Offshore energy storage device

Abstract

An aggregate to store energy as kinetic energy, includes a float body and conversion element. The float body is at least partially placed in a liquid and arranged to rotate in direct contact with the liquid and the float body is used by the aggregate to store energy in form of movement together with the surrounding liquid. Energy is supplied or extracted from the float body and surrounding liquid via conversion element or via a part that absorbs energy of movements in a fluid. The aggregate could further include the conversion element or the part that absorbs energy of movements. The energy is supplied or extracted from the float body and the surrounding liquid or from a combination of these.

1 - 13 . (canceled) 
     
     
         14 . Offshore energy storage device ( 10 ), storing energy as rotational kinetic energy, comprising conversion means ( 16 ), an elongate, upright central part ( 14 ), which is rotatable around its longitudinal axis, floating means arranged to keep it upright and floating, a fly wheel ( 28 ) arranged concentrically around the central part and anchorage means ( 15 ) below the fly wheel ( 28 ) for anchoring to the sea bed ( 18 ), characterized in that the upper end ( 29 ) of the central part ( 14 ) is freely movable. 
     
     
         15 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that a lower section of the central part ( 14 ) has a substantially larger vertical extension than its horizontal extension. 
     
     
         16 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that the fly wheel ( 28 ) is arranged around an upper section of the central part ( 14 ), for keeping the fly wheel ( 28 ) above the water level ( 12 ) when the device ( 10 ) is floating in water. 
     
     
         17 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that the storage device ( 10 ) comprises a generator coupled to the central, rotating part ( 14 ) as well as to the anchorage means ( 15 ). 
     
     
         18 . Offshore energy storage device ( 10 ) according to  claim 17 , characterized in that the generator is coupled to the central part ( 14 ) and the anchorage means ( 15 ) by a single axle. 
     
     
         19 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that the storage capacity of the storage device ( 10 ) is alterable by altering the rotational speed either by supplying or removing energy via conversion means ( 16 ); energy absorbing part ( 13 ) or by changing the mass and/or the position of the mass from the longitudinal axis. 
     
     
         20 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that the storage capacity of the storage device ( 10 ) is alterable by altering its mass and/or its distance from the longitudinal axis. 
     
     
         21 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that a first pump is provided for introducing a liquid into and expelling a liquid from the storage device ( 10 ). 
     
     
         22 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that a second pump is provided for moving water between the fly wheel ( 28 ) and the central part ( 14 ). 
     
     
         23 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that contact with the sea water, are provided on the lower section of the central part ( 14 ), for bringing the surrounding sea water to rotate with the storage device ( 10 ). 
     
     
         24 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that separating walls ( 21 ) are arranged around the central part at a distance therefrom, for separating a rotating liquid portion from the surrounding liquid. 
     
     
         25 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that it comprises a wind turbine, for providing a rotational force to the energy storage device ( 10 ). 
     
     
         26 . Offshore energy storage device ( 10 ) according to  claim 14 , characterized in that it comprises a water turbine, for providing a rotational force to the energy storage device ( 10 ). 
     
     
         27 . Offshore energy storage device ( 10 ) according to  claim 15 , characterized in that a lower section of the central part ( 14 ) has a substantially larger vertical extension than its horizontal extension.