NOVELTY - The wave power plant (1) has an energy accumulation device (105) which is arranged in a buoy (3) or floating body and which drives the rotatable units of an electric generator (21) by second water motions, separated from first water motions, in the same first rotational direction in relation to each other and generates electric current with the same polarity as when a driveshaft (11) drives the rotatable units of the electric generator to rotate relative to each other.    USE - Wave power plant for extraction of electrical energy from motion of water waves.    ADVANTAGE - Provides efficient wave energy plant which absorbs motions of water waves for driving electric generator. Equalization over time of the motive force, which drives the electrical generator, can be achieved. Accumulation of energy can be used for equalizing the energy of the water waves and generate electricity at an even level, which provides a high capacity factor of the generator and associated power electronic circuits and connections, and a low complexity of the electric power system. Excess energy from large waves can be accumulated and used over time to compensate for shortage in smaller waves, which contributes to the high capacity factor. Absorption of energy from the water waves can be limited while full power can be maintained even during very heavy wave conditions, contributing to the high capacity factor, and also works as a very simple and efficient storm protection system where the wave energy plant all the time works in harmony with the waves, only absorbing the amount of energy that it has a capacity to convert. Power output of the generator can be controlled by the fact that the rotation speed of the generator can be adapted to the average rotation speed of the driveshaft, thus, wave energy plant can deliver an even power level in relation to the current wave climate. Wave energy plant is highly scalable and its capacity and pattern producing electric power can be optimized for specific wave climates for the highest cost efficiency. Wave energy plant has a completely mechanical transmission having a high efficiency, which in simple way converts the oscillating wave movements into a unidirectional rotation, well adapted to a standard electric generator having a rotating rotor. Construction can be made from concrete, a cheap material which is well tested for ocean environment. Electronically adjustable sliding clutch can be used, which is arranged to influence the winding of a line between a bottom foundation and the buoy and which also makes it possible to adjust the force which is needed to maintain the horizontal position of the wave energy plant. Sliding clutch might replace and enhance the function of a counterweight.    DETAILED DESCRIPTION - The buoy or floating body is arranged at or in a pool of water to be put into motion by motions of the water in the pool of water. The driveshaft, which is rotatably journaled in bearings to the buoy or other device is arranged to provide a counteracting force against the motions of the water in the pool of water. A first oblong unit with one end coupled to the buoy and other end coupled to the driveshaft is arranged to provide a counteracting force against the motions of the water in the pool of water. The electric generator is coupled to the driveshaft and includes two rotatable units. The driveshaft and the energy accumulation device are coupled together, so that the coupling between the first oblong unit and the driveshaft so that the driveshaft rotates to first motions in the buoy or the other device, in a unidirectional direction and drive the rotatable units of the electric generator. An INDEPENDENT CLAIM is also included for a method of extracting electrical energy from more or less periodical motions of a floating body in pool of water.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic front view of the wave energy plant including an energy accumulation device and a return feed mechanism.    Wave power plant (1)    Buoy (3)    Driveshaft (11)    Electric generator (21)    Energy accumulation device (105)