Zero export system without interconnection agreement

[analog8484]

I've been told by a few people that there is no need for POCO interconnection agreement/PTO if the grid-tied solar system ensures zero export. That doesn't seem correct to me but I can't find any explicit POCO rules or local/federal laws/codes that address this situation. Can anyone point to relevant rules/laws about zero export systems?

 

[pv_n00b]

Not true. I don't know of any utility in the USA that allows parallel operation without an interconnection agreement even if it is non-export. Even non-export systems could energize the utility system if not installed properly with the right equipment.
What you are hearing about is guerilla solar where you just don't tell the utility and hope they don't come out someday and pop off your meter for having an unsanctioned PV system.
Now having a fully off-grid PV+storage system and no grid connection could be an option.

 

[winnie]

Dunno. I could imagine some zero export designs which would be possible without utility permission.

One example would be something like a solar air conditioner. The PV panels feed DC to the air conditioner. The AC also has a rectifier and can consume mains power.

There is zero parallel operation on the AC side of things. As far as the utility is concerned you simply have a very efficient air conditioner with zero possibly of export.

So if you did your entire home as a dc system with a rectifier for the mains connection? I don't see what the utility could say.

Jon

 

[gadfly56]

Dunno. I could imagine some zero export designs which would be possible without utility permission.

One example would be something like a solar air conditioner. The PV panels feed DC to the air conditioner. The AC also has a rectifier and can consume mains power.

There is zero parallel operation on the AC side of things. As far as the utility is concerned you simply have a very efficient air conditioner with zero possibly of export.

So if you did your entire home as a dc system with a rectifier for the mains connection? I don't see what the utility could say.

Jon

It sounds like you'd be spending a pretty penny to make an obscure point. But hey, as long as it's not my money, go for it.

 

[analog8484]

Not true. I don't know of any utility in the USA that allows parallel operation without an interconnection agreement even if it is non-export. Even non-export systems could energize the utility system if not installed properly with the right equipment.
What you are hearing about is guerilla solar where you just don't tell the utility and hope they don't come out someday and pop off your meter for having an unsanctioned PV system.
Now having a fully off-grid PV+storage system and no grid connection could be an option.

That's what I thought too but the push back is show me the laws that are broken. And what would be the penalty for zero export PV systems without interconnection agreement? I had assumed there would be some legal means for POCO's to force disconnection but haven't seen one yet. I doubt POCO's would/can disconnect electric service.

 

[ggunn]

That's what I thought too but the push back is show me the laws that are broken.

I don't believe that you necessarily have to be doing something illegal for a utility to disconnect you. Their rules do not necessarily have the force of law.

 

[electrofelon]

That's what I thought too but the push back is show me the laws that are broken.

I'm kinda with you here. Show me the laws or rules. I'll do whatever I want on my property thank you as long as it doesn't back feed the grid.

 

[ggunn]

I'll do whatever I want on my property thank you as long as it doesn't back feed the grid.

That's not the way it works in most places. If you are going to interconnect with the electrical grid, in most jurisdictions the AHJ will have some control over what you do with anything that touches their wires no matter if you never export a single kWh.

 

[Hv&Lv]

We find out there is a grid-tied system tied to our system (i.e., with the capability to backfeed) without being tested to our standards or without an inter tie agreement, we can (and will) disconnect our system from yours.

 

[analog8484]

We find out there is a grid-tied system tied to our system (i.e., with the capability to backfeed) without being tested to our standards or without an inter tie agreement, we can (and will) disconnect our system from yours.

That's good to know. In CA, there are laws that can make it more difficult for POCO's to disconnect service even when an account hasn't been paid for a long time (a typical reason for disconnection) in some situations.

Apparently, there is at least one UL compliant grid-tied inverter vendor telling consumers they don't need interconnection agreement for zero export systems.

 

[winnie]

So is the system making that claim (no interconnection needed because of zero export) _incapable_ of export by design, or is it virtual, using a grid interactive inverter combined with metering and software to prevent energy export.

If the export prevention is virtual, then does it instant by instant prevent export, or does it prevent export over some small averaging period.

As I said above it is certainly possible to design a perfect zero export system. But unless you are talking some crazy difficult POCO requirements, getting that interconnection agreement seems saner.

Jon

 

[Hv&Lv]

That's good to know. In CA, there are laws that can make it more difficult for POCO's to disconnect service even when an account hasn't been paid for a long time (a typical reason for disconnection) in some situations.

Apparently, there is at least one UL compliant grid-tied inverter vendor telling consumers they don't need interconnection agreement for zero export systems.

We have that here, but grid tie is completely different than non pay.

The vendors will tell you whatever lies you need to hear to get you to write the check.

 

[ggunn]

Apparently, there is at least one UL compliant grid-tied inverter vendor telling consumers they don't need interconnection agreement for zero export systems.

Which vendor(s)?

 

[jaggedben]

...

As I said above it is certainly possible to design a perfect zero export system. But unless you are talking some crazy difficult POCO requirements, getting that interconnection agreement seems saner.

...

This thread no doubt exists because proposed changes in California would diminish the reasonableness of that statement.

 

[analog8484]

Which vendor(s)?

Craftstrom is the one I heard about.

 

[analog8484]

So is the system making that claim (no interconnection needed because of zero export) _incapable_ of export by design, or is it virtual, using a grid interactive inverter combined with metering and software to prevent energy export.

If the export prevention is virtual, then does it instant by instant prevent export, or does it prevent export over some small averaging period.

As I said above it is certainly possible to design a perfect zero export system. But unless you are talking some crazy difficult POCO requirements, getting that interconnection agreement seems saner.

Jon

Don't know the specific mechanism but not sure how it would be relevant.
Getting interconnection agreement/PTO can take months in some places and maybe tied to NEM agreement with additional costs.

 

[winnie]

IMHO the reason that 'virtual' zero export _might_ be different than 'assured' zero export is that with 'virtual' you might see some really funky power factor issues. You might see power exported during part of the AC cycle and consumed during the rest of the AC cycle, netting out to no export. A home with such a system might consume very few watts but lots of volt amperes.

I don't know enough the validate their claims, but at the prices being quoted ($4 per watt for a DIY install system) seem a touch high. That is what the local professionals are quoting to me for a soup to nuts professionally installed system (though on a larger scale).

-Jon

 

[ggunn]

Apparently, there is at least one UL compliant grid-tied inverter vendor telling consumers they don't need interconnection agreement for zero export systems.

The inverters are (or are not) UL compliant, not the vendors who sell inverters. There are indeed unscrupulous solar companies who will feed prospective customers misinformation or leave out important information when they are trying to sell them a PV system.

 

[analog8484]

The inverters are (or are not) UL compliant, not the vendors who sell inverters. There are indeed unscrupulous solar companies who will feed prospective customers misinformation or leave out important information when they are trying to sell them a PV system.

This https://ramuk.intertekconnect.com/W...3d1b9bca75c9b9a8862586fc000b0adb?OpenDocument shows the inverter has UL1741 compliance.

 

[analog8484]

IMHO the reason that 'virtual' zero export _might_ be different than 'assured' zero export is that with 'virtual' you might see some really funky power factor issues. You might see power exported during part of the AC cycle and consumed during the rest of the AC cycle, netting out to no export. A home with such a system might consume very few watts but lots of volt amperes.

I don't know enough the validate their claims, but at the prices being quoted ($4 per watt for a DIY install system) seem a touch high. That is what the local professionals are quoting to me for a soup to nuts professionally installed system (though on a larger scale).

-Jon

True but I was referring how the zero export mechanism would be affect how POCO's or government agencies might or might not require interconnection agreement.