Since that step is closed it may not matter to anyone not already in process. Interesting that Tesla wouldn't go there. Maybe independent installers are more willing to ask for exceptions.
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Will PGE okay charging batteries from grid with solar?
- Thread starter h2ofun
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Yep, that is a tesla limit, not a sgip limit. Yep, one must provide green button data to support the request.
There is no exception process. The process for any installer, including Tesla, is one needs to provide green button data for
over 2. Tesla seems to have elected to just do the simple stuff, like other things they are doing
Thanks for clarifying. So the deal is that you can get two Powerwalls, and if you want more than that, then you have to submit Green Button data and ask for more powerwalls. No exceptions.
Yep, anything over 2 must provide green button data to justify. Also I am not sure but 2 may not have to report and cycle either. In the past, getting 2 was pretty much a rubber stamp, which is why I see many installers only doing that process. A lot less work
RKCRLR
Active Member
It wasn't just Tesla. I got multiple bids (including non-Tesla products) and discussed this with the installers. In my case I would be unlikely to justify more than 2 batteries based on my history (and on my needs) so I didn't pursue it. But, the way it was explained to me, individual spikes in consumption don't make the case. The power demand needs to be for a sustained period. And that is a lot of power. I.e., 5 batteries would equate to a sustained consumption of 25Kw.
Green button data is based on an hour period. Yep, the hour period much be equal or greater than the request. Yep, I had green button data over 25kwh.
FWIW: I'm in process with a third party, where we are at the permitting stage, so it is not a done deal.
With that caveat, prior to ordering powerwalls, I looked at our outage history (long outages, not infrequently in winter) and demand (not that high as we rarely run AC), and put in a request for three powerwalls via PG&E equity reserve plan. PG&E pushed back on three. I was asked to provide green button data, and, or that included, sustained demand data, the latter being a demonstrated demand of more than 21kw for more than an hour. I did provide both. We were approved under SGIP for three.
The two powerwall limit would appear to be a Tesla (cookie cutter) requirement.
My logic for three was really just being able to eke out a five day outage on little to no solar in December/ January, on the thought that winter storms are often bracketed by overcast weather. Three powerwalls over five days is a little over three hundred watts per hour of load. Not trying to run a server farmer here or a zillion AC units, just pump water for us and the animals, run some low wattage medical devices, and keep some food cool.
For perspective, we have had four outages so far this month, one for over ten hours. December was worse. PG&E has real trouble with our local area in terms of keeping the grid up.
All the best,
BG
With that caveat, prior to ordering powerwalls, I looked at our outage history (long outages, not infrequently in winter) and demand (not that high as we rarely run AC), and put in a request for three powerwalls via PG&E equity reserve plan. PG&E pushed back on three. I was asked to provide green button data, and, or that included, sustained demand data, the latter being a demonstrated demand of more than 21kw for more than an hour. I did provide both. We were approved under SGIP for three.
The two powerwall limit would appear to be a Tesla (cookie cutter) requirement.
My logic for three was really just being able to eke out a five day outage on little to no solar in December/ January, on the thought that winter storms are often bracketed by overcast weather. Three powerwalls over five days is a little over three hundred watts per hour of load. Not trying to run a server farmer here or a zillion AC units, just pump water for us and the animals, run some low wattage medical devices, and keep some food cool.
For perspective, we have had four outages so far this month, one for over ten hours. December was worse. PG&E has real trouble with our local area in terms of keeping the grid up.
All the best,
BG
Too bad you did not put in for 4, since you green button data would have supported 4.
So is your county requiring one blade disconnect per battery? Equity reserve is 85% and no cycling requirements? And you can take the ITC?
- I think that we would not benefit from four, so no. In what I think are the foreseeable use cases for us, four wouldn't materially change virtually any outcomes. So far, outages longer than five days have been nonexistent, and what we would really benefit from during an extended outage with no solar is something like Enphase's generator injection for recharging the powerwalls in a post earthquake event with weeks of zero power during winter storms/overcast, or weeks of fire induced power outage with heavy smoke. Under more normal scenarios, outages from March to October would appear to be within our sustainable solar power recharging budget. (Not true for weeks of bad smoke, but again there I think that the solution is a generator, not an extra battery, as far as I can tell.)
