Georgia Power monthly net metering (RNR-monthly)

[n.one.one]

I've ordered a 16 kW + 4 PW setup (from Tesla) and I'm rethinking the kW size because of the 10 kW limit on the Georgia Power monthly net metering plan (RNR-monthly). I'm looking for advice both for a qualifying 10 kW system as well as for a 16 kW system that will generate more than I will need (as of now).

• Can I use the PEV super off-peak rate ($.01) to recharge the Powerwalls and run the house on solar/PW during the day.
• If I have excess kW that go back to the grid what do they pay for that (after my other usage is netted out).

Any other advice would be appreciated.

 

[jjrandorin]

I've ordered a 16 kW + 4 PW setup (from Tesla) and I'm rethinking the kW size because of the 10 kW limit on the Georgia Power monthly net metering plan (RNR-monthly). I'm looking for advice both for a qualifying 10 kW system as well as for a 16 kW system that will generate more than I will need (as of now).

• Can I use the PEV super off-peak rate ($.01) to recharge the Powerwalls and run the house on solar/PW during the day.
• If I have excess kW that go back to the grid what do they pay for that (after my other usage is netted out).

Any other advice would be appreciated.

Point 1 = No
i have no idea what they will pay you for over production for point 2, but expect it to be minimal. US utilities are not interested in individual homeowners becoming mini utilities and dont compensate in a manner that makes that a feasible thing. Your plan should be for 100% of your current, and near future planed consumption.

 

[h2ofun]

I've ordered a 16 kW + 4 PW setup (from Tesla) and I'm rethinking the kW size because of the 10 kW limit on the Georgia Power monthly net metering plan (RNR-monthly). I'm looking for advice both for a qualifying 10 kW system as well as for a 16 kW system that will generate more than I will need (as of now).

• Can I use the PEV super off-peak rate ($.01) to recharge the Powerwalls and run the house on solar/PW during the day.
• If I have excess kW that go back to the grid what do they pay for that (after my other usage is netted out).

Any other advice would be appreciated.

Point 1 = No
i have no idea what they will pay you for over production for point 2, but expect it to be minimal. US utilities are not interested in individual homeowners becoming mini utilities and dont compensate in a manner that makes that a feasible thing. Your plan should be for 100% of your current, and near future planed consumption.

someone posted they make their system right below the 10K to avoid what ever costs happen above 10K

 

[wjgjr]

I do not know anything about the rules in GA, but something to be aware of is how a "10 kW" system is defined - is it the size of the array, the size of the inverter, or whichever is less? I bring this up because I believe this has been a point of potential confusion in other states, and it is of particular note with Tesla now that they are moving to their own inverters, with the only options being 3.8 kW and 7.6 kW, with no option for a 10 kW inverter (like the SolarEdge one they have been installing.)

 

[n.one.one]

I do not know anything about the rules in GA, but something to be aware of is how a "10 kW" system is defined - is it the size of the array, the size of the inverter, or whichever is less? I bring this up because I believe this has been a point of potential confusion in other states, and it is of particular note with Tesla now that they are moving to their own inverters, with the only options being 3.8 kW and 7.6 kW, with no option for a 10 kW inverter (like the SolarEdge one they have been installing.)

Thanks for the heads-up. After seeing your answer I read the tariff and it states: Renewable Energy Resources are residential applications with a peak generating capacity of less than or equal to 10 kWAC...". While I'm new at this it seems good that it doesn't say anything about 'whichever is less'.

 

[wjgjr]

Thanks for the heads-up. After seeing your answer I read the tariff and it states: Renewable Energy Resources are residential applications with a peak generating capacity of less than or equal to 10 kWAC...". While I'm new at this it seems good that it doesn't say anything about 'whichever is less'.

This seems to indicate the inverter is the limiting factor. What this seems to mean is you could pair, for example, 12 kW DC of solar panels with a 10 kW AC inverter and still be within the rules. Oversizing is a pretty standard practice (there are threads discussing it) as in most cases 12 kW of panels will rarely (and maybe never, depending on panel orientation) exceed the 10 kW inverter limit. When it does, it causes some clipping, but this is usually minor and can be offset by efficiency gains elsewhere. And, in this particular case, it is a good way to maximize production when the state is setting a fixed limit. In fact, it is most likely the case that your system is a 16.32 kW (48 340W panel) system and will be paired with 15.2 kW of inverter capacity (two 7.6 kW inverters.)

The specific issue with Tesla is that they are apparently phasing out their 10 kW inverter offering as they focus on selling their own inverters, which do not come in that size. So, with Tesla, if you need to stay under 10 kW, your only option may be to use a single 7.6 kW inverter. Potentially that could be paired with around a 9-10 kW solar array, depending on the specifics of your situation. It is possible Tesla might still have some 10 kW SolarEdge inverters available or that they might be installing them in specific cases like this, but it is something to confirm in writing as they typically reserve the right to use whatever they have available.

