Hello everyone. Hopefully this question isn’t off topic. Several months ago my wife and I recently had 5kW NEM2 rooftop solar installed at our residence in California Bay Area (PGE). At the time it was sized ~110% according to our previous non-solar billings with PGE. Since then however, some of our family members are no longer at our residence, and now we will have a substantial net surplus at true-up time later this year, somewhere between 2000-4000 kWh (sizing on the order of ~200% of need). Are we in any sort of “jeopardy” with PGE for having over-produced this much? If so, please elaborate. Like do we lose some or all of the pitiful credit paid out at true-up? And/or can we lose our NEM2 status? Thanks
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over-production with PGE
- Thread starter HariSeldon
- Start date
Hi @h2ofun, thanks, yes I am aware of how I can reduce the surplus, if I choose to do that. But must I is the primary question. My main concern is if my surplus exceeds some threshold, will PGE force me to do something about it, or penalize me in some form (besides the pennies credit at true-up)? You have an impressive system (at least to me it is). Have you ever had a surplus, and if so, what was the biggest approximately? I'm looking for feedback from anyone who has overproduced significantly in the past ( specifically >1000 kWh in any NEM2 true-up period), with PGE, and what if any ramifications occurred from PGE as a result. Thanks
Assuming you got a PTO for you system size, you are fine. When you get your bill, you look at what you sent back vs what they agree you can send back. As long as their number is higher than yours, you are fine.
My numbers are much larger credit than years. I have been up to 2300 bucks. About 1800 now. I way over produce at time
My numbers are much larger credit than years. I have been up to 2300 bucks. About 1800 now. I way over produce at time
I’m not in CA but I’m hoping no power company would penalize people for producing clean energy that gets added to the grid. It seems like part of the solution to climate change and stress on the grid is more people with solar producing more than they need and sending the rest to the grid. I know there are politics involved so it’s likely not that simple, though.
I "think" but am not 100% sure, that the absolute worst that could happen for your "already permitted, already PTO'ed" installation that over produces by a significant amount right now (under NEM 1 or 2) is:
1. Payment at the wholesale rate at the yearly true up, and
2. no payment at all for any amount that is deemed to be above what your system could have possibly generated, on a yearly basis
I dont think there would be any changing of your agreements etc, until they implement NEM 3 and your grandfathering period runs out (or you trigger it yourself by adding more than 10% generation.
You are right, its not that simple. as the gigantic stickied thread on "NEM 3.0 in CA" in this subforum would attest.
Ok, thanks to all for your responses.
@chrstna4, I agree with you 100%. However, I would not put anything past an InvestorOwnedUtility monopoly trying to protect erosion of its profits. NEM3 in California is a case in point. The demise of net-metering to net-billing is in full swing and utilities all over the country are grinding away at it. But I don’t want to turn this thread into an NEM3 thread.
@jjrandorin, yes my system is permitted and PTO’ed, so I’m good on that. And have no plans for alterations until batteries get cheaper. My little research into batteries suggests that they will need replacing every 8-10 years on average, as they slowly lose capacity and aren’t warrantied for more than that or 15-35 megawatt-hrs, whichever is sooner, amounting to indirectly adding at least $50/month to the utility bill. And my use case would be cycling it every day (time shifting), not for infrequent events such as wildfire outage backups. Also battery technology is much in flux still, new battery announcements often. If I had to now, I would choose LiFePO for safety, despite lower energy density.
My concern for an over-production energy surplus at true-up time relates to sections 5f and 5g of Special Conditions, NET SURPLUS ELECTRICITY COMPENSATION (NSC), pages 20-22 of https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_NEM2.pdf
Section 5.f.1 states “No documentation of QF status is required of any NEM2
customer-generators with a net power production capacity of one
megawatt or less”
Section 5.g states “Generator Size – Nothing in this Special Condition alters the existing
NEM2 system sizing requirement. Specifically, in order to be eligible
for NSC, a system must be intended primarily to offset part or all of the
customer’s own electrical requirements. Systems that are sized larger
than the customer’s electrical requirements are not eligible for NEM2
and therefore, are not eligible for NSC either.”
So my initial (perhaps too hasty) interpretation of these sections was that if I over-produced by 1000 kWh or more at true-up (which is a megawatt-hr), then the utility would disqualify me and rescind my NEM2 status, thus destroying any ROI of my installation. I thought that section 5.g “net power production capacity of one megawatt or less” was maybe a typo and really meant 1 megawatt-hr of energy (only 1000 kWh). But now I’m thinking that it wasn’t a typo, and it really is referring to power capacity, not kWh energy production capacity. Further thought is that 1000 kWh is only ~83 kWh per month on average, which is not difficult to exceed even for a small 5kW system like mine, particularly when people permanently leave. For larger systems, 1000 kWh over-production is a drop in the bucket, I would think. So my current thinking is that the 1 megawatt power capacity clause does not apply to any typical residential installation, unless it is the size of a farm.
