CPC H02S 10/20 (2014.12) [F03B 13/06 (2013.01); H02K 7/1823 (2013.01); H02S 20/32 (2014.12); B65D 88/16 (2013.01)] | 19 Claims |
1. An energy or fluid storage system comprising:
a bag comprising a deformable boundary defining a bag interior that can be filled with said fluid and emptied of said fluid as desired, said bag being capable of occupying a less-filled configuration and a more-filled configuration; and
a mass of overburden overlying said bag, said overburden being able to be raised and lowered as a function of a degree of filling of said bag interior,
wherein said overburden has a variation in composition or particle size or particle size distribution from one location in said overburden to another location in said overburden,
wherein said variation comprises overburden in contact with said bag at an outer 20% of a width of said bag having a smaller average particle size than overburden in contact with said bag at a center-most region of said bag that is a center-most 20% of a width of said bag.
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