Help the old guy decide about his new grid-tied system.

I have PG&E NEM2 approval for a 24 panel 9.6KW ground mount system with Solark 12K inverter but no battery storage. I contacted PG&E and said I wanted to change to an EG4 18KPV inverter and add two 14.3KWH batteries. I was told the inverter change was no problem because they were the same 12KW capacity but that I couldn't add a battery in NEM2 because mine is a "large" system, meaning it has an over 10KW inverter. Truth is I want/need an even bigger system.
My Goal: Reduce energy purchases, replace old R22/propane HVAC, install heat pumps, and eliminate power outages.
I have: Lots of space, 36ea 400W bifacial panels, and a H.D. 10KW low-speed water-cooled stationary generator w/dedicated 299-gallon propane tank.
Questions:
Do I try to stay in NEM2 and not use a battery?
Just go off grid and do whatever I want?
Do I go the NEM3 and install whatever I want, like two or three 14.3KWH batteries, maybe more panels, and just minimize grid use?
Do NEM3 and configure the system to meet my needs plus transfer maximum power to the grid during summer evening peak time of use periods?
When the grid pays enough (Aug. & Sept.) do I run the generator a few evening hours to sell an additional 10KW per hour to the grid?
WHAT I DO KNOW: I want to order at least one heat pump, and one inverter this week but really want to add two 14.3KWH batteries too.
Your opinions please!

In very very few worlds is switching to NEM3 a good deal.

Under NEM2 there is a very, very long break even point to paying off a ESS. I calculated mine at 10 years using forced export to push out energy between 4-9PM. Not great.

The PG&E rules for ESS are very complicated. It's quite possible whoever picked up the phone didn't know what was going on. Especially with the EG4 18kpv, EG4 is at present sorting out paperwork issues with PG&E.

SolArk has their paperwork sorted out better, so potentially you can call back PG&E and ask them if you can add batteries to the SolArk under nicer terms than with the 18kpv.

Gold Country Russ said:

WHAT I DO KNOW: I want to order at least one heat pump, and one inverter this week but really want to add two 14.3KWH batteries too.

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NGL, I'm not a huge fan of impulse buying equipment like this. Unless I get a lot of enjoyment out of installing equipment.

Gold Country Russ said:

When the grid pays enough (Aug. & Sept.) do I run the generator a few evening hours to sell an additional 10KW per hour to the grid?

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This is aggressively in violation of the NEM agreement.

zanydroid said:

In very very few worlds is switching to NEM3 a good deal.

Under NEM2 there is a very, very long break even point to paying off a ESS. I calculated mine at 10 years using forced export to push out energy between 4-9PM. Not great.

The PG&E rules for ESS are very complicated. It's quite possible whoever picked up the phone didn't know what was going on. Especially with the EG4 18kpv, EG4 is at present sorting out paperwork issues with PG&E.

SolArk has their paperwork sorted out better, so potentially you can call back PG&E and ask them if you can add batteries to the SolArk under nicer terms than with the 18kpv.


NGL, I'm not a huge fan of impulse buying equipment like this. Unless I get a lot of enjoyment out of installing equipment.

This is aggressively in violation of the NEM agreement.

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I could certainly start in NEM2 by installing the system with the 9.6KW of panels and a 18KPV mounted at the proper elevation so that future batteries can just be slid underneath. I would start first with 24K of heat pump strictly on PV temporarily while I assemble the system. That would reduce my July-Aug-Sep bills by about 1,800KWH. The other 4.8KW of panels and batteries could be phase two.
Do you have any details of the EG4 12KPV? I have seen a picture, but no details.

Gold Country Russ said:

I could certainly start in NEM2 by installing the system with the 9.6KW of panels and a 18KPV mounted at the proper

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Annoying situation is if you pay $5k for an 18kpv and EG4 never gets their together with PG&E.

What about installing an equivalent capacity of grid tie capacity with the cheapest grid tie inverter (might as well do 1:1 overpaneling, you have approval for that already), and switch to a hybrid at a later date.

This costs an extra $1k though unless you are good at Craigslist or eBay. Maybe $1k can get a good price on a SolArk partner battery.

I think you can direct connect panels to the 24000 BTU inverter without Permission to Operate

Gold Country Russ said:

Do you have any details of the EG4 12KPV? I have seen a picture, but no details.

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I am actually waiting for it to show up with details. It would be a better fit for my needs than an 18kpv

MidNite One (or whatever it’s called) is coming out shortly.

I need the 200A pass-thru, and don't want to do it twice. The 18KPV is on the CA state approved list both with & without EG4 14.3KWH batteries. What problem can PG&E have? When I talked with PG&E they did think it was an 18K output inverter though. They did say I could use it to replace the Solark 12K though.

