From the announcement thread:
Need an extra incentive to go green in SimCity? Maybe you need a little boost in the form of the new Nissan LEAF® Charging Station that is available today. This free in-game item is the perfect way to kick start your desire to create a city that will make you (and your Sims) happy. In the case of your Sims, In the case of your Sims, the Charging Station provides happiness to the Sims that use it and a onetime wave of happiness to the nearby businesses. Need another bonus? It produces no sewage or garbage. That’s right! Green indeed.
