I am not sure... where I live (Australia), the electricity supply policy is essentially aimed at avoiding brownouts on hot days, I suppose for the fear of losing building cooling (this has resulted in fatalities in the past). This incidentally results in having a massive amount of standby power generation, and rather high electricity prices.

I think the low hanging fruit (in Australia at least) is various industrial users (eg aluminium smelters). The politics around this are fascinating, but unfortunately too complex to describe properly here...