Gold Country Russ said:

I need the 200A pass-thru, and don't want to do it twice. The 18KPV is on the CA state approved list both with & without EG4 14.3KWH batteries.

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OK the MidNite One does not have 200A bypass so that is out. I suspect the 12kpv will not either, but EG4 also showed what looks like a Microgrid Interconnect Device (presumably 200A capable) at a convention last month so that would be a way to get the bypass.

Along those lines maybe you can ask if SolArk plans to sell a MID that will give 200A bypass to the 12k

Look for recent threads about PRD PCS on that inverter and you’ll see how the CEC list is not the final say about ESS installations with PG&E.

After I saw those threads here over the past 6 weeks I’ve put 18kpv and EG4 back in the penalty box.

I believe PG&E will let you pick any inverter with similar kW AC

FWIW 200A bypass and the service bypass switch some people like to use with their solar installs really stacks up the equipment costs vs 100 or 125A

MidNite One thread somewhat has an explanation from their engineers on why they picked 100A bypass

zanydroid said:

FWIW 200A bypass and the service bypass switch some people like to use with their solar installs really stacks up the equipment costs vs 100 or 125A

MidNite One thread somewhat has an explanation from their engineers on why they picked 100A bypass

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I will call EG4 tomorrow. Maybe PG&E is OK with it as a LUX, after all they make it & it is also listed a Lux, but I don't know who else sells it.

Gold Country Russ said:

I will call EG4 tomorrow. Maybe PG&E is OK with it as a LUX, after all they make it & it is also listed a Lux, but I don't know who else sells it.

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Good luck with it.

I think Fortress rebadged the luxpower

zanydroid said:

OK the MidNite One does not have 200A bypass so that is out. I suspect the 12kpv will not either, but EG4 also showed what looks like a Microgrid Interconnect Device (presumably 200A capable) at a convention last month so that would be a way to get the bypass.

Along those lines maybe you can ask if SolArk plans to sell a MID that will give 200A bypass to the 12k

Look for recent threads about PRD PCS on that inverter and you’ll see how the CEC list is not the final say about ESS installations with PG&E.

After I saw those threads here over the past 6 weeks I’ve put 18kpv and EG4 back in the penalty box.

I believe PG&E will let you pick any inverter with similar kW AC

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"Look for recent threads about PRD PCS on that inverter and you’ll see how the CEC list is not the final say about ESS installations with PG&E."?
I don't understand what you have said here, please explain. PRD PCS? ESS?

These acronyms are from regulations/UL standards. These are referenced in Rule21 (power company rules)

ESS - Energy Storage System. Referenced in Rule21, building code (most onerous are in Residential Code - Section R328. Review carefully the system size limits and physical placement rules, & have the plans approved before buying or mounting anything), and UL (there is a specific listing for it - UL 9540)

Sorry, I misspelled it - it's CRD / PCS. Here is an example thread. PCS = Power Control System (Basically it is a specification describing what the import/export logic is on the ESS). CRD = Certification Requirement Decision = the formal paperwork trail for proving that a device implements a PCS.

The PG&E Rule21 has 2-3 very densely written pages on what PCS functions are required for what kind / size of customer / power topology. EG, the rules are different for AC coupled ESS, DC coupled ESS, and different storage capacity/output power of each.

Example of different PCS and also defines CRD.

This appears to have been resolved a while back. EG4 says there is no problem with PG&E, and they have many approved PG&E installations. I am still working to confirm it though. Still hope to order a heat pump & 18KPV this week. Will wait to order the batteries until sometime after PG&E sign's off on my actual installation.
And you were right, the Fortress is functionally the same, just a little more money. There may be differences at the bottom of the Fortress enclosure from the 18KPV that might create an issue with the EG4 battery conduit box and maybe installation height.
I think everything will work out for using the EG4.

Gold Country Russ said:

This appears to have been resolved a while back. EG4 says there is no problem with PG&E, and they have many approved PG&E installations. I am still working to confirm it though.

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My questions would be -- What is the AC size, DC size of those installations? Are they DC coupled or AC coupled?

IIRC AC coupled is a lot more onerous than DC coupled.

EG4's answer I think is fine as long as you are willing to wait for final PG&E approval of the plans (not PTO, I mean engineering approval) before buying stuff. To avoid being sadly stuck with the 18kpv (or mailing it back to EG4)

Gold Country Russ said:

I have PG&E NEM2 approval for a 24 panel 9.6KW ground mount system with Solark 12K inverter but no battery storage. I contacted PG&E and said I wanted to change to an EG4 18KPV inverter and add two 14.3KWH batteries. I was told the inverter change was no problem because they were the same 12KW capacity but that I couldn't add a battery in NEM2 because mine is a "large" system, meaning it has an over 10KW inverter. Truth is I want/need an even bigger system.

