With many automakers exploring electric cars, BMW is now jumping onto the 'green' bandwagon. BMW has announced that it is holding a press conference on Friday to preview its "i" sub-brand. We don't know anymore details at this point but we do know that BMW is planning to show the first two models of the "i" series at the Frankfurt Motor Show.

The first one is the i3, a pure-EV plug-in city car that was previewed a year ago through a sketch of the Megacity concept. The second model is the i8, a plug-in hybrid sports car based on the Vision EfficientDynamics concept unveiled at the 2009 Frankfurt Motor Show.

Both models are based on a construction concept that uses an aluminum chassis to house the powertrain while the passenger cell is made out of carbon fibre-reinforced plastic. The i3 and i8 will both be manufactured at the BMW's Leipzig plant and launched in 2013.