Nevertheless, the last sentence of section 5.g indicates that “Systems sized more than current requirements are not eligible for NEM2, and are not eligible for NET SURPLUS ELECTRICITY COMPENSATION, either.”
So, technically, anyone that over-produces is at risk. This is difficult for me to accept. Maybe I have lost context somewhere? I do think that @jjrandorin’s 2nd suggestion “no payment at all for any amount that is deemed to be above what your system could have possibly generated, on a yearly basis”, makes the most common sense. But again, I would not trust the utility an iota to rely on “common sense.”
I now expect my annual consumption to be 3000-5000 kWh because of unplanned reduced occupancy, and my production to be 6000-7000 kWh without any active management to limit production, for a net surplus of 1000-4000 kWh. Are my concern(s) baseless?
Comments and education, etc. are appreciated.
@chrstna4, I agree with you 100%. However, I would not put anything past an InvestorOwnedUtility monopoly trying to protect erosion of its profits. NEM3 in California is a case in point. The demise of net-metering to net-billing is in full swing and utilities all over the country are grinding away at it. But I don’t want to turn this thread into an NEM3 thread.
@jjrandorin, yes my system is permitted and PTO’ed, so I’m good on that. And have no plans for alterations until batteries get cheaper. My little research into batteries suggests that they will need replacing every 8-10 years on average, as they slowly lose capacity and aren’t warrantied for more than that or 15-35 megawatt-hrs, whichever is sooner, amounting to indirectly adding at least $50/month to the utility bill. And my use case would be cycling it every day (time shifting), not for infrequent events such as wildfire outage backups. Also battery technology is much in flux still, new battery announcements often. If I had to now, I would choose LiFePO for safety, despite lower energy density.
My concern for an over-production energy surplus at true-up time relates to sections 5f and 5g of Special Conditions, NET SURPLUS ELECTRICITY COMPENSATION (NSC), pages 20-22 of https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_NEM2.pdf
Section 5.f.1 states “No documentation of QF status is required of any NEM2
customer-generators with a net power production capacity of one
megawatt or less”
Section 5.g states “Generator Size – Nothing in this Special Condition alters the existing
NEM2 system sizing requirement. Specifically, in order to be eligible
for NSC, a system must be intended primarily to offset part or all of the
customer’s own electrical requirements. Systems that are sized larger
than the customer’s electrical requirements are not eligible for NEM2
and therefore, are not eligible for NSC either.”
So my initial (perhaps too hasty) interpretation of these sections was that if I over-produced by 1000 kWh or more at true-up (which is a megawatt-hr), then the utility would disqualify me and rescind my NEM2 status, thus destroying any ROI of my installation. I thought that section 5.g “net power production capacity of one megawatt or less” was maybe a typo and really meant 1 megawatt-hr of energy (only 1000 kWh). But now I’m thinking that it wasn’t a typo, and it really is referring to power capacity, not kWh energy production capacity. Further thought is that 1000 kWh is only ~83 kWh per month on average, which is not difficult to exceed even for a small 5kW system like mine, particularly when people permanently leave. For larger systems, 1000 kWh over-production is a drop in the bucket, I would think. So my current thinking is that the 1 megawatt power capacity clause does not apply to any typical residential installation, unless it is the size of a farm.
Nevertheless, the last sentence of section 5.g indicates that “Systems sized more than current requirements are not eligible for NEM2, and are not eligible for NET SURPLUS ELECTRICITY COMPENSATION, either.”
So, technically, anyone that over-produces is at risk. This is difficult for me to accept. Maybe I have lost context somewhere? I do think that @jjrandorin’s 2nd suggestion “no payment at all for any amount that is deemed to be above what your system could have possibly generated, on a yearly basis”, makes the most common sense. But again, I would not trust the utility an iota to rely on “common sense.”
I now expect my annual consumption to be 3000-5000 kWh because of unplanned reduced occupancy, and my production to be 6000-7000 kWh without any active management to limit production, for a net surplus of 1000-4000 kWh. Are my concern(s) baseless?
Comments and education, etc. are appreciated.
Tesla powerwalls are warrantied for "at least 70% capacity at 10 years, unlimited charge / discharge cycles as long as charged primarily from Solar" so its a little different than what you said above.. but thats not what you are asking.
I dont have any further feedback other than what my opinion already was, but I have also not combed through the agreements like it appears you have.
1 megawatt is really the power rating of the system. They are not mixing up MW and MWh. There is also a different type of interconnection for systems 30kW and larger called "Expanded NEM".
Net surplus export of 1,000kWh (1 MWh) is not consequential and will have no particular consequences for you.
