How Green Is Your Hummer?

A Ferrari that runs on garbage?
An eco-Hummer?

Either this is an environmentalist's wildest dream or it's the annual Detroit Auto Show.

Maybe it's both.

Officially known as the North American International Auto Show, it's where beautiful cars, models and the people who love both show up after New Year's to check out what's under everybody's hood.

The Worst From the Detroit Auto Show

General Motors(GM) , which is kind of like the old uncle you thought had died a few years ago (actually it was his son, Olds) seemed to draw the biggest headlines in Detroit with its "green" Hummer concept car. The Hummer HX is a little smaller and its V-6 is Flex-Fuel powered, meaning it can run on regular gas or ethanol.

The company used the introduction of the HX to announce that it would be bringing out 16 new hybrid models over the next four years, and it had also made an investment in Coskata, a biofuel corporation that converts garbage into ethanol.

Could a Ferrari really run on waste? We'll see.

Ferrari's F430 Spider Biofuel has green racing stripes -- a tip-off that this V-12 beauty drinks E85, the blend of the 85% ethanol, 15% gasoline that's hard to find outside of Omaha, but which we're told is going to become more common in gas stations over the next couple of years. The engine is tuned to work with the fuel and is part of the company's efforts to reduce tailpipe emissions by 40% in 2012.

Volkswagen(VLKAY) introduced its ill-fated Phaeton luxury sedan a few years ago at this show, and it's hoping that debuting the new Passat CC in Detroit will reverse its luck in this segment. The new Passat is longer, wider and lower with a 3.6-liter 280-horsepower V-6 or a 200-horsepower turbo four- and a six-speed automatic.