Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Understanding What PG&E Pay’s For Excess Solar?

jaed

Member
Jan 6, 2017
69
84
California
I am new to getting my Tesla solar and power walls installed now that I have PTO I am trying to understand my PGE bill.

I can’t wrap my head around what PGE does for excess solar power sent back to the grid.

Some places I read they give 3 cents a kwh sent back. Looking at a bill example they show online it appears to show more of a one to one ratio so if you use 10kw at peak from the grid but send back 10kw at peak it is a wash.
So is it a one to one or do I buy the 10kw at normal cost then sent back to them at 3 cents a kw?

Thanks in advance.
 

Redhill_qik

Member
Aug 16, 2020
252
155
South SF Bay, California
It's both. You get 1:1 credit for any generation that does not exceed your annual consumption. Over that, you get a credit of about 3 cents per kWh.

If you are with a Community Choice Aggregator for power generation they may buy the net generation at a higher rate. Silicon Valley Clean Energy buys the annual excess at the retail rates in the range of 6-8 cents/kWH.
 

jaed

Member
Jan 6, 2017
69
84
California
Thank you for that helps.
I am in Castro Valley, Hayward area.

This leads to another question lets say I am +50 kw at peak and negative -50kw at non-peak. Do they close each other out?

I guess I am trying to figure out what the best route would be to save money. Because if they are 1:1 why would I fill and drain the power walls could I just leave them at 100% and use PG&E as the "power wall". Leaving the reserve at 100%?
 

Redhill_qik

Member
Aug 16, 2020
252
155
South SF Bay, California
Thank you for that helps.
I am in Castro Valley, Hayward area.

This leads to another question lets say I am +50 kw at peak and negative -50kw at non-peak. Do they close each other out?

I guess I am trying to figure out what the best route would be to save money. Because if they are 1:1 why would I fill and drain the power walls could I just leave them at 100% and use PG&E as the "power wall". Leaving the reserve at 100%?

That would not cancel out. The annual true up totals are by rate period, so winter peak, winter off-peak, summer peak and summer off peak. If you are on EV2 there is also partial peak in both summer and fall.

The PW cost savings mode will switch to powering the house at the start of peak and send any solar to the grid.
 
  • Informative
Reactions: run-the-joules

jaed

Member
Jan 6, 2017
69
84
California
So in an effort to figure out the best way to save money might be. Setup my system so it fills up the batteries by 3pm my peak time. Then all excess solar goes back to the grid at a higher rate in keeping enough available to get me through the peak times after the sun goes down?

Is that how other people are doing it?
I have a somewhat large system of 19kw solar and 4 Powerwalls but my main house and in-law unit are both ran off the system so we can't fully offset during the winter and mostly offset during the summer.
 

getakey

Active Member
Jan 28, 2020
1,223
403
95762
So in an effort to figure out the best way to save money might be. Setup my system so it fills up the batteries by 3pm my peak time. Then all excess solar goes back to the grid at a higher rate in keeping enough available to get me through the peak times after the sun goes down?

Is that how other people are doing it?
I have a somewhat large system of 19kw solar and 4 Powerwalls but my main house and in-law unit are both ran off the system so we can't fully offset during the winter and mostly offset during the summer.

yes, charge PWs during low rate and power house through peak rate to send as much solar back to grid during peak as possible
I'm ssurprised you cannot make it through Peak on PWs during the winter with that big a system. Electric heat?
 

jaed

Member
Jan 6, 2017
69
84
California
I should have made it clearer. I can make it through peak no problem just not 100% self powered most of the time. During summer and off times when I have more solar I can be 100% self powered it is just during the winter months where I am around 60% to 70% self powered.
 

getakey

Active Member
Jan 28, 2020
1,223
403
95762
I should have made it clearer. I can make it through peak no problem just not 100% self powered most of the time. During summer and off times when I have more solar I can be 100% self powered it is just during the winter months where I am around 60% to 70% self powered.

got it
 

jaed

Member
Jan 6, 2017
69
84
California
So looking at the plans and thanks to you all I switched to EV2A and I will try and use Balanced I think and see how that works. So I send back during peak times and have the batteries cover me until the peak is over at midnight.
Also this video helped me understand if someone else reads this thread later:
 

aesculus

Still Trying to Figure This All Out
May 31, 2015
4,431
2,509
Northern California
So looking at the plans and thanks to you all I switched to EV2A and I will try and use Balanced I think and see how that works. So I send back during peak times and have the batteries cover me until the peak is over at midnight.
Balanced Mode prioritizes both sustainability and cost savings. Reduce your peak usage while maintaining a high Self-Powered score. Cost Savings Mode prioritizes savings. Your Self-Powered score may be lower.
 

wwhitney

Member
Nov 2, 2017
857
1,118
Berkeley, CA
Not sure that the complete answer to the OP has been given, so here it is:

During each billing interval (15 minutes?) your house is either a net consumer or net generator. When it's a net consumer you accrue a charge based on the consumption and the TOU category; when it's a net generator, you get a credit (at a slightly lower rate per kWh, for NEM2).

