Abstract: An apparatus and method are provided that comprise the use of a water-filled vessel having two vertical sections and two horizontal sections that connect the respective upper and lower ends of the vertical sections. A sprocket is mounted for rotation with a horizontal output shaft in one of the horizontal sections, and an idler pulley is mounted for rotation in the other horizontal section. An endless drive chain carrying a plurality of gas receptacles, or buckets encircles the sprocket and the idler pulley within the vessel. A gas inlet is positioned at the bottom of the vessel such that a portion of the gas entering the vessel enters the open ends of the downwardly facing buckets and forces part of the water out of the buckets. The hydrostatic pressure of the water exerts an upward buoyant force on the gas in the bucket moving the bucket upwardly.