One question is about the long term considerations of wind patterns, etc. What I'm asking about is the short term variability that can lead to voltage oscillations in the grid, like this:

In large wind farms connected to the transmission network the main technical constraint to take into account is the power system transient stability that could be lost when, for example, a voltage dip causes the switch off of a large number of WGs.

A system experiences a state of voltage instability when there is a progressive or uncontrollable drop in voltage magnitude after a disturbance, increase in load demand or change in operating condition. The main factor, which causes these unacceptable voltage profiles, is the inability of the distribution system to meet the demand for reactive power. Under normal operating conditions, the bus voltage magnitude (V) increases as Q injected at the same bus is increased. However, when V of any one of the system's buses decreases with the increase in Q for that same bus, the system is said to be unstable. Although the voltage instability is a localised problem, its impact on the system can be wide spread...

Voltage Stability Investigation of Grid Connected Wind Farm
Trinh Trong Chuong

According to my limited understanding of the subject, to successfully integrate a large fraction of wind generators into your grid you need to have pretty sophisticated real-time monitoring of the voltage and current phases throughout the grid, and a system that tells you what to do when you have a troublesome transient condition, and then the appropriate resources (reactive power sources, for example) appropriately distributed within the system.

I don't know much about this, but my impression is that there is a lot of electrical engineering work going on in the background that is not immediately apparent. And my fundamental worry is that while "we" are all working vigorously for additional sustainable resources in the overall supply system, some of the hard technical problems have not actually been solved yet...

Maybe I'm full of it, which is why I would ask such questions at an appropriate conference...