Powerwall 2 and SCE TOU

[insaneoctane]

I am looking for guidance on the allowable use case and SGIP (and fed credit?) in my situation.

I am with SCE net metering on TOU-D-A. This TOU plan allows me to heavily leverage my PV output and results in me having a ~$500 credit at the end of my true up period even though I am truly a net consumer from the grid.

My use case is about to change. While I currently have 1 EV, it is used lightly. I am about to add a second EV to the mix and it will be used heavily. This new consumption model will not only consume ALL of the ~$500 credit, but I estimate that it will require another 3,000 kWh / year more. Now, at today's night time TOU rate for me that is $300 to $400.

This is where I am wondering if the powerwall 2 helps me? If I fill it at night from the grid, any of my consumption at peak TOU would be nicely offset by the powerwall. I don't think that I would want to fill the powerwall from peak TOU PV energy, because I generally push that to the grid for lucrative leverage per my statements above.
I'm trying to see if the powerwall is a fit for my use case. I'm currently not looking to increase my PV generation, but rather increase my leverage to cover my new needs. Adding new PV panels would be very hard to justify an ROI for because it would entirely be offsetting $0.13 / kWh power! I do like the proposition of using less grid, but only after I have "payed the bills", meaning I would need relatively short ROI.

I don't want to wake up in a few months or years and ask why I didn't take advantage of SGIP if it applies.

Thanks for listening!

[sensij]

If the storage is paired with onsite generation (required for the ITC), you'll need at least 75% of the charging energy to come from the PV system to be eligible for the SGIP credit. Check on the SGIP handbook for more calculations.

Furthermore, as I understand it, the 30% ITC credit is proportional to the amount of RE used... If only 75% of the charging comes from RE, then ITC drops to 22.5% (75% of 30%).

Below 75%, ITC drops to zero, and it is no longer considered a "paired" system.

[max2k]

...My use case is about to change. While I currently have 1 EV, it is used lightly. I am about to add a second EV to the mix and it will be used heavily. This new consumption model will not only consume ALL of the ~$500 credit, but I estimate that it will require another 3kWh / year more. Now, at today's night time TOU rate for me that is $300 to $400.

extra $300-$400 / year? That's not too bad for extra car. Wouldn't Powerwall run you down much deeper? Please keep in mind it has limited lifespan so in some 7-8 years it would lose its capacity not to mention if something goes wrong with it all these calculations might go out of window- depending on exact details of the warranty.

[bcroe]

I am about to add a second EV to the mix and it will be used heavily. This new consumption model will not only consume ALL of the ~$500 credit, but I estimate that it will require another 3kWh / year more. Now, at today's night time TOU rate for me that is $300 to $400.

3KWH per year? That is like half a dollars worth many places. Bruce Roe

[FFE]

We are in a similar situation. The first year with solar and one EV on SCE TOU-D-A I had a net zero year. We added another EV we will drive about 16,000 miles this year and we are getting close to the end of our second year. I will gladly pay $300 to $400 per year to SCE considering gas for the vehicle we replaced was about $800 per year. I wouldn't spend $7,000 after the tax credit to avoid paying a relatively small sum for electricity every year.

Edit: I added "per year" a couple places. Also, The reason for the low gasoline cost is because the vehicle replaced was a PHEV.

[max2k]

3KWH per year? That is like half a dollars worth many places. Bruce Roe

I think it was typo and he meant to say 3,000 kWh but still wouldn't make me move my lazy ...

[insaneoctane]

Yes, sorry I meant 3,000 kWh