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Estimated PV Generation PGE

power.saver

Grid Specialist
Supporting Member
Mar 4, 2018
641
673
Arcadia, CA

Ampster

Active Member
Oct 5, 2012
1,832
511
Kenwood, California
I did not look at the details of the EPBB calculation, but in my recent application they used the square footage times a factor to go with a number. If that is not sufficient to justify my current application I now have two months af actual usage including charging two Teslas and my wife baking a lot. That cosumption was over 1 mega Whrs and would justify an even larger number. This is Phase One for just the Grid Tie. Phase Two will be more, but it will be behind the meter and self consumed so I do not have to ask PG&E for permission.
 

miimura

Well-Known Member
Aug 21, 2013
6,717
6,563
Los Altos, CA
Thats great, but none of that stuff was sent in to PGE, so nothing to use. So, how are they calculating the number? All panels best angle? No shading? Or all panels worst angle and max shading?
The interconnection application is supposed to include everything in the linked PDF. That is all the data anyone needs to make a good estimation of system production.
 

h2ofun

Active Member
Aug 11, 2020
3,108
685
auburn, ca
I did not look at the details of the EPBB calculation, but in my recent application they used the square footage times a factor to go with a number. If that is not sufficient to justify my current application I now have two months af actual usage including charging two Teslas and my wife baking a lot. That cosumption was over 1 mega Whrs and would justify an even larger number. This is Phase One for just the Grid Tie. Phase Two will be more, but it will be behind the meter and self consumed so I do not have to ask PG&E for permission.
Seems there is no 100% clear process of what they use to approve. But I am happy.
 

sorka

Well-Known Member
Feb 28, 2015
8,338
6,281
Merced, CA
My interconnection application had this data. It was not complete the first time so PGE rejected it until Tesla re-submitted it.

The EPBB calculator WAY underestimates actual production. You'd for sure be better of installing an NGOM if there are times you're going to be away from home with things off otherwise you'll lose credit.
 

h2ofun

Active Member
Aug 11, 2020
3,108
685
auburn, ca
My interconnection application had this data. It was not complete the first time so PGE rejected it until Tesla re-submitted it.

The EPBB calculator WAY underestimates actual production. You'd for sure be better of installing an NGOM if there are times you're going to be away from home with things off otherwise you'll lose credit.
That is what I am worried about, shall see. But since I have lots of panels in poor directions, and shading, I might be okay. Meaning, the most I will get out of my about 30KW of solar is 22.8kw, and I have never even seen that.
 

swedge

Member
May 12, 2020
83
68
Oakland, CA
That is what I am worried about, shall see. But since I have lots of panels in poor directions, and shading, I might be okay. Meaning, the most I will get out of my about 30KW of solar is 22.8kw, and I have never even seen that.
h2,

The form used to apply for solar NEM includes tilt, azimuth, location, number and model of panels, see below. I don't see a shading correction, but I think that is OK for us.

https://www.pge.com/pge_global/comm.../interconnection-renewables/Form_79-1151B.pdf

I don't think you need to worry abut them overestimating your production. The estimate is only used to limit the amount of export for which they credit you. Since you alway produce less than their estimate, no harm done. The reason they do it at all is that PG&E really does not want you putting more kWh on the grid than you solar is estimated to be capable of producing.

One way that might happen is charging a battery from the grid at off peak, and then dumping it back onto the grid at peak. At current EV2-A rates, that'd be .35 - .18 = $.17 per kWh, $2.29 per full PowerWall per day, ~$67 per month, over $800 per year of illegal NEM credit per powerwall engaged in this energy arbitrage. At that rate, one could pay for a PW in what, maybe 15 years? Not an attractive ROI, so it is mostly just paranoia on PG&E's part. PG&E has an exclusive franchise to buy kW cheap and sell them expensive. In larger installations they do require certified meters on the solar production which report directly to PG&E, so this estimation thing is pretty OK for us. But it is why we get the "complex" (i.e. incomprehensible) billing.

In other news, as you know I have solar, but using my "hack" since the cloudy weather several weeks ago, I have been charging my PW from the grid after midnight every night, and then discharging to run the house after 3PM when the rate goes up. When it is sunny enough, my excess solar production still goes out to the grid, and because I'm still on NEM1 gets full retail credit, so it exactly offsets the cost of what I drew to charge the PW. The newest version of the Tesla app fixed the bizarre grid flow numbers, though the hack still makes the app show solar production and export as zero because it is added to the grid numbers. Anyway, grid charging is alive and well, and saves me a few $ even when it got cloudy a few weeks back.

SW
Screen Shot 2021-11-29 at 4.19.24 PM.png
 
Last edited:
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Reactions: h2ofun

h2ofun

Active Member
Aug 11, 2020
3,108
685
auburn, ca
h2,

The form used to apply for solar NEM includes tilt, azimuth, location, number and model of panels, see below. I don't see a shading correction, but I think that is OK for us.

https://www.pge.com/pge_global/comm.../interconnection-renewables/Form_79-1151B.pdf

I don't think you need to worry abut them overestimating your production. The estimate is only used to limit the amount of export for which they credit you. Since you alway produce less than their estimate, no harm done. The reason they do it at all is that PG&E really does not want you putting more kWh on the grid than you solar is estimated to be capable of producing.

One way that might happen is charging a battery from the grid at off peak, and then dumping it back onto the grid at peak. At current EV2-A rates, that'd be .35 - .18 = $.17 per kWh, $2.29 per full PowerWall per day, ~$67 per month, over $800 per year of illegal NEM credit per powerwall engaged in this energy arbitrage. At that rate, one could pay for a PW in what, maybe 15 years? Not an attractive ROI, so it is mostly just paranoia on PG&E's part. PG&E has an exclusive franchise to buy kW cheap and sell them expensive. In larger installations they do require certified meters on the solar production which report directly to PG&E, so this estimation thing is pretty OK for us. But it is why we get the "complex" (i.e. incomprehensible) billing.

In other news, as you know I have solar, but using my "hack" since the cloudy weather several weeks ago, I have been charging my PW from the grid after midnight every night, and then discharging to run the house after 3PM when the rate goes up. When it is sunny enough, my excess solar production still goes out to the grid, and because I'm still on NEM1 gets full retail credit, so it exactly offsets the cost of what I drew to charge the PW. The newest version of the Tesla app fixed the bizarre grid flow numbers, though the hack still makes the app show solar production and export as zero because it is added to the grid numbers. Anyway, grid charging is alive and well, and saves me a few $ even when it got cloudy a few weeks back.

SWView attachment 738824
At this point, I believe I may have enough over production compared to my use I have not used the hack again. Batteries do not get back to 100% so I pull from grid during peak. Will see if this approach works.

Not sure anyone filled out that form completely. I still have not seen another true up change because of my latest panels, so not sure what is happening. As long as I get full credit for generation, do not care. But next april when I am producing TONS, will see.
 

holeydonut

Active Member
Supporting Member
Jun 27, 2020
2,381
1,723
East Bay NorCal
At this point, I believe I may have enough over production compared to my use I have not used the hack again. Batteries do not get back to 100% so I pull from grid during peak. Will see if this approach works.

Not sure anyone filled out that form completely. I still have not seen another true up change because of my latest panels, so not sure what is happening. As long as I get full credit for generation, do not care. But next april when I am producing TONS, will see.


Time for...

offshore-renewable-energy-wind-solar-wave.jpeg


 

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