Suggestions on choosing an inverter?

[rebelrider.mike]

I've been using the Emporia Vue to watch circuits I'd like to put on the solar sub panel. One is my dedicated freezer circuit.
Freezer.png
I've noticed that when the compressor isn't running it uses 13-15W all the time. I don't think it's supposed to do that. I'm also seeing that it uses 3.2kWh per day pretty consistently. That adds up to around 1,195kWh per year. There's some nice chest freezers at Home Depot that only use around 227kWh per year. That might save me a few dollars.

My old freezer was made in 1988. Still works great as far as keeping food frozen. It has a pretty high peak draw at about 14A. Runs on 2.5A. Looks like new ones peak at only 5A. Seems a shame to get rid of it while it works. But a new one would go a lot easier on an inverter.

[Ampster]

......., that means any nationally recognized testing lab can give it a label and it's all good.

In my research I discovered that 15 states also use the CEC list as a reference, so if that is the case in WA it may be useful. At least your first order of rankon products on your list will be that criteria. Unfortunately for those who are not UL listed they often use confusing language to obscure that isse and it is alway nice to have an independent means to verify. Good luck with your install.

[rebelrider.mike]

Ok, I did some digging and here's what I found:

The PUD is not an AHJ and since I'm not back-feeding to the grid, their policies, whatever they are, don't matter. So we can drop that one.
Washington L&I is the only AHJ I have to worry about. They use the Washington Administrative Code (WAC) and do the permits and inspections. Since I'm not back-feeding to the grid, I don't need a specific UL standard certification. The inverter simply needs to be "listed". Under their definitions, that means any nationally recognized testing lab can give it a label and it's all good.

[azdave]

Seems I caused some confusion, LOL. I'll see if I can clear it up.

No. You did not clear that up. I did not find anything in your provided links that says they prohibit stand-alone solar generation behind the meter during an outage. I strongly feel you (or whoever explained it to you) have misunderstood the requirements, especially since they do allow stand-alone generators to be used in the exact same situation. If your assumption is correct, your PUD would be the only utility that I've ever heard of anywhere in the USA with such a requirement applied only to solar.

I did find this. "PUD 3 requires inverters to have an automatic voltage-sensing disconnect switch built into them to prevent backfeeding." It says it must prevent backfeeding which is 100% correct but it does not say it must prevent stand-alone solar generation. Solar generation during a grid outage does not mean you are backfeeding. I think your whole selection process is based upon an incorrect assumption and I agree with J.P.M. You first need 100% clarity of the requirements before you do any actual component selection. At least you are learning plenty along the way with all your research. No harm in that.

[J.P.M.]

If Washington state is on NEC 2020 you will have to pick a UL liste inverter if you want to pass building inspection, Any UL listed inverter will be able to isolate from the grid when the power goes out. In your case, since you want to use the grid but not sell back your criteria needs to include the ability to take grid input and Zero export. that narrows the selection especially if you want to comply with the building codes. You may need to use external CTs to control export depending on how it is wired. Many of the inverters on your list are not UL listed but some of them can be configured for zero export and use grid power to supplement solar or battery. It is my strongly held belief that you do not need to get agreement from your utility if you are not exporting but it is a gray area in the sense that the inverter is connected even though it may be set for zero export.. That said, you always need to comply with the building code.

Seems to me that the OP needs to get in touch with AHJs (note plural) in his jurisdiction and explain to them just what he wants to do.
Seems like we're all drifting around with a bunch of assumptions. Meanwhile, the OP seems quite uninformed about what's available and what rules need to be followed. No one on this forum from WA has offered any info specific to what's required, and others here - including me - are most likely ignorant of what the OP needs - partly because the communication has not been good and partly because the OP is a PV neophyte.
Just my opinion.

[rebelrider.mike]

Here is a link to my local L&I page listing different certification laboratories that they accept testing from. From what I've read, any of these labs can certify that a product conforms to UL1741, which I think is the magic number for passing an inspection. This isn't really a response to anyone, just an FYI that I found interesting.

So far as I know, Washington doesn't have a list of specific inverters. Any that are certified by one of the above labs as conforming to UL1741, are fine. I found the CEC inverter/batter/solar list here. I guess I'll start going through the 1,542 devices and see which ones might work and if I can afford them. One thing that bothers me is that these are all "Grid Support" devices. I'm thinking that means that only inverters that can send power back to the grid are listed. Might be faster to just look up the manufacturers and see what they sell. There's no info on the list as to whether each inverter is split phase or not. But there are a lot of manufacturers that I've never heard of. Maybe I'll find something good that I've been overlooking.

[Ampster]

If Washington state is on NEC 2020 you will have to pick a UL liste inverter if you want to pass building inspection, Any UL listed inverter will be able to isolate from the grid when the power goes out. In your case, since you want to use the grid but not sell back your criteria needs to include the ability to take grid input and Zero export. that narrows the selection especially if you want to comply with the building codes. You may need to use external CTs to control export depending on how it is wired. Many of the inverters on your list are not UL listed but some of them can be configured for zero export and use grid power to supplement solar or battery. It is my strongly held belief that you do not need to get agreement from your utility if you are not exporting but it is a gray area in the sense that the inverter is connected even though it may be set for zero export.. That said, you always need to comply with the building code.

