The photovoltaic activity in Italy, in last years, has been characterized by an effort focussed in the field of large grid connected power plants. The basic scope of the effort was the investigation of issues arising from the grid connection of such plants, and the identification and validation of satisfactory solutions It was also necessary to assess the reliability of subsystems and components in MW size and in grid-connected operation. The size of the plants erected was limited by economical reasons. It was large enough, however, to permit easy extrapolation to much larger sizes, such to be significant on the production point of view. Among the plants on service we shall mention first of all the largest one, Serre, 3300 kW, designed, erected and operated by ENEL. For Serre ANIT has supplied modules for 5 of the nine 330 kW plant segments presently in operation. The tenth segment, with 1 axis sun tracking, is still in the execution phase. Moreover ANIT has designed and erected for private operators large grid connected PV power plants.