In October 2002, London underground (LU) switched off its last working turbine at Lots road generating station after 97 years of service. Although the city's tube operator had always used in-house generation to power its fleet of trains, by the 1980s, the ageing generating plant had forced the business to review its policy of islanded generation. The decision to source power from the national grid came in 1998 as part of the bid by Seeboard Powerlink (SPL), the Seeboard, Balfour Beatty and ABB, consortium, for a 30 year contract to operate and maintain the city's underground power supply system. To ensure that the LU power supplies could be safely taken from the national grid, SPL had a lot of ground to cover before Lots road could be switched off. And from the beginning the partners knew that connecting the underground's aggressive power load to the public supply network would be a real challenge.