BEIJING, Jan. 16 -- China's top five electricity companies on Thursday reported a combined net profit of 47.39 billion yuan (7.78 billion U.S. dollars) last year, attributing an increase in gains to lower coal prices.

Combined profits of the companies in 2012 was 40 billion yuan.

The five companies, China Huaneng, China Guodian Corporation, China Huadian Corporation, China Datang Corporation and China Power Investment Corporation, reported net profits of 12.79 billion yuan, 10.34 billion yuan, 9.67 billion yuan, 7.43 billion yuan and 7.15 billion yuan respectively.

The companies attributed the profit increase to continuously low coal prices in 2013 amid high coal inventory and slowing coal consumption. The China National Coal Association announced Wednesday that the country's coal consumption growth slowed to an annualized expansion of 2.6 percent last year.

The total power generating capacity of the five companies reached 584 million kw as of the end of 2013, accounting for 47 percent of the nation's total, according to data from the companies.

Meanwhile, the China Power Investment Corporation said that its solar power generation capacity increased 328 percent and totalled 2.5 million kw as of the end of 2013, which made it the world's top solar power producer.