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.