Abstract: A method and apparatus for producing compressed air includes sealing air in a container capable of reducing its volume by external hydraulic pressure. A weight having a larger specific gravity than water is attached to the container to sink the container deep under water. Compressed air is produced when the volume of the container is reduced by hydraulic pressure, and is transferred into a recovery vessel connected to the container via a check valve. The weight is then separated from the container use and cause the container to float on the water by the action of buoyancy. The compressed air can then be recovered from the recovery vessel.

Abstract: An ocean current power generation system includes a support placed on or in a state spaced apart from the ocean surface so that it is not rotated by an ocean current, a ring-like rotating member horizontally suported by the support for rotation about an axis, a plurality of ocean current-receiving members coupled in a hanging fashion to the ring-like rotating member for receiving the ocean current and rotating the ring-like rotating member at all times in a fixed direction corresponding to a direction of the ocean current, a drive gear provided on the ring-like rotating member for rotating in a concentric relation to the ring-like rotating member, a rotation accelerating gear train provided inside the support for receiving the rotation of the drive gear to accelerate its rotation, and a power generator provided inside the support and connected to the rotation accelerating gear train for receiving the accelerated rotation of the rotation accelerating gear train.

Abstract: A method and apparatus for producing compressed air includes sealing air in a container capable of reducing its volume by external hydraulic pressure. A weight having a larger specific gravity than water is attached to the container to sink the container deep under water. Compressed air is produced when the volume of the container is reduced by hydraulic pressure, and is transferred into a recovery vessel connected to the container via a check valve. The weight is then separated from the container to cause the container to float on the water by the action of buoyancy. The compressed air can then be recovered from the recovery vessel.