The Rocky Mountain Institute is promoting the Smart Garage concept, which aims to kill two birds with one stone by powering our transportation infrastructure, while simultaneously reducing the variability of renewable power generation. The Smart Garage concept is the intelligent interconnection of plug-in hybrid vehicles with the electrical grid. An intelligent grid would charge the batteries in your car in cheap off-peak periods of electricity use (like the middle of the night), and sell power back to the grid during peak periods (like the middle of a hot summer's day while your car sits in a parking lot). This would lower the cost of charging your vehicle (and maybe even make you some money), and provide a vast, distributed storage network for electricity. This storage network of potentially millions of car batteries could soak up power from renewable power generators during periods of low demand/high generation, which could then be sold back to the grid during periods of peak demand/low power generation.
Given the utility is experiencing a peak load period, it asks my house if it can use the spare power in the car's battery and send that electricity elsewhere in the grid. What's more, it will pay me for that power. Since I like being paid, I have already programmed the system to accept such requests.
So, while I am snacking in the kitchen, I am actually being paid for the unused power remaining in my car battery, and yet have complete confidence there will be more than enough power left in the vehicle to get me to where I need to go.