BEIJING, May 21 (Xinhua) -- Chinese Vice Premier Zhang Dejiang said it's important to develop ultra-high-voltage (UHV) power transmission technology as part of China's energy distribution strategy.

    Zhang made the remarks at an international conference on UHV power transmission technology which opened Thursday in Beijing.

    It will be a long and strenuous task for China to ensure stable energy and power supply when China is picking up speed in industrialization, modernization and urbanization, as China's energy sources and production capacity are not evenly distributed, hang said.

    The country's electricity demand may almost double to 7.4 trillion kilowatt-hours by 2020 and the installed generating capacity may increase by a similar rate to 1.47 billion kilowatts, the State Grid Cooperation of China (State Grid) or SGCC said.

    Zhang met with representatives from the International Council on Large Electric Systems, the International Electrotechnical Commission and other international organizations before the conference.

    He also visited an experiment base on UHV power transmission technology at the SGCC, China's largest power supplier, Wednesday morning. Zhang encouraged the SGCC to continue with technology innovation on UHV power transmission.

    UHV, defined as voltage of 1,000kv or above in alternating current and 800 kv or above in direct current, is designed to deliver large quantities of power over long distances with power losses less than the most commonly used 500kv lines.

    In January 2009, the SGCC said it would start building three more UHV power lines this year. The plan would bring the number of China's UHV lines to six.

    The company expected UHV capacity to reach 300 million kilowatts by 2020, with 78 million kilowatts dedicated to hydropower transmission.