Grid Tie w/ Micro Inverters... an alternative to tying into breaker panel (load center).

[TimC]

No, I'm not proposing an alternative. I'm wonder about the situation with my utility and my proposed grid-tied micro inverter system.

If I understand correctly, the wiring from micro inverters in a grid tied system comes out of the safety disconnect (near meter socket ideally) and goes directly to a double pole breaker in my home's load center panel. Now, please take a look at my utility's one-line diagram of the system they require (attached). The wiring goes from the disconnect straight to a net metering meter. Their design includes a second, revenue meter. Wires from the inverters don't connect directly to the breaker panel.

So, I don't have any particular problem with any of that. However, the equipment supplier is trying to sell me an Enphase Envoy ($500) to go along with my system order while insisting that it will diagnose any problems with individual micro inverters and/or panels and provide me with data about my panel productivity. First, I'm not really a data geek (no insult intended to those that lean that way). I am OK with results showing up on my monthly utility bill's details. And I'm thinking checking individual panel and micro inverter status might be accomplished by a much cheaper, though more labor intensive method if I suspect problems. The other concern I have is having quickly looked through the installation of the Envoy, it connects to and is powered by the breaker in the load center. I'm not sure how you connect that thing with my utility's design (two meters) without any direct run to a load center breaker. I'm thinking a safety disconnect with a breaker instead of just a mechanical shutoff?

While I am waiting for a response to my request for details/explanation from the local utility's technical rep I thought I would run it by the forum to see if anyone has dealt with a micro inverter, grid-tied system involving two separate meters and no wire to the load center.

Any thoughts?

Tim

 

[Knighthawk]

The diagram looks right. I personally would want the data that box provides. I understand if you don't. A tech working on your system will thank you if you have it. May save a world of hurt when you need to diagnose a problem diy style.

 

[TimC]

Yeah, I haven't written it off totally yet. Though, it adds almost a year to my payback time. Are these systems unreliable enough to justify it... is my big concern. That, and how would you power/connect it if nothing is running into the load center? That's really the gist of the post. Not an argument for or against the Envoy.

But as long as we are on the subject of the Envoy's usefulness... As a risk taking DIYer I'm thinking I could find a faulty micro inverter simply bypassing one inverter at a time with a patch cable. If a bypassed inverter makes a difference in watts it would be OK. If no difference then it, or the panel is possibly faulty. A similar process to eliminate the panel would tell you if a particular panel was faulty. Maybe worth an experiment before I invest in the Envoy. Im probably being too simplistic. Maybe I'll ask that question in the "Danger Zone"! ?

 

[TimC]

Road Block in my solar plan...

After contacting several reps for my electric utility I have been told that for my grid tied, micro inverter system I do not route the array output out of a disconnect to my load center (breaker panel). I assumed that the utility will replace my single meter with a net metering meter and away we go. At least that's how I have viewed it on many video tutorials about using a micro inverter, grid tied system. Then they threw the dual meter requirement at me. I assumed that installing a second meter and wiring it to the system would not change my plan completely.

According to my utility reps, who have admitted they have never overseen a customer generation project, I have to take my current service entrance (overhead, one meter) and tear it out and replace it with a dual meter (one revenue meter, one net metering meter) service entrance. Then, from my disconnect I have to terminate the wiring in the net metering meter. As I look at this I am realizing that my estimates for installation costs just went up a minimum of $1500 if I attempt to change out the meter without a licensed electrician (not gonna happen). It probably is more than that as the dual meter socket alone is around $750 shipped. So, my payback for the system just went from about five years to close to ten if I end up hiring someone to redo my service entrance.

I was happy with my equipment quote of under $4500 and estimate for my PV rack of another $550 for a 4500 kWh system and was about to start digging post holes and setting posts in concrete. Miss Dig did their marking and I'm ready to get that accomplished. Then the big fat road block developed.

Anyone experienced this kind of complication with a grid tied micro inverter build? I was aware that I might have to add a meter to the system and that would add a hundred bucks to my plan, but, this is a game breaker for me.

