in case of plant outages those reserves are activated automatically after the immediate fall of frequency and are restored as soon as possible by the intervention of frequency restoration and replacement reserves terna according with those recommendations the largest normal contingency in italy would correspond to the maximum generation infeed loss the difference between the new largest contingency and the one without the new plants will determine the amount of additional spinning reserves required the italian electric system was split into the same eight areas used by the national control centre of the italian tso terna and terna and shown in figure