Avista Utilities currently has 50% of generation from hydro and a small portion from one wind farm. Oh yes, a token quantity of solar panels are available for selected customers who pay a slight premium.
The rest is from a CCGT and the Colstrip MT coal burner which is scheduled to be turned off. So it appears that Avista is going to replace it with these planned wind farms and a substantial dose of so-called energy efficiency.
I suppose that is about the same as what other utilities in the USA are doing. I just included here because Avista Utilities is my electricity provider and so I know a little about their performance .
I gather that the idea is to partially feather the turbine blades to provide a reserve for the grid. Seems impractical to me
It's just plain silly and reflects thinking that is not only inside the box, it couldn't punch through a wet paper bag. If you've got an excess of power available it would make sense to run it to dump loads of low but non-zero value rather than to spill it. If you've suddenly got a power deficit you turn the local dump loads off, and the opposite in case of surplus.