Utility jerking me around.

[TheFlumph]

My utility is well known for really disliking net metering. Several installers in the area have told me they make it difficult on purpose.

Anyway they have put my project on hold.

The second paragraph is easy for me to refute. The inverter is UL1741SA compliant. I don’t need an auto transfer switch.
And I don’t plan on using a generator. I’m using the EG418kpv inverter.

The first paragraph here makes no sense to me. They want me to buy another inverter?? The first one was expensive enough. Can anyone with experience help me to respond here?

Email follows. “
We have two main issues that we are trying to resolve with the way the inverter manufacturer has your system designed.



First, VT PUC Rule 5.500 requires us to record production of your solar array separately. This requires a separate production meter from your exiting usage meter. We are currently working with another installer who is using a different inverter manufacturer with a similar setup and their solution is to install separate inverter(s) for the solar array and install the production meter between those and the main inverter. We would like to see the drawing below modified to show that setup before WEC can move forward.



Second, we need to have the exact model number for the 18kPV inverter you intend on using and a description from the manufacturer of its operation so we can thoroughly evaluate how that is functioning. Our main concern here is that with the inverter controlling the different inputs: solar, batteries and an AC backup generator, (basically replacing an automatic transfer switch which is required in WEC’s standard), we need to understand how it will be separated from the grid during outages so our people are protected from back feeding.”

This all started because I sent them this drawing and nicely asking which way they preferred my ground to be set up. Because they are particular about it. I wanted to have it ready and the way they like.
Now because they haven’t kept up with new inverter technology, they don’t know what to make of this inverter. Asking me to “just add another inverter” is absurd.

 

[Oldphile]

It sounds like they are insisting on a revenue grade meter on the output of the inverter. Since current may be flowing to the load terminals, you cannot measure what the PV production is from the grid terminals. I don't know why they are insisting on this. It is required for SRECs, but that should be optional. I have a Sol-Ark that also can't accommodate this. However, my utility didn't require it.

Maybe SRECs are mandatory in VT.

 

[Mattb4]

As I read the first requirement they seem to be saying they expect a grid tie inverter setup to feed their outgoing meter with your hybrid setup added into the system for your battery backup needs.

The second statement is simply they do not understand that your unit functions as a ATS to prevent your generator from back feeding the grid.

Could be tough to educate whoever is in charge of approving your interconnect.

 

[TheFlumph]

It sounds like they are insisting on a revenue grade meter on the output of the inverter. Since current may be flowing to the load terminals, you cannot measure what the PV production is from the grid terminals. I don't know why they are insisting on this. It is required for SRECs, but that should be optional. I have a Sol-Ark that also can't accommodate this. However, my utility didn't require it.

Maybe SRECs are mandatory in VT.

No SREC issues here. I have no idea, as I said, I think they may be trying to make it difficult. They already sprang the expense of a new transformer on me. Then said they are two years out, then said maybe in July. Had to pay upfront of course.

 

[hwy17]

>First, VT PUC Rule 5.500 requires us to record production of your solar array separately.

This is the worst possible rule you can face. It's not common but some places have it.

The ramifications of this rule are every bit as bad as they seem. You could basically only use your 18kpv as a battery backup system, with separate grid tied inverting for the solar. And I'm not sure if any method would allow AC coupling of the solar for off grid operation.

 

[TheFlumph]

As I read the first requirement they seem to be saying they expect a grid tie inverter setup to feed their outgoing meter with your hybrid setup added into the system for your battery backup needs.

The second statement is simply they do not understand that your unit functions as a ATS to prevent your generator from back feeding the grid.

Could be tough to educate whoever is in charge of approving your interconnect.

How would I even set up that grid tie inverter? The seem to adding complication on my end to make it easy on their end.

 

[TheFlumph]

>First, VT PUC Rule 5.500 requires us to record production of your solar array separately.

This is the worst possible rule you can face. It's not common but some places have it.

The ramifications of this rule are every bit as bad as they seem. You could basically only use your 18kpv as a battery backup system, with separate grid tied inverting for the solar. And I'm not sure if any method would allow AC coupling of the solar for off grid operation.

I can’t even wrap my head around what they are wanting me to do.
The hybrid inverter will be taking in more from the panels than it will be exporting to the grid. It can only to 12kw I think.

So I put another inverter between this invert and their meter? Where would it even be wired from?

 

[hwy17]

I can’t even wrap my head around what they are wanting me to do.
The hybrid inverter will be taking in more from the panels than it will be exporting to the grid. It can only to 12kw I think.

So I put another inverter between this invert and their meter? Where would it even be wired from?

They're talking about dual metering. Separate systems. A house meter with no solar and solar meter with no house.

Not to be the bearer of bad news, but yeah it's very very bad news. No hybrid inverter compatibility.

 

[jonas]

They're talking about dual metering. Separate systems. A house meter with no solar and solar meter with no house.

