Grid storage that stabilizes a grid [...] Your comment made me think - what if a state-power or hacker group were able to make a large number of these energy s

Grid storage that stabilizes a grid [...] Your comment made me think - what if a state-power or hacker group were able to make a large number of these energy storage units dump their energy back on the grid en mass? Would there be ways to protect the grid from being overloaded by a centralized energy store dumping its energy?