The car touted as Bentley's greenest, fastest and most powerful ever will only hit two out of three of those marks when it makes its U.S. debut next year. The first Bentley to be able to drink ethanol-heavy fuels like E85 as well as gasoline, the flex-fuel ultra-coupe will have to wait until after the first 200 deliveries in the U.S. to come through on its 'green' claims.

The reason for the seemingly arbitrary 200-car mark? That's how long it will take Bentley to get the re-worked flex-fuel V-12 past U.S. homologation testing. To add ethanol capability to the engine, Bentley's engineers had to fit hardened valve seats among other minor tweaks, and that means the first Supersports will have to be delivered without the flex-fuel capability.

Once the first batch is sold, however, Bentley will bring the fully-ethanol-capable version of the Supersports to the States.

The Continental Supersports will still be nothing to sniff at, even without ethanol capability, as its 621-horsepower rating and 243-pound lighter weight than the Continental GT will make it a screamer behind the wheel. Bentley promises 3.7-second 0-60 mph runs and a 204 mph top speed, putting the ultra-luxury coupe fully into supercar territory.

Read up on our coverage from the 2009 Geneva Motor Show for more the 2010 Bentley Continental Supersports, or check out our recent story on how Bentley is rumored to be considering a convertible version based on the Continental GTC.

[Green Car Advisor]