China Yangtze Power Co Ltd, the country's biggest hydro power operator, plans to buy a Sichuan hydro power firm for 79.7 billion yuan ($12.55 billion).

Yangtze Power is to buy a 100 percent of the company with 37.4 billion yuan in cash and 42.3 billion yuan in shares, the Beijing firm said in a filing on the Shanghai stock exchange.

Part of the 37.4 billion yuan cash payment will come from a private placement of shares worth up to 24.2 billion yuan to seven investors, including China Life Insurance, Guangdong Development and Singapore's sovereign wealth fund GIC.

China Life will take 165 million shares, Guangdong Development 100 million and GIC 40 million, Yangtze Power said. The shares will be priced at 12.08 yuan per share, it said.

China has been trying to reduce its reliance on coal-fired power plants to cut pollution and shift towards other energy sources, including hydro power.

China generated 454.8 billion kilowatt-hours (kWh) of power in September, down 3.1 percent from the same month last year, with industrial demand still under pressure as the economy slows.