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 Chile, Peru and USA. With 75,236 kilometres of power lines or around 98% of the Italian high-voltage power transmission grid, Terna is the leading independent grid operator in Europe and 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