Demand side management is one way of addressing the same issues resolved by building new power plants (the new blog "Green Building in Denver" looks promising).
The key point is that power plant construction is driven by peak demand, so you can forego quite a bit of power plant construction by smoothing out peaks by giving power users an incentive to use more electricity when there is a surplus, and less at peak times.
Historically, this has focused on industrial users, and selected thrifty A/C users. But, some uses that are pretty easy to shift (e.g. delayed start functions on clothes driers and dishwashers) also make sense. The trouble is, of course, the culprit number one, which is air conditioning in summer months, is very time sensitive.
Also, while saver's switches on A/C may help, the better options IMHO would be a much stronger pitch for evaporative cooling in homes and cooling towers in larger buildings, as well as improved insulation (which helps keep cool cold in the summer, as well as keeping heat in during the winter). These methods of cooling aren't quite as intensely cold as traditioncal A/C but use far less power.
In Italy, there has been a push to encourage casual dress during summer months, so offices don't have to be kept so cold, so peak power demand is reduced. As one of my former bosses used to say, if the British could conquer the world in shorts, I can practice law in shorts.
Perhaps the best solution, however, is simply to follow the sensible sustainable and low tech solution of Spain and Mexico in places with hot climates -- shut down businesses during the hot midday, and get out and about during the cool evening. A work schedule designed for London doesn't necessarily make sense in a mountain desert.