One of the biggest vehicles on the road is now available with flex-fuel capability across the range following the announcement on Friday that all 2009 Cadillac Escalades will be able to run on E85 ethanol blended fuel as well as petrol or any combination of the two. Cadillac won’t be charging customers extra as the feature is fitted standard on all 2009 models, including the new Escalade Hybrid.

The Escalade, Escalade EXT and Escalade ESV as well as the GMC Denali, join the previously announced 2009 Chevrolet HHR, Buick Lucerne and Hummer H2 and H2 SUT as additions to GM’s new flex-fuel lineup.

The latest E85 product announcements coincided with the opening of a dozen new E85 fueling stations in the Greater Atlanta area this week. According to GM there are already seven million vehicles in North America that can run on E85.

GM has already confirmed that half of its U.S. lineup will be flex-fuel capable by 2012 providing the infrastructure is in place, and the carmaker built more than a million flex-fuel vehicles in the past year alone.

Not only is the fuel cheaper than regular petrol, it’s also a cleaner-burning fuel. The Escalade running E85 produces up to 23% less greenhouse gas emissions than it would on petrol alone.