Powerwall with solar = no grid charging

[zanary]

Where did you find that policy? I've been asking Tesla, and this is the closest I've gotten to an answer:

"When Powerwalls are installed with PV systems, the PV system is its charging source, and will not be set up to pull and store energy from the grid. We can also reach out to your designer for a more detailed explanation if you would like."

Tesla can only install a small solar system, but it takes two powerwalls to really provide backup power. It seems like most of the value would come from doing peak shaving, or demand shifting along with the solar. Thanks for the info!

I can't find the actual bill for the ITC (Investment Tax Credit), but here is a 3rd party who has summarized that if you take it because you have both PV and Battery, that the battery needs to be charged from renewal energy system (which in our case is PV only), and it also mention that the ITC vests over 5 years, so maybe that's the 5 year before the rule no longer applies as your ITC credit is officially over.

URL = https://www.nrel.gov/docs/fy18osti/70384.pdf

 

[Sailnavy]

I’d just like to know what Tesla’s plan is, if there is a plan.

 

[jjrandorin]

I’d just like to know what Tesla’s plan is, if there is a plan.

If you are asking if they have some sort of algorithm where they will be automatically enabling grid charging after 5 years, no one knows.... but I highly doubt it.

I bet they dont even have a plan around it other than "as long as there is a federal tax credit that requires batteries charged by solar, we will not enable this. Once that goes away, maybe we change it" Just a guess, though, no idea what they will actually do.

 

[RKCRLR]

I asked PG&E if I would be allowed to charge the Powerwalls from the grid if I had solar. This is what they said:
"The batteries store the renewable energy that you generate from your solar system. You are not able to store energy in the battery from PG&E's grid. The battery is to store energy that you produce from your solar system, not from the PG&E grid."
So, for PG&E customers, it is a PG&E requirement.

 

[Sailnavy]

Is it a condition of net metering then?

Seems like an odd amount of influence over what you can do with power you’re buying.

 

[RKCRLR]

I asked PG&E why I would be allowed to store power in my battery from the grid if I didn’t have solar but am not allowed to store power from the grid in my battery if I do have solar. The just repeated the same answer.

 

[Sailnavy]

Blazing a trail!

 

[zanary]

I’d just like to know what Tesla’s plan is, if there is a plan.

I asked PG&E why I would be allowed to store power in my battery from the grid if I didn’t have solar but am not allowed to store power from the grid in my battery if I do have solar. The just repeated the same answer.

Powerwall without solar doesn't give you NEM so you can't export to them.
Powerwall with solar give you NEM so you're allowed to export up to 100% of what you generate.

They don't want you exporting energy that you didn't generate...

 

[Sailnavy]

I don’t want to export anything to them... hence the powerwalls. ‍

 

[zanary]

I don’t want to export anything to them... hence the powerwalls. ‍

Hmm. You should contact them to see if they have a special interconnect agreement that does not allow you to export to them under any condition. If they do, and they allowed you to have that, then they need to provide you with a written letter stating that it is OK to charge the Powerwalls from the grid. Hopefully that would be sufficient for Tesla to turn on that capability. The question is if they will actually turn it on for you.

 

[wwhitney]

Yes, per a recent-ish PUC decision that has previously been quoted here, you've got two options with a battery and solar:

1) Never export--charging the battery is not restricted. (Non-Export Interconnection agreement)
2) Only charge the battery from solar--exporting is not otherwise restricted. (NEM Interconnection agreement)

Of course, there is often a time lag between a PUC decision and its actual implementation by PG&E et al.

Cheers, Wayne

 

[RKCRLR]

Do you have to be on an EV rate plan if your utility is PG&E and you have solar and Powerwalls?

 

[miimura]

Do you have to be on an EV rate plan if your utility is PG&E and you have solar and Powerwalls?

No. You can choose whatever "otherwise applicable rate" you like. Basically, anything shown by the Rate Comparison Tool in your account.

To go on the EV rate you have to either have a plug-in vehicle or a battery storage system.

I will add that the EV rate is by far the lowest cost of the available plans, given my solar, Powerwall, and usage pattern.

 

[jjrandorin]

Do you have to be on an EV rate plan if your utility is PG&E and you have solar and Powerwalls?

I doubt it. I am not in PGE territory (I have So Cal Edison) and I am NOT on any sort of TOU plan at all, EV or otherwise. I am on a regular old school tiered rate plan where "the more you use, the more they charge you". I have 3 tiers, 19c, 29c, 42c or something like that. Since I had solar in 2015, I was never in anything higher than tier 1 because I sized the solar to cover my needs pre EV at a bit over 100%

I never go out of tier 1 in my case anyway, and my plan has full net metering and currently, under NEM 1 so I havent changed it. Its still significantly cheaper for me to be on this old school tiered plan rather than ANY time of use plan, EV or otherwise.

