Abstract: A power generating apparatus, in which air is discharged into a lower portion of a rotatable, underwater wheel or the like, so as to provide buoyancy, in order to rotate the wheel and drive an electric generator; the apparatus including, in one design thereof, an endless bucket-line around a periphery of an upper and lower rotatable wheel, the buckets at a lower end of the line being turned into inverted position where an air nozzle, directed under the buckets, fills them with air, so as to cause the buckets to lift.