In Beijing, a heat wave pushing temperatures as high as 39 degrees Celsius has driven many residents to crank up air conditioning at home, in office buildings and in shopping malls.
But city officials warned Thursday that Beijing is facing severe electricity shortages, and are urging residents to conserve energy.
Analysts say China's booming economic growth is pushing the limits of its electricity grid. In the capital, the heat wave has made the situation worse. Mao Yushi is an adviser to the Chinese energy sector.
"Two years, or three years ago, China had surplus electric power. At that time, the government determined not to construct any more fuel power plants. Now, we have too few capacity to generate power.
State media reported Thursday that Beijing hoisted for the first time what it calls its "yellow alert," the lowest of three warnings signaling that energy consumption is outpacing generating capacity.
City authorities are asking residents to turn off air conditioners for at least one hour a day and to set their thermostats to 26 degrees Celsius or higher. Factories were urged to work at night, when demand for power is lower.
Many of China's industrial and commercial centers are also facing electricity shortages, some so serious that factories are being shut down.
Prime Minister Wen Jiabao previously called the issue of energy sufficiency of "strategic importance."
China is seeking new sources of energy. Overseas, China is now negotiating energy purchase agreements with countries in Asia, Africa, South America and the Middle East. Locally, it is allowing state oil companies to explore possible reserves near disputed islands in the South China Sea.