MA Smart Program with ESS Backup Loads

[soby]

In about a month, I'm having a 10.075kW PV system installed with a StorEdge Inverter and LG Chem battery. For the Massachusetts SMART program, National Grid requires a dedicated meter to be installed between the inverter and your distribution panel to measure your PV generation so they can calculate how much to pay you.

The problem I see is the ESS and how the StorEdge Inverter is wired. Basically, the SMART meter will not measure the full PV generation when there is power draw from the backup loads panel. Please take a look at the attached diagram and let me know if I'm missing something or if there really is a potential problem.

- Soby

[ButchDeal]

If you get the StorEdge with built in revenue grade meter (option) then it will measure ALL production as you want.
It will also be integrated into your monitoring and will be able to be configured to automatic upload for the credits.

[soby]

If you get the StorEdge with built in revenue grade meter (option) then it will measure ALL production as you want.
It will also be integrated into your monitoring and will be able to be configured to automatic upload for the credits.

I am aware of that capability from SolarEdge and it is likely the solution that they envisioned when designing the StorEdge. The additional money for that option makes a ton more sense than how National Grid envisions it. The problem is that National Grid dictates how the PV generation is measured. They want to use their own meter and they want that meter outside where they can access it.

I asked this question of my installer and I'm curious to see what they get as a response from SolarEdge and NG. Mine can't be the first PV system with ESS on the SMART program so I wonder how others have wired it.

My install becomes SIGNIFICANTLY easier with an integrated revenue-grade meter and without that utility sub-meter located outside.

[soby]

My installer is still trying to sort this out. They got word from SolarEdge that this is a known issue without a solution. I have to wonder how many MA Smart installs currently exist with ESS and the owners are blissfully unaware that they are getting shortchanged on generation revenue from SMART.

My installer recommended not having high-draw circuits on the backup panel but that eliminates the main benefit of a battery (backup power). I was planning to have 2 refrigerators and a large freezer running on the backup panel. They are hoping to get a response from SMART and/or National Grid officials but my install date is weeks away. I really don't want to delay the install but I also want it done right the first time...

I guess something is better than nothing but it really makes me angry that SMART requires that secondary utility-owned meter vs just allowing the built-in inverter revenue grade meter.

[brianbsl]

I was going to reply earlier but wasn't sure if this was dead since it was a few weeks old.
We just turned up a SMART system in National Grid territory. We found NG to be incredibly responsive on everything. They approved the DG in under 1 business day after application. They came out to install our net & gen meters 1 day after the town called in the completion (that call in was the hardest part). I actually emailed them myself at Distributed.Generation@nationalgrid.com with a question or two and found them responsive.
However I think the rules are very strict on using a utility provided meter, not something National Grid can even give you a waiver for as it is part of the state regulation.

Personally if I were in your situation, I would change out the StorEdge for an HDWave and add a Powerwall.
There is a Demand Response program launching very soon, and from what I have heard, StorEdge will only be supported through Vivint and Sunrun.
If you want to use a local installer you will need to use Tesla or Pika (although Pika is also DC-coupled storage and may have the same issues your StorEdge design has).
I think the $ will be enough to make it worth choosing something else. You don't have to get the Powerwall straight from Tesla, you can use a certified installer, which is what we plan to do (onto our Enphase system).

[soby]

I was going to reply earlier but wasn't sure if this was dead since it was a few weeks old.
We just turned up a SMART system in National Grid territory. We found NG to be incredibly responsive on everything. They approved the DG in under 1 business day after application. They came out to install our net & gen meters 1 day after the town called in the completion (that call in was the hardest part). I actually emailed them myself at Distributed.Generation@nationalgrid.com with a question or two and found them responsive.
However I think the rules are very strict on using a utility provided meter, not something National Grid can even give you a waiver for as it is part of the state regulation.

Personally if I were in your situation, I would change out the StorEdge for an HDWave and add a Powerwall.
There is a Demand Response program launching very soon, and from what I have heard, StorEdge will only be supported through Vivint and Sunrun.
If you want to use a local installer you will need to use Tesla or Pika (although Pika is also DC-coupled storage and may have the same issues your StorEdge design has).
I think the $ will be enough to make it worth choosing something else. You don't have to get the Powerwall straight from Tesla, you can use a certified installer, which is what we plan to do (onto our Enphase system).

The quoted lead times I got for a Powerwall were 1-1.5 YEARS so that's not happening. The PV system and battery need to be installed at the same time to be eligible for the SMART program ESS adder.

I was under the impression that StorEdge could also be programmed for Demand Response when installed with the SolarEdge Meter: https://www.solaredge.com/us/product...modbus-meter#/. Can you cite where you heard only Vivint and Sunrun are compatible?

[brianbsl]

The quoted lead times I got for a Powerwall were 1-1.5 YEARS so that's not happening. The PV system and battery need to be installed at the same time to be eligible for the SMART program ESS adder.

I was under the impression that StorEdge could also be programmed for Demand Response when installed with the SolarEdge Meter: https://www.solaredge.com/us/product...modbus-meter#/. Can you cite where you heard only Vivint and Sunrun are compatible?

