For solar energy, I don't really see the need for storage. Peak electricity usage is during the day, especially on hot summer days when the sun is shining the most.

For night time electrical generation, nuclear, geo-thermal, wind, and hydro will suffice.

Yeah, V2G always seemed counterproductive to me. I mean, it is a way to get a lot of distributed power storage capacity out into the world in a hurry, but it also means that my car might decide to sell its fuel load back to the source right when I need to get in the car and drive my wife to the hospital to deliver my baby!

A better plan is to design a storage solution for home use that can be a combination backup power supply for wind/solar systems and a real-time buyer-seller; it maintains itself at a level defined by its owner or guessed at by smart software based on projected need, and then any capacity above that is used to buy low and sell high throughout the day. Maybe build it from still-useful but not roadworthy batteries removed from EVs, and install it behind the garage? If it's capable of outputting at a faster rate than the grid, it could also be used as a way to fast-charge an EV as well. Lithium cells can charge a lot faster than they currently do, it's the plug coming out of the wall that limits them right now.

In the event I had a Volt; and the power industry were going to use my electric vehicle as an electricity storage device for overcoming their generation-load gap, I hope they would pay me, the average customer, with one of these EV a pretty penny for the service. A battery has a cycle dependant lifetime and utilities could drastically reduce the lifetime of a Volt battery by using it to charge and discharge to stabilize the grid. This could spell reliability issues that are not even the fault of GM.