When does a mac laptop startup automatically after a power failure? I'm trying to get the hang of this.  I notice that sometimes when I plug the charger the macbook boots automatically, other times it doesn't.  I know in desktop macs this is determined by a setting in Energy preferences, but not sure when this is supposed to happen with macbooks. Does it change with the model? It's good to know this for troubleshooting.  Any insights would be much appreciated.
Regardless of of the Mac model, the power settings determine if it will boot upon power failure.  If this option isn't set, it won't boot.