Beijing's power supply network is groaning under the strain this week as more families and businesses are forced to switch on the air conditioners in the early summer heat.

The city's peak electricity demand hit 10.51 million kilowatts at 3:50 p.m. on Friday, the highest so far this year, said sources with the Beijing Electric Power Corporation.

The figure is already close to last year's peak demand of 10.81 million kilowatts even though the city still has three months of searing heat to come.

The company forecasts Beijing's maximum demand will hit 13 million kilowatts, up 20 percent on last year. Air conditioners alone will consume 4.9 million kilowatts of electricity, 38 percent of the total consumption, it said.

Beijing's electricity demand was around 8.4 million kilowatts before June 5 but has climbed sharply ever since as the temperature has hovered around a high of 36 degrees Celsius for the last five days.

The municipal meteorological station said it saw no sign of immediate temperature drops.

Beijing Electric Power Corporation said the company was ready to cope with the growing demand for electricity and its network was stable enough for an uninterrupted supply of power.

Yet the growing demand for electricity will almost certainly challenge Beijing's goal in reducing energy consumption and cutting emissions.

Beijing is committed to reducing energy and water consumption for every 10,000 yuan of GDP by five percent each this year, in the run-up to the Olympic Games scheduled for August 2008.

It has also vowed to cut chemical oxygen demand (COD) by three percent and sulfur dioxide emissions by 10 percent.

To that effect, the city is closing down high-polluting, energy-guzzling businesses, including 16 small coal mines, said Zhang Yanyou, an official with the municipal development and reform commission.

Beijing met its energy-saving goals last year by reducing energy consumption per unit GDP by 0.78 tons of standard coal, down 6.9 percent from the previous year.

A summer power crunch has been reported in many other Chinese cities in recent weeks.

In Shanghai last week, the power supply to 1,000 families and businesses in the financial district of Pudong had to be suspended after a major transformer buckled under the pressure of an abrupt spike in demand.

A spokesman at the local power supply corporation said such measures would be "inevitable" this year, as the city's electricity demand was forecast to increase 10 percent from last year to 21 million kilowatts in peak times.

Meanwhile, a serious power shortage in south China's Guangdong Province has led to production cuts in many cities in the booming region since mid May.