National Grid plc

National Grid plc is a British multinational electricity and gas utility company headquartered in London, England. Its principal activities are in the United Kingdom, where it owns and operates electricity and natural gas transmission networks, and in the Northeastern United States, where as well as operating transmission networks, the company produces and supplies electricity and gas, providing both to customers in New York and Massachusetts.

National Grid plc is one of the largest investor-owned utility companies in the world; it has a primary listing on the London Stock Exchange where it is a constituent of the FTSE 100 Index, and a secondary listing in the form of its American depositary receipts on the New York Stock Exchange.

Before 1990, both the generation and transmission activities in England and Wales were under the responsibility of the Central Electricity Generating Board (CEGB). The present electricity market in the United Kingdom was built upon the breakup of the CEGB into four separate companies in the 1990s.

Its generation (or upstream) activities were transferred to three generating companies — PowerGen, National Power, and Nuclear Electric (later British Energy, eventually EDF Energy)—and its transmission (or downstream) activities to the National Grid Company.

In 1990, the transmission activities of the CEGB were transferred to the National Grid Company plc, which was owned by the twelve regional electricity companies (RECs) through a holding company, National Grid Group plc. The company was first listed on the London Stock Exchange in December 1995.

With the beginning of the new millennium, National Grid pursued mergers and international acquisitions. In March 2000, National Grid Group acquired United States companies New England Electric System and Eastern Utilities Associates.

In January 2002, National Grid Group acquired Niagara Mohawk Power Corporation, a New York State utility. In October 2002, National Grid Group merged with Lattice Group, owner of the Transco gas distribution business (Lattice had demerged from BG Group in 2000).

National Grid Group changed its name to National Grid Transco plc. It sold the telecoms business 186K Ltd. which was acquired as part of the merger with Lattice Group for a nominal £1 to Hutchison Whampoa in December 2002. In 2004, the company was found liable for a gas explosion in Transco plc v HM Advocate and subsequently fined £15 million. In August 2004, National Grid Transco agreed to sell four of its regional gas distribution networks for a total cash consideration of £5.8 billion. NGT kept ownership of four other distribution networks, which make up almost half of Great Britain's gas distribution network. In July 2005, National Grid Transco was renamed National Grid plc. On 26 July 2005, National Grid Company was renamed National Grid Electricity Transmission plc, and on 10 October 2005, Transco was renamed National Grid Gas plc.