[zdragnar]

You would have to retrofit every residence to handle daily brownouts (circuits for lights, furnaces and medical equipment stay on, everything else off).

You would have to completely rebuild most of the manufacturing industry, as many plants have startup times measured in hours or days.

It'd be cheaper to just build nuclear.

[awestroke]

Industry uses most of the energy. The industry is already moving towards their own price optimizing energy usage and/or storage.