GM unveiled today an ethanol-adapted "green" version of its heavy gas-guzzling military compact truck derivative, the Hummer, at the Detroit auto show, where media continued getting a preview on Monday before the show opens later this week to the public.

The unveiling, coupled with an announcement of a partnership in a bio-fuel company, was part of GM's efforts to raise its image as a company trying to reduce carbon emissions blamed for global warming.

“GM has been at the forefront of developing and promoting ethanol and ethanol-capable vehicles to reduce petroleum consumption and emissions,” said Beth Lowery, GM vice president, Environment, Energy and Safety Policy.

“We believe ethanol used as a fuel, not just as a gasoline additive, is the best near-term alternative to the surging global demand for oil because ethanol is renewable and it significantly reduces CO2 emissions compared to gasoline,” she said. “Best of all, it is available today.”

The Hummer HX has a flex-fuel V6 power train that will run on biofuel and is somewhat smaller than its bigger brothers. Yet it is still packed with "all the legendary capability" of the iconic vehicle, according to a video posted on the internet. Doors, roof and bumper panels are removable. It "still screams Hummer," the announcer said.

GM chief executive Rick Wagoner on Sunday unveiled plans to bring 16 new hybrid models onto the market within four years, and also revealed it would buy a stake in bio-fuel company Coskata Inc, a pioneer in efforts to convert waste into cheap ethanol.

After working alongside ethanol producers to develop fuel formulations to provide optimum performance in vehicle engines, GM began promoting ethanol more than two decades ago and was the first manufacturer to enable its entire U.S. fleet to operate on E10, a blend of 90 percent gasoline and 10 percent ethanol.

Besides Hummer HX, GM unveiled the Cadillac 2009 Escalade Hybrid, the world’s first fuel-saving hybrid applied to a large luxury SUV. Powered by an innovative, fuel-saving advanced hybrid system, Escalade Hybrid will deliver more than a 50-percent improvement in fuel economy in city driving – while delivering the same distinctive style, segment-leading features and full-size capability that have made the Escalade an icon.

The North American International Auto Show opens to the public on Saturday and closes January 27.