The Hybrid-cycle is one that has yet to be tested but uses principles from both the closed and open cycle OTEC systems to obtain maximum efficiency. The Hybrid cycle uses both seawater and another working fluid, usually designed using ammonia. [9] The fresh water is initially flashed into steam, similar to the closed-cycle; this occurs in a vacuum vessel. In the same vessel the ammonia is evaporated through heat exchange with the warm water. The ammonia is then physically mixed with the warm seawater in a two-phase, two-substance mixture. The evaporated ammonia is then separated from the steam/water and re-condensed and re-introduced into the closed loop cycle. The phase change of the water/ammonia vapor turns a turbine producing energy [10]. Two regular process for the hybrid- OTEC are: • Those using hydraulic turbines