- There are powerwall cycling requirements as far as I am aware, but I don't know for sure. (Online SGIP documents say so, but nothing that I have been given says so.)
- There is an opportunity for a small amount of ITC on this project, but I won't take it if it turns out to conflict with grid charging of powerwalls: hence the interest in this thread.
- I don't have an answer on blade disconnects at the moment. It is Santa Clara county, and that hasn't been one of their issues. So far. @Vines will know better than I do.
I do believe that powerwalls have the potential to make for a more resilient grid, exporting power during peak needs. I am happy to have that be their moonlighting job, but to me their day job is delivering power during catastrophic events. Without power, we don't have water. Everything else is icing on the cake in my book. I can wear mittens, or sit in the shade. And yes, we have backup backup generators, and have used them. No, I am not preparing for the end of the world. We just live near some major faults, in a wildfire zone, and with a power utility that has trouble keeping the lights on. No hurricanes or tsunamis or tornados here, so I don't sweat those.
This isn't my first rodeo in disaster planning, and I have spent a fair amount of time creating marginal cost / marginal benefit analyses of low probability, but high impact events. There is a cost to being prepared for a disaster, and a cost for not being prepared. To be happy, I think that you just need to be explicit on what you are trying to achieve and the price that you are willing to pay for it. Sometimes you are better off waiting for help. Sometimes not.
I have an acquaintance in the Sierra foothills forested area who has 5,000 gallons of propane in addition to her solar. She never wants to have any discomfort. Me? I would die from just thinking about the fire risk. (The tanks are well within blast distances of her house.)
Different strokes for different folks...YMMV...
All the best,
BG
Wow, 5000 gallons, would not want to see that light up. I have 500 gallons of propane connected to my generator. Being at 1500 feet, not concerned of a week long outage.
Nope. but I got my HOA permission, and county permit. Your point is taken but it just seems no one has a clear answer. I just wrote my installer with a number of the comments since they have contacts with Tesla and SGIP. Some say you cannot, and I say why not. Some say impossible and I say nothing is impossible. If I do nothing, the impossible folks win. If I try and get no where, the impossible folks win. But if I were to be successful, ..
I just am looking for someone to give me a logical or legal answer. I got batteries to help take load off the grid especially in peak hours. That is all I am trying to help with. Will I be successful? Probably not, but costs me nothing to try.
I have tons of examples in my life where someone told me something could not be done. I could give you a list of things I got done that they told me were impossible, but I succeeded just by asking and pushing.
NEM Paired Storage rules in the NEM and NEM2 tariffs specify that small systems without NGOM can only receive NEM credits for exports up to their estimated generation. Any excess exports will be disallowed and deducted from Peak credits first, then Part-Peak, then Off-Peak as necessary. This is enforced in the NEM-PS billing system for each billing cycle. Presumably, larger systems with NGOM have the same restrictions, but they will just use the interval data from the NGOM and main meter directly to disallow NEM excess credits.
If PG&E thinks your solar system is smaller than it actually is, then you could get penalized by this rule. Just ask @arnolddeleon he has been trying to straighten this out since PG&E "forgot" about his original solar system when he added more solar and Powerwalls.
Yes, my point is you can do anything you want behind the meter. I am not saying that asking PG&E for permission is impossible.
I just want other readers to understand that it is not necessary to ask PG&E for permission. If other readers want to do that it is a free country. Most people will realize that they will get the same answer that @RKCRLR did, and asking PG&E will be a waste of time. Tesla is the one controlling the software. Why not go direct to Tesla? Why not collaborate with other Powerwall users who are not taking the ITC? Would that be a more effective way to resolve what you see as an ambiguity?
Interesting, for me first, I have zero desire to sell back battery power. Totally agree this would be gaming the system and have zero interest in this.
The max export limit back is interesting. One person posted they were hit with that. So, how does one find this limit? I know I have export back what I think is a lot and gotten 100% credit. Mine we applied, my system is actually a lot smaller than my 12 month data use stated.
The NEM-PS billing has a table like this that shows their estimate of your generation and how much you actually exported.
I just looked at my PGE bill. See nothing like this. Now, since I have no batteries, I believe I have no paired storage, and am on TOU-c rate. Am I looking at the wrong place?
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