Power Plant Condenser

• Electrical condenser/capacitor?
• Exhaust steam condenser?

Its Steam Turbine Condenser, i've corrected the question.

This is a question on the efficiency of thermodynamic cycles, then, that any textbook on the subject will tackle with vigour.

In principle, the condenser lowers the pressure in the exhaust steam manifold to that of the boiling pressure of the steam at the condenser temperature, which will be sub-atmospheric. The increased differential pressure given by steam condensation produces more shaft work on the final turbine for any given fuel consumption than were condensation not provided.