Imagine this a lake a large pipe a sealed cylinder inside the pipe valves on top and bottom water comes in top valve from lake bottom valve from lake closed Valve to pipe open pressure from lake pushes water out pipe as cylinder comes down. when down, valve at bottom opens and top closes, pressure from lake pushes cylinder up, water goes out valve to pipe, other valve closed.
Long ago they proposed putting large rotors in the gulf stream which could power cities the size of New York from a single unit. The several hundred foot tall vanes only spin at a rate of less than ten miles per hour, thus minimizing the danger to Seal Life. The moon and the sun do the rest.
