China Guangdong Nuclear Power Holding, the developer of the mainland's first commercial nuclear project at Daya Bay, plans to double capacity at the site. Daya Bay is 25 per cent owned by Hong Kong-listed CLP Holdings, which bought 70 per cent of the plant's output to supply the city's power needs. China Guangdong signed a framework agreement on the 2,000-megawatt phase two expansion with the Shenzhen municipal government on Tuesday, according to a statement on the website of the State-owned Assets Supervision and Administration Commission. A CLP spokeswoman said the company is not involved in phase two and it is too early to say whether it will be interested in buying the resulting power. The target market of the expanded plant will be Shenzhen and Hong Kong and the municipal government will include the project in its Shenzhen-Hong Kong economic co-operation plan, the statement said. China plans to more than quadruple its total nuclear power generating capacity to 40,000 megawatts in 2020 when it will account for 4 per cent of total power generation if that target is met, up from 1.8 per cent last year. China Guangdong, whose responsibilities for the Daya Bay expansion will include preliminary design, construction and fund-raising, did not provide a cost estimate or timetable for the project. A 2,000-megawatt nuclear project proposed by Datang Power International Generation and state-owned China Guangdong in Fujian province this year is expected to cost 23.44 billion yuan and take five to six years to build. The central government is also localising construction and design of nuclear plants. Phase one of Daya Bay, which came on stream in May 1994, was built with French technology.