China's power output in September reached 394.48 terawatt hours (TWh), up 2.17 percent year-on-year but down 11.25 percent from August, according to State Electricity Regulatory Commission (SERC) data released on Tuesday.

"The sharp month-on-month decline in power output can partially be attributed to falling demand as the peak consumption period draws to an end, but the main factor is slowing factory activity amid a weakening economy," power industry analyst Yang Sili told Interfax.

"China's September power production has not reached a satisfactory target, reflecting the country's slowing economic expansion," the SERC wrote in a monitoring report at the end of last month.

Electricity output in the first nine months totalled 3,640 TWh, up 5.6 percent on an annual basis.

Guangdong, Zhejiang, Jiangsu and Shandong provinces and Jingjintang – the municipalities of Beijing and Tianjin and Tangshan City in Hebei Province – were the biggest consumers of power in September, said the SERC. The regions are China's largest industrial bases.

Cross-regional electricity trade totalled 15.27 TWh in September, said the SERC.

Year-on-year power consumption growth in September slowed to 2.6 percent from 3.6 percent in August and well below the 11.7 percent increase for 2011, according to SERC data released separately on Wednesday.

Power output and consumption is expected to stabilise in the fourth quarter as the effects of the RMB 1 trillion ($154 billion) of government capital spending plans announced in September begin to trickle through and Beijing takes additional action to boost the economy.

"The low CPI reading of 1.9 percent for September indicates that inflation is not the greatest threat to China's economy, rather it is the bigger-than-expected slowdown," Yang Li'an, an economist, told Interfax. That gives the central government room to simulate growth through monetary easing in addition to stimulus measures, added Yang.