Huaneng Power International, Inc. (NYSE:HNP; HKEx: 902; SSE: 600011) has announced an 18.87% rise in its power output to 48.83 billion kWh for the first half of 2004. It said most of that increased output came from its plants in Fuzhou, Dandong, Weihai, Jining and Nantong, and from two plants in Yushe and Xindian acquired…