Its not that long anymore, and the installer I am using has them in their warehouse and when I talked to Tesla direct they were also ready to install as soon as I was ready to (but Tesla direct will only sell you 2+, singles only along with Tesla PV). You also do not actually have to install at the same time, but you only get the energy storage adder from the date you turn on the storage through the end of the contract (as in, you would not get 10 full years of ES incentive).

The docs are not public yet, I am just going by what is on the application that my installer sent me. While SolarEdge may have the technology to support it, they have to tie into whoever is managing the program, and it does not look like they are part of the program when it launches. I think it should show up on the MassSave website soon, maybe 6/1?

[brianbsl]

The quoted lead times I got for a Powerwall were 1-1.5 YEARS so that's not happening. The PV system and battery need to be installed at the same time to be eligible for the SMART program ESS adder.

I was under the impression that StorEdge could also be programmed for Demand Response when installed with the SolarEdge Meter: https://www.solaredge.com/us/product...modbus-meter#/. Can you cite where you heard only Vivint and Sunrun are compatible?

I just found this which is public, and shows for MA, only Tesla, Pika, Vivnt and Sunrun are participating https://files-cdn.masscec.com/NGrid%...erpoint%20.pdf

[brianbsl]

FYI it looks like they added support for generic SolarEdge in the past week or so

https://www.solaredge.com/us/connected-solutions-ma

Your installer has to enroll you.

[soby]

FYI it looks like they added support for generic SolarEdge in the past week or so

https://www.solaredge.com/us/connected-solutions-ma

Your installer has to enroll you.

This is similar in nature to a program I signed up for for electric customers with smart thermostats. I've been noticing that our Ecobee thermostats are automatically raising the AC temp during the afternoon for an "event". You can manually cancel if you're home and its getting too hot.

I had never heard of the Connected Solutions program. I guess this is in addition to the SMART program add-on. The two programs combined make opting for a battery a no-brainer when getting a new PV system installed. I'll ask my installer about enrolling in this program too.

Thanks,
Soby

[JSchnee21]

Perhaps NG doesn't support this, but if the separate, non-StoreEdge integrated production meter (similar to the SREC meter we use in NJ) was bi-directional, couldn't you just take all of the production/output from the combined PV/Storage system and subtract any grid feed in (e.g input) that was used, occasionally, to charge the batteries?

Wouldn't that tell you the total output from the PV system -- irrespective of whether it was "live" or "cached" in the batteries? That said, I agree the revenue grade meter in the StoreEdge would be the most elegant solution.

BUT, that said, I'd still favor the Tesla Powerwall. Assuming you can get one in a reasonably time frame (I've also heard Tesla is pushing to expedite them) and for a reasonable price (not sure about this part) the key benefit of the Tesla solution is the increase current carrying capability of paralleling multiple units. Thus often avoiding the need to install a subpanel for a subset of your loads. Modestly sized (~3-5 Ton) AC's should be fine with 2 PowerWalls.

[ButchDeal]

Perhaps NG doesn't support this, but if the separate, non-StoreEdge integrated production meter (similar to the SREC meter we use in NJ) was bi-directional, couldn't you just take all of the production/output from the combined PV/Storage system and subtract any grid feed in (e.g input) that was used, occasionally, to charge the batteries?

Wouldn't that tell you the total output from the PV system -- irrespective of whether it was "live" or "cached" in the batteries? That said, I agree the revenue grade meter in the StoreEdge would be the most elegant solution.

BUT, that said, I'd still favor the Tesla Powerwall. Assuming you can get one in a reasonably time frame (I've also heard Tesla is pushing to expedite them) and for a reasonable price (not sure about this part) the key benefit of the Tesla solution is the increase current carrying capability of paralleling multiple units. Thus often avoiding the need to install a subpanel for a subset of your loads. Modestly sized (~3-5 Ton) AC's should be fine with 2 PowerWalls.

You can put two LG RESUE10H units on a single StorEdge 7.6kW inverter and get about the same output as two powerwalls..You can also parallel two or more StorEdge inverters on larger installs each with one or two batteries, or no batteries if you wish.

[JSchnee21]

Thanks Butch, so you're saying parallel two SE7600A-US'es. From the spec sheets it looks like these are 240V @ 21 amps continuous (in backup mode) and 6600VA peak (aka 27.5 amps). So in theory that wold be 55 amps peak. I wonder if that would be enough handle the inrush from my AC compressor starting up. It generally runs ~25 amps continuous, but of course, inrush is much higher.

SE

https://www.solaredge.com/sites/default/files/se_storedge_inverter_datasheet_na.pdf

Tesla claims
https://www.tesla.com/sites/default/files/pdfs/powerwall/Powerwall%202_AC_Datasheet_en_northamerica.pdf

Apparent Power, max continuous 5.8 kVA (charge and discharge) -- 24.17 amps
Apparent Power, peak (10s, of-grid/backup) 7.2 kVA (charge and discharge) -- 30 amps
Maximum Output Fault Current 32 A
Imbalance for Split-Phase Loads 100%

So that's ~60 amps peak, maybe 64 amps for a second or less.

How does the auto transformer capability compare? Residential single pole loads are often very poorly balanced -- since the home owner randomly turns different loads on and off.

the LG Chem batteries are fairly expensive and a bit smaller. The Tesla solution might be slightly cheaper and offer longer runtimes for around the same price.

But, I was not aware that SE would support a paralleled configuration, thanks Butch for the idea.