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Is here a reason you don't just add batteries to the SolArk 12K? Is this a case of the 12K won't meet future electrical needs as you electrify (heat pumps, etc)?

CA NEM 2.0 rules allow you to add 10%/1kW to an existing system, after that you essentially start over with new agreement (meaning NEM 3.0 for you). In general, as noted earlier, better to stay on 2.0. With 3.0, the whole point is that grid is already saturated mid-day sunny days for a decent portion of the year, and battery adaption wasn't progressing along well enough with Time-of-Use rates, so NEM 3.0 essentially requires batteries to enable a decent residential solar ROI (return on investment). As you are planning batteries anyway, then that bypasses that significant cost consideration, making NEM 3.0 it little less undesirable.

Beware
- PG&E has detailed history of your electricity export and can easily tell if you expand your system and allow that expansion to export. And it is in their interest to find those breaking the rules, so don't expect to get away with anything for long.
- EG4 is relatively new, with firmware glitches not that uncommon. So do NOT expect setting a limit on electricity export (to make it harder to see you expanded outside NEM 2.0 allowable limits) on low-cost (low maturity) products (like EG4) to not glitch at some point (in this case, export at rate above threshold, triggering automatic awareness of violating your NEM 2.0 terms) [see these forums for all kinds of report.. I'm not making this up]. There are times you get what you pay for. See William's video on the Canadian Solar hybrid inverter and batteries [and his comment about using more mature solutions like that when going grid-tied, and why]. In my opinion the risk of a glitch is fairly high causing you to get 'caught' and cost you way more than up-front price difference for a more mature solution. This reeks of 'penny wise, pound foolish'.
- that what the solar company sold you in terms of system output capability and the NEM 2.0 agreement are likely to be different numbers (ex . my Dec '22 SunPower AC coupled install contract lists "Installation of new photovoltaic: 8.08kW (solar energy) system" my util co Permission to Operate (interconnect) references "installation of your 7.392 kW"... the difference is theoretical panel ability # [ideal circumstances] (contract) vs actual expected peak system output at my specific location, panel mounting angle/orientation, etc. The 10%/1kW system output I mentioned is above that permission to operate #, not the solar installer contract #). In your case, not sure which number your 9.6kW is,

It is NOT in PG&E interest to enable you to not provide them with revenue (profit). so don't expect them to make it easy for you. Do NOT, under any circumstance, trust the word you hear over the phone. The Util Co rep could be wrong and it would still be 100% your problem (not theirs), unless you get it in writing (and even then, you may need to get a lawyer involved). You mention having 36x400w panels. Is that in addition to the 24 panels already operational (60 panels total), or is it 12 extra panels (replace existing 24 panels)? or ??

The issue, is that technically, if you had a separate (and certainly not easily bridged) power system with the other panels (like powering a separate building, with no power connection between them), then you might need permit per local building codes, but not PG&E, to install/use those 36x400w panels. But as soon as those extra panels are wired up and PG&E finds out (easily done, with drone or satellite imagery), they could disconnect you completely until your site is audited. And even if extra panels not wired into existing grid-tied house electrical system, if it wouldn't be much effort to connect them, then don't expect approval to continue to operate under NEM 2.0. And don't expect getting re-connected to grid to be fast, easy, nor cheap.

In terms of hypothetical... let's say you have an additional 36 panels (so 60 panels total?) and you are going to ground mount these new panels.
- I'd do some research, but I'd be inclined to tell PG&E you were going to install those panels, and what off-grid system they'd be attached to. PG&E will balk, and then they'll come out, and hopefully (part that you get to research or someone who has 'been there, done that' can comment) see they are truly not inter-connected and couldn't be without significant effort, then maybe they'll sign off. This way PG&E is aware of the extra panels, and won't flag them going forward as violating your NEM 2.0 permission to operate agreement.
- though a technical violation, there are certain rules I'm willing to ignore... you could then tie the isolated new panel system into more loads at your house. HOWEVER (huge caveat) - I'd only consider such a setup with a more mature hybrid inverter than EG4 or similar. Better yet, I'd be inclined to keep the SolArk 12K for an electrical sub-section, with the extra panels connected there, and it configured to NOT allow export. This would potentially limit you depending on where batteries connected and which loads on this electrical load sub-section, and you might not be ok with such limitations

Or, if you truly want/need 60 panels production, then I'd assume you need (a lot) more battery capacity than 28.6kWh, and if you want it simple, everything to work in grid-down situation (ex. local grid de-energized for wildfire risk), then moving into NEM 3.0 may be 'cleaner'. An analysis of cost impact of moving to NEM 3.0 not easily done in a forum setting like this. You'd like need your electricity consumption details (SDG&E has a 15-minute CSV report available) for a year, along with panel production info, planned electricity changes (heat pump, etc), and then some number crunching (solar installers have such, but how accurate/reliable are these??) to determine which approach makes best financial sense, or where break-even is.

