The study also assumes a 40% capacity factor rather than projecting from historical data, which are much less.
And the modest cost they find for integrating wind is simply a comparison with the cost of using the same amount of dispatchable energy. It does not consider the extra cost of wind itself and its low effective capacity. In other words, the cost of building and maintaining capacity just to cover for the wind is ignored. As is the actual effect on fuel burning in such plants. The assumption is that the electricity from wind simply replaces the electricity from other sources and that's that.
Even with smoothing the available 5-minute data into hourly data and exaggerating the likely average production levels, the study found the effective capacity (or "effective load carrying capability") of the wind plant to be about 17-21% in 2003's wind conditions, 11-12% in 2004's, and 4-5% in 2005's.
That is, for practical planning purposes -- even using the fudged data from this study -- one megawatt of wind power could be counted on to "replace" only 50 kilowatts of other sources.
The study is currently available from the Minnesota Public Utilities Commission here.
wind power, wind energy, Minnesota