If a person pays a higher price for electricity during peak times, it's possible that charging a battery at night and drawing on it during peak times could save consumers money. That's the vision of many battery companies which envision home energy storage as a way to store energy from the grid or solar panels.
The problem with Nissan's proposed setup is that after the car battery is drained, e.g. during a blackout, it becomes useless for transportation too. Not good. They need a source of cheap and/or intermittent energy that would be wasted if not stored in the battery.
In system terms, they have to solve a synthesis problem, not just graft Leaf onto an existent grid. Maybe they should make a deal with Google to build distributed local storage infrastructure.
tags: innovation, synthesis, storage, s-curve, source, control, energy, 4q diagram, environment, trade-off, breakthrough, example