Cause 1 — not enough production
Usage vs. what the panels cover
Covered by your panels
What you still buy
The straightforward one. The system was sized for the house you had years ago — before the EV, before the heat pump, before the last few rate increases. The fix is more panels.
Cause 2 — the hours don't line up
What a kWh costs, by time of day
Cheap hours
Peak hours, 4–9pm
This one blindsides people. Your panels make their power in the cheapest hours of the day. Your house wants power in the most expensive ones. Produce plenty and you can still owe money at the end of the year, because you gave away the cheap hour and bought back the expensive one. The fix is a battery — hold your own power until the hours that actually cost something.
Current SCE summer rates. The 4–9pm window runs close to double the middle of the day — the exact hours your panels have already quit for the evening.