The wind tech is way better than it was even ten years ago. The expiration of GE's patent on variable speed turbine generators opened the versatile technology up to everyone. These turbines can control voltage more dynamically.

Separately, the cost of power electronics have come down, so now some turbines use full converters to change the generator output to the power system frequency. These can eliminate gearboxes, too, and also control voltage.

In the US, FERC has made a number of rulings that forced wind plants to improve. FERC Order 661-A (pdf) required wind turbines have low voltage ride through, forcing them to remain online during system faults. 661-A also mandated a power factor range, relating back to the GE patent and full converter turbines with their ability to control voltage.

We're also able to push the power system harder than ever. Fifty years ago we still had manned substations. People would sit there and call the control center every so often to tell them what the analog meters showed. Today we scan every analog and digital point every few seconds. And every few minutes the entire system is simulated to see what would happen if a failure occurred. That lets the system accept more wind. The output is variable, of course. The system was easy when it was the same generators running all the time. The variable wind output means one day to the next could be drastically different. The tools allow us to be confident the system is still reliable.

There were a couple wind output records broken in the US a week or two ago. I think MISO topped 13,000 MW. For comparison, that's about double the maximum output of Grand Coulee.

To me, the issue is wind doesn't provide capacity like a gas, coal, nuclear or hydro plant does. I think MISO allows something like 16% of wind nameplate capacity to count as capacity to serve load. So you build a 100 MW wind farm, and you get 16 MW of capacity. Build a 100 MW gas combustion turbine and you get 100 MW of capacity. Load needs capacity to ensure all load can be served.