There is an interesting paper in the most recent issue of PNAS by Kempton et al,
Electric Power from Offshore Wind by Synoptic-Scale Interconnection. The paper is in a tradition of literature looking at how to solve the problem that renewables are intermittent by averaging over production in a wide geographical area - on the theory that the wind must be blowing (or the sun shining) somewhere. In this particular paper, the region studied is the US east coast. This map shows the study sites S1 - S11:
HTML clipboard 
As you can see, the individual sites are extremely noisy, and the composite signal (the Pgrid at the bottom) is smoother and doesn't fluctuate as extremely. Thus the paper claims:
In the study region, using our meteorologically designed scale and orientation, we find that transmission affects output by reducing variance, slowing the rate of change, and, during the study period, eliminating hours of zero production. The result is that electric power from wind would become easier to manage, higher in market value, and capable of becoming a higher fraction of electric generation (thus more CO2 displacement).
...the east coast is not really where the wind is. This
map from the National Renewable Energy Laboratory shows the distribution:
A very important point: the power in the wind is
proportional to the
cube of the wind speed, so those purplish regions in the high plains have about 10 times the potential per unit area of the yellowish-green regions on the coasts. That's where the wind is. And clearly, by feeding wind into the grid across the US, the performance is going to be smoother again,
since a single high cannot cover the whole country.It seems like with renewables, when feeding small amounts into a mainly fossil fuel grid, that's workable as they basically displace fuel use when they are available, but don't displace much capacity so the fossil fuel plants are still there to smooth the renewables out. An all-renewables grid would also be possible, but requires averaging over huge areas (and/or enormous amounts of storage). In between those extremes, things are going to be awkward.In the study region, using our meteorologically designed scale and orientation, we find that transmission affects output by reducing variance, slowing the rate of change, and, during the study period, eliminating hours of zero production. The result is that electric power from wind would become easier to manage, higher in market value, and capable of
becoming a higher fraction of electric generation (thus more CO2 displacement). Please read full from EarlyWarningNOTE: Gary said... The variability of surface winds is one of the main reasons that high altitude wind power (HAWP) looks more attractive (as well as the higher wind speeds). Looking at the east coast, one of the best locations for HAWP is near metropolitan New York.
Here is (Gary's) post on this subjectThis paper by Archer and Caldeira considers the intermittency problem for the New York area utilizing large battery storage for low wind periods.
"To just have one program that would preempt states and have a one-size-fits all federal approach really not only ignores the whole history of success in the environmental area but also would not be the wisest way to go in terms of either maximizing greenhouse gas reductions or to maximize the amount of job creation," 
