My memory is blurry as this I read that almost 10 years ago now, and it probably changed since then, but one vision was, assuming you have an electric car that

My memory is blurry as this I read that almost 10 years ago now, and it probably changed since then, but one vision was, assuming you have an electric car that has a capacity of 200 miles. You drive on average 20 miles to get to work, get into the parking lot, plug in your car. It doesn't need to be charged, because you'll be doing the same 20 miles at night. So instead of charging, the grid is able to "buy" electricity from your battery during stress times (say maybe during lunch hour or something). You end up having the grid having access to all electric car's battery when not needed.