The key thing about today is that it is very windy. The strength of the system is determined by how many power plants you have running all at once. If there are a lot of power plants running and one has an outage, then the others can pick up the slack.
Windfarms don’t have the same level of stability as a power plant. So, on a windy day when we rely more on wind power thermal power plants, it is more difficult to manage. We need to know exactly what happened from National Grid and the network operators to understand the full cause of the blackout.