2013-3-6 Introducing Vapor Power Plants In subsystem B,the water vapor expands through the turbine,developing power.The water then condenses and returns to the boiler. Introducing Vapor Power Plants In subsystem C,power developed by the turbine drives an electric generator. 72013-3-6 7 Introducing Vapor Power Plants ►In subsystem B, the water vapor expands through the turbine, developing power. The water then condenses and returns to the boiler. Introducing Vapor Power Plants ►In subsystem C, power developed by the turbine drives an electric generator