What we usually mean by "supercharger" is an electric car charger using DC power instead of AC power. DC charging is much faster, hence "super." The idea is this: Plug in for 30 minutes and get an 80% charge.
This is what BMW will first launch in California later this week, and the stations are free to use until the end of 2015. It seems obvious this charging network will be built out in areas outside California over time, but there is nothing to report at this time. Stay tuned.
In terms of BMW's superchargers being free to use "only" until the end of 2015, I assume that BMW does not want to over-promise from Day One. No charger is truly "free" -- there is a cost involved, and someone has to pay it. The question is only how.
One can simply bake the cost of free lifetime charging into the price of the car. This would be like selling someone a house with free lifetime electricity included. One might think that this would be very unfair and induce heavy use, i.e., waste.
As such, it is probably more rational to have people simply pay for whatever they use. We do this with electricity at home, so why not also for the car? It's not as if there is a billing problem. You have a card, and you swipe it.
After all, when you buy a regular gasoline or diesel car, you don't get free gasoline or diesel for life either. For the economically illiterate, "free gas" might sound nice, but it's so obviously a disaster for reasons that should be clear to any person after a couple of seconds thinking about it.
In any case, BMW is kicking off its supercharger rollout by offering free service until the end of 2015. I predict that a more rational pricing model will be introduced by then, so that some BMW electric car customers don't run around subsidizing their neighbors or those who don't have the ability or need to plug into one of these superchargers as often.
Opening the door for a far more resourceful infrastructure buildout, BMW has joined with Ford (F), General Motors (GM), Chrysler (Fiat, etc.), Mercedes and the Volkswagen Group (Audi, Porsche) on its technical standard. This was already announced in May 2012, but few people outside the "inside baseball" industry observers appeared to pay attention. One can therefore surmise huge economies of scale as these companies pool their resources in the months ahead.