When There is Too Much Wind
In general wind generation increases as the wind speed increases. At some point the generator reaches its maximum output and further increases in wind speed yield no greater MW output.
On rare occasions if wind speed continues to increase wind generators shut down to avoid damage, and output drops to nothing until the wind speed drops to safe limits. This normally happens when wind speeds exceed about 90 km per hour.
When wind generators reach a cutoff the MW output from wind generators can drop rapidly. Off course not all generators will drop off together but if many generators are clustered in close proximity this could lead to a significant drop in generation.
When wind speeds drop to safe but still high levels wind generation can ramp up very fast as well.
On Dec 29, 2018 in the early afternoon the website https://windalert.com/spot/16593 reported wind speeds averaged 93 km/hour with gusts to 113 km/hour in the Pincher Creek area.
What happened to wind generation in the area? Some Pincher Creek wind generators rapidly went to zero MW output only to rapidly return to near full output. Three examples taken from PSTI’s website at https://psti.ca/agt-dashboard are shown below.
Overall the effect on the total MW output from wind generation in Alberta was muted because of the geographic diversity of wind generation and the fact that wind speeds did not reach the sustained levels to cause widespread cut off in larger areas. However, I would bet that for people in the Pincher Creek area, wind speeds were plenty high on the afternoon of December 29th.