Construction of Heysham 1, which was undertaken by British Nuclear Design & Construction (BNDC), a consortium backed by English Electric, Babcock & Wilcox and Taylor Woodrow Construction, began in 1970, with the first reactor commencing operations in 1983 and the second reactor following in 1984. However, initial production levels were low, and full commercial operation was only declared in 1989. It is likely to remain in operation until 2024. Its generating capacity is 1150 MWe. The reactors were supplied by National Nuclear Corporation and the turbines by GEC. There were 4 × 17.5 MW auxiliary gas turbines on the site, these had been first commissioned in January 1977.