Huaneng Renewables Corp., a unit of China’s biggest electricity producer, said first-half profit more than doubled as the company expanded wind-farm capacity.

Net income increased to 673.3 million yuan ($105 million), from 291.5 million yuan a year earlier, the unit of China Huaneng Group Corp. said today in a filing to the Hong Kong stock exchange. Sales jumped 87 percent to 1.6 billion yuan.

Installed wind-power capacity grew 125 percent to 3.7 gigawatts by the end of June from a year earlier, the company said. Building costs fell, with average procurement charges down 17 percent in the first half from the same period a year before.

Developers are expanding to meet China’s goal of installing 110 gigawatts of capacity by 2015. They will earn more income as China directs them to build in areas where the electricity grid is better able to take on new capacity, according to Bloomberg New Energy Finance. Huaneng Renewables said in May it planned to boost capacity by 45 percent to about 5.1 gigawatts this year.

The company, based in Beijing, rose 2.9 percent to HK$1.79 by the close of Hong Kong trading, before the earnings release. That’s 28 percent below the HK$2.5 level of an initial public offering in June that raised HK$6.6 billion ($846 million). It was China’s second-biggest clean-energy share shale this year.

Huaneng’s utilization hours at its wind farms declined 12 percent following the expansion of operations, the company said.