The windy plains of the United States are mostly in MISO or SPP, two large independent system operators. Both MISO and SPP see wind peak outputs of about 15,000 MW.

A very quick scan of their generator interconnection queues finds over 40,000 MW in the MISO queue and over 50,000 MW in the SPP queue.

I'm not sure what either system peaks at, but MISO is currently at 72,000 MW of load and SPP is 27,000 MW of load.

All of the queued wind generation won't get built. But we're already well along the way to wind being a serious contribution. Wind doesn't peak all the time, of course. MISO real time is 2500 MW, and SPP is 3500 MW. That's still a lot of power.

Note: all of this information is publicly available.