July 18 (Bloomberg) -- China, the world's second-biggest energy consumer, may face a worse-than-expected power shortfall when demand peaks in summer, the nation's largest electricity distributor said.

The estimated deficit is 18 gigawatts, about 2.5 percent of the nation's generation capacity, Dai Hongcai, an analyst at State Grid Corp. of China, said in Beijing today. The summer shortfall will reach 16 gigawatts, state-run China Daily reported on July 1.

China is experiencing its sixth year of shortages as demand for electricity in the world's fastest-growing major economy expands. Consumption rose 11.67 percent to 1.69 trillion kilowatt-hours in the first half, more than the nation's output of 1.68 trillion kilowatt-hours, government figures showed today.

``Unexpected coal shortages are forcing some power plants to shut in northern China, whereas we predicted the biggest shortfall to happen in the south,'' Dai said at the Asia-Pacific Coal Market Summit in Beijing today. ``Local governments are trying to ensure adequate coal supplies to the Beijing-Tianjin- Tangshan areas before the Olympic Games.''

Power use may rise as much as 13.5 percent this year, State Grid said in a statement today. Thermal-coal supplies will remain tight through the year, it said.

China's economy has expanded by more than 10 percent for 11 quarters and grew 10.1 percent in April-to-June. The expansion is the fastest of the world's 20 biggest economies and is helping to sustain global growth as a housing slump and credit-market turmoil threaten to send the U.S. into a recession.

Power consumption may rise 12.7 percent annually through 2010, State Grid said. Growth will slow to 5.7 percent between 2011 and 2015 and 4.4 percent between 2016 and 2020, it said.

Electricity consumption by households jumped 16.5 percent to 192.6 billion kilowatt-hours in the first six months, the China Electricity Council said on its Web site today.

Only the U.S. uses more energy than China.

To contact the reporters on this story: Wang Ying in Beijing at ywang30@bloomberg.net; Winnie Zhu in Shanghai at wzhu4@bloomberg.net.

Last Updated: July 18, 2008 06:09 EDT