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PV production meter (for SRECs) with Sol-Ark hybrid inverter

troy303

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I live in Colorado and must work with XcelEnergy as my utility for grid-tie/net-metering. XcelEnergy also has an optional “Solar Rewards” program that purchases Solar Renewable Energy Certificates (SRECs). I am not sure how they meter solar production for these SRECs on systems below 10kW, but for larger systems (like the one I am designing) they require a revenue-grade PV production meter. I am assuming that I provide the socket for the meter and XcelEnergy plops in the meter for generating SRECs... not sure who is the owner of the PV production meter.

As I started to design my system with a Sol-Ark 15k hybrid inverter, I realized that there is no place to put an AC PV production meter that will measure actual PV production. While I am sure this information is gathered by Sol-Ark, I have no idea if it is sufficiently accurate for SREC creation or how to integrate it with XcelEnergy.

If the AC PC production meter is the only option with XcelEnegry, and I stay with Sol-Ark, I see the following options:
  1. Only create SRECs from exported power, not generated power. In this case, I don’t think a production meter is even needed as the net meter records exported power.
  2. Don’t bother joining the “Solar Rewards” program and don’t worry about SRECs at all.
  3. Redesign my system with Microinverters and AC-couple with the Sol-Ark 15k
Does anyone out there have experience with generating SRECs with Sol-Ark or other hybrid inverters? Any experience with XcelEnergy and their “Solar Rewards” program and options for tracking SRECs?

Thanks.
 
Did you solve the problem?
I had the same issue years ago with a different brand of battery backup grid-tie inverter. The revenue grade meter had CTs to measure the power. On that inverter I was able to open up the front panel on the inverter and got the CTs on the inverter output wires.

Now I have a sol-ark that replaces the other brand. My system is now too old and has aged out of the SREC program. But I'd still like to monitor inverter power output from the sol-ark using the same method using CTs on the revenue grade meter.
 
Illinois pays $82.28 per MWH for a SREC so very much worth tracking them. Sounds like CO has been as high as $200 from a google search.

I have a Solar Edge inverter with an internal revenue grade meter which is allowed but I also wired in my own "classic wattmeter" so I'd always have a "hard copy" of my solar output.
 
Does anyone out there have experience with generating SRECs with Sol-Ark or other hybrid inverters? Any experience with XcelEnergy and their “Solar Rewards” program and options for tracking SRECs?

Thanks.

Troy. Did you ever figure out a solution. I’m running into the same issue in Oklahoma when trying to use a Sol-Ark 15k. The utility company noticed that part of the PV production was going straight to the load and not to the grid through the production meter. I need a solution before they will allow me to connect to the grid.
 
I would reach out to Sol-Ark as I suspect this issue has come up with other people. As I mentioned in a prior post I was able to make it all work by taking the cover off the inverter(not Sol-Ark) and placing the revenue grade meter's CTs into the inverter on the inverter output wires.

Initially the state used engineering estimates to calculate production and therefor SRECS. But it did not take long for them to then say you have to install a revenue grade meter. Even for existing PV systems. But I was able to pick the meter I wanted off a list of acceptable meters. Since I knew the problem I was facing I had to pick one with external CTs that I could place into the inverter. I did not have a choice - it had to work or I would not have received SRECS.
Your state must have a list of meters they will accept.
 
I would reach out to Sol-Ark as I suspect this issue has come up with other people. As I mentioned in a prior post I was able to make it all work by taking the cover off the inverter(not Sol-Ark) and placing the revenue grade meter's CTs into the inverter on the inverter output wires.

Initially the state used engineering estimates to calculate production and therefor SRECS. But it did not take long for them to then say you have to install a revenue grade meter. Even for existing PV systems. But I was able to pick the meter I wanted off a list of acceptable meters. Since I knew the problem I was facing I had to pick one with external CTs that I could place into the inverter. I did not have a choice - it had to work or I would not have received SRECS.
Your state must have a list of meters they will accept.
What meter did you use? I would like to propose it to the utility company to see if that will be acceptable for them.
 
You need to contact Sol-Ark to see if you can open the inverter up and find the correct wires. And if there's space in the Sol-Ark for the CTs. I used a meter made by Elkor. They are from Canada.
Don't waste you time with the utility until you know if you can install the CTs in the Sol-Ark. I'm sure your state has a list of approved revenue grade meters. You should pick off that list.
The Elkor meter has a Modbus RS485 interface. There is an optional display but I did not use the display.
 
