At the 2013 Detroit Auto Show, BMW displayed once again the i3 concept coupe which made its world debut at last year’s LA show. For Automotive News, Herbert Diess, BMW’s Head of R&D, said that the i3 will be offered with a two-cylinder motorcycle engine and a generator to extend its range.

The extended range package will be offered as an option to the standard electric drivetrain which has a range of 60 to 90 miles on a single charge. The two-cylinder engine comes from the Motorrad Division and will extended the driving range to 250 miles on a tank of gasoline.

The engine is housed in the trunk and connected to a generator that recharges the battery. The engine doesn’t transmit mechanical power directly to the wheels.

bmw-i3-driving-range

The reason behind the range extender? To simply deal with the range anxiety common in first time owners of electric vehicles. “I imagine many buyers will order the range extender to cure their range anxiety, discovering later they need it very seldom,” Diess told Automotive News.

Furthermore, Diess says that initially BMW sees the option buying rate to be over 50 percent, but in time it should drop at about 20 percent.

The BMW i3 will come to the U.S. market in the fourth quarter of this year.