Tim

 

[svetz]

AFAIK there's no reason for a revenue meter (I don't have one, but if it's a utility requirement not much you can do) and it doesn't matter where the AC from the inverter's join's into the system as long as it's on a breaker (which I believe can be in the combiner box). The closer to the meter the better IMHO. A "normal" house usually has the load center on the opposite wall from the meter, so it usually makes a great place to tie in (my load center is about 60' from the meter due to the BFE).

Rather than tap into my load center, my installation taps into a cutoff switch at the service entrance. My utility just swapped the old meter for a net-meter (that is, just the glass part that sticks out of the mounting case as shown to the right). My meter is an Itron (see Using RF to read ITRON utility meters)

I'm not sure how you turn up an Enphase system without an Envoy, as I understand it the Envoy talks IP over the AC wire to microinverters and the microinverters as shipped need to be "activated". There's probably some alternate way to do it, but I don't know what it is. I do have an Envoy, but I'm a data geek and I'll eventually need it for the battery as it controls that too.

I'm assuming the Enovy is reliable, it's rated to sit outside and has a 10 year warranty (although you might need to be a qualified installer to get that warranty).

See Solar Prices Plummeting? ... could be time to renegotiate a price.

 

[TimC]

AFAIK there's no reason for a revenue meter (I don't have one, but if it's a utility requirement not much you can do) and it doesn't matter where the AC from the inverter's join's into the system as long as it's on a breaker (which I believe can be in the combiner box).

Yup, I'm aware of most of that. Except I'm not forum savvy enough to know what AFAIK means.

I am beyond the Envoy issue as the model available today for outdoor use is now priced just above what the indoor model was a few weeks ago when I began looking for pricing. I'm hoping someone with experience with the dual meter socket, grid tie system will chime in to share their experience.

At my PV experience level (very low) I don't want to tell the utility that their design is out of date for use with micro inverters, but, I suspect it may be. Matbe they are designed solely for string inverters and MAYBE don't take into account newer technology. Looking through the utility's Electric Service Manual that we (and contractors I assume) are supposed to use to ID the correct dual meter socket models that are acceptable I found that many of the model numbers they list, from SQ D, Midwest, Milbank, CH, Siemens and Murray cannot be found in current Mfr catalogs.

Tim

 

[SmartElectric]

I was aware that I might have to add a meter to the system and that would add a hundred bucks to my plan, but, this is a game breaker for me.

I had many options here in Ontario Canada.

One of them was to implement "load shed", meaning, deploy only as much solar as you would reasonably need to shed the load of your house over the sunny summer months. In my case that was 2 kW of panels. I wouldn't get paid to push power back to the utility, I'd only be reducing my own load on the utility, and any surplus would be a bonus for the utility.

In my case that worked because
1. Have pool pump and air conditioning running on hot summer days.
2. Have electric car that can be configured to charge slowly during the day when #1 isn't a big draw (meaning, sunny but colder day in April).
3. Outside of the peak summer months, the solar output is less, and our electricity usage is less during peak sun hours

This allowed a deployment without changing the meter and reduced my cost by $1500.
Since 2 kW of solar with micro inverters is very cheap, that was my plan ...

Until I completely redid my plan, further info on that when I get time to make a "my system" post.

 

[TimC]

I had many options here in Ontario Canada.

So far no "other" options with WE Energies. If I want to go grid tied I must change out my single meter to a dual meter. I can pick up a Siemans dual for as little as $200 shipped (yes, I know that doesn't complete the materials for the project), and I suspect an electrician will charge me up to $1k to change it out. If I get that done for around $1200 that increases my costs for the system by 25% and throws my payback period out another three years.

It's beginning to look like it just wasn't meant to happen. Oh well, designing the system was a fun way to cope with Covid-19. I may not get a chance to have the fun time building it, but, the robins are singing and the lakes are free of ice now and there's backpacking to do!

Tim

 

[sed6]

This forum is full of other members who's plans are blocked by their stupid utility company. Myself included. Many of us just keep on building and tie into the grid anyway without the blessing of the utility company. My plan is just to load shed and save about $30/mo. I'm not jumping thru any beauracratic hoops for that kinda savings.

