I don't think it's ever going to be viable at the suburban level. However, for off-grid use I can definitely see it making sense. Large scale batteries for ph

I don't think it's ever going to be viable at the suburban level. However, for off-grid use I can definitely see it making sense. Large scale batteries for photovoltaic use make off-grid solar quite expensive on kWh basis. This is considerably less efficient (although I think you could up the efficiency with a turbine generator) but costs scale on throughput, not on capacity.