LAND, PUBLIC WORKS AND UTILITIES
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one is due for commissioning in early 1987. The Castle Peak ‘A' and 'B' power stations together will have a combined capacity of over 4000 MW and will become the largest power station complex in Southeast Asia.
CLP's transmission system operates at 400 kV, 132 kV and 66 kV, and distribution is effected mainly at 33 kV, 11 kV and 346 volts. The supply is 50 hertz alternating current, normally at 200 volts single phase or 346 volts three phase. Supply for bulk consumers is available at 33 kV and 11 kV.
Work continued during the year on the development of an extra high voltage transmis- sion system at 400 kV to transmit power from the Castle Peak Stations to the various load centres. This 400 kV network comprises two transmission rings. One ring, a primary ring encircling the New Territories, was completed in late 1985. It consists of 90 kilometres of double circuit overhead lines and four extra high voltage sub-stations at Lei Muk Shue, Tsz Wan Shan, Tai Po and Yuen Long. The other ring, scheduled for completion in 1988, will provide 22 kilometres of cable circuits linking the major sub-stations at Tsz Wan Shan, Tai Wan and Lai Chi Kok.
Electricity for Hong Kong Island, Ap Lei Chau and Lamma, is supplied by HEC's Ap Lei Chau Power Station and Lamma Power Station. The Ap Lei Chau Power Station, with an installed capacity of 935 MW, is made up of two 60 MW and six 125 MW oil-fired generating units together with two gas turbines with a combined capacity of 65 MW.
The demand for electricity has grown by 244 per cent over the last decade. To ensure that HEC can meet rising demand in the future, a site on Lamma Island was granted to the company for development of a new dual coal-fired or oil-fired power station. The first 750 MW phase of the station was completed in February 1984. The next phase, when completed, will add another two 350 MW units to the station.
In HEC's system, transmission of electricity is carried out at 275 kV, 132 kV and 66 kV and distribution is effected mainly at 11 kV and 346 volts. With the exception of a small propor- tion of 132 kV overhead transmission lines, all transmission and distribution are carried out underground or by submarine cables. The supply is 50 hertz, 200 volts single phase and 346 volts three phase. Supplies at high voltage are also made available to the larger consumers.
The transmission systems of CLP and HEC are interconnected by a cross-harbour link, thereby achieving cost savings to consumers through economic energy transfers between the two systems and a reduction in spinning reserve requirements. The interconnector, which was commissioned in 1981, now has a capacity of 480 MVA. Upon full completion, the total capacity will rise to 720 MVA.
CLP's system is also interconnected with that of Guangdong General Power Company of China and over three million units of electricity are exported to Guangdong Province each day. This interconnection results in better utilisation of the company's generating plant during off-peak demand periods. In July 1985, CLP signed a contract with the China Merchants Steam Navigation Company to supply power to the industrial zone of Shekou from August 1986. This arrangement, which affords to Shekou a reliable electricity supply without subsidy from Hong Kong consumers, is another example of the close co-operation on energy matters which has developed on both sides of the border.
On January 18, 1985, the Hong Kong Nuclear Investment Company (a wholly-owned subsidiary of CLP) and the Guangdong Nuclear Investment Company signed the Joint Venture Contract for the formation of the Guangdong Nuclear Power Joint Venture Company, to construct and operate a nuclear power station at Daya Bay in Guangdong Province. About 70 per cent of the power from the station will be supplied to Hong Kong to help meet the territory's rising demand for electricity well into the 1990s.