I actually don’t think the utility would cycle them fully every single day, but rather use them strategically based on amount of excess renewable generation early in the day and usage demand later in the day. Each full cycle of a battery has an approximate known cost and the utility operator would need to determine the value based on each day’s projected demand each hour and known generation sources throughout the day.
I don’t think this is the usage model. They charge up early in the day hopefully with excess renewable generation. However if projected demand later is higher than the excess they might charge with other available sources. Then they discharge using the battery as one of many sources to fulfill the peak demand in the late afternoon/evening. There isn’t another source that could be used. And no other source is needed after the peak.
See the duck curve for a visual of how this typically works
Yes I am because the current cost for batteries is (relatively) high and they only really make economical sense for a few use cases – some only time-shift electrical demand for a few seconds or minutes and others (that we are discussing) a few hours, but maybe even a day.
IMO, maybe when they are 5x - 50x cheaper it will make economical sense to shift from week to week or season to season. (Maybe/probably this involves new technologies, innovative thinking or just higher baseline prices for electricity)
See here for some good info on utility battery pricing near the middle to end of this article