Ocean thermal gradients are interesting as a power source and should be researched. However I wonder if there is a hidden "gotcha". The hidden "gotcha" with solar voltaics is in the energy required to manufacture them and their limited working life span. Until fairly recently it required more energy to manufacture a solar volatic panel than the panel produced over its entire lifespan. Supposably Siemens and some other manufacturers are now producing panels that can actually produce positive energy when manufacturing cost is included. With ocean thermal gradients there might be hidden energy costs that negate any advantage. For example, how much energy will be required to produce the working fluid used for the turbines? For example, ammonia requires a fair amount of energy to manufacture due to the high cost of nitrogen fixation. An ocean gradient power plant will tend to get covered with barnacles and other marine life. This will degrade thermal performance. How much energy will be required to scrape off the marine life? Certainly this concept should be explored. However it will be interesting to see what the economics are of a complete working power plant.

Gary