A cold wave sweeping across large swathes of the country since Saturday has forced some provinces to ration electricity for industrial use, but State power company officials promised yesterday that supply to residents across those regions would not be affected.

"Even under extreme circumstances, we will ensure residential electricity supply, which is always the top priority," said Wang Changxing, spokesperson for the Shanghai grid, a major branch of the East China grid.

Regions across east and central China, such as Hubei and Jiangxi provinces, have resorted to rationing of power for industry to tide over the icy weather that has pushed up energy demand while disrupting coal transportation.

In Hubei alone, one of the worst-hit regions, power cuts have been imposed on "several thousand" energy-intensive companies such as those in the metallurgy and steel industries, said Wang Chaoying, spokesperson for Hubei Electric Power Company.

In Wuhan, capital of Hubei, soaring demand for residential electricity led to brownouts in some districts after the thermal power generating system broke down in a local power plant under excessive load.

By the end of 2009, coal stockpiles in the Central China grid network were sufficient for only 10 days, less than the recommended 15 days, according to official data.

Altogether, China took offline 4,780 megawatts linked to its main network as of Jan 3, according to data provided by State Grid Corp of China, the country's major grid operator. It accounts for about 0.55 percent of the country's overall capacity at the end of last year.

In early 2008, 7 percent of the coal-fired power generation capacity was shut because severe snowstorms cut transportation of the fuel, according to a Xinhua News Agency report.

Cities in eastern coastal regions such as Jiangsu and Zhejiang, two economic hubs, have so far not resorted to power cuts to industry but local authorities did not rule out the possibility should the necessity arise.

Shanghai Grid confirmed that power in Shanghai will not be switched off or rationed in the next couple of days. "The power load at the Shanghai grid dropped from 19.42 million kilowatts on Tuesday to 19.32 million kilowatts on Wednesday, thanks to the rising temperature," said Wang Changxing.

"The power shortage won't last long since it's caused mainly by the abnormal weather," said Dai Yande, deputy director of the Energy Research Institute affiliated to the National Development and Reform Commission.

Zhuang Jian, senior economist at the Asian Development Bank in China, said increasing power generation facilities, a result of the country's $586 billion stimulus package initiated in late 2008, would gradually help make up for the shortage.

Another reason for the current shortage is the haggling over prices between power and coal companies, analysts said. "They must be made more market-oriented to resolve differences over prices," Zhuang said.

Dai also urged a contingency mechanism be put in place to tackle such weather-triggered power shortages.

Overall electricity consumption rose nearly 6 percent in 2009 to 3,643 billion kilowatt-hours, the National Energy Administration said in a statement on its website yesterday.

Coal-based thermal power plants generate about 90 percent of the country's supply.

Wu Yiyao, Zhou Lihua, and agencies contributed to the story