Huaneng Power International (0902) expects net profit to have soared by 340 percent last year, thanks to a tariff hike and falling coal prices.
The firm, a subsidiary of state- owned China Huaneng Group, is Asia's biggest independent power generator.
Net profit attributable to shareholders in 2011 hit 1.27 billion yuan (HK$1.58 billion), or nine fen per share, according to China accounting standards.
Based on the 340-percent outlook, that means a net profit of about 5.6 billion yuan last year.
But executives are quick to stress that the figure is no more than a preliminary estimate.
During January-September last year, though, the firm booked a net profit of 4.2 billion yuan.
The final profit surge for the year is being attributed by Huaneng to the carryover effect of tariff adjustment in 2011 and lower coal prices in 2012.
With thermal power stations in 17 provinces and cities, Huaneng generated 302.433 billion kilowatt hours for the year, down by 3.56 percent in 2011.
And it sold 285.455 billion kWhs, a fall of 3.47 percent on weak domestic demand.
But the sales price was raised by the National Development Regulatory Commission, which hiked electricity tariffs in 15 provinces in mid-2011 to support state-owned power generators.
Amid the economic downturn, the price of coal - the primary source for power generation in the mainland - slumped as much as 30 percent in the first seven months of 2012, stabilizing at a low level.
Shares of Huaneng Power International rose steadily and have gained 71.5 percent in 2012.
The stock hit a 12-month high of HK$7.39 on January 2. It closed at HK$7.27 on Friday.