A Utility Bill Alone Cannot Fully Size a Battery

Battery capacity depends on seasonal daytime production, nighttime usage, EV charging timing, and future load changes, which is why Green Button data can be far more valuable than a standard bill.

In California, anyone who recommends battery capacity from the utility bill alone is either missing critical information or ignoring the customer's real interest. A bill does not directly reveal how much electricity the home uses at night, and it does not show how seasonal daytime solar production will line up against that evening demand.

That is why Green Future asks follow-up questions about how the household actually uses energy, including whether EV charging can happen during the day after solar is installed and whether major new loads may appear over the next few years. Those behavior details directly affect how much daytime production can be self-used and how much evening storage is worth carrying.

The best input is Green Button data, which many utility portals let customers download. It can show fifteen-minute interval usage across the prior year, making it possible to size both solar and battery much more accurately around seasonal daytime production and time-of-day behavior.