I've often wondered about those % measurements of electricity generation. Because of high variability balancing wind/solar is apparently tricky since rarely is storage capacity built along with the wind/solar (I kinda wish that subsidies focused on that). So... of that 10%, how much of it is excess power that had to be soaked up wherever a place could be found to dump it, and or rapid ramping down of base generation, causing waste. It's probably a hard thing to calculate though.