 

[TimC]

I found an electrician who seems interested in my needs. He is going to take the utility's spec sheets and find a source and work up a bid to change out the meter. I don't feel comfortable doing this myself. If the change over is under $750 for time and materials I may go forward even though it will add up to two additional years to my payback estimate.

The utility's local Engineer for Customer Owned Generation is also looking at specific directions that I can take. I'm still of the opinion that my utility is not necessarily fighting the movement to customer owned generation. Are they behind the curve, yeah, I might argue that that is true. I think electricity demand is going up. And the utility has always been in the lead trying to use alternatives to just building more power generation. They still have to answer to stock holders, but, I think their stockholders have realized from decades of the utility focusing on conservation that their investment is in it for the long run.

Tim

 

[Skull_Leader]

This forum is full of other members who's plans are blocked by their stupid utility company. Myself included. Many of us just keep on building and tie into the grid anyway without the blessing of the utility company. My plan is just to load shed and save about $30/mo. I'm not jumping thru any beauracratic hoops for that kinda savings.

"Load Shed" Is that what it's called when you only only generate as much power as you use? If your array is generating 1KW, and the house is running 1KW worth of appliances, then it's like the array is powering it by itself.
If you generate more than 1KW, then the excess goes back to the Electric company, and if you have an agreement with them, they'll pay you for it. If no agreement, then you just don't get paid for it

 

[sed6]

"Load Shed" Is that what it's called when you only only generate as much power as you use? If your array is generating 1KW, and the house is running 1KW worth of appliances, then it's like the array is powering it by itself.
If you generate more than 1KW, then the excess goes back to the Electric company, and if you have an agreement with them, they'll pay you for it. If no agreement, then you just don't get paid for it

"Load Shed" Is that what it's called when you only only generate as much power as you use? If your array is generating 1KW, and the house is running 1KW worth of appliances, then it's like the array is powering it by itself.
If you generate more than 1KW, then the excess goes back to the Electric company, and if you have an agreement with them, they'll pay you for it. If no agreement, then you just don't get paid for it

Correct on load shed and sorta correct on the excess power. Old spinning meters will credit you for what goes out, the new digital meters will CHARGE you for what goes out, if you don't have a net metering agreement with your utility company. As such I generate enough PV power (about 5kWh per day) to offset only about 10-20% of my use and never feed any back to the grid.

 

[kernel]

There are a number af ways to accomplish dual meter enclosures and id have to say that unless the utility (isnt) supplying the enclosure(s) which is common a dual meter base is cost effective in the end versus some electricians labor knocking it together from a pile of parts.

It also allows you to backfeed up to the limit of your service conductors instead of 20, 30A, 40A and 80A for 100A-400A service equipment.

Some meter bases have dual lugs and can feed another meter along with a disconnect. Water heaters, space heaters air conditioning and car chargers use this arrangement for special incentive billing.

 

[Ampster]

There is a setting in the Envoy for no export. Depending on your building code you may be able to install a system that does not export and as others have said "load shedding". In that case you dont have to ask permission of your utility. Unless you have a municipal utility which controls the building code you can do whatever you want behind the meter as long as your installation meets code.. The economics will depend on whether giving up net metering is worth it. The Envoy would be less expensive than an extra meter if i understood you correctly.
BTW, to answer an earlier question the micros will work without an Envoy. I ran mine without an Envoy for a year. Activating them only refers to logging them into the Envoy so it can track their output individually.

 

[TimC]

BTW, to answer an earlier question the micros will work without an Envoy. I ran mine without an Envoy for a year. Activating them only refers to logging them into the Envoy so it can track their output individually.

I was hoping someone that didn't go with the Envoy would pop up! That is good information to have. I've been told by a rep at one supplier that the micro inverters will not work without the Envoy. Other suppliers have been less than honest about it at first then admit that it is not a requirement. Solaris is the only online supplier that I have contacted that right up front said it is an option, then detailed the advantages.

