The Bentley EXP 9F prototype during its 2012 unveiling.

Those who think batteries are for pint-sized electric vehicles and hybrids need to visit this year’s Geneva Motor Show where “electrification” has become the buzz word among high-line makers like Ferrari, Porsche, McLaren – and Bentley.

In an exclusive conversation with TheDetroitBureau.com, the British marque’s technology chief confirmed that Bentley will go into production with a long-rumored gas-electric driveline.

“The SUV will get a plug-in,” declared tech chief Rold Frech, during a discussion at the Geneva Motor Show. But he stressed that a number of details have yet to be locked down, including the layout of the plug-in package and the precise introduction date.

Bentley first revealed its EXP 9F sport-utility concept at the 2012 Geneva show, hoping to gauge reaction to the prototype before committing to build it – though it was clearly the pet project of the marque’s then-CEO Wolfgang Durheimer.

Despite some sharp media criticism of the EXP’s front styling, the project won a more upbeat response from potential customers – echoing the way things went for sibling brand Porsche when it first announced plans to produce what became the Cayenne SUV.

Bentley’s new CEO Wolfgang Schreiber confirmed that an updated version of the EXP will go into production and it is now expected to reach showrooms in 2015. But it will be a rapidly evolving market that the big sport-ute enters. Among other things, Bentley is facing far stricter emissions and fuel economy standards in all its key markets, from Berlin to Boston to Beijing.

Further complicating matters, a number of global mega-cities are closely considering the possibility of putting restrictions on the use of internal combustion engines, possibly to the point of banning the use of anything but zero-emissions vehicles in the densest urban areas.

That’s a key reason why a plug-in option “is a technology that fits for Bentley,” explained tech chief Frech. As with the new Audi A3 e-Tron, he said drivers would be able to choose the mode of operation in the ultra-lux ute. They could, for example, remain in conventional hybrid mode on the freeway into town then go full electric to avoid driving restrictions.

Also, as with Audi, Frech believes buyers will be surprised to discover that they won’t need to trade off the fun-to-drive factor for fuel efficiency. Electric motors generate maximum torque the moment they start turning, so the right design could prove pleasantly peppy. That’s something Ferrari and McLaren, also plan to take advantage of.

And so will Porsche, which has a plug-in of its own in the works for the Panamera sports sedan – as Frech is well aware, having spent 28 years with the sports car maker before joining Bentley.

The Porsche system will likely be similar in concept to Bentley’s approach, though the British maker won’t lift the German sibling’s technology whole cloth.  It will need a plug-in design that reflects the size, weight and driving characteristics of a Bentley SUV.

And that is something that the ultra-luxury marque is still trying to finalize, Frech acknowledged, telling TheDetroitBureau.com he hopes to have details locked into place by late 2013.

Among the questions still unanswered: what gasoline engine will the SUV plug-in system use and what type of electric drive will it be mated to?  There are a variety of potentially radical alternatives.

Acura’s MDX, for example, will soon get a three-motor hybrid. Its V-6 and a single motor will power the front wheels while two additional motors drive the rear axle. The Japanese maker’s NSX supercar, meanwhile, will reverse the layout, with the two motors up front and the IC engine and single motor in back. Bentley could, alternatively, go with a gas engine and single motor or put the IC engine up front, for example, and the electric motor in back.

Bentley only last year delivered its first V-8, a clear advantages in markets like China that are penalizing big-displacement powertrains. But when asked if the SUV could even go with a V-6, Frech said, “If it is necessary for the legislative side, why not?”

Obviously, meeting potential environmental regulations will be a critical challenge, but the plug-in system will, first and foremost, have to be a perfect fit for Bentley in terms of customer expectations.

“The challenge,” Frech concluded, “is to find a middle way.”