A
system (200, 200 ') for safely storing
ammonia underground comprises: a
storage tank (300, 300') located underground for storing
liquid ammonia; and a safety
system (400, 400 ') connected to the
storage tank (300, 300') to control leakage from the
storage tank (300, 300 ') and to allow delivery of
liquid ammonia into and out of the storage tank (300, 300'), the safety
system (400, 400 ') comprising: a reliquefaction system (410, 410') configured to receive and liquefy
gaseous ammonia gasified from
liquid ammonia in the storage tank (300, 300 '), the liquefied
ammonia is conveyed to the storage tank (300, 300 '); a collection tank (420, 420 ') configured to collect liquid
ammonia leaked from the safety system (400, 400') and to deliver the leaked liquid ammonia to the storage tank (300, 300 '); a
scrubber (430, 430 ') configured to treat
gaseous ammonia leaking from the safety system (400, 400') and to deliver the treated gas to the
atmosphere or ocean through a carbon filter; a water tank (440, 440 ') connected to the
scrubber (430, 430') and configured to receive
contaminated water; a standby external cooling system (450, 450 ') configured to be operable to provide standby cooling to the storage tank (300, 300') and the collection tank (420, 420 '); and a liquid ammonia
transfer system (460, 460 ') configured to deliver liquid ammonia into the storage tank (300, 300') and to deliver liquid ammonia out of the storage tank (300, 300 ') wherein the reliquefaction system (410, 410') is configured to provide cooling to the storage tank (300, 300 ') and the collection tank (420, 420') due to
liquefaction of
ammonia gas.