I have a 12K and I don't know what requirements you have with the 15K model. You mentioned they require a revenue grade meter for any system over 10K and I think I remember seeing that when I got started looking into SREC's. I don't know who requires that is it the power company you have or is it the GATS system? I didn't think the local utility had much to do with SREC's at all. I realize you sell power to the grid via your local utility, but the GATS system records your total production each month and then you sell the SREC on an open exchange just like the stock market (kind of) regardless of who your local utility may be. You have to record your production into the GATS system and if you're below I think the 10K that you mention, you can manually read your monthly production total and enter that manually by typing it into the GATS system.
 
If you meet the requirements (you have a 15K so I don't know what is required), you can look at total production for the month within PowerView and then manually record that into the GATS system each month. I imagine you can automate it with a meter of some type, but my view is the SREC's aren't going to last forever so manually recording monthly production number each month is not a big deal and worth it. You can automate the exchange that you decide to use where it can automatically pull the info from GATS and sell the SREC's but if you want to kind of go old school and manually do it each month, try Flett Exchange. You enter production each month into GATS, then you sell the SREC on Flett. Flett will do direct deposit or postal mail a check to you. Again, I'm unsure why you need the power company involvement for SREC.
 
Not sure if this helps but I think its a list of SREC brokers by State

btw, SRECtrade, SunTribe, Flett, SolSystems, are all brokers and theres more out there, depends on the State you live in on which ones serve your area I think. Some will say they can do it all for you and set it all up and make it more automated but I'd suggest you compare the rates and what you get to pocket when looking to go with a SREC broker. Some are better than others and depends on what you want to do (more automated or more manual), what State you're in, etc. Also, not sure about this but was thinking you can sometimes sell SREC's in other States, not just the State that your solar system is in.

Trying Googling "SREC Brokers" and go from there. Read until your eyeballs glaze over.

Also, makes me wonder, how many solar companies install solar systems for customers, yet they lease the system to the property owner, so the property owner doesn't own the solar system, the solar installer does. Then the solar installer gets the SREC's maybe? Do they always disclose this info to the property owner/customer that they are installing solar for? I'm not certain but thinking if you lease your solar system then you don't get the benefit of being able to sell SREC's (since you don't own the system). Don't quote me, I may be wrong, just thinking out loud so to speak.

Sorry I am not more help, I just try to get people to thinking and hopefully point them in a direction that they can jump and state learning more.
 
Also, I think too you have to think about SREC contracts, some are 3 years, 5 years, 10 years and you get roped in. I think many of the SREC brokers that want to do it all for you will have you sell 3 years worth (if you choose that way) and you get a lump up front. I think they are buying your SREC's out front and you get a lump , yet they get more over the contract term because you decided to get all your candy bars up front and not wait for them. Too, I imagine some brokers are betting on that the price for an SREC will increase over the coming years so they buy you out day one with a lump. Personally, I'd stay away from the contracted terms and just do Flett manually and go month-to-month without a term contract. Food for thought.
 
It seems like this thread has gone off topic.

I also have the same problem as the original poster. New Jersey's SREC program requires that that the inverter or revenue grade meter conform to ANSI C12.1-2008. The Sol-Ark does not currently comply. I reached out to Sol-Ark technical support. They are currently developing "revenue grade" CT's that allow the Sol-Ark to comply. Although Sol-Ark did not commit to a release date, they did indicate that it should be within a few months.
 
I hate to be the bearer of more bad news, but I also talked to SolArk about this exact problem, and the CTs they are designing are only for the Grid connection; upgraded versions of the ones that shipped with the 15k. The shipped ones are 5% accurate. The new ones will go in the same place and only allow you to monitor the exported power more accurately, not monitor production . . . So we could potentially put a revenue grade meter on both the load and the grid and do the math . . . or do as @SolarRich suggested and find a spot in the 15K to put CTs and to monitor the full production. However, I live in OH and SRECs are pretty cheap, so maybe I'll give up on the idea of monitoring them. SolArk also through out the idea of monitoring DC power, but I don't think that will fly or is any improvement: accuracy will be off because of the DC --> AC conversion and would probably need 3 Meters or to find a common DC bus to clamp onto inside of the 15K. Definitely will keep following this thread though. Thanks for the discussion all.
 
