Datang International Power Generation and Huaneng Power International have reported significant rises in generation volumes, although rapid growth in new plant supply saw utilisation rates decline. Datang said its generation volume jumped 27.1 per cent to 70.98 billion kilowatt-hours (kWh), while Huaneng said its volume surged 31.7 per cent to 150.5 billion kWh. The companies attributed the growth to the commissioning of new plants driven by the rapid increase in demand. But Datang said the average utilisation rate at its plants fell 'slightly' to 6,320 hours last year, while a Huaneng spokeswoman confirmed utilisation also dropped, although specific figures were not yet available. Aggressive plant construction by all five mainland generation groups has raised concerns about oversupply in 2007, with analysts expecting plant utilisation to decline after peaking out in 2004 on the back of power shortages. Meanwhile, Datang has struck a deal to sell a 30 per cent stake in a power project to one of its significant shareholders in a move to spread investment risks and funnel funds into other projects. The agreement requires independent shareholder approval. Under the deal, Hebei Investment will invest in Datang's 5.94 billion yuan Wangtan power project in Tangshan, Hebei province. The project consists of two 600-megawatt coal-fired generating units, which are undergoing pre-commissioning testing. Hebei Investment holds a 13.01 per cent stake in Datang.