There's not much play in demand at the moment, but there could be if more systems were aware of the price of electricity. A/C can be turned off, cars can stop charging, dishes can wait, etc.

Variation in renewable energy generation can be reduced by averaging over larger geographic areas. Wind speeds and cloud cover vary much more on local scales than on continent-wide scales.

A combination of demand adjustment and linking of power generation over large geographic areas can reduce the need for energy storage.