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

[GXMnow]

The diagram with the dual meter just looks bad. Even if you consume all the power you produce, and nothing from the grid, your consumption meter will show all of the power. It is up the them to decide how much they will compensate you for the power you produce and send out the second meter back to them. I know they did systems like that before there were smart meters, but this is an obvious rule to make solar electric far less economically viable.

There is no reason that the Enphase inverters would not work going to the separate meter. It is just a matter of how the utility will use the data for billing you. In the more normal installation like mine, if I am producing less power than I am using, my consumption meter just runs slower, so I only pay for the power I still need to buy. That is how it really should be. With the dual meters, your consumption meter reading will not change, it always will count the power you use in your house. You are basically feeding your power out to the whole neighborhood and selling your power to the utility, at whatever they feel like paying you for it. And I will bet it is far less than they are charging to use that power, even as you are making it.

If I was stuck with a utility that required that, I would certainly do a self consumption system with a battery bank and set it up for zero cell to the grid. Even with your dual meter setup, you could put the system on the second meter. Use a Hybrid type inverter system, with it's "grid" input connected to the production meter. Then it should also have a backup power output. Have that side feed a sub panel in your home for your "essential loads". Depending on the utility requirements, you may be able to just use some power on the second meter, or you could have an automatic transfer switch move the "essential loads" to the main meter when the batter runs low and can't supply it. This way, all the solar will run your loads, and charge up a battery while the sun shines. As the sun goes down, the battery runs your loads. If you made more than you use, the battery will still have some charge, and it may eventually top out, but more likely, the battery will run down, and if it get's too low, then you pull the power you need from the utility again. In many areas, a system like this is completely legal and does not require any special agreement with the utility since you are never pushing power out to them. You are just using less power from them. Many people do this without even contacting the utility.

My system is an Enphase grid tie setup and I did get a net meter agreement and can legally push up to 4,000 watts peak or 900 Kwh per month back to the grid. My utility is Southern California Edison, and it uses a single iTron smart meter. I have seen it counting backwards at up to 3,100 watts. But even with this setup, SCE has found ways to make it less valuable. They forced me to "Time of Use" billing so when I over produce, the power is cheap, and when the sun goes down and I need to buy power, the rate is double. Because of this, I am in the process of installing a Schneider XW-Pro battery based inverter/charger. It will be able to take all of my over production and store it in the battery bank. I will then use the battery power during the peak rate time and not buy any of the over priced power from my utility. The cost of the inverter and batteries will take about 12 years to pay off on the electric rate savings, so it really is not a financial help in that regard since the batteries will probably only last 10 years. But this setup will also give me backup power and keep the Enphase solar working with the grid down. With what I know now, I sort of wish I did the battery bank from the start and never got the net meter agreement. My old tiered power billing would be much cheaper than the Time of Use they stuck me on.

 

[Ampster]

In many areas, a system like this is completely legal and does not require any special agreement with the utility since you are never pushing power out to them. You are just using less power from them. Many people do this without even contacting the utility.

In fact in the state of Hawaii, most people are doing that because the monopoly utility was dragging their feet on approving solar installations. Other policy decisions were not favorable to solar so people just spent the extra money to install battery backed systems. My brother installed a Tesla Powerwall when he installed solar on a home on Maui. It is all electric there and the home is rented to vacationers who typically leave the Air Conditioning on with all the doors and windows open. The solar and semi self consumption dropped their energy bill more than half. He maxed out his roof with solar or he could have saved more.

 

[Ampster]

They forced me to "Time of Use" billing ....................
I sort of wish I did the battery bank from the start and never got the net meter agreement. My old tiered power billing would be much cheaper than the Time of Use they stuck me on.

That is good input for other readers in the future. Also it gives me an opportunity to talk about the leverage you can get with another type of battery. I have been driving EVs for almost 10 years and had solar for most of that. I had way over panelled my solar and did not have much consumption after the solar production zeroed out. What I did was use the grid to store solar at peak rates of $.45 per kiloWatt hour during the day and charged my EV at super off peak rates during the late night. In those days I was on SCE TOU rates and I was a net consumer of electricity but I had a negative bill in dollars at True Up so they balanced out. I basically charged my EV for free.

 

[GXMnow]

I have spent many hours in the last 2 months reading over the Southern California Edison interconnection rules, and they have done a great job at making it as confusing as possible with no benefit to anyone, and slowing the adoption of distributed power generation.

