A heat wave in Guangzhou, capital of South China's Guangdong Province, has forced the local power grid to stagger electricity use to tackle a serious power shortage.

Among the 12 districts and counties of Guangzhou, three have implemented the measure to stagger power use, while six switched on a red early warning system on Friday.

The city-wide red warning system will be on from Saturday to Monday, according to the Guangzhou Electricity Supply Bureau.

A region with the red early warning system alight may have its power cut at any moment, the bureau said.

Guangzhou's power shortage was estimated at 200,000 kilowatts on Thursday, accounting for 2.5 per cent of the total power load at 7.73 million kilowatts on that day, a source with the Guangzhou Electricity Supply Bureau said.

The maximum power load for Guangzhou expected this year is 8.8 million kilowatts, and the largest power shortage will be between 600,000 kilowatts and 800,000 kilowatts, the source said.

Although the current power load and power shortage did not hit expected peaks so far, Zhou, an official with the bureau, said "the current figures have broken the records of last year."

In 2005, the peak power load was 7.28 million kilowatts.

Zhou said there are three peak periods of power use every day between 9 and 10 am, 11:30 am and 12 pm, and 7 and 8 pm.

The bureau will cut power in some regions during these periods when consumption approaches the maximum power load to prevent the city's power grid from collapsing.

Tension between electricity supply and demand in Guangzhou will worsen in August. The Economy and Trade Commission of Guangzhou Municipality pledged it would give priority to the power demands of residents.

"Staggering electricity usage is a temporary solution to the acute power shortage, but not a complete cure," Zhang Bo, an electrical engineering professor at South China University of Technology, told China Daily on Friday.

To solve the issue of the power shortage at its source, Zhang said the government should install more power generation units with high efficiency, but less pollution; enhance cross-regional electricity and power exchanges; develop power generation through clean energy sources; and promote the concept of saving energy among the population.

Source: China Daily