 

[RKCRLR]

No. You can choose whatever "otherwise applicable rate" you like. Basically, anything shown by the Rate Comparison Tool in your account.

To go on the EV rate you have to either have a plug-in vehicle or a battery storage system.

I will add that the EV rate is by far the lowest cost of the available plans, given my solar, Powerwall, and usage pattern.

I'm currently on TOU-A but I'm getting a SGIP incentive and one of the conditions is I switch to an EV rate plan. My current rate plan is better for me since I have a heat pump and in the winter the peak rate isn't much higher than the off-peak (I actually use more power in the winter). And I rarely exceed my baseline allowance but there is no baseline allowance on the EV plan. The spread is higher in the summer but still lower with my baseline credit than an EV plan.
The PG&E calculator shows a significant bump when I go to the EV plan. It wouldn't be so bad if I could recharge from the grid in the winter.
Once my SGIP commitment is over in 5 years I'm hoping there will still be similar plans available.

 

[Sailnavy]

I did finally hear from Tesla sales rep that the restriction was tied to the ITC. They said they don't know how long the restriction on charging the Powerwalls from the grid (if we have solar / claimed solar tax credit) will be in place, or if it will be lifted.

 

[RKCRLR]

I doubt it. I am not in PGE territory (I have So Cal Edison) and I am NOT on any sort of TOU plan at all, EV or otherwise. I am on a regular old school tiered rate plan where "the more you use, the more they charge you". I have 3 tiers, 19c, 29c, 42c or something like that. Since I had solar in 2015, I was never in anything higher than tier 1 because I sized the solar to cover my needs pre EV at a bit over 100%

I never go out of tier 1 in my case anyway, and my plan has full net metering and currently, under NEM 1 so I havent changed it. Its still significantly cheaper for me to be on this old school tiered plan rather than ANY time of use plan, EV or otherwise.

I was grandfathered in NEM1 and a tiered rate until I upgraded my solar. They made me go into a TOU rate and NEM2 when I upgraded my solar. I miss it.

 

[miimura]

I'm currently on TOU-A but I'm getting a SGIP incentive and one of the conditions is I switch to an EV rate plan. My current rate plan is better for me since I have a heat pump and in the winter the peak rate isn't much higher than the off-peak (I actually use more power in the winter). And I rarely exceed my baseline allowance but there is no baseline allowance on the EV plan. The spread is higher in the summer but still lower with my baseline credit than an EV plan.
The PG&E calculator shows a significant bump when I go to the EV plan. It wouldn't be so bad if I could recharge from the grid in the winter.
Once my SGIP commitment is over in 5 years I'm hoping there will still be similar plans available.

Yes, SGIP madates the rate plan. You didn't mention that in your question. The thing is that the Powerwalls will drastically change your usage pattern if you use Time Based Control. Therefore, the Rate Comparison Tool is useless because it's using historical usage patterns to calculate how much each rate plan costs. No matter what, your bills will be higher in the Winter because of lower solar production, greater lighting needs, and in my case, more HVAC costs because I don't have A/C. Just running the air handler for the furnace is a significant electrical load even though all the actual heat is coming from gas.

 

[jjrandorin]

I was grandfathered in NEM1 and a tiered rate until I upgraded my solar. They made me go into a TOU rate and NEM2 when I upgraded my solar. I miss it.

Yeah if I had upgraded my solar SCE would have forced me off NEM 1. I remember the documents stating something like "10% change or less" or something like that. I figure that might allow for a replacement of a non functional panel with a higher wattage one for example but not adding on any solar.

I just added storage and it didnt trigger the "nem 2 / TOU" forced swap. I am considering trying to get another PW so I have 3, but the cut off line was 10k storage (or 2 powerwalls) before it triggered "something else". seemed like that might move me to another plan or force another interconnect.

 

[RKCRLR]

Yes, SGIP madates the rate plan. You didn't mention that in your question. The thing is that the Powerwalls will drastically change your usage pattern if you use Time Based Control. Therefore, the Rate Comparison Tool is useless because it's using historical usage patterns to calculate how much each rate plan costs. No matter what, your bills will be higher in the Winter because of lower solar production, greater lighting needs, and in my case, more HVAC costs because I don't have A/C. Just running the air handler for the furnace is a significant electrical load even though all the actual heat is coming from gas.

Yeah, I hope this all comes out in the wash.
I have a hybrid HVAC system with a heat pump and furnace. Previously, it was more economical for me to run the heat pump in the winter unless it was very cold out. My furnace uses propane which is about 3X the cost of natural gas. I may have to raise the temperature at which the system switches over to propane.