Why is it necessary that wind+solar+storage systems be “sized to meet peak demand”? That’s particularly true if capital costs per kWh for constructing them are very low, fractions of operating costs of fossil fuel installations. Why not build them to be multiples of peak demand, thereby protecting generation from lack of wind or insolation on a portion of the generating footprint.

This assumes, of course, that adequate land is available to site these, which is why constraints upon land use is effectively a subsidy to fossil fuel generation.