Ocean Thermal Solution

First, warm surface water from the ocean enters the evaporator. This warm water heats a fluid (usually ammonia) inside, causing it to turn into water vapor. 

Second, The gas from the evaporator goes into the turbine. The gas pushes against the blades of the turbine, making it spin. The turbine is connected to the generator. When the turbine spins, the generator also spins thus producing electricity. 

Third, The gas that comes from the turbine goes into the condenser. Cold water from deeper in the ocean cools the gas, turning it back into a liquid. The pipe from the condenser brings cold water back into the evaporator where it becomes a closed loop.