Without any experience with these micro inverters and the Envoy I suspect that trouble shooting is possible without the Envoy. It may be more labor intensive, but, possible. Like bypassing micro inverters one at a time and watching production... no effect on production may mean that micro inverter is not doing its job. Same with panels. Unplug a panel and check production. No change means that panel wasn't contributing to production and it may be faulty. I've found much of the communication technology in our world is necessary. It is mostly for those who want to be at a coffee shop, whip out their phone and see their current production. I am not going to be that actively looking at production. If someone needs that great. Once a month on my utiltiy bill will be enough for me.

I'm also not really interested in work a-rounds when it comes to the utility. I may be putting the house on the market in the next ten years. I don't want to explain that to potential buyers.

Tim

 

[TimC]

Well, here is the response from Enphase about my concern that their installation PDFs on the micro inverters and Envoy don't mention connecting to a net metering meter rather than straight from a disconnect to my load center breaker...

support@enphaseenergy.com via 0mnx18vjx8j8.a-aq9dmau.na95.bnc.salesforce.com	Mon, May 4, 12:07 PM (23 hours ago)
to me, noreply@enphaseenergy.com

Hello Tim,

Thank you for contacting Enphase Energy. I hope you and your family are safe and well.

I am sorry but Enphase is not aware of the connections that should be on the utility side meters and so, I will not be able to give you an example installation for this.

I would request you to hire an electrician if you self-install the system or contact a local installer to help you with the installation. You can find an Enphase authorized installer from the list available below:

https://installers.enphase.com/locator.html

I am closing this case now, however, please reach out to me if you have any further questions to reopen the case.

Not sure about someone with an Electrician's License, or an Engineer working with solar PV systems, but, this response brings me no comfort that the Enphase equipment will function properly with my utility's requirements. Besides that comforting message, my local utility's contact person for service entrances and his Engineer for Customer Generation have no experience with Micro inverters connecting directly to a load center breaker. I'm beginning to think they have no experience with string inverters either.

I was going to go back to the drawing board and research string inverters connecting to a dual meter system, however, the two inverters I checked installation docs for both connect directly to a breaker in the load center. No mention of other possibilities.

I wish there was a simple solution to all this, but, there's just too many unanswered questions and I have failed to find anyone with a dual meter system install. It's no longer a matter of spending over what I originally budgeted for this project. It has now landed on - after spending said moneys will the system work?

Tim

 

[TimC]

So, related to the post above, I threw some questions at a rep at Solaris and that resulted in a great deal of assistance answering questions about my utility's dual meter requirement. Ive worked through three or four on line suppliers and I'm amazed at the abundance of sales reps who just want to quote you a price and take an order. No offer to check with their technical department to answer concerns. Solaris is definitely the above and beyond exception. Now, if i can find an electrician who will take the job of swapping out the meter socket. Its not a difficult job, but, im sure i want someone with experience doing it. Three electricians have turned me down, wouldnt even quote the job. There's ttwo more locally i am trying, but, so far the first hasnt replied to direct phone calls, Wish me luck!

Oh, and Solaris was the first and only supplier I contacted that said up front that an Envoy is not required to use the Enphase micro inverters.

 

[Supervstech]

AFAIK
As Far As I Know...

 

[patdown45]

I decided to go with qs1 microinverters from AP systems that could take 1200 watts AP systems documentation would lead you to believe that it can only take 4 inputs I'm using two modules of 180 watts on each input so for my 46 modules I can use 6 microinverters still testing so time will tell. No two meter requirement here, the utility will swap out my smart meter for a smarter meter.....I hope after I get the coc ( certificate of completion) if I can find an electrician, to sign off the electrical permit. My town will allow me to sign my own work and because of covid they are not doing in person visits.....photos perhaps?

 

[Ampster]

At my PV experience level (very low) I don't want to tell the utility that their design is out of date for use with micro inverters, but, I suspect it may be. Matbe they are designed solely for string inverters and MAYBE don't take into account newer technology.

My guess is it is a policy decision to discourage people from installing solar. Fundementally micro inverters connect to load panels the same way string inverters connect. Your choices are do it their way or reduce your overall consumption by installing a battery system so you can consume all your solar production. I dont know what the building permit issues are in your state but in California, I can generate electricity behind the meter with only a building permit as long as I do not export to the grid.