Full integration of the power distribution grids in Hong Kong and Guangdong remains a far-off vision, CLP Holdings chief executive Andrew Brandler said yesterday. A complete linkage of the networks would improve efficiency and might reduce power costs on both sides, Mr Brandler said. But huge differences in reliability of supply and environmental protection meant it would be a long-term undertaking. 'In 15 to 20 years, we will see much closer integration of the networks,' he said. 'But for the Pearl River Delta to have one electricity network, we have a long, long way to go.' Network interconnection should proceed cautiously to avoid a repeat in Hong Kong of the recent blackouts in North America, London, Scandinavia and Italy, he said. The networks were not designed to be interconnected when they were built and they should be brought to similar levels of reliability or there would be substantial blackout risks, he added. 'I don't think Hong Kong would want to expose itself to reliability and environmental risks [from Guangdong] ... Unlike other commodities, power cannot be stored.' Hong Kong's power market has about 36 per cent excess capacity, according to a research report by European brokerage CLSA. While this is lower than the excess capacity in Singapore, Malaysia and the Philippines, it is considered sufficient to cope with surges in demand. Having sufficient excess capacity is a pre-requisite for the introduction of power pooling and competitive bidding - the goal of full-fledged network integration. The Hong Kong government is studying the feasibility of connecting the networks of CLP and Hongkong Electric - which supplies power on Hong Kong island - as part of preparations for possible changes after 2008 to the scheme of control governing the generators' investment returns and profits. In contrast to the city, power supplies in Guangdong are among the tightest on the mainland, where 19 provinces suffered from power rationing during demand peaks last summer. The central government has a long-term strategy to interconnect provincial power grids in three phases by 2020, to drive down electricity costs and raise efficiency by allowing energy-rich regions to sell power to power-short ones.