> So it matters when wind is providing 20%, but it doesn't matter when it's providing 100%.

Of course. Because when there's no electricity, there's no electricity.

> even though coal use is at a historic low, it's actually increasing

You pretend this is a contradiction when it's not. Germany has just shut down its last reactors. So yes, the usage of coal will increase because when renewable generation is low you still need to provide electricity. Guess what provides that electricity.