I do want to make sure that my battery storage addition is not only safe, but also legal. I can't find any pages that talk about adding storage to an existing solar generation system. I know my proposed wiring all meet the NEC codes, and I am over spec'ing the wire and keeping it all in metal conduit. They have fast track forms for a system that will not export power, and if the batteries and hybrid inverter went in at the same time as my solar panels, I would have been able to use that process. I still may be able to use it as the storage addition will basically be "non-exporting" as I want to store my over production and use it myself. Any amount I do end up exporting, is going to be far less than my current system which has been approved and operational for a full year now. Last month, it looks like I exported almost 10 KwH on average every day. That was 310 KwH that I pushed onto the grid in 33 days on my bill. In the same 33 days, I had to buy 777 KwH from them. 185 KwH was at the highest "On Peak" rate. If I can optimize the battery, I should be able to make that exporting less than 10 KwH, and also use NO peak rate power. Then I am only buying about 480 KwH of the "Off Peak" power. Yes I rounded up a little as I know there is a roud trip loss to charge and then discharge the batteries.

My current rate plan "TOU-D-4-9PM" has the off peak rate at $0.25 / KwH and goes to $0.33 to $0.40 / KwH from 4 PM to 9 PM. If I do have the system all legal under SCE, I should also then be able to change to the "TOU-D-Prime" rate plan. To have this plan you must have a plug in electric car and/or a home battery storage system. I currently drive a Hybrid, but it is not a plug in and the battery is too small, to qualify. The "Prime" plan has a slightly higher fixed daily charge, but has an off peak rate of just $0.15 / KwH. But the peak rate is still $0.30 to $0.41 from 4 PM to 9 PM, depending on season and weekend/weekday. As long as you use some power during off peak, that rate should be a decent savings. With the peak rate being almost the same, I hope to zero that out from the batteries. So all the power I have to buy should go from $0.25 down to $0.15 for most of the day. My next car will likely be a plug in. But I just can't go full electric yet, I am spoiled by 500+ mile range.

Under my current rate, that last month cost me $85 in purchased electricity and another $15 or so in taxes etc., even after they credited me for what I exported. Yes, my air conditioner was running the whole time. My Fall, Winter, and Spring usage is much less. If I can move to the "Prime" plan and buy just the 480 KwH, even that bad last month would only cost me about $70 in electricity, and $10 in taxes. This has been a hot summer here, and this is not a good example month, but it still shows me saving about $20 per month just by doing self consumption. Even if I stay on my existing rate plan, it should save me about $15 per month. Back in April/May, I only purchased a total of 87 KwH for the whole 32 day billing month. In total, I hope to trim my payments to SCE by about $200 a year. The grid tie solar already chopped my bill to 1/3 what it was. In summer I used to top $300 a month trying to stay cool in 110 F heat. My worst month since is under $100. And with the batteries, my worst month should go under $80. I may very well end up with some Fall, Winter, and Spring months going negative since I can still export power if I top out the battery bank.

 

[Ampster]

I had a Radian hybrid for a while when I had an EV rate with SCE. It was installed according to code but I moved and rented that house and sold the Radian on Ebay so I never got a permit.
I am now in a house in Sonoma with a 5.7 kW roof mount Solaredge system with a PTO from PG&E. Subsequently I installed the Skybox and the permit is pending but I have no intention of asking PG&E for permission because I do not want them putting a cap on my production. I am limited to an inverter capacity of 3.8 kWs plus I am allowed to add 1 kW of capacity.

Per my signature I have 4 panels on micro inverters and another 7 panels feeding the Skybox. That is a lot more capacity than PG&E allows but I can control that only 4.8 is exported which keeps me within my limit. However some of the new panels are west facing and they start generating as my GT system starts fading so I could theoretically export more while never going over 4.8 kW because my production extends later into the day.

However with the new pack I just installed I am moving more toward self consumption because my current NEM agreement has Non Bypassable charges and I don't want to be paying a lot of those when I charge my EVs. After I charge my house batteries by Noon I can generally get 3 or 4 hours of EV charging in using solar as the house loads are also covered by solar. The whole point of this long dialogue is that our needs change and you are looking at the right stuff to try to reduce your bills and self consume. The rates are going to change, the time periods are going to continue to get less favorable and self consumption will be the way to hedge against the increase cost of those changes.

 

[Camthecam]

I have an envoy and I have come to realize that its just for carbon trading. You can go into the menu and turn off share with enphase. I unplugged the rj45. If you want to go and check details as soon as you connect it to the net it sends all your data to them and they can sell your offsets to polluters. Didn’t know you could make amps without it! It’s a pain having it plugged into a wall near the meter.

 

[Ampster]

I have an envoy and I have come to realize that its just for carbon trading.

I use the data all the time to monitor my system. Do you have a source for this theory?
Enphase is not in the market selling carbon credits. If they were they could not sell your carbon offsets without compensating you. Do some research before you start some conspiracy theory rumor.

 

[GXMnow]

I certainly have my Envoy up and check it frequently. If I have a panel that is outputting low etc. it is nice to know right away. It is true the data is going to Enphase, but they are not directly profiting from it. They use it to keep track of how thier equipment is working in the real world and probably use some of the data to help with product updates. I would like a totally local version of the enlighten app though. svetz has been using the API to read out all the data. Maybe I will get really bored one day and try writing a VB program to grab and chart it? Probably not though. I just want to get my self consumption working a bit better.