Balancing wind variations means this will just have to be used a few times more often each year, adding a small cost penalty and undermining the carbon savings from using wind very slightly. (environmentalresearchweb.org)
Milborow admits that balancing wind variations has the effect of reducing the load factor for thermal plant, but says that this only costs ~ # 2.5 / MWh at 20 % wind, or ~ # 6 / MWh at 40 %. (environmentalresearchweb.org)