In 1998 when I was in high school I dreamt up this kind of power plant and asked my physics teacher where the power really came from. Not happy with his answer I asked a university physics Q&A service [1]. Not happy with their answer either I did a masters in engineering physics and kept asking this question whenever I got the chance. Never got a really good answer. But I’m glad to see it works.
My instinct here is just to wave it away saying "I bet the temperature of the system falls when you do this, and you need a minimum temperature for it to work over a given salinity gradient". Is it not that simple?
1. https://fragelada.fysik.org/index.php?amne=Energi&stage=&key...