Redes Energéticas Nacionais, SGPS, S.A. (REN) is a Portuguese energy sector company which is the current concession holder of the country's two main energy infrastructure networks: the National Electricity Transmission Grid (RNT) and the National Natural Gas Transportation Grid (RNTGN). It is responsible for the planning, construction, operation, maintenance and global technical management of both these grids and associated infrastructures. The company is also involved with the storage and transportation of liquefied natural gas, and owns and operates LNG regasification terminal at Sines.