The issue as it is today is affordability. The problems remain mass, capacity and cost of batteries. Right now you can have any two. Jacoby expects plug-in vehicles to become more common, but until the costs come down while still meeting customer performance expectations, the masses won't be adopting.
In the near term, VW plans to focus on optimizing existing gas and diesel powertrains by expanding availability of direct injection, downsizing and turbocharging. Automatic start-stop capability will also help, along with weight reduction to achieve the goal of halving fuel consumption over the next ten years.
[Source: The Car Connection]