Everything I've read about a smart grid is based on houses being able to run without electricity, with the electricity being supplied by a PHEV. However, if I'm driving a PHEV and lose power at my house, I don't want to use my car to power my house, then also run my car dead. I want to be able to take my car and leave without it causing my house to break down again.
Instead, the smart grid technology should be giving houses their own battery. Then my house is not broken if I need to go somewhere in my car. Also houses could be cycled and not all run off the grid at the same time. If every house has their own battery, then only half would have to be on the grid charging at a time. This would immediately cut the electricity need in half. It's much more realistic to have clean energy generated when the demand is only half of what it is now.
If you take RMI's approach and make houses even more efficient, then we wouldn't even need half the power that we need now.
Let's get some of the battery technology that we have been trying to build for cars, and take advantage of the cost improvements, in order to make houses able to run without the grid.