I think with NEM 2.0 reservation for GT PV no battery, you have to complete the installation and get permission to operate without installing a battery.

You can add a battery later, with PG&E permission, and keep your NEM 2.0
I'm not aware of PV capacity limit affecting permission to add batteries, but it is possible. At least, they need to approve the additional export.

A "PCS" system with PV and battery might serve to keep maximum export kW within allowed limits. PCS approval is noted in one of the CEC inverter list columns. You'll want to export from battery during peak rate hours (4:00 to 9:00 PM?) when PV is less, so not a problem.

You want NEM 2.0, don't do anything that will get you bumped over to NEM 3.0.

You may be allowed to power the house by generator or off-grid PV system at times, while having 100% of your original GT PV system export.

But I don't think you want to run a generator. PG&E rates are something like $0.40 to $0.60/kWh. Generator will cost $1.00/kW or more. Unless you are using it for CHP, combined heat and power, with waste heat used for the house. Even then, I suspect more effort that worth what you get compared to grid. Just calculate cost and hours for oil changes, compare to value of power.

You can select brands that are cheap and seem to have lots of complaints, or you can select brands most everyone is happy with. An inverter already approved on CEC website as ESS, with a supported battery, is the safe way to achieve compliance. It can still have functionality issues.

My next install will be SMA Sunny Boy (GT PV). I've had good luck with them before, and this will be a new model for me but has been in use several years (SB -41). The installation after that I plan to use Sunny Boy Smart Energy (hybrid, batteries optional). I don't know how well that will perform, and compatible batteries are 2x the cost of alternatives, but I want to use Tier-1 for that "customer".

To clarify everything:
My goals: A. Reduce overall energy costs for electricity & propane by installing the PG&E NEM2 agreed 9.6KW PV system. B. Eliminate frequent power outages. C. Replace (obsolete) split unit ducted HVAC 4-ton R22/propane heat with a new ducted inverter 4-ton heat pump (Will be phase-2). D. Immediately install a mini split PV powered heat pump (temporary PV panels and no AC wiring initially) in the house common area for daytime use this summer. E. Integrate the stationary 10KW generator into PV inverter. F. Find a way to get PG&E agreement to add battery storage.
I have: A. PG&E NEM2 agreement at 9.6KW for 24 ground mount panels and Solark 12K inverter. B. I own 36 Canadian Solar 400W bifacial panels. C. Generac 10KW stationary water-cooled 4-cyl 1.5L 1,800RPM generator w/299-gallon dedicated propane tank.
Summary: This week I will order and when available install a hybrid 24K mini-split temporally wired to PV panels. This will save me at least 1,800KWH in the next 3 summer months. Next, I will do site prep to place a 40' shipping container parallel with and 8' from the south side of house & garage. I am using a professional engineer to design the required structural footing to support and anchor the container along with the steel structure and 24 panel mounting on container roof. The mount will either be adjustable 15-45deg or fixed at 30 and due south. I will do the steel fabrication, welding, wiring, and concrete. I have forklift, Bobcat w/backhoe attachment, and welding equipment at home. The feds will pay 30% of the container & installation and I save $1,860 a year on a storage unit! Before placing the container, I will trench for the underground generator conduit. The Inverter will be mounted to the house virtually under the top back of the panels. The county and our HOA are good with this plan, and everything will be permitted. That said, I think I will be short power with the 9.6KW even if the bifacial adds 10-15% and I desperately want to add batteries. My peak summer day last year was about 78KWH, but my old Freus A/C is super high efficiency even against todays best. I have space for adding many panels and just going off grid is definitely an option but I'm not sure about the effect that would have on home value when/if sold.
Thanks in advance for your help,
Russ

Decision made! Going with at least 1, maybe 2, EP Cube 7.6KW inverter w/19.8KWH battery. The EG4 system (18KPV & 14.3KWH battery) are not approved for the $200. per KWH SGIP rebate. The 18KPV & battery are on the CEC approved equipment list both individually and combined but are not on the battery rebate list. If PG&E will approve my SNEM application with that size system, I will use two of the EP Cube inverters and another 19.8KWH of battery. That would give me 15.2KW of inverter & 39.6KWH.
EDIT --- Ordering: Ep Cube w/15.2 Kw inverter & 39.6 KWH battery.