May I recommend Hugh Sharman's ICE Proceedings paper Why UK wind power should not exceed 10GW'?
This explains why statements in last week's cover story about the actual output of wind turbines being 30% of capacity are just silly.
If the wind speed is too low, the output is negligible so that 100% back up power is required.
If Mr Van Lieshout really thinks that there is a close correlation between wind and energy demand, I suggest he disconnects from the grid and relies on wind power - he will quickly see the folly of his view.
Ben Tatham (F), St Anthony, Pilgrims Way, West Humble, Dorking, Surrey, RH5 6AW