Net surplus export of 1,000kWh (1 MWh) is not consequential and will have no particular consequences for you.
As an aside, I forgot to mention that section 5.b calculates the NetSurplusCompensation rate based on 7AM-5PM hours over the previous 12 month period. That's cheap energy times. I wonder why (I can surely guestimate) that only includes the first hour of the ETOU-C rate plan (peak hours 4PM-9PM everyday) that PGE solar NEM2 customers are forced to use in CA? Doesn't sound very fair to me..........I would think that the compensation rate would go up if ALL of the peak hours were considered in the calculation.
thank you @miimura . Sounds good. My initial interpretation was naive. Can you also say that up to 4000kWh is not consequential for me? I am not obsessing about the compensation rate, juat the potential level of over-production. @h2ofun indicates in post #4 that he was credited once for $2300 but didn't indicate if it was NEM or NEM2. I surmise that it was NEM, because if it were NEM2, at say $0.04/kWh compensation rate, his $2300 means he had net 57500kWh exported (which is an astounding 4792kWh/month). I'm contemplating asking PGE later this week, depending on any further posts here.
@jjrandorin I looked at the PowerWall2 warranty. What you say is true, but only for backup purposes where # of cycles is small (thus unlimited). I've learned that battery warranties typically have additional fineprint for cycle/day time-shifting purposes that limits total aggregate energy throughput to 37 megawatt-hrs, which for a PowerWall2 energy capacity of 13kWh, is 2846 daily cycles or 7.8 years.
I am NEM2
Why 30kw, because I was able to get it approved. If you search my posting of how I got. I told the wife the other day. Some spend 100K on a tesla. Instead, I spent 100K on solar so I can live my life in total comfort all year long. Like 74 degrees in the house in the winter and summer. For me, much better investment of my 100K. Instead, I drive a 1990 car with 120K miles.
Now, if I can get 5 EV charges installed, you understand my moto, either go big or go home.
I also have a 99% electric house, and a large big house. I use like 70 to 80 KWH per day when its cold in the winter, which most do not have to worry about
I am NEM2
Why 30kw, because I was able to get it approved. If you search my posting of how I got. I told the wife the other day. Some spend 100K on a tesla. Instead, I spent 100K on solar so I can live my life in total comfort all year long. Like 74 degrees in the house in the winter and summer. For me, much better investment of my 100K. Instead, I drive a 1990 car with 120K miles.
Now, if I can get 5 EV charges installed, you understand my moto, either go big or go home.
I also have a 99% electric house, and a large big house. I use like 70 to 80 KWH per day when its cold in the winter, which most do not have to worry about
This was my mindset as well. People spend money however they like/want and if you go into home energy storage not really looking at it as a pure ROI play, but as a peace of mind (power outages), give utilities less control/power, independence/flexibility option (ToU is now going to cost what?), it's easier to stomach the cost.
Like you say, a more expensive car more than makes up any cost for powerwalls or batteries (could replace cars with trips, purses, shoes, video games with constant DLC/gacha, dating, going out, clothes, outdoor furniture, etc depending on spender).
Who has the oldest PWs here? Would be curious what the real battery degradation is since I keep hearing people post that you'll need to replace all your batteries after 10 years and 1 day so many times and really don't think that'll be the case for most people.
Could you link to the part of the warranty that says "for backup purposes only" or intimates that the warranty excludes time shifting? The limit you talk about is throughput when charged from the grid. You say "battery warranties", but I am talking specifically about "Tesla powerwall 2 or 2+ batteries", not in generalities.
It says "Solar self consumption / Backup only", which I read to mean that slash to be " Or".
I'm the SDG&E area and have had no problem from them with overproducing ~2,000kWh per year. They seem to be happy taking that excess power I produce and selling it to others at high rates while paying me about $0.04 per kWh at true up time.
hi, no I don't believe that I said it excluded time-shifting; if I did somewhere then I was wrong. The true measures of a rechargable battery are retention over time and total energy throughput, with the latter usually more important. Total energy throughput refers to how many times you can cycle the battery. My 7.8 year calculation assumed 100% energy retention. If you can manage cycling a battery twice a day instead of once, your warranty will be voided in half of the time. I don't believe any battery has an unlimited # cycles unless DepthOfDischarge is limited to small percentages such as 10%. That's fantasy. So for a time-shifting application (charge offpeak, discharge onpeak) where the battery is cycled nearly 100% once per day, it might first encounter the aggregate throughput limitation, depending on the battery. If I were looking for any reason to void someone's warranty performance claim, I would look first to the net accumulated aggregate throughput. Here is the link: https://www.tesla.com/sites/default/files/pdfs/powerwall/Powerwall_2_AC_Warranty_USA_1-1.pdf
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