eml2
Member
What is the definition of NEM? I get paid for exporting energy, but it's only at a fraction of what I pay. Also, I have TOU rates for usage, but fixed rate for export. So, is this NEM?
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I would not call that NEM. I would call that a Feed-In Tariff system.What is the definition of NEM? I get paid for exporting energy, but it's only at a fraction of what I pay. Also, I have TOU rates for usage, but fixed rate for export. So, is this NEM?
I spoke too soon about the virtues of 1.37.0. Friday was good, but Sunday has been terrible. There's nothing worse than discharge into Off-Peak. I will post the chart near the end of the day. The problem is that even after powering the house through the Peak on Saturday, the SOC was still relatively high. I think the Powerwall software doesn't logically handle what it feels is surplus energy.
Once again, I spoke too soon. I just checked the Backup History and evidently there was a 1 hour and 5 minute outage today. I have no idea when it was. There were no notifications. The chart shows the Powerwalls discharging for 15 minutes starting at midnight when the Model 3 started charging, then again for nearly 4 hours from ~4am-7am, but there is a taper on both ends, not a hard cutover. If there was only one interval with an intermediate value, you could say that the outage started in the middle of that interval, but the Powerwalls started discharging with 0.2kW at 03:45 and the grid did not read 0.0 until 04:00. The house was drawing 0.7kW continuously during that time.
So, here's today's chart, with just the home and Powerwalls shown for clarity in the second chart.I spoke too soon about the virtues of 1.37.0. Friday was good, but Sunday has been terrible. There's nothing worse than discharge into Off-Peak. I will post the chart near the end of the day. The problem is that even after powering the house through the Peak on Saturday, the SOC was still relatively high. I think the Powerwall software doesn't logically handle what it feels is surplus energy.
Once again, I spoke too soon. I just checked the Backup History and evidently there was a 1 hour and 5 minute outage today. I have no idea when it was. There were no notifications. The chart shows the Powerwalls discharging for 15 minutes starting at midnight when the Model 3 started charging, then again for nearly 4 hours from ~4am-7am, but there is a taper on both ends, not a hard cutover. If there was only one interval with an intermediate value, you could say that the outage started in the middle of that interval, but the Powerwalls started discharging with 0.2kW at 03:45 and the grid did not read 0.0 until 04:00. The house was drawing 0.7kW continuously during that time.
Actually, the Peak period behavior is unchanged. I would not call what it's doing during Peak "Self-Powered". I would call it "Discharge to export All Solar". The thing I was pointing out in my "good" chart on 1.37.0 was the behavior at the start of the Part-Peak period where it is discharging to zero out the grid before the solar ramped up above the household load. In the past, at best, it would put the Powerwalls in Standby at the start of Part-Peak until there was Surplus Solar, thereby reducing the grid contribution until it went to zero when the solar exceeded the household load.It’s odd because I’m on 1.34.2 / TBC / cost-saving and all my graphs look like your good graph, which is what I would call 100% self-powered by Powerwall during peak. (See my other thread on a bug in Tesla calc of this percentage, but the graphs and sum totals agree). And the only time I’ve seen off-peak discharge was the first day before TBC appeared. Now I hope I haven’t jinxed myself.
I would not call that NEM. I would call that a Feed-In Tariff system.
With the NEM that is implemented in California, they total the net kWh for each TOU period and multiply it by the rate ($/kWh). They total the dollars for that billing period and add it to your annual true-up balance.
For example: (totally made up numbers)
Peak: -75kWh @ $0.32/kWh = -$24.00
Part-Peak: -200kWh @ $0.25/kWh = -$50.00
Off-Peak: 800kWh @ $0.12/kWh = $96.00
Total: $22.00
That is true net metering.
This is an area of nuance which depends on the state and the utility. My utility is PG&E in Northern California. If PG&E is also your energy provider (ie. you didn't sign up with a DA provider or CCA) then they will only issue a check if you are a net generator. That means that at the end of the year you exported more kWh to the grid than you consumed from the grid. It is possible to have a couple hundred dollar credit balance due to TOU differentials on retail energy prices and have it wiped out because you were not a net generator. The Net Surplus Compensation for net surplus kWh is "wholesale" at about 3.5c/kWh.New to NEM. Let's assume the $22 is a credit. If all other months total net zero, at the annual settlement period, you will NOT be issued a check for $22, correct? This is due to the fact that (at least in my area) you would instead be credited at the wholesale rate. The $22 represents the consumer rate.
I'm same service, same rate, NEM2. Looks like I'm not missing anything with only 1.35.2. Sounds like only "self-powered" is predictable and usable.I have been upgraded to 1.37.1 recently.
I am in SCE service area of CA. Rate Plan TOU-D-A.
I don't have any shoulder time configured under the price schedule in the App. My peak time is 2pm-8pm. I then have everything else off-peak. I used to have issues with the PW going into discharge status during shoulder time. After a call into Support it was recommended that I eliminate the shoulder time so I just have peak and off-peak time scheduled. This fixed the issue with my PW going into discharge status during shoulder time.
I noticed that after the update my PW is now discharging during off-peak times. Just today my PW discharged during the night while my EV was charging and in the morning at 5am I could see the unit still discharging.
