Unveiled in August before making its public debut at the Frankfurt auto show earlier this month, the BMW Concept X5 eDrive is a 61.8-mpg take on luxury utility driving. And it may soon spawn a production plug-in hybrid X5.

While still cautious to couch the news in tentative, future terms, BMW's head of large vehicle production Peter Wolf told Australia's Motoring.com.au that BMW is "working on such a concept [and] we are very far [along]. But it's not a part of next year."

So we're not likely to see the X5 plug-in hybrid reach production in 2014, but 2015 isn't out of the picture.

The Concept X5 eDrive's 90-horsepower electric motor is paired with a four-cylinder turbocharged gasoline engine of indeterminate power output (though the same engine makes 240 horsepower in other applications).

That means the production X5 plug-in hybrid isn't likely to light the world on fire with its performance, but if it can get close to the eDrive's conceptual 61.8-mpg rating, it will  blaze trails in green SUV driving, to be certain.

BMW also says the X5 eDrive can drive at speeds of up to 75 mph on electricity alone, with an all-electric range of up to 19 miles. And even with its rather limited power output, the Concept X5 eDrive is still good for 7.0-second 0-60-mph runs.