Terna S.p.A. is a transmission system operator based in Rome, Italy. It operates through Terna Rete Italia, that manages the Italian transmission grid and Terna Plus which is in charge of new business opportunities and non-traditional activities in Brazil, Chile, Peru and USA. With 75,140 kilometres of power lines or around 98% of the Italian high-voltage power transmission grid, Terna is the sixth largest electricity transmission grid operator in the world based on the size of its electrical grid. Terna is listed on the Borsa Italiana and is a constituent of the FTSE MIB index. Wikipedia