Those batteries only have a few hours of storage at max power, they're for solving the duck curve not a week-long supply shortage (let alone seasonal fluctuations). If we got the Midwest on heat pumps, how you planning to keep places heated when there's a week of blizzard? Right now we have no plan for addressing the occasional bad week besides overbuilding natural gas. That's worse than keeping our nuclear running and expanding, but the solar and wind is subsidized but not the natural gas. The way the market for power works, bidding on a daily or hourly basis, doesn't account for seasonal variation. The solar and wind builders are off the hook on blizzard week but get subsidized enough to run the reliable plants out of business the rest of the year.