Includes at least one floating body (1), and is characterised in that includes a device (2) fitted inside said body (1) for transforming the movement of the floating body (1) into pneumatic or hydraulic energy and means for transmitting the energy to dry land or to a fixed structure. An energy-generation system is obtained thereby with a manufacturing time and cost lower than the systems currently known. Moreover, the fact that the transforming device (2) is fitted inside the floating body (1) means that it is protected against corrosion caused by the water, against sharp movements caused by marine currents and against other possible outside agents which might harm or damage any of the components which make up the device.