Electricity (Supply) Act (Northern Ireland) 1948 the Ministry of Commerce transferred to the Board all the electricity property and assets held by the Ministry including the power stations at Ballylumford and Larne. In 1957 the generating capacity of Ballylumford power station was 124.5 MW. There were 160,025 consumers, and 510.961 GWh of electricity were sold. The station at Curran Point Larne was used for winter peak loads and maintenance outages. In 1957 it generated 48.9 MWh. The Board also owned a hydro-electric station at Limavady. The Electricity (Supply) Act (Northern Ireland) 1948 also established the Northern Ireland Joint Electricity Committee (NIJEC). The committee had a duty to co-ordinate, control and improve the generation of electricity and primary transmission throughout Northern Ireland, to make adequate supplies available to electricity undertakings, and to encourage rural electrification. The Board and other undertakings were required to sell to the NIJEC the electricity generated at Ballylumford, Larne, Belfast and Londonderry power stations which the NIJEC bought at cost of production. The NIJEC resold electricity at a standard tariff to the distributing authorities. In 1973 the Northern Ireland Electricity Service (NIES) was formed as a public utility to generate, transmit and supply electricity to Northern Ireland. During the Ulster Workers' Council strike in 1974, when electricity supplies were severely disrupted, the government considered generating power using a Royal Navy nuclear submarine in Belfast Lough but the idea was abandoned as being technically unfeasible. Establishment and divestments In 1991, the company was incorporated as a government-owned public limited company, Northern Ireland Electricity plc. In 1992 the power stations at Belfast Harbour, Ballylumford, Coolkeeragh and Carrickfergus (Kilroot) were demerged and sold. In 1993 the remainder of NIE (transmission, supply and retail businesses) was privatised as Northern Ireland Electricity plc. In 1998, Northern Ireland Electricity plc became part of Viridian Group plc, with Northern Ireland Electricity a subsidiary of that holding company. NIE Networks sold SONI, the operator of the transmission network, to EirGrid in March 2009 for £30 million. Purchase by ESB On 7 July 2010 BBC News reported that ESB was to purchase NIE for £1 billion. In September 2010 unionist politicians Peter Robinson and Reg Empey wrote to the Taoiseach objecting to the transaction. They said it was "inappropriate" and that it amounted to the purchase of a "key component" of Northern Ireland's infrastructure. ESB is a statutory corporation in the Republic of Ireland whose board