Abstract: This invention is concerned with an apparatus of potentially large size for producing electrical energy from the rays of the sun. The apparatus utilizes an air housing mounted on a hillside exposed to sunlight. The air housing, having a roof of light admitting panels, causes air to be heated and transported upwardly in a convergent manner to an apex opening which communicates with a tunnel. A bladed member mounted within the tunnel and rotated by the flow of air therein activates an electrical generator. The exit extremity of the tunnel communicates with a collector chamber which in turn communicates with a vertically oriented chimney stack which intensifies the velocity of air passing through the tunnel.