I do not know if Georgia would approve a system with over 10 kW of inverters but 10 kW or less of panels. Even if they would, that is likely not a great option, but that was where the "whichever is less" could potentially be a benefit.

So, in sum, I would say you might generally have three options to mover forward with Tesla:

1. Stick with the ~16 kW system from Tesla, likely paired with two 7.6 kW Tesla inverters
2. Accept a Tesla inverter within the 10 kW limit, which would likely mean ~9.5 kW of solar paired with one 7.6 kW Tesla inverter.
3. Convince Tesla to provide you with a 10 kW inverter (likely from SolarEdge), paired with ~12 kW of solar.

You will have to run the numbers on how each of these might work out, based both on current and expected future usage. If you could convince Tesla to provide the 10 kW inverter, I would say #1 and #3 are likely your best options, depending on the details of your usage.

 

[n.one.one]

....................So, in sum, I would say you might generally have three options to mover forward with Tesla:

1. Stick with the ~16 kW system from Tesla, likely paired with two 7.6 kW Tesla inverters
2. Accept a Tesla inverter within the 10 kW limit, which would likely mean ~9.5 kW of solar paired with one 7.6 kW Tesla inverter.
3. Convince Tesla to provide you with a 10 kW inverter (likely from SolarEdge), paired with ~12 kW of solar.

You will have to run the numbers on how each of these might work out, based both on current and expected future usage. If you could convince Tesla to provide the 10 kW inverter, I would say #1 and #3 are likely your best options, depending on the details of your usage.

Thanks for taking the time to do this comprehensive write-up. With all of the issues you raised I'm now thinking I may stick with the 16 kW system depending on how the panel layout works on my roof.

 

[Enginerd]

Hi @n.one.one, I'm checking in to see if there's an update regarding how you moved forward. I have a similar dilemma, so I'm also wondering if there was a substantiated answer regarding:

Can I use the PEV super off-peak rate ($.01) to recharge the Powerwalls and run the house on solar/PW during the day.

@jjrandorin said "no", but he lives in California and may not be familiar with the Georgia tariffs. Details of the Georgia Power RNR-10 renewable resources schedule discuss time of use (TOU) rate plans, and the plug-in EV rate plan, which I'm currently on, is one of these. There doesn't seem to be any explicit exclusion.

Obviously if I could generate 9.99 kW during the day, satisfying most of my needs except winter and summer peaks, sell any excess to Georgia Power at 3.4 ¢/kWh (ref: Participant FAQs net metering question), and only pay 1.437 ¢/kWh at night... I'd be in pretty good shape, even if I'm somewhat constrained by the 10 kW RNR-10 program max.

 

[jjrandorin]

Hi @n.one.one, I'm checking in to see if there's an update regarding how you moved forward. I have a similar dilemma, so I'm also wondering if there was a substantiated answer regarding:

@jjrandorin said "no", but he lives in California and may not be familiar with the Georgia tariffs. Details of the Georgia Power RNR-10 renewable resources schedule discuss time of use (TOU) rate plans, and the plug-in EV rate plan, which I'm currently on, is one of these. There doesn't seem to be any explicit exclusion.

Obviously if I could generate 9.99 kW during the day, satisfying most of my needs except winter and summer peaks, sell any excess to Georgia Power at 3.4 ¢/kWh (ref: Participant FAQs net metering question), and only pay 1.437 ¢/kWh at night... I'd be in pretty good shape, even if I'm somewhat constrained by the 10 kW RNR-10 program max.

Has nothing to do with georgia tarrifs. Tesla does not currently setup "charging powerwalls from the grid" for powerwalls in the US, so thats why the answer is "no" with tesla. Other storage systems may have a different answer, but the answer for tesla powerwalls charging overnight from the grid, when you also have solar power, is "no" (not without basically logging in as an installer and changing settings we are not supposed to touch).

 

[Enginerd]

Has nothing to do with georgia tarrifs. Tesla does not currently setup "charging powerwalls from the grid" for powerwalls in the US, so thats why the answer is "no" with tesla. Other storage systems may have a different answer, but the answer for tesla powerwalls charging overnight from the grid, when you also have solar power, is "no" (not without basically logging in as an installer and changing settings we are not supposed to touch).

Ah, thanks, I see I misread the OP's question. For myself, I'm envisioning using solar to power the house and charge (discharge as needed) the PWs during the day, then using cheap grid power at night after the PWs run low. It would bring me great joy to mostly buy low (1.437 ¢/kWh) and sell high (3.4 ¢/kWh), if Georgia Power allows it.

 

[jjrandorin]

Ah, thanks, I see I misread the OP's question. For myself, I'm envisioning using solar to power the house and charge (discharge as needed) the PWs during the day, then using cheap grid power at night after the PWs run low. It would bring me great joy to mostly buy low (1.437 ¢/kWh) and sell high (3.4 ¢/kWh), if Georgia Power allows it.

