Curiously, despite being "already well known" and "numerous" you neglect to actually mention any such storage system. Because then you'd actually have to defend

Curiously, despite being "already well known" and "numerous" you neglect to actually mention any such storage system. Because then you'd actually have to defend the claims of such miraculously cheap storage. We've been down this road plenty of times before: we have no known way of storing energy at the required scales, your plan essentially amounts to "hope compressed air, hydrogen, or some other exotic form of storage becomes nearly-free".