I don't think it would do anyone any good for grid-scale lithium batteries to fail. I don't believe Lithium batteries are a viable long term solution for grid-scale energy storage (cost and longevity issues) but they are probably the most mature technology currently available that is widely applicable (no geographic constraints like pumped hydro). So in the short term they are probably the lowest risk technology to demonstrate that grid-scale storage can bolster the reliability of the grid as the proportion of intermittent renewable energy rises, while waiting for newer technologies to mature and prove themselves.
(... and I don't believe Redflow is the answer to grid scale storage either - it's not designed for that.)
(20min delay)
