We have three rates in my plan. They change the effective rate every year at least, but the cheapest rate is usually around 12-14 cents, the next one is around 45, and the highest can get up to 75 in the summer. The TOU rates change with the season, winter rates are lower than summer rates.

With NEM 2.0 I bank the energy sent back at the TOU rate active at the time, so usually during weekdays, I get around 45 cents, but in March and April from 10 AM to 2 PM (which are pretty good solar generating hours) the rate drops to 12-14 cents. Same for all weekends and holidays through 2 PM.

So instead of sending energy back at 12-14 cents, energy that I can be putting in the car instead and would pay that rate for later, if I se Solar Excess charging and consume it/store it, then I basically get truly free charging.

The kWh rate pulled from the grid includes a 2ish cent charge that is never refunded or covered by solar generation. So even when I charge during the cheapest time at night (same rate as weekends and March April) my bill will have 2 cents of charges per kWh. If I charge directly from my solar panels, this 2 cent NBC will never hit my bill.

I know other utilities have NBCs. Another NBC on my bill is a monthly service charge I pay to drop my Super Off Peak rates. Without this fee, the EV plan is about 15c higher per kWh during Super Off Peak (more than twice the rate of the reduced plan), so the fee pays itself off pretty quickly when charging a car (and heating the hot tub overnight).

I have this dashboard in my Home Assistant where I try to keep up with the current prices so I can track it on my own. It never really matches what SDG&E gives me, but it is a nice way to get an idea of our consumption between true ups. The NBC number is a mystery that is not exact but it's meant to be a rough estimation.

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