Abstract: An apparatus is provided for generating electricity in response to a fluid flow. The apparatus includes a top rotor element coupled to a center axis with an arm extending substantially perpendicular to a center axis. The arm moves in response to the fluid flow to rotate the center axis. The apparatus also includes a bottom rotor element coupled to the center axis also having an arm extending substantially perpendicular to the center axis. The arm of the bottom rotor element is substantially fixed in a position relative to the arm of the top rotor element, wherein the position is offset about the center axis by about 90° from the top rotor element.