Spain will need to make some very hard choices, they have a relatively - by European standards - fragile grid and some weak interconnects. This situation has been flagged years ago but so far priorities have been to do other things first. The outage has definitely given people food for thought and I expect that when the final report is presented that it will come with some recommendations on how to prevent future recurrence. In particular the voltage / frequency regulation aspect of some of the local grids will become a focal point because these have the potential to destabilize much larger sections than just their own. The real puzzler to me is that there were multiple signals of pending grid instability and no action was taken when they easily could have, this is the bit that I'm most interested in learning about.

I look at energy companies about twice every year in some detail and I know that the typical grid operator is extremely careful and pro-active on this subject (at least, in NL and Germany, my work area, they are), the energy market has introduced some potential for abuse and for instability but so far that seems to be under control. Which makes me quite curious about what the root cause here was.