That the amount of electricity we can generate from wind turbines is inherently variable is well known. What isn't as well known is how they intend to deal with it:
Households' lights could be dimmed and kettles take longer to boil when the wind isn't blowing, under Government-backed plans to routinely dip the voltage of Britain's electricity supplies. As Britain builds more wind farms, the measures to dip voltage could be used when there is an unexpected lull in wind power output. New technology to instantly dip the voltage of power to entire regions “at the press of a button” has already been quietly trialled on half a million households across north-west England. The system could be rolled out across the UK in coming years, ministers have indicated - after trials showed consumers did not notice any difference.
That is just fine for domestic supplies. No one does notice although we do have a technical word for this: "brownout". It's something that we consider to be part of a Third World (for which read "bad") electricity supply system.
For while there's pretty much no problem with domestic supplies this causes absolute chaos in industry. Something that is already being seen in Germany. There, it's not so much that the grid is intentionally lowering (or, as is proposed, raising at times) the voltage, it's that the country's reliance upon wind just makes it happen. And modern production machinery simply cannot deal with variations in voltage.
There have been cases not just of production runs faltering, ruining what was being produced, but of voltage variations damaging the actual machinery itself. This has in turn led to German industry scrambling to deal with the problem: effectively, the solution is to put something like a giant UPS on the side of every piece of production machinery.
This, of course, has costs, substantial costs, and needs to be added to the cost of this new electricity generation system. And it isn't added: so, therefore, the costs of wind power are not fully accounted for. Just as with the original carbon emissions, we've got an uncosted externality in the system making the numbers even worse than the current massive price.