Electricity supplier investigates sites for more turbines Hongkong Electric is studying the feasibility of building a wind farm south of Lamma Island, but says there are huge technical difficulties to overcome. The proposal follows one by Wind Prospect, a renewable energy company based in Britain, to build 50 wind turbines off Sai Kung. Hongkong Electric said it had carried out a general survey of local waters and found there were few suitable sites for an offshore farm because of limitations such as navigation, conservation and the presence of undersea utilities. Tso Kai-sum, managing director, said: 'We are looking at places where we can build more windmills. These places could be on land and sea. But we need further study. The key consideration would be the cost as we need [to sink] piles at least 20 metres deep into the seabed to support the windmills. This is very expensive.' Asked whether these proposals, if realised, would mean a substantial tariff rise, Mr Tso replied: 'We don't do costly things.' The company yesterday officially opened the city's first commercial wind turbine at Tai Ling on Lamma. Costing about $15 million to build, it is expected to generate around 1 million units of electricity a year and save 350 tonnes of coal. While it reported smooth turbine operation, the company expressed concern over the reliability of wind energy as the peak and lowest levels of daily electricity generation could differ by more than 300 times. It said coal-fired generation was necessary as a back-up. During a 147-day period of trials up to February 20, the wind turbine generated 348,700 units of electricity, with the peak day on February 8 with 9,687 units. The lowest was recorded two days earlier, with only 29 units. 'This phenomenon lets us realise the characteristic of wind energy - that is it is easily affected by weather and geographical locations. Sometimes it is weak and sometimes it is strong. We can't forecast with ease,' said Mr Tso. Sarah Liao Sau-tung, Secretary for the Environment, Transport and Works, said she had been told by the company that it was assessing whether an area south of Lamma was a suitable site for a wind farm. She said scarce land resources meant offshore wind farms could be an option for a wider scale of renewable energy development. But she also said an offshore wind farm would pose greater environmental and maintenance challenges, and on cost. A particular problem was corrosion from seawater. Friends of the Earth assistant director Edwin Lau Che-feng urged Hongkong Electric to expand its wind turbine programme and release more information on its study of offshore wind farms.