I'm currently involved in a 'Smart grid' rollout. The HAN component is currently de-scoped, but is intended to be included post 2012.
A number of collegaues and I have been trying to identify how this will actually benefit that aveage consumer.
The vast majoriy of eletrical devices we use in the average domicile are on demand devices. That is, they draw power when we use them, and we use them at a time when we most need/desire to do so.
To gain significant benefit from load shifting consumption will come from demand shifting. But people will still want to watch their favourite TV show when they get home from work before they go to bed. The fridge will still be on 24x7. They will still run the AC during the evening on hot days. There are very few patterns of significant consumption which can be moved. Maybe run your laundry overnight on a timer, but you can only run one load a night.
Unless people are load balanced - different schedules creating different peak demand periods - this will have only a minor impact.