An apparatus for extracting energy from a fluid flow including a secondary fluid channel, a fluid driveable generator unit and a primary fluid channel. The primary fluid channel comprises a fluid intake in fluid communication with a throat. The throat is configured to increase the flow velocity and reduce the pressure of the primary fluid flowing through the primary fluid channel and includes at least one plenum in the interior of the throat configured to further reduce the pressure of the primary fluid flowing through the primary fluid channel. The plenum includes at least one perforation through its exterior surface in fluid communication with the secondary fluid channel. As such, the flow of primary fluid through the primary fluid channel draws the secondary fluid into the primary fluid channel through the secondary fluid channel and the perforation and thereby into driving engagement with the generator.