Not to be the bearer of bad news, but yeah it's very very bad news. No hybrid inverter compatibility.

View attachment 197625

You might need to pay regular kWh price for the solar you produce in worst case scenario.

 

[TheFlumph]

This would have been wonderful for them to tell me last year when I filled out the paperwork and included the damn model of inverter I was using.

 

[TheFlumph]

They're talking about dual metering. Separate systems. A house meter with no solar and solar meter with no house.

Not to be the bearer of bad news, but yeah it's very very bad news. No hybrid inverter compatibility.

View attachment 197625

But where would I wire a grid tie inverter between the 18kpv and the export meter? Based on my diagram I don’t see how that would work. It would need to be radically different.

 

[Hedges]

To make that work, would need a DC meter instead of AC. Not aware of those being available.

DC Revenue Grade Metering Standard – EMerge Alliance

www.emergealliance.org

Inverter likely meters PV power harvested. Doubt utility will accept that.

This would have been wonderful for them to tell me last year when I filled out the paperwork and included the damn model of inverter I was using.

Did your submission include a 1-line diagram, or reference a standard diagram provided by them?
This extra metering would be a change to system architecture. Did they approve what you submitted?


Workaround might be to AC couple a GT PV inverter to your hybrid, with utility meter in between.
Small system now, more panels later DC coupled? Maybe even permitted, only involving the city. But then you'd better limit export to what utility knows about.

Always a pain when they aren't reasonable.

 

[Q-Dog]

I don't understand why they need to know how much power your panels generate. Seems logical to me the only thing they should care about is how much power they send to you and how much you send to them. But logic doesn't always have much to do with anything.

This may just be a case of technology moving faster than the regulations that govern it's use.

 

[kscessnadriver]

I don't understand why they need to know how much power your panels generate. Seems logical to me the only thing they should care about is how much power they send to you and how much you send to them. But logic doesn't always have much to do with anything.

This may just be a case of technology moving faster than the regulations that govern it's use.

Because they're probably going to charge him for the kWh he produces in some way. Maybe not the value of the electricity, but maybe the transport and infrastructure cost of those kWh.

 

[TheFlumph]

To make that work, would need a DC meter instead of AC. Not aware of those being available.

DC Revenue Grade Metering Standard – EMerge Alliance

www.emergealliance.org

Inverter likely meters PV power harvested. Doubt utility will accept that.



Did your submission include a 1-line diagram, or reference a standard diagram provided by them?
This extra metering would be a change to system architecture. Did they approve what you submitted?


Workaround might be to AC couple a GT PV inverter to your hybrid, with utility meter in between.
Small system now, more panels later DC coupled? Maybe even permitted, only involving the city. But then you'd better limit export to what utility knows about.

Always a pain when they aren't reasonable.

I don’t have permits here.no diagrams No inspections either. Very rural. The electric co just comes to verify when the interconnect happens.
I just filled out the net metering amount I wanted to do and they started the process. They’ve been very hands off. I can tell they don’t want more net metering. Their news letter complain about net metering constantly.

I’ve got 60 panels already bought.

So you’re saying grid tie inverter putting AC to their meter, and then to my Gen port on the hybrid?
That grid tie would be to be UL1741sa rated correct? Because it’s hitting their meter before the hybrid inverter?

 

[Q-Dog]

Because they're probably going to charge him for the kWh he produces in some way. Maybe not the value of the electricity, but maybe the transport and infrastructure cost of those kWh.

They only have to "transport" whatever power he sends to the grid. If he consumes everything he makes he would export nothing.

 

[Mattb4]

I don't understand why they need to know how much power your panels generate. ...

I sorta see it. They look at your PV produced power as if you are a supplier (and likely pay you wholesale for it) Whereas the power your home uses is a retail sale for them. Not exactly a friendly deal since you end up paying for the power you produce. Just at a lesser amount since it is discounted.

 

[hwy17]

But where would I wire a grid tie inverter between the 18kpv and the export meter? Based on my diagram I don’t see how that would work. It would need to be radically different.

Yes. Radically different. Standalone grid tied AC production on the sell side, and then battery only backup on the house side.

 

[kscessnadriver]

They only have to "transport" whatever power he sends to the grid. If he consumes everything he makes he would export nothing.

Sure, but they don't see it that way. The cost of the infrastructure to his house is the same if he uses 1kWh/month or 4000 kWh/month. They're gonna get their money somehow.

 

[hwy17]

I sorta see it. They look at your PV produced power as if you are a supplier (and likely pay you wholesale for it) Whereas the power your home uses is a retail sale for them. Not exactly a friendly deal since you end up paying for the power you produce. Just at a lesser amount since it is discounted.

Yes, it can be implemented with or without "Buy all / Sell all" as you are describing.

Usually it is more friendly than that, and dual metering does not have to be buy all sell all, they can use an hourly consumption/production comparison table to net out the self consumption. But a dual meter set up is ready to be converted to buy all sell all if they choose to later.