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

The estimated deficit of 18 gigawatts, about 2.5 percent of the nation's generation capacity, is higher than a previous projection, 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.

Power use may rise as much as 13.5 percent this year, State Grid said in a statement today. An expected increase in electricity output will ensure demand and consumption will be ``generally balanced'' in the fourth quarter, it said. Thermal- coal supplies will remain tight through the year, it said.

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

The country's power consumption may rise 12.7 percent annually through 2010, State Grid said in its statement. 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.