Places painted in a red color are zones with a higher geothermal potential than blue ones.
Advantages of OTEC:
For example, fresh water can be used to supply a village; nutrients can be used for multi-species mariculture producing harvest yields which far surpass naturally occurring cold water upwelling zones; cold water for cooling greenhouses or for cold bed agriculture. The cold water can also be used for air conditioning systems or for refrigeration systems.
OTEC closed cycle uses a fluid with a low boiling point to spin a turbine and, by means of an electrical generator, generate electricity. Warm surface water is pumped through a heat exchanger to vaporize the fluid.The expanding vapor turns the turbo-generator. Cold water (from deeper water) is pumped through a second heat exchanger, condenses the vapor into a liquid, which is then returned to the system.
An open cycle OTEC uses the surface seawater directly to generate electricity. First, the warm seawater is pumped into a low-pressure container where the fluid boils. Sometimes the steam drives a low-pressure turbine attached to an electrical generator. The steam, which has left its impurities in the low-pressure container, is now pure fresh water. It is condensed into a liquid (due to cold temperatures from deep-ocean water). This water is suitable for applications as drinking water, irrigation or aquaculture.In other cases, the steam is used in a gas lift technique of lifting water to significant heights.