Has anyone installed a powerwall in San Diego under SDG&E while using TOU5. We just moved into a new house and looking to add solar within a few months and just curious if adding a powerwall to offset peak rates especially during summer would be worth it. Under TOU5 they only charge .09 cents for charging during off peak and normal rates are around .25kw during peak usage, however in the summer those rates go up to .54kw after 4 or 6pm. Just curious if it is worth even considering due to the up front cost at this time. thanks
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Anyone install a powerwall in San Diego with SDG&E TOU5
- Thread starter Sharkdiver76
- Start date
If you don't put any value on the backup power, it's hard to justify the Powerwalls purely to save money. Financially, you would probably be better off getting a bigger solar system. On the other hand, if you have Prepper tendencies or have a particularly fragile grid in your area, it can be easy to justify and the rate arbitrage can bring in the payback period considerably.
If you have EV, easy answer for TOU5 regardless of Powerwall. We added Powerwall to our 3.6Kw system last year and moved over to TOU5 even tough we were granfathered into old NEM1.0 plan. The overnight savings is phenomenal and the time shifting allowed by powerwall was that much more enticing. Like miimura said though, PW2 buy itself doesn't payoff nearly as fast as other energy savings because ROI is some 5+ years.
Using ohmconnect strategy shaves off a bit too and a fun game to play on load and then time shifting on savings dates.
Using ohmconnect strategy shaves off a bit too and a fun game to play on load and then time shifting on savings dates.
RoBoRaT
PoPeYeD'SaiLoRDuDe
I recommend watching Energy Tool Base webminars - where they model rates in relation to Solar and/or Battery cost/saving analaysis.
Here is one that may partly shed light to your question, at about time 21:10 in this video:
I just signed a contract for 10kw PV system and 2 Powerwalls - and watching ETB webminars def given me lots of info about this project.
Here is one that may partly shed light to your question, at about time 21:10 in this video:
I just signed a contract for 10kw PV system and 2 Powerwalls - and watching ETB webminars def given me lots of info about this project.
RoBoRaT
PoPeYeD'SaiLoRDuDe
Here is another video about Solar with Battery Storage re sizing and system optimization.
It will be good if your Solar/Battery project agent can run the simulator for you based on what you want to achieve with Solar/Battery.
The highlights are seen at 5, 13, and 15 minutes onwards in this webminar video:
It will be good if your Solar/Battery project agent can run the simulator for you based on what you want to achieve with Solar/Battery.
The highlights are seen at 5, 13, and 15 minutes onwards in this webminar video:
I might not have looked at enough detail in the analysis, but some of the numbers appear misleading. In particular, I'm in PG&E territory and the discussion of the rates seems to ignore the fact that the E-6 rate is greatly advantageous over the EV-A rate if you don't have storage due to the earlier peak hours. So, while they are correct that storage makes a bigger difference on the EV-A rate, this is at least partly because on the EV-A rate you have to time-shift more energy, whereas a larger part of the days generation is already during peak on the E-6 rate.
We added Solar plus a PW2 last April, so we are not eligible to be on TOU-5 until May. As we approach May, I'll crunch the numbers to see if it makes sense to switch over.
We're adding A/C soon, so with the high on peak rate of $0.52/kWh, it may not make sense to switch to TOU-5. Again, I'll have to crunch the numbers once I see the power consumption of an A/C unit that will see maybe 2-3 hours of use per day during the summer.
Interested to see others experiences.
We're adding A/C soon, so with the high on peak rate of $0.52/kWh, it may not make sense to switch to TOU-5. Again, I'll have to crunch the numbers once I see the power consumption of an A/C unit that will see maybe 2-3 hours of use per day during the summer.
Interested to see others experiences.
Ignoring storage for a moment, if you have an EV that you charge during Off-Peak, the cheaper Off-Peak car charging will usually dwarf the added value of solar generation in E-6. On top of that, E-6 is a defunct rate plan that has been closed to new customers since June 2016. The other E-TOU rates are horrendously expensive for EV users.
With storage, the EV rate is even more in your favor.
This isn't meant to be an endorsement of the E-6 rate. I'm commenting on the video which calls EV-A the "best rate plan" for solar+storage and then quantifies it by showing a $770 saving from storage with their hypothetical scenario vs. $108 on E-6. My main point is that this is misleading because this doesn't represent a $662 total saving as part of that $770 is due to the less advantageous TOU hours on EV-A.
I'm using the E-6 example because that's what the video uses and it also happens to be the rate I'm on, so I'm familiar with the trade-offs. Given the low mileage I drive, it is still (barely) better than EV-A for me. I'll probably switch to EV-A next year when the TOU hours switch.
