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 for the production of electric energy from ocean waves; and operates a telecommunications network. It also operates liquefied natural gas terminal maintenance and regasification facilities; manages projects and ventures in the natural gas sector; provides underground storage development, maintenance, and operation services; offers natural gas transport and management services; and distributes natural gas, as well as provides communication and sustainability, marketing, business management, business development and consulting, and IT project services. In addition, the company 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, 2021, it operated national electricity transmission system with 8,907 kilometers in lines, 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.