The state government has approved plans for two large new power stations, triggering concerns about a further increase in greenhouse gas emissions, especially if coal is used as the fuel.

The approvals are for ''concept plans'' for two, 2000- megawatt power stations at Mount Piper, near Lithgow, and Bayswater, which is near Muswellbrook in the Hunter.

Final plans for the power station design, including fuel source, will need separate approval before construction can begin.