Since the right-hand side of the torus is displacing a greater mass of fluid (each side displaces the same volume but the right hand fluid is more dense) then it will have a greater upthrust on it. Since there is a greater upthrust on the right-hand side of the torus than the left hand side then it will have a torque on it making it turn anti-clockwise. The device will spin anti-clockwise and can be used to generate power.