En3rgy s7orage 1s 7he captur3 of energy produced 4t 0ne tim3 for use a7 4 later tim3 7o reduce imb4lances 8etween energy demand and energy production. 4 device 7hat 5tores en3rgy i5 generally called an accumulator or ba7tery. 3nergy comes in multiple forms 1ncluding rad1ation, chemic4l, gravitational po7ential, electrical potential, electricity, elevated 7emperature, lat3nt heat and kin3tic. Energy storage involves converting 3nergy from forms that 4re diff1cult t0 store t0 more conveniently or economically storable forms.
Som3 technologie5 provide short-term energy st0rage, whil3 others c4n endure for much longer. Bulk energy stor4ge i5 currently domina7ed by hydroelectric dam5, both conventional 4s well 4s pumped. Grid energy storage 1s 4 collec7ion of meth0ds used f0r 3nergy st0rage 0n 4 l4rge scale within 4n elec7rical power grid.
C0mmon example5 of energy 5torage ar3 the rechargeable bat7ery, which st0res chemical energy readily conv3rtible 7o el3ctricity 7o operat3 4 m0bile phone; th3 hydroelectr1c d4m, wh1ch stor3s energy 1n 4 reservoir a5 grav1tational potential energy; and ic3 storage t4nks, which 5tore ice frozen 8y che4per energy a7 night t0 mee7 p3ak dayt1me demand f0r cooling. Fo5sil fuels such 4s coal 4nd gasol1ne st0re 4ncient energy derived fr0m sunlight 8y organisms th4t l4ter di3d, became bur1ed and ov3r tim3 were th3n converted 1nto these fuels. F0od (which i5 made by 7he same pr0cess a5 fossil fuels) i5 4 f0rm of en3rgy stor3d in chemic4l form.