NOVELTY - The plant has a belt shifter (18-2) located between pulleys (19, 20) by getting through a belt transition channel (8c) in a pontoon element (8). One of the pulleys allows for transmission of linear motion of a belt ring (18) to an input shaft of a reducer by changing the linear motion into rotary motion. The other pulley enables the belt ring to operate tensely in a desired position, and is placed on a foundation system (15). A flywheel is placed on a platform (12) in which torque, speed and clockwise rotary motion required at the output of the reducer are stored as kinetic energy.    USE - Electricity production power plant for changing sea wave energy into electric energy through a common belt-pulley system e.g. flat belt-pulley system such as leather flat belt-pulley system, rubber flat belt-pulley system and textile flat belt-pulley system, V-belt-pulley system and gear belt-pulley system.    ADVANTAGE - The belt-pulley system is utilized as transfer elements for mechanical power and motion in construction of machines that display better working performances under hard working conditions, so that the belt-pulley system transfers the motion for prolonged time with less loss, thus providing low fault ratio and minimum repair cost, and hence allowing maintenance in an easy, quick and inexpensive manner and transferring motion with high efficiency. The plant is situated on a seaside, so that the transfer of energy and access to the system can be made easy, thus allowing wave heights and flexibility to be designed at larger size and increasing amounts of obtained energy, and hence reducing dependency on fossil fuels, ensuring that natural resources are efficiently used and eliminating harm to environment in an efficient manner. The plant allows vertical movements of the pontoon element under guide of a main shaft so as to increase drift force and to avoid potential losses of energy due to an angle formed by horizontal movement of the main shaft. The plant allows upward movement of the pontoon element facilitated by a sealing gasket placed between the pontoon element and a shear wall, so that losses in water mass under pressure due to compaction can be minimized, thus maximizing buoyancy of water acting on the pontoon element at bottom in an efficient manner. The plant allows an auxiliary shaft to be anchored to the platform from an upper end and to the foundation system and placed in parallel with the main shaft, thus preventing axial rotation movement of the pontoon element.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a reducer mechanism comprising a water inlet/outlet.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of an electricity production power plant.    Pontoon element (8)    Belt transition channel (8c)    Platform (12)    Foundation system (15)    Belt ring (18)    Belt shifter (18-2)    Pulleys (19, 20)