Green has always been an essential part of the Bentley experience… lots and lots of green. But today the British automaker unveiled its plan to join the wave of manufacturers offering more environmentally-friendly drivetrains. You know; eventually. The German-owned British brand will begin its transformation from maker of CO2-spewing playthings for the over-moneyed set to eco-conscious planetary champions by offering a flex-fuel option next year. ("James, take the Bentley down to London and fill it up with ethanol"). By 2015, Bentley will provide E85 compatibility across their entire lineup (all six models). And while you're recovering from that shock, the Bentley Boyz will begin development of an unspecified drivetrain that will deliver 40 percent better fuel efficiency than their normal gas-sucking mills. In the short term, Bentley says its socially responsible engineering efforts will focus on enhanced engine management; new, improved transmissions and drivelines and weight reduction. Torque about greenwashing…