More than 8,000 enterprises in Shanghai began shifting their working hours yesterday to nights or weekends in order to ease peak-time winter power demands.

"The implementation, to last through next March, is supposed to save 600,000 kilowatts of power at most, and will hopefully fill the electricity gap the city faces unless any extremely bad weather comes up," said Yu Qinde, an official from the Shanghai Municipal Electric Power Company, on Tuesday.

"This is only the first of four measures the local government will adopt to ensure an adequate power supply, especially for household consumption and for key manufacturers."

Fu Yin, a Shanghai General Motors spokesman, said the company has not received any notification to cut its power use during peak times.

But he added that "losses could be reduced to minimums upon being informed beforehand as was proved in summertime blackouts that were instituted."

ABB Shanghai acknowledged that it was notified.

"But the impact it will have is acceptable," said Pan Xiaoying from the company.

According to Yu, the city will witness a maximum 14.2 million kilowatts of power demand during peak times this winter, a 2.28 million kilowatt power increase year-on-year.

"With the maximum capacity the local power grid could produce being 11 million kilowatt, and another 2.1 million kilowatt purchased from other cities, there is still a 1.1 million kilowatt electricity deficit," said Yu.

In this past summer, many local enterprises in the city were asked to temporarily shut down, scenic lights in some places were turned off when temperatures reached above 37 C and officials were asked to keep their air-conditioners in offices and hotels above 26 C.

But the situation will become even worse in the next two years according to Ling Fangming, an official from the Shanghai Energy Savings Association.

It is said that Shanghai's power consumption in 2005 will reach a record 18.8 million kilowatts with a shortage of 4.2 million kilowatts.

Apart from Shanghai, four provinces in East China - Jiangsu, Zhejiang, Anhui and Fujian - will face power shortages this winter, with Zhejiang suffering the severest situation.

"The power gap for Zhejiang will reach 8.8 million kilowatts," said Ling.

"The shortage is not expected to be alleviated until 2007 when more power facilities are completed and put into use."