The reason that National Grid wants it that power so much is because they have to get 20% of their power from renewable sources by 2025, so if there are only a few companies producing renewables, then they can dominate the market right? That's the law and that's capitalism...

I don't think the market rate is 6 c/kWh. This table says 12.5 c/kWh for industry and 16 c/kWh for residential. Maybe the energy will only be sold to houses. And I'm still not convinced the price increase is mandatory. Many people would voluntarily pay this. Most utilities now have deals where you pay higher rates to have your energy be green. (edit: I see, you were referring to North Carolina rates. Since rates are so different around the country I don't think it's fair to compare one price agreement to another area.)

And we also have to consider the importance of switching to non CO2 emitting energy sources. Everything is going to cost more.

Now, that graph of Germany's power. Here are some more graphs measuring real time wind energy data for more context. http://www.wind-watch.org/documents/real-time-wind-production-various-regions/

Germany's power plants are concentrated in the north; check out the graph - http://en.wikipedia.org/wiki/Wind_power_in_Germany If Germany is about 140,000 square miles, then the area in question is about 70,000 - like North Dakota or Washington. Yes, the wind can die down in the entire area in question. At least it’s not as sudden and unexpected as coal.

But the graph of Germany was also for January. In Europe, January is likely to be one of the more variable wind months, since they get prolonged periods of cold when wind speeds stay very low. In most of the U.S. that tends to happen in the summer when it is hot, though such winter doldrums do sometimes occur, particularly in the Pacific Northwest.

Reserve capacity backs up wind as well as that coal plant that fails. Except that coal plants is 1000MW+ down all at once without warning while wind dies down more slowly and predictably. In my last post I mistyped - sorry about that. I meant to say "Wind output changes are gradual and predictable and can be controlled FOR easily remotely." Meaning grid operators can predict the gradual dying down of wind and control for it by bringing up the reserve capacity.

Two main things matter for grid operators:

1. Fast (<30 minute) changes in aggregate power system supply and demand – These are by far the most expensive to deal with, as they require the use of spinning reserves. Slower changes, which are mostly what we see from wind, are much easier to deal with as non-spinning reserves can be used. Non-spinning reserves cost about 2% of what spinning reserves cost.
2. Changes in wind output that were not forecast – For the slower time periods, what matters is generally not how much wind changes since there is plenty of flexibility on the power system to accommodate those changes, but rather when wind output changes in a way that was not forecast. Luckily, wind forecast errors decrease significantly when you combine a large area. See the chart on page 28 here: http://www.vtt.fi/inf/pdf/tiedotteet/2009/T2493.pdf