Questions:
1. How is this different from a UPS? (Similar capacities can be obtained for less money.)
2. How many cycles can we expect to get out of these? (One assumes these are designed to be cycled more often than a UPS)
3. What are the risks when temperature is outside the operating range? (If non-negligable, the stated operating range of -20C to +43C limits use in some applications, such as field stations without heating (or AC, depending on locale).
4. Is this technology viable on the scale of an entire powergrid? If it's advantageous for individual users, one would think economy of scale would make this more efficient to implement grid-wide.
5. Do these present an additional hazard in the case of fires, floods, etc.?