Comment by GuB-42

Even without talking about batteries, I think a lot can be done using smart grids. For example, your A/C and heaters can run a little later or a little earlier, it won't have a significant effect on your room temperature, especially if your house is well insulated. It means a lot can be done just by remote controlling thermostats with minimal effect on confort. This can apply to other appliances that are not too time sensitive or can have a delayed start, like washing machines, refrigerators, dishwashers, etc... but thermostats are likely to be the biggest ones.

As with batteries, it would require some work with the utility companies, so that they can signal the best times to power on/off, and offer the appropriate financial incentives to do so. We are already doing that in some way with peak/off-peak pricing, but it doesn't help with high frequency, unplanned variations.