National Grid Company plc (NGC) was established on 31 March 1990 as the owner and operator of the high voltage transmission system in England and Wales. The company is a wholly owned subsidiary of National Grid Transco, which is listed on the stock exchange and is one of the UK's FTSE 100 companies.
Prior to March 1990, the vast majority of electricity supplied in England and Wales was generated by the CEGB (Central Electricity Generating Board), which also owned and operated the electric power transmission system and the interconnectors with Scotland and France. The great majority of the output of the CEGB was purchased by the 12 area electricity boards, each of which distributed and sold it to customers.
On 31 March 1990, the electricity industry was restructured and then privatised under the terms of the Electricity Act 1989. The National Grid Company plc assumed ownership and control of the transmission system and joint ownership of the interconnectors with Scotland and France, together with the two hydroelectric pumped-storage stations in north Wales, but these stations were subsequently sold off.
The CEGB's remaining non-nuclear generating stations were transferred to National Power and PowerGen, while its nuclear generating stations were transferred to Nuclear Electric. Subsequently, the new PWR (Pressurised Water Reactor) and AGR (Advanced Gas Reactor) nuclear power stations of Nuclear Electric and Scottish Nuclear were combined and a new company called British Energy created. The old magnox nuclear power stations were left in government ownership as Magnox Electric and then acquired by BNFL (British Nuclear Fuels Limited).
The property, rights and liabilities of the 12 area electricity boards, including the local electricity distribution systems, were transferred to the 12 Regional Electricity Companies (RECs), which are still in existence today although under different ownership. The Regional Electricity Companies were the main shareholders in National Grid until the company was floated on the stock exchange in December 1995.
The electricity market in the UK was established as a result of the electricity reforms, and the NGC became the platform for competition, allowing competing generators to connect to the grid and providing an independent system operating service to the market.