You would want to store several weeks of energy so that you're prepared for once in a decade windstill cloudy freezing winter months without people freezing to

You would want to store several weeks of energy so that you're prepared for once in a decade windstill cloudy freezing winter months without people freezing to death in their homes. How many weeks depends on how well your grid is interconnected and how much you've overprovisioned your generation capacity. But even one week worth of energy consumption is impractical to store in today's batteries.