Some industries have been forced to shift their hours of operation to lower power output during peak times in Shanghai, the country's financial hub.

The move, which affected about 700 local enterprises, is the latest in a string of moves the metropolis has taken to ensure the local power supply this summer. Another heatwave started last weekend and raised fears among officials that the number of high-temperature days may outnumber meteorological predictions.

The 700 affected enterprises, all big energy consumers, were asked to temporarily shift operations to the early hours of the morning, from midnight to 8 am.

While the enterprises would receive authorities' notification regarding the change one day in advance, the length of the change is unknown, officials said.

Home to more than 16 million people, Shanghai reported on Sunday the hottest day of the summer as the temperature hit more than 37 C.

The city would face a power supply gap of 2 million to 2.6 million kilowatts this summer, said Zhang Hongtao, publicity official of the Shanghai Municipal Economic Commission (SMEC).

Earlier, another 500 local enterprises were asked to make similar adjustments to their operating hours.

The involved enterprises are mostly operating in small scale and engaged in energy-consuming sectors such as steel refining, cement or iron alloy manufacturing. Officials said changes to production times will not affect the city's overall economic performance.

The time shift will cut up to 500,000 kilowatts to the power demand, which can be used to supply those parties in need, said He Changqun, power department director of SMEC.

"We have been in good contact with the enterprises... the key issue now is to what extent they will carry out the move," said He.

Refusing to reveal further specifics about the related enterprises, He said foreign-invested businesses, on the whole, are not included in the move because of their energy-saving operations and advanced technology. There are, however, a few exceptions.

Meanwhile, other enterprises are expected to halt production on a weekly basis, while a number of local construction sites in non-essential industrial or infrastructure projects are supposed to stop working whenever the temperature exceeds 35 C.

Also, the city plans to adopt different electricity charges, while local government departments, official buildings and large retail facilities are expected to keep air conditioners no lower than 26 C to save power.

At the same time, many local scenic lamps will be shut off during peak power-use times.

"We are basically ready for the power demand this summer, but we are worried about high-temperature (above 35 C) days that may last longer than what has been forecast," said Zhang.

(China Daily July 13, 2004)