That report concentrates on the forensics, but it doesn't really look at any of the root causes which were failures at the regulatory or political level. The Spanish electricity network was designed such that it would fail.

Working out why the regulator failed is no easy task. And fixing regulators is highly political.

You might compare against another country that successfully integrated massive solar systems such as Australia. They had a functional regulatory environment that designed their systems to handle the supply changes. Some of that was through world leading deployment of battery systems to help regulate their network.

There is a lot of specialist expertise (e.g. nera.com economic consultants) that is paid by a countries network operator to design their networks and markets. The staff within individual countries either lack sufficient analytical skills or lack sufficient political clout to make their networks deeply resilient.