An apparatus and method for extracting energy from an oscillating working fluid, such as ocean waves includes an apparatus (10) having an internal flow passage (40) for the working fluid, a turbine (44) and a flow control device (38), each of the turbine (44) and the flow control device (38) being in direct fluid communication with the flow passage (40), where the flow control device is selectively moveable between a first configuration in which the flow control device is open to allow a flow of the working fluid, such as air, to exit the flow passage therethrough, and a second configuration in which the flow control device restricts a flow of the working fluid therethrough, the working fluid then entering the flow passage via the turbine, which can be harnessed to generate electricity.