>>alex_d+(OP)
Oh well, yes and no. Assuming the demand maintains the same, unless something can fill up the gap when wind/solar dropped quickly enough, the current capacity of coal/gas plant simply cannot be reduced or the whole power grid will for sure be brought down by such fluctuations. But if the current capacity of coal/gas plant cannot be reduced, then there isn't much point in increasing solar/wind generation capacity. It's an interlocked problem, cannot be solved by simply changing one parameter only IMO.