Pretty good bet those aren't Tesla batteries in there though.
Plug-in hybrid versions of European luxury cars are going to be hitting the market in large quantities over the next few years. The realization that Tesla found an apparently untapped market has automakers scrambling to combine luxury with electric power. BMW's upcoming shot at this is currently known internally as "the Thing," because apparently they haven't heard of the Volkswagen Type 181, although that obviously won't be the production name.
The concept is pretty simple, it's a 5-Series GT with a plug-in hybrid powertrain. But realizing that frugality isn't the chief aim of the luxury electric car buyer, BMW has heaped tons of power onto the thing, a total of 700 horsepower in fact. The car is meant to operate in pure electric mode about two-thirds of the time, but this will depend largely on how far your commute is and just how quickly you need to get there. Great as all of this sounds, it's hard to imagine it would take sales away from the Model S. Even if BMW used a more attractive car than the 5-Series GT, it lacks the "look at my electric car" appeal of the Tesla.