[rebelrider.mike]

Seems I caused some confusion, LOL. I'll see if I can clear it up.

In order to sell power back to the PUD, I'd have to enter an agreement which comes with certain requirements. I don't remember them all, but one that stood out (because I can't agree to it) is that the solar system shuts down in the event of a grid outage. I don't know what would happen if I were to backfeed power to the grid without their permission. I've never tried it. At the very least, I'd be giving power back to the grid for free. The meters here are electronic, but I don't know how "smart" they are.

One would think that an automatic disconnect that mechanically isolates the solar from the grid in the event of a grid outage would be sufficient. It is when using a generator. The PUD disagrees. I've found though that questioning policy doesn't change it. Just have to find a way to work around it. Here is a link to their Solar FAQ page.

The good news is that if I don't want to sell power back to the PUD, I don't have to. I have no legal obligation to do so, as far as I know. And if I don't sell power back to the grid, I don't have to comply with PUD policy. Only local code. I'm still working on that one, but I'm pretty sure keeping my solar/battery system active during a grid outage is allowed as long as it's isolated from the grid. Same as using a generator. Washington uses the 2020 NEC. I don't remember if I mentioned that.

So the inverter I have in my diagram is theoretical, but the idea is that there is an AC input from the grid or generator (some inverters have separate inputs for each) and an output for the load. The idea is that the AC input will be input only. No output. I'm not sure what the correct terminology is, but I want an inverter that can use power from the grid but not send power back. I know that grid-interactive can send power back, and off-grid has no power from the grid. Grid-tied seems to imply grid-interactive. Best I can describe it is that I want a grid-supplemented-but-non-interactive device.

From my studies around the internet, I've found that my PUD is not the only power provider with this sort of policy. There's a popular brand of microinverter called Enphase that designs some of its devices to automatically shut down during a grid outage. It's a hard-wired sort of thing that can't be changed. Some providers actually require these exact products in grid-interactive solar setups. So sayeth some You Tubers anyway.

[azdave]

My PUD wouldn't allow solar to function during a grid outage.

I don't quite follow this statement so maybe I'm not understanding your PUD regulations. If your system automatically disconnects from the grid during a grid outage, how would the they know or why would they even care that your panels are being used as a stand-alone system while the outage is occurring? Why would they approve using a gas generator (with a proper grid disconnect switch) but not solar generation with a proper disconnect as well? What am I missing here?

[Ampster]

..........

I have yet to find a list of Washington approved inverters. I kind of doubt any inverter that would work for me will be listed anyway.

I read somewhere that 15 states have adopted the California CEC list. Perhaps that is the case in WA as well?

[Ampster]

.......... what is the utility preventing you from doing exactly?

Good question. I had the same thought. There are some municipal (public) utility districts in which the building permit authority is the same entity. On the otherhand I am of the opinion that if one has a UL approved transfer switch separate or in an inverter that there should be no reason you cannot generate your own power. That assumes it wojuld comply with building codes.

[jflorey2]

I live in Washington, and won't be sending power to the grid. My PUD wouldn't allow solar to function during a grid outage.

But you have drawn a system that can 1) export power, 2) do net-zero if the inverter can use CT's for that purpose and 3) allow solar to function during an outage. So what is the utility preventing you from doing exactly?

[J.P.M.]

I live in Washington, and won't be sending power to the grid. My PUD wouldn't allow solar to function during a grid outage. For me, the whole point of having solar is to be able to use it during an outage. I don't plan to generate enough solar power to have any left over anyway. The sub panel I'm going to install will be powered from solar/battery, as well as either grid or generator as needed. Something like this:
InverterBatterySolar.png
Of course, this diagram changes every time I learn something. So it's really only a snapshot of what I'm thinking today.

I have yet to find a list of Washington approved inverters. I kind of doubt any inverter that would work for me will be listed anyway.

Thank you.

[rebelrider.mike]

I live in Washington, and won't be sending power to the grid. My PUD wouldn't allow solar to function during a grid outage. For me, the whole point of having solar is to be able to use it during an outage. I don't plan to generate enough solar power to have any left over anyway. The sub panel I'm going to install will be powered from solar/battery, as well as either grid or generator as needed. Something like this:
InverterBatterySolar.png
Of course, this diagram changes every time I learn something. So it's really only a snapshot of what I'm thinking today.

I have yet to find a list of Washington approved inverters. I kind of doubt any inverter that would work for me will be listed anyway.

[J.P.M.]

@ Rebelrider.mike:

Please, if you would, clear a couple of things up for me:
1.) Do you plan to ever send power to the grid for any reason ?
2.) What state (or country) will the generating system be located in ?

Thank you in advance.

J.P.M.