The series' organizers and the Argonne National Laboratory, in conjunction with the EPA, DOT, and SAE, arrived at a formula "that calculated the winning entries in the Prototype and GT classes based on energy used, greenhouse gases emitted, and petroleum fuels displaced."
Corvette Racing's cellulosic ethanol is derived, remarkably, from dead branches, wood chips, and undergrowth cleared from the Black Hills National Forest as part of a wildfire prevention effort. The organic waste, which would otherwise have been burned, was sent to Wyoming's self-sustaining KL Energy plant, which converts the biomass into ethanol. And it was this ethanol that powered the Z06-related 7.0-liter, specially tuned small-block V-8 that propelled the GT1 Corvette to victory.
With American manufacturers' (somewhat abandoned) recent push toward E85 facing harsh criticism from consumers and environmentalists, GM was wise to go with cellulosic ethanol for this challenge. The technology is in the true spirit of recycling, as opposed to corn-based ethanol, which arguably interferes with the food chain and wastes huge amounts of water for production. And it appears GM was, in effect, forced to go cellulosic, as every part and piece of the competing vehicles in the Green Challenge were factored into the overall scores. Corn-based ethanol, presumably, wouldn't score very high with regard to environmental impact.
GM impressed until the very end of their post, at which point the PR folks seem to have thrown in a shameless plug for their E85 program. They claim that Corvette Racing's success in the Green Challenge "proved the validity of E85 as a good choice for those of you who drive some of the 3 million GM flex-fuel vehicles on the road today." We won't fully agree until a cellulosic ethanol infrastructure that can supply a significant percentage of those 3 million vehicles exists. "Fool me once...shame on...shame on you...fool me...well, we can't get fooled again!"--Colin Mathews