Comment by pfdietz
16 hours ago
It's useful for storing cheap solar energy for use in winter. Sizing the solar collectors for winter would require them to be much larger. Basically, this lets 2.5 W of solar in summer deliver 1 W of solar in winter. For a high latitude where the change in insolation is higher than that, this is superior. In Hamburg, for example, insolation varies by more than a factor of 10 from July to December.
Put another way: if you oversize the solar to be adequate in winter, you have enormous amounts of surplus solar in summer. So why not store it?
> So why not store it?
Because 0.10 $/kWh(th) / 0.4 kWh(e)/kWh(th) is expensive.
That's the capex for storage capacity. It's amortized over the number of charge/discharge cycles. Divide by 20 or more. It's amazingly cheap, actually.