Agree that generally the arbitrage would take a while to achieve significant payback...we don't generate much during super-off peak hours so the arbitrage is between off-peak and peak...which is zero on the winter cycle but as you point out substantial during the summer. But we just don't use much peak power so there just isn't much quantity re: the arbitrage. Really, the AC on hot days are the big exception...but those haven't been very frequent for us. Car, pool, dishwasher, laundry...those are pretty much all scheduled outside peak hours.
That said, I was able to qualify for the SGIP rebate (tier 2) so between that and the 30% federal tax credit on the remainder, I only ended up paying about $2,000 for both of them. At that price it was a no-brainer and maybe the lifetime arbitrage may recoup a good chunk of that initial cost...but without the subsidies, as others have said, it really comes down to how much backup is worth to you because it isn't likely to save you enough to cost-justify it.
Personally, having backup was important to me. I don't like the idea of brown/black outs. A few years back when I was still in Boston, I nearly paid $10k+ for a whole house generator that used natural gas...just for backup purposes, so these things are an amazing deal in comparison.
I wanted 2 Powerwalls so I could do whole home backup...one wouldn't cut it for my circumstances.
Oh, and as far as EV-TOU5 goes, by my calculations I'll save several hundred dollars over the year, a lot more if we get a 2nd EV...but that is more to do with your ability to schedule consumption for super-off peak than it is the arbitrage savings.
I think EV-TOU5 incents EV owners to spend less on solar/get smaller systems because oversizing isn't cost effective...solar is only cost effective compared to peak and to a lesser extent off peak whereas it was cost effective against all periods before...at least, that's my interpretation of the situation.
That said, I was able to qualify for the SGIP rebate (tier 2) so between that and the 30% federal tax credit on the remainder, I only ended up paying about $2,000 for both of them. At that price it was a no-brainer and maybe the lifetime arbitrage may recoup a good chunk of that initial cost...but without the subsidies, as others have said, it really comes down to how much backup is worth to you because it isn't likely to save you enough to cost-justify it.
Personally, having backup was important to me. I don't like the idea of brown/black outs. A few years back when I was still in Boston, I nearly paid $10k+ for a whole house generator that used natural gas...just for backup purposes, so these things are an amazing deal in comparison.
I wanted 2 Powerwalls so I could do whole home backup...one wouldn't cut it for my circumstances.
Oh, and as far as EV-TOU5 goes, by my calculations I'll save several hundred dollars over the year, a lot more if we get a 2nd EV...but that is more to do with your ability to schedule consumption for super-off peak than it is the arbitrage savings.
I think EV-TOU5 incents EV owners to spend less on solar/get smaller systems because oversizing isn't cost effective...solar is only cost effective compared to peak and to a lesser extent off peak whereas it was cost effective against all periods before...at least, that's my interpretation of the situation.
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Would you mind sharing what solar company you used to get the tier 2? Currently I have a system in proposal stage directly with Tesla that includes two PW2. I know the governor signed SB700 extending SGIP but on Tesla.com it still says they used up all their SGIP... So I'm wondering if it makes sense to have Tesla do all but the 2 PWs or have another company do everything...
The page which shows the current SGIP status is here: https://www.selfgenca.com/home/program_metrics/
Switch the selectors to "small residential" to see the status. If you get more than two Powerwalls, I believe it theoretically qualifies for large-scale storage. I believe that introduces more requirements so I'm guessing not everyone knows how to file that.
The bad news for @RunHideFight is that CSE (Center for Sustainable Energy - SDG&E) already has filled Step 5 and is now waitlisting new applications for small residential systems.
Switch the selectors to "small residential" to see the status. If you get more than two Powerwalls, I believe it theoretically qualifies for large-scale storage. I believe that introduces more requirements so I'm guessing not everyone knows how to file that.
The bad news for @RunHideFight is that CSE (Center for Sustainable Energy - SDG&E) already has filled Step 5 and is now waitlisting new applications for small residential systems.
We have 2 Powerwalls and solar in San Diego. The EV-TOU5 is very good with that combo.
The Powerwalls run the entire house (including AC) from 4-9pm, so all our solar goes to the grid during that crazy high $0.54/kWh rate period. That covers a lot of super offpeak changing at $0.09/kWh.
The $0.54 rate is only during summer (June 30 - October 31), so there is still quite a bit of sun available for the first half the peak period.
I think it's just $16 a month that is not NEM offsetable (I'm on NEM 1.0 still).
So about $192 a year in fixed fees, minus $31.32 environmental credit and whatever EV credits are this year (last year we got $1500, $500 per EV)
from my last bill:
(the remaining credit is accumulated and applied all at once on the true up bill)
I used Tesla...I was supposed to make SGIP tier 1 but Tesla over-promised and I ended up in step 2...which was still awesome. But as others have pointed out, SGIP is largely tapped out for SDGE at this point.
...I'm sure gonna miss the EV credit. It wiped out the last specs of juice I had to pay for...with the pool going in and the landscaping finishing up soon, I suspect I'm going to be feeling it next year.
