BMW is attempting to seize the alternative-drive initiative from luxury rivals by creating a new subbrand, under which it plans to sell a range of purpose-built electric, hybrid and range-extended models.

The company is planning to take its new subbrand, called BMW “i,” public in September at the Frankfurt motor show, where an initial two-model lineup consisting of the diminutive i3 and a larger, more sporting two-plus-two i8 will be revealed in concept guise for the first time.

Additional “i” models, including a Chevrolet Volt-rivaling hatchback expected to be badged the i5, are on the drawing board. But BMW’s focus at this early stage is on developing the technically advanced i3 and i8 to meet a planned 2013 on-sale date