REN - Redes Energéticas Nacionais, SGPS, S.A., through its subsidiaries, engages in the transmission of electricity and natural gas in Portugal. It operates in two segments, Electricity and Gas; and Telecommunications. The company operates as a national electricity transmission network; purchases, sells, imports, and exports electricity and natural gas; manages a concession to operate a pilot area to produce electric energy from ocean waves; and operates a telecommunications network. It also operates liquefied natural gas terminal maintenance and regasification facilities; and manages projects and ventures in the natural gas sector. In addition, the company provides underground storage development, maintenance, and operation services; natural gas transport and management services; and distributes natural gas, as well as communication and sustainability, marketing, business management, business development and consulting, and IT project services. Further, it invests in assets, shares, companies, and associations; transmits and transforms electricity in Chile, as well as participates, finances, collaborates, and conducts management of companies; and manages back offices. As of December 31, 2023, it operated national electricity transmission system with 9,409 kilometers of line circuits, 70 transformer substations, and 17 switching and transition stations; and national natural gas transmission network with 1,375 kilometers of high-pressure gas pipelines, 66 junction stations for pipeline branching, 45 block valve stations, 5 T-branch interconnection stations, 85 gas pressure regulating and metering stations, and 2 custody transfer stations. The company was founded in 1994 and is headquartered in Lisbon, Portugal.