So we could potentially put a revenue grade meter on both the load and the grid and do the math ...
 
We were required to do the same thing for our SRECs. I just installed a revenue grade meter next to our inverter between the meter base and the inverter. This met requirements. Now that is just going to provide “net” kWh used. You are not required to have revenue grade data for your loads. I did add another (not revenue grade) energy monitor on my loads panel so I can have an accurate account of my loads. I am able to mathematically calculate my PV production from these 2 data sources (one revenue grade one not revenue grade). Yes you could go to the expense as suggested above and purchase a revenue grade monitoring system (it would be nice for sure) but I don’t think it’s necessary for compliance. As long as you have one attached. I was able to calibrate my non revenue grade system to within 2-3 kWh per month for the past 8 years.

My question is who do you report this revenue grade data to if anyone? I can testify that within my 5 yr SREC period not once did anyone ask for or I report this data to anyone. I gave my SREC provider a log in to my non revenue grade energy monitor and I’m guessing they used those figures as my checks kept coming until my 5 yrs was up. Since we only have one shot at SRECs (no renewals) and my time period is up I recently removed it altogether.
 

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Now that is just going to provide “net” kWh used. You are not required to have revenue grade data for your loads. I did add another (not revenue grade) energy monitor on my loads panel so I can have an accurate account of my loads. I am able to mathematically calculate my PV production from these 2 data sources (one revenue grade one not revenue grade). Yes you could go to the expense as suggested above and purchase a revenue grade monitoring system (it would be nice for sure) but I don’t think it’s necessary for compliance.
It's definitely required for compliance. Since all of my PV goes to my loads and my batteries, and none goes to the grid, a single meter would not register any production. Either two sets of CT's are required or one set inside the inverter on the inverter's output. Th elater may not be possible.

My question is who do you report this revenue grade data to if anyone?
The data is read the data from the meter and then entered into the State's SREC program' web site. Although it's the honor system, you could get audited. Just like taxes, I prefer that everything be on the up and up.
 
It's definitely required for compliance. Since all of my PV goes to my loads and my batteries, and none goes to the grid, a single meter would not register any production. Either two sets of CT's are required or one set inside the inverter on the inverter's output. Th elater may not be possible.

The data is read the data from the meter and then entered into the State's SREC program' web site. Although it's the honor system, you could get audited. Just like taxes, I prefer that everything be on the up and up.
I get it and I actually like that metering system you posted. I was faced with a similar dilemma when I installed my Sol Ark. previously I had a set of CTs on the output of my GT inverter and a set on my Loads panel. Since my new install I left the CTs on my loads panel so I know exactly what my loads are. I had to move the other CTs to the Grid input on the Sol Ark and make the bidirectional so now I get a “net” grid usage. If I have used grid at the end of the billing cycle I then have to a subtract that from my load kWh to obtain my PV production in kWh. If I have a negative kWh (grid sold) then I have to add that amount to my load total to get my PV production.

I also bought an interface so I can read my smart meter on the house so I have beginning and ending meter reads for my billing cycle. I keep spreadsheets for the past 8 years and I can account for every single kWh used or produced since commission.

It took a lot of trial and error to get my energy monitoring calibrated properly. Buying one already calibrated and certified would be great and even if you could use revenue grade CTs on the Sol Ark I think an argument could be made to install the system you mentioned anyway.

How much is that system anyway?
 
I get it and I actually like that metering system you posted. I was faced with a similar dilemma when I installed my Sol Ark. previously I had a set of CTs on the output of my GT inverter and a set on my Loads panel. Since my new install I left the CTs on my loads panel so I know exactly what my loads are. I had to move the other CTs to the Grid input on the Sol Ark and make the bidirectional so now I get a “net” grid usage. If I have used grid at the end of the billing cycle I then have to a subtract that from my load kWh to obtain my PV production in kWh. If I have a negative kWh (grid sold) then I have to add that amount to my load total to get my PV production.

I also bought an interface so I can read my smart meter on the house so I have beginning and ending meter reads for my billing cycle. I keep spreadsheets for the past 8 years and I can account for every single kWh used or produced since commission.

It took a lot of trial and error to get my energy monitoring calibrated properly. Buying one already calibrated and certified would be great and even if you could use revenue grade CTs on the Sol Ark I think an argument could be made to install the system you mentioned anyway.
Just over $500 with (4) 200A CT's. Not bad.
 
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