Not sure exactly what is going on but I would rather my PW not discharge during off-peak times.
I can see that I am not the only one noticing some different behavior because of this latest update.
I think prior to 1.37, eliminating the shoulder period was the correct strategy. However, they have "fixed" the shoulder period starting 1.37 so that it usually runs like Self-Powered. The early discharge during shoulder is gone. However, my system has discharged during Off-Peak when the SOC was high, like over 80%. It never used to discharge during Off-Peak at all. I am running TBC-Balanced mode.I have been upgraded to 1.37.1 recently.
I am in SCE service area of CA. Rate Plan TOU-D-A.
I don't have any shoulder time configured under the price schedule in the App. My peak time is 2pm-8pm. I then have everything else off-peak. I used to have issues with the PW going into discharge status during shoulder time. After a call into Support it was recommended that I eliminate the shoulder time so I just have peak and off-peak time scheduled. This fixed the issue with my PW going into discharge status during shoulder time.
I noticed that after the update my PW is now discharging during off-peak times. Just today my PW discharged during the night while my EV was charging and in the morning at 5am I could see the unit still discharging.
Not sure exactly what is going on but I would rather my PW not discharge during off-peak times.
I can see that I am not the only one noticing some different behavior because of this latest update.
This is an area of nuance which depends on the state and the utility. My utility is PG&E in Northern California. If PG&E is also your energy provider (ie. you didn't sign up with a DA provider or CCA) then they will only issue a check if you are a net generator. That means that at the end of the year you exported more kWh to the grid than you consumed from the grid. It is possible to have a couple hundred dollar credit balance due to TOU differentials on retail energy prices and have it wiped out because you were not a net generator. The Net Surplus Compensation for net surplus kWh is "wholesale" at about 3.5c/kWh.
On the other hand, if you are on a CCA (Community Choice Aggregation) then they have their own policies for the generation portion of the bill that they handle. Most will actually cut you a check for credit balances based on retail generation rates whether you are a net surplus generator or not. PG&E will still wipe out your credit balance on the transmission and distribution part of your bill at true-up and of course you have to pay the minimum delivery charges of ~$10/mo every month as well.
I have been upgraded to 1.37.1 recently.
I am in SCE service area of CA. Rate Plan TOU-D-A.
I don't have any shoulder time configured under the price schedule in the App. My peak time is 2pm-8pm. I then have everything else off-peak. I used to have issues with the PW going into discharge status during shoulder time. After a call into Support it was recommended that I eliminate the shoulder time so I just have peak and off-peak time scheduled. This fixed the issue with my PW going into discharge status during shoulder time.
I noticed that after the update my PW is now discharging during off-peak times. Just today my PW discharged during the night while my EV was charging and in the morning at 5am I could see the unit still discharging.
Not sure exactly what is going on but I would rather my PW not discharge during off-peak times.
I can see that I am not the only one noticing some different behavior because of this latest update.
Generally, you've got it. One more nuance, or should I say nuisance? If you have a recent solar system on PG&E or SoCal Edison, you will be on NEM 2.0 which also has Non-Bypassable Charges. So, even if you have 2,000 kWh surplus generation, you will owe a small amount for every kWh that you take from the grid that cannot be offset by your generation. So, let's say you use about 500kWh/mo charging your car during overnight hours. You will owe about 1 cent/kWh (made up number, I've never been able to figure out the exact calculation) so you will owe about $5/mo more, in addition to the $10/mo minimum delivery charges.Thanks for the feedback.
Arbitrary numbers below conceptually reflecting actual bill at annual settlement. Are my calculations and conclusions correct?
TOU: Yes
Total @ consumer rate: -$500
Net Surplus: -2000 kWh (generation to grid)
Net Surplus Compensation @ 0.04: $80 (2000 * 0.04)
Monthly Mandatory Charge for 12 months @ $10/month: $120
- Total annual liability to my utility is $40 (120 - 80).
- Size of total consumer rate, if reflecting a credit, is irrelevant to my bottom line.
- Monthly mandatory charge is NOT offset by monthly net generation at consumer rate.
- Should target to have a Net Surplus to cover the mandatory charge.
- For simplicity, self-powered mode, is the "better" option given difference in consumer rate I pay and the surplus rate paid by my utility.
It's odd how some see discharging during off-peak. I've always used Balanced and have never seen my system discharge during off-peak. What do you have your reserve set to?Set your TBC to Cost Saving, not Balanced. I have the exact same setup as you do, and 1.37.1 discharged off-peak on the first day because I was still using Balanced. Changing TBC to Cost Savings stopped all off-peak discharge.
It's odd how some see discharging during off-peak. I've always used Balanced and have never seen my system discharge during off-peak. What do you have your reserve set to?
We typically have ours set to 30% and have a shoulder period set. Ours discharge predictably during the shoulder but never during off-peak. I might try eliminating the shoulder to see if they discharge during off-peak as you've seen.I have the reserve at 40%. I also have no shoulder, just peak and off-peak.
I have the reserve at 40%. I also have no shoulder, just peak and off-peak.
Improved Time-Based Control algorithm for customers with Net Energy Metering (NEM)