Annual (temporary) goodbye to grid power?

[lodar]

I would agree with using Self Powered mode for any NEM 3.0 customer, but for those on NEM2.0 and a net producer extensively using the Powerwall results in less exports to the grid and a lower Net Surplus Compensation amount at true-up.

In fact, the most optimal algorithm for maximizing income is neither all TBC nor all Self Powered. The best algorithm is to use TBC during peak and Self Power off-peak. With this algorithm, fine-tuning utility rate settings is moot.

During peak, you ideally want every Wh of solar to be going to the grid, earning at the highest rate.

At off-peak, you want to avoid “banking” grid power that you would have to pay back with NBC “interest”. Ideally, solar should be powering your home and charging your batteries back to 100% without grid help. Any excess off-peak solar can be dumped to the grid for a small gain, as there’s nothing more you can do with it.

The end result is effectively no grid draw, with no NBCs, and maximum revenue from solar exports during peak.

Of course, this only works when you have a daily solar surplus. For me, this is spring time before AC kicks in.

 

[yblaser]

In fact, the most optimal algorithm for maximizing income is neither all TBC nor all Self Powered. The best algorithm is to use TBC during peak and Self Power off-peak. With this algorithm, fine-tuning utility rate settings is moot.

During peak, you ideally want every Wh of solar to be going to the grid, earning at the highest rate.

I don't think that is true for everyone. As a net produced sending all my solar to the grid during peak just increases my energy credits which I end up losing at true up. It also uses more of my PW energy during peak to cover the house loads which means less off peak energy that my PW could cover overnight.

 

[Redhill_qik]

Note: Everything I write below is for California NEM rules and may not apply to other NEM rules.

In fact, the most optimal algorithm for maximizing income is neither all TBC nor all Self Powered. The best algorithm is to use TBC during peak and Self Power off-peak. With this algorithm, fine-tuning utility rate settings is moot.

There is no single right answer for everyone. What is optimal for a NEM 2.0 net consumer, is not the same as for a NEM 2.0 near zero consumer/producer which is not the same as a NEM 1.0 net generator. For NEM 3.0 sites the potential solutions is much more narrow, but there is likely still some uncertainty for some situations.

How exactly do you think TBC during Peak is any different than Self-Powered during Peak?

During peak, you ideally want every Wh of solar to be going to the grid, earning at the highest rate.

If you are under NEM 3.0 where it is extremely hard to get to a negative annual true-up balance then exporting as much as possible during the few hours a day that have the highest export rates would be beneficial. This isn't just solar, but also enable the Powerwall to "Export Everything" during those hours.

Under NEM 2.0 a net consumer with a need to drive down the true-up balance then the also want to export as much as possible during the Peak period. If you are near zero consumer/producer then a slight maybe if you are a net generator then this doesn't matter.

Once the projected true-up balance goes negative having it go even more negative has no value. Using a Powerwall to increase exported kWh or cover the house load is detrimental because the Net Surplus Compensation is based on net kWh not the net price (except for 1-2 CCAs) and the efficiency loss in the Powerwall discharge/charge cycle leads to lost kWh exported.

Of course, this only works when you have a daily solar surplus. For me, this is spring time before AC kicks in.

What happens day-to-day doesn't really matter, what matters is how your entire year accumulates.

 

[CrazyRabbit]

I’ve started running self powered. My utility will now pay me the avoidance cost (retail rate minus 4.5 cents) for my export, but I buy back at full retail rate. Should result in money in my pocket.

 

[sunwarriors]

Adding a bit of my own anecdote, these batteries also have an aspect of “use it or lose it” to them as well. My 10 year old Model S’s battery died with only 80,000 miles on it. All that careful driving and micromanagement and it didn’t buy much more life on the battery. Compared to others who drove their Model S farther, harder, and supercharged all the time.

Haha, that could be equated to health too. Just random variables/things really. Some chain smoker living till 95+ and friends passing at 60 or something. Can't be helped and probably some impact, but not that much in terms of batteries.

 

[Matt-FL]

Following up on this, probably the best month so far. 30 days and no pulling from grid other than sync.

Even looks great going back 90 days to February...

 

[GregBallantyne]

Following up on this, probably the best month so far. 30 days and no pulling from grid other than sync.

Even looks great going back 90 days to February...

Today will be the 28th consecutive day for me. But my delusion regarding the possibility of continuing that stretch until September may be in jeopardy already. I may end up drawing some grid power in a day more two, if the forecast is true. After 3 in the afternoon today, only generated 5.7 kwh today. Generation not keeping up with demand - PWs just dropped below 70% or 30.4 kwh remaining. We will be down to around 15-18 kwh left in the PWs by the time generation starts again tomorrow, but don't expect to do as well. Much more rain and less sun is forecast. The next day of decent generation appears to be Monday at the earliest.... might squeak thru, but looks unlikely. Temps are at a helpful point, but.....
Another PW (or 3) sure would be helpful for a credible claim of seasonal off grid capability. Matt-FL, what software are your screen shots from?

 

[Matt-FL]

Today will be the 28th consecutive day for me. But my delusion regarding the possibility of continuing that stretch until September may be in jeopardy already. I may end up drawing some grid power in a day more two, if the forecast is true. After 3 in the afternoon today, only generated 5.7 kwh today. Generation not keeping up with demand - PWs just dropped below 70% or 30.4 kwh remaining. We will be down to around 15-18 kwh left in the PWs by the time generation starts again tomorrow, but don't expect to do as well. Much more rain and less sun is forecast. The next day of decent generation appears to be Monday at the earliest.... might squeak thru, but looks unlikely. Temps are at a helpful point, but.....
Another PW (or 3) sure would be helpful for a credible claim of seasonal off grid capability. Matt-FL, what software are your screen shots from?

Sorry to hear that, but even so, 28 days is a great run! Hopefully it doesn't end with zombies

The screenshots are from Powerwall Dashboard:

GitHub - jasonacox/Powerwall-Dashboard: Grafana Monitoring Dashboard for Tesla Solar and Powerwall Systems

Grafana Monitoring Dashboard for Tesla Solar and Powerwall Systems - jasonacox/Powerwall-Dashboard

github.com