I don't really think this is correct. Wind turbines are not switched off due to grid power demand fluctuation unless there is some major and rare event. Sure it is no fast to adjust Nuclear or Coal plants. But gas or hydro is very fast. and because the grid is so large, the wind fluctuation have a overall smooth slopes, and even Coal and Nuclear can handle it somehow. Only at night on a very windy day the wind farm output can reach levels where it is not possible to cope with it.,(reply>), it is correct, the uk and especially Scotland where this windfarm is, our national grid is rubbish and we don't have much surge protection