Yes, you can do that. The powerwalls (in the US) need to be charged with energy from your PV system, if you have PV. If you use teslas advanced modes to setup time of use times in the tesla app, the powerwalls can cover the higher priced times, and you can let your home run from the grid in the lower priced times.

What you cant do, is charge the powerwall to full fromm cheap grid power overnight, then sell all of your solar power from the day to the grid (because you filled your powerwalls from the grid overnight).

 

[n.one.one]

Hi @n.one.one, I'm checking in to see if there's an update regarding how you moved forward. I have a similar dilemma, so I'm also wondering if there was a substantiated answer regarding:.............................................

I'm glad I didn't see your question until now because @jjrandorin answered it much better than I could have. I suspected that was the limitation but could not have stated it with as much confidence as he did.

 

[Enginerd]

So did you end up with the 16 kW then? And the <10 kW inverter kept you in the RNR-10 program?

 

[n.one.one]

So did you end up with the 16 kW then? And the <10 kW inverter kept you in the RNR-10 program?

I have been told by Tesla that I have been approved for the larger system which will probably mean I won't get net metering. If Tesla had an inverter that was exactly 10 kW AC I could probably put up enough panels for 15+ kW DC and still get net metering, but since their inverters are currently either 7.6, 3.8, or a combination, I can't optimize the system.

I haven't gotten a design yet for the larger system and I don't expect to have installation until this fall since they are just getting started in the metro Atlanta area. Are they in Savannah, or planning to be there?

 

[h2ofun]

I have been told by Tesla that I have been approved for the larger system which will probably mean I won't get net metering. If Tesla had an inverter that was exactly 10 kW AC I could probably put up enough panels for 15+ kW DC and still get net metering, but since their inverters are currently either 7.6, 3.8, or a combination, I can't optimize the system.

I haven't gotten a design yet for the larger system and I don't expect to have installation until this fall since they are just getting started in the metro Atlanta area. Are they in Savannah, or planning to be there?

Maybe you should not use Tesla since without net metering I might never have put on solar.

 

[n.one.one]

Maybe you should not use Tesla since without net metering I might never have put on solar.

Georgia has some significant differences from California that prompted my decision.

• The payment rate for power sent to the grid is pretty low and with a cap of 10 kW AC I wouldn't generate enough to make it worthwhile.
• My utility has a very attractive EV rate at night (1.33 cents per kW). I'm hoping to time shift vehicle charging, etc. to take advantage of that.
• The area I live in has a LOT of power outages ranging from a few minutes, to a few hours, to many days in the event of an ice storm. I'm installing the system to solve that more than for cost savings or payback.

 

[Enginerd]

Are they in Savannah, or planning to be there?

I found an installer to put in a PW system, but Tesla isn't doing roofs here yet. Even if they were, I'm probably going to stay within the 10 kW cap, so I'm not sure a Tesla solar glass roof would make much sense with such a low ratio of active tiles.

 

[darhall993]

Georgia has some significant differences from California that prompted my decision.

• The payment rate for power sent to the grid is pretty low and with a cap of 10 kW AC I wouldn't generate enough to make it worthwhile.
• My utility has a very attractive EV rate at night (1.33 cents per kW). I'm hoping to time shift vehicle charging, etc. to take advantage of that.
• The area I live in has a LOT of power outages ranging from a few minutes, to a few hours, to many days in the event of an ice storm. I'm installing the system to solve that more than for cost savings or payback.

I'm a Georgia Power customer in Atlanta area as well. (Sandy Springs). A few things to consider:

1. The EV Rate for SuperOffPeak runs the entire house so that is something to take advantage of with everything you can shift to that timeframe, (car charging, electric hot water heating, dishwashing, running the dryer, pool pumps, crypto mining etc)
2. Even if you had solar only it can help quite a bit during the summer Peak which is around 22cents per kW when your AC units will be, is this a new place?
3. Have you been through a summer with this location? Avoiding 1000's of kWh's at the peak would be huge in this area of the country
4. I have quite a bit of power trouble here as well, I do have a generator at this location to help with that. Last year alone we had ~70hrs of outage, gets pretty hot after an hour or two without power here in summer

 

[Enginerd]

Checking in again. I just picked up a PW2 at a good price, and I was thinking about finding another PW2 so that I might have a chance to run my AC if I lose power. Now I'm realizing that since the inverters are integrated into the PW2, if I want to stay below the 10 kW inverter capacity for net metering in Georgia, this means I can't have more than one PW2? If so, bummer. I see there's legislation on the horizon to increase the 10 kW limit to 20 kW. Even with 20 kW, that would prevent me from getting the recommended 3x PW2's (3 x 7.5 > 20) to run my AC. This is so constraining... I'm guessing this is why @n.one.one is bypassing Georgia net metering. I have to run the #'s to see if I should do the same.

 

[n.one.one]

............ If so, bummer. I see there's legislation on the horizon to increase the 10 kW limit to 20 kW. ...........

Thanks for posting about the potential legislation. This was the first I had heard about that.