HUANENG Power International Inc, China's second-largest power producer by market value, paid 1.52 billion yuan (US$206 million) for a 9.08-percent stake in Shenzhen Energy Investment Co. Huaneng bought 200 million shares at 7.60 yuan each through a private offer, the company told Shanghai's stock exchange yesterday. That's a 67-percent discount to Tuesday's closing share price of 22.81 yuan in the Shenzhen-based company, which has gained 174 percent this year.