Method and apparatus for storing energy

Abstract

An energy storing system, which includes a plurality of weights; a first storing unit and a second storing unit, wherein the first storing unit is arranged below the second storing unit and each of the storing units includes a guiding track on which weights can be placed and along which weights can be moved, wherein each of these guiding tracks includes a first portion and a second portion, wherein the second portion is arranged below the first portion; and a loading unit configured to lift at least one weight from the first storing unit to the second storing unit during a first period thereby converting electrical energy to potential energy.

The invention claimed is: 
     
       1. An energy storing system, comprising
 a plurality of weights ( 12 ); 
 a first storing unit ( 14 ) and a second storing unit ( 16 ), wherein the first storing unit ( 14 ) is arranged below the second storing unit ( 16 ) and each of the storing units ( 14 ,  16 ) comprises a guiding track ( 18 ,  20 ) on which the plurality of weights ( 12 ) can be placed for storage and along which weights ( 12 ) can be moved, wherein each of said guiding tracks ( 18 ,  20 ) comprises a first portion ( 22 ,  26 ) and a second portion ( 24 ,  28 ), wherein the second portion ( 24 ,  28 ) is arranged below the first portion ( 22 ,  26 ); and 
 a loading unit ( 30 ) configured to use an electric motor to lift at least one weight ( 12 ) from the first storing unit ( 14 ) to the second storing unit ( 16 ) during a first period, thereby converting electrical energy to potential energy, said loading unit ( 30 ) further configured to lower at least one weight ( 12 ) from the second storing unit ( 16 ) to the first storing unit ( 14 ) during a second period while the at least one weight (12) is coupled to a generator to generate electricity in response to the at least one weight being lowered, thereby converting potential energy to electrical energy, wherein the loading unit ( 30 ) is configured to collect a weight ( 12 ) from the second portion ( 24 ) of the first storing unit ( 14 ) and to place said weight on the first portion ( 26 ) of the second storing unit ( 16 ) during the first period and to collect a weight ( 12 ) from the second portion ( 28 ) of the second storing unit ( 16 ) and to place said weight ( 12 ) on the first portion ( 22 ) of the first storing unit ( 14 ) during the second period; 
 wherein for each of the first and second storing units, each of the weights placed on the first portion is collected from the second portion. 
 
     
     
       2. The energy storing system according to  claim 1 , wherein each weight ( 12 ) comprises means such as wheels ( 13 ) configured to allow said weight to move freely along the guiding track ( 18 ,  20 ), on which said weight is placed, from the first portion ( 22 ,  26 ) to the second portion ( 24 ,  28 ) of said guiding track ( 18 ,  20 ). 
     
     
       3. The energy storing system according to  claim 1 , wherein the loading unit ( 30 ) comprises a loading stage ( 32 ) having a stage guiding track ( 54 ) configured to co-operate with the respective guiding track ( 18 ,  20 ) of any of the storing units ( 14 ,  16 ) to facilitate transfer of a weight between the loading stage ( 30 ) and the respective guiding track ( 18 ,  20 ). 
     
     
       4. The energy storing system according to  claim 1 , comprising a multitude of storing units arranged at different heights. 
     
     
       5. The energy storing system according to  claim 1 , wherein the duration of the second period is different from the duration of the first period. 
     
     
       6. A method comprising the following steps
 providing a plurality of weights;   providing a first and a second storing unit, wherein the first storing unit is arranged below the second storing unit;   lifting at least one weight from the lower storing unit to the upper storing unit during a first period thereby converting electrical energy to potential energy; and   lowering at least one weight from the upper storing unit to the lower storing unit during a second period, wherein the duration of the second period is different from the duration of the first period, thereby converting potential energy to electrical energy.   
     
     
       7. The method according to  claim 6 , wherein the second period is shorter than the first period. 
     
     
       8. The method according to  claim 6 , wherein the second period is longer than the first period. 
     
     
       9. The method according to  claim 6 , wherein the first period is an off-peak electricity period and the second period is a peak electricity period. 
     
     
       10. An energy storing system, comprising:
 a loading unit;   a first storing unit at a first elevation;   a second storing unit at a second elevation that is higher than the first elevation, wherein the first and second storing units are each configured to store a plurality of masses offloaded thereto by the loading unit;   wherein the loading unit is configured to (i) collect a mass from the first storing unit, (ii) use a motor to lift the collected mass from the first storing unit to the second storing unit during a first lifting time period, thereby converting electrical energy to potential energy, and (iii) offload the lifted mass to the second storing unit, the loading unit further configured to (i) collect a mass from the second storing unit, (ii) lower the collected mass from the second storing unit to the first storing unit during a first lowering time period while the collected mass is coupled to a generator to generate electricity in response to the collected mass being lowered, thereby converting potential energy to electrical energy, and (iii) offload the lowered mass to the first storing unit, wherein the average released power level provided by lowering of a mass of a particular weight from the second storing unit to the first storing unit during the first lowering time period is controlled by varying the duration of the second period relative to the duration of the first period such that the average released power level is capable of being greater than and capable of being lower than the average power level used for lifting of a mass of said particular weight from the first storing unit to the second storing unit during the first lifting time period;   wherein each of the storing units comprises a track along which a plurality of the masses offloaded to the storing unit can be stored, wherein the track of each of the storing units extends between a first portion and a second portion of the respective storing unit, the first portion being at an elevation higher than the second portion; and   wherein the loading unit is configured (i) to collect the mass from the second portion of the first storing unit and to offload the mass onto the first portion of the second storing unit, and (ii) to collect the mass from the second portion of the second storing unit and to offload the mass onto the first portion of the first storing unit, wherein for each of the first and second storing units each of the masses offloaded onto the first portion freely moves by action of gravity along the respective track to the second portion.   
     
