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.