You get a monthly bill showing the net charge/credit for the month plus any fixed charges (not sure about those). Then once a year everything is reconciled: if you have a net charge, you pay it. If you have a net credit, it is wiped out, and instead a different computation is made, namely the net kWh generated or consumed for the whole year (ignoring TOU categories). If that shows overall net generation, you get reimbursed at the lower rate discussed. If that shows net consumption, then there's no charge or credit.

Cheers, Wayne
 

run-the-joules

Turgid Member
Aug 13, 2017
3,769
6,822
SF Bay
Hnnngh so envious of the powerwall crew.

My solar is going on the roof as we speak, but I won't be able to get powerwalls until sometime next year. I'm not 100% sure if my system is going to be big enough to totally cover my electricity consumption without powerwalls but I suppose I'll find out!

I think for the next few months while I am still heating with gas I'll be generating quite a bit more than I use, even with winter sun angles (8kw system, 1500 sqft house), but once the central AC/heat pump setup goes in I suspect winter consumption will be high enough to rely on credits from summer generation. With 2 powerwalls, though… maybe not?


My goal is that once I've got the solar, the heat pump, and the powerwalls all up and running, that I'll generate enough excess to get a true-up cheque that'll cover the minimum $10/mo bill or whatever it works out to. If I can get to that point, the only money I'm actually paying to PG&E will be for my water heating bill (which will stay on gas for the foreseeable future)
 

getakey

Active Member
Jan 28, 2020
1,223
403
95762
Not sure that the complete answer to the OP has been given, so here it is:

During each billing interval (15 minutes?) your house is either a net consumer or net generator. When it's a net consumer you accrue a charge based on the consumption and the TOU category; when it's a net generator, you get a credit (at a slightly lower rate per kWh, for NEM2).

the bill is in kWhours, so the billing period is each hour. The credit is at the same rate as usage except for the NBCs.
 

h2ofun

Active Member
Aug 11, 2020
2,437
418
auburn, ca
Hnnngh so envious of the powerwall crew.

My solar is going on the roof as we speak, but I won't be able to get powerwalls until sometime next year. I'm not 100% sure if my system is going to be big enough to totally cover my electricity consumption without powerwalls but I suppose I'll find out!

I think for the next few months while I am still heating with gas I'll be generating quite a bit more than I use, even with winter sun angles (8kw system, 1500 sqft house), but once the central AC/heat pump setup goes in I suspect winter consumption will be high enough to rely on credits from summer generation. With 2 powerwalls, though… maybe not?


My goal is that once I've got the solar, the heat pump, and the powerwalls all up and running, that I'll generate enough excess to get a true-up cheque that'll cover the minimum $10/mo bill or whatever it works out to. If I can get to that point, the only money I'm actually paying to PG&E will be for my water heating bill (which will stay on gas for the foreseeable future)

From what I understand, no way do the PW's basically help much. Currently, I am just solar, and TOU-C. The difference on cost between peak and non peak is trivial. I have a 14.5kw solar. I am 99% electric, with 9 mini split heads. My solar in the winter now is about 25% of what it is during the summer. After 3 months summer I had a 600 buck credit. I am expecting like a 200 buck per month charge in the winter, but will not fully know this until the next bill. Still hoping my overall net for year is negative, and with NO powerwalls!!

I currently have a 22K generator for any power outages. Would have been more cost effective with a small generator but what the heck, only live once, so I did it "right".

Now, am trying to get some sgip batteries. PGE is reviewing my second set of inputs. Not sure which way I want this to go. Batteries do have a number of negatives! And since I sized my solar hoping to have no true up bill, and I have a generator, batteries really are not needed for the issues.

Now, why did you change to eva 2? I see this TOU rate as a BIG hassle! I would not change unless forced. IF forced, this is one of mnay negatives to batteries, IMO.
 

getakey

Active Member
Jan 28, 2020
1,223
403
95762
That doesn't necessarily follow, I've heard both 15 minutes and 60 minutes. Would be happy to get a reference to a definitive answer.


Yes, the NBCs under NEM2 result in the "slightly lower rate" I mentioned.

Cheers, Wayne

doesn't really matter if 15 minutes or 60 minutes. It's the net usage/production over the rate period which is in hours
 
  • Like
Reactions: charlesj

wwhitney

Member
Nov 2, 2017
857
1,118
Berkeley, CA
doesn't really matter if 15 minutes or 60 minutes. It's the net usage/production over the rate period which is in hours
With the NBCs it does matter a little, as the the credit rate is different from the consumption charge. NBCs are charged per billing interval, not per rate period per day, to my understanding.

Cheers, Wayne
 

wwhitney

Member
Nov 2, 2017
857
1,118
Berkeley, CA
NBCs are per kWhour used
Sure, but say the usage pattern is this:

First quarter hour: net generate 1 kWh
Second quarter hour: net generate 1 kWh
Third quarter hour: net consume 1 kWh
Fourth quarter hour: net consume 1 kWh

If the billing period is 60 minutes, the net consumption/generation is 0 kWh, no charge/credit. But if the billing period is 15 minutes, you have 2 periods with 1 kWh of net generation, and 2 periods with 1 kWh of net consumption. You get charged for 2 kWhs and then credited for 2 kWhs at the slightly lower rate. You end up paying 2 kWhs of NBCs.

Cheers, Wayne
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top