     
       11. The energy storage system according to claim 10, wherein the duration of the first lowering time period is capable of being varied relative to the duration of the first lifting time period. 
     
     
       12. The energy storing system according to claim 10, wherein each mass comprises wheels configured to facilitate the mass moving freely by action of gravity along the track onto which the mass is offloaded. 
     
     
       13. The energy storing system according to claim 10, wherein the loading unit comprises a loading stage having a stage guiding track configured to cooperate with the respective track of the storing units to facilitate transfer of a mass between the loading stage and the respective track when offloading and collecting the mass. 
     
     
       14. The energy storing system according to claim 10, wherein the second storing unit comprises a plurality of tracks. 
     
     
       15. A method for converting energy in an energy storage system that comprises a plurality of masses, a lower storing unit at a first elevation and an upper storing unit at a second elevation, wherein the first elevation is lower than the second elevation, the method comprising:
 (a) during an off-peak electricity time period, transferring a plurality of the masses from the lower storing unit to the upper storing unit, each of the masses being transferred by:
 collecting the mass from the lower storing unit, the mass having a corresponding given weight; 
 using an electric motor to move the mass from the first elevation to the second elevation during a corresponding first time period, thereby converting electrical energy to potential energy; and 
 offloading the mass to the upper storing unit; 
   (b) during another time period, following the off-peak electricity period, transferring a plurality of the masses from the upper storing unit to the lower storing unit, each of the masses being transferred by:
 collecting the mass from the upper storing unit, the mass having a corresponding given weight; 
 moving the mass from the second elevation to the first elevation during a corresponding second time period while the mass is coupled to a generator to generate electricity in response to the collected mass being lowered, thereby converting potential energy to electrical energy; and 
 offloading the mass to the lower storing unit; 
   wherein the average released power level provided by lowering of a given one of the masses of a particular weight from the upper storing unit to the lower storing unit during the second time period is controlled by varying the duration of lowering the particular weight during the second period relative to the duration of lifting said particular weight during the first period such that the average released power level is capable of being greater than and capable of being lower than the average power level used for lifting of a given one of the masses of the same particular weight from the lower storing unit to the upper storing unit during the first time period;   wherein each of the storing units comprises a track along which a plurality of the masses offloaded to the storing unit can be stored, wherein the track of each of the storing units extends between a first portion and a second portion of the respective storing unit, the first portion being at an elevation higher than the second portion; and   wherein (i) during the off-peak electricity time period, said collecting comprises collecting the mass from the second portion of the lower storing unit, and said offloading comprises offloading the mass onto the first portion of the upper storing unit, and (ii) during said another time period, said collecting comprises collecting the mass from the second portion of the upper storing unit, and said offloading comprises offloading the mass onto the first portion of the lower storing unit, wherein for each of the upper and lower storing units each of the masses offloaded onto the first portion freely moves by action of gravity along the respective track to the second portion.   
     
     
       16. The method according to claim 15, wherein said another time period is a peak electricity period. 
     
     
       17. The method according to claim 15, wherein the second time period corresponding to a given one of the masses having a particular weight is capable of being varied relative to the first time period corresponding to a given one of the masses having the same particular weight. 
     
     
       18. The method according to claim 15, wherein the second time period corresponding to a given one of the masses having a particular weight is less than the first time period corresponding to a given one of the masses having the same particular weight. 
     
     
       19. The method according to claim 15, wherein the upper storing unit comprises a plurality of tracks. 
     
     
       20. A method for converting energy in an energy storage system that comprises a plurality of masses, a lower storing unit at a first elevation and an upper storing unit at a second elevation, wherein the first elevation is lower than the second elevation, and wherein the lower and upper storing units each comprise a guiding mechanism between a first portion and a second portion of the respective storing unit, the first portion being at an elevation higher than the second portion, the method comprising:
 (a) during an off-peak electricity time period, transferring a plurality of the masses from the lower storing unit to the upper storing unit, each of the masses being transferred by:
 collecting the mass from the second portion of the lower storing unit; 
 using an electric motor to move the mass from the first elevation to the second elevation, thereby converting electrical energy to potential energy; and 
 offloading the mass to the first portion of the upper storing unit for storage on the guiding mechanism of the upper storing unit; 
   (b) during another time period, following the off-peak electricity period, transferring a plurality of the masses from the upper storing unit to the lower storing unit, each of the masses being transferred by:
 collecting the mass from the second portion of the upper storing unit; 
 moving the mass from the second elevation to the first elevation while the mass is coupled to a generator to generate electricity in response to the collected mass being lowered, thereby converting potential energy to electrical energy; and 
 offloading the mass to the first portion of the lower storing unit; and 
   wherein for each of the upper and lower storing units, each of the masses offloaded onto the first portion moves along the guiding mechanism to the second portion such that each of the masses offloaded to the first portion is collected from the second portion.   
     
     
       21. The method according to claim 20, wherein each of the masses offloaded onto the first portion freely moves by action of gravity along the guiding mechanism to the second portion. 
     
     
       22. The method according to claim 20, wherein each of the storing units comprises a track along which a plurality of the masses offloaded to the storing unit can be stored. 
     
     
       23. The method according to claim 20, wherein the upper storing unit comprises a plurality of tracks. 
     
     
       24. The method according to claim 20, wherein the duration of a first time period for moving a given one of the masses having a particular weight from the first elevation to the second elevation is capable of being different from the duration of a second time period for moving a given one of the masses having the same said particular weight from the second elevation to the first elevation. 
     
     
       25. The method according to claim 24, wherein the second time period is capable of being varied relative to the first time period. 
     
     
       26. The method according to claim 24, wherein the second time period is less than the first time period.