If your California solar system was installed under NEM 2.0, you hold one of the best residential solar deals ever offered, and you keep it for 20 years from your original permission to operate. NEM 3.0 applies only to new systems. This guide explains what changed, how your grandfathered status works, what happens at annual true-up, and when a battery makes sense.
- NEM 2.0 customers are grandfathered for 20 years from their original permission-to-operate date. NEM 3.0 does not touch your credits or rate structure.
- NEM 3.0, officially the Net Billing Tariff, cut export payments by roughly 75 percent for systems installed after April 15, 2023.
- Your annual true-up still settles net usage once a year, with grandfathered customers banking retail-rate credits as before.
- Adding a battery to a NEM 2.0 system is allowed, but the configuration can affect your NEM status, so get written confirmation first.
- When grandfathering ends, you move to whatever tariff exists then, so plan the long term accordingly.
What NEM 3.0 Actually Changed
Net metering decides what your utility pays for excess solar power. Under NEM 1.0 and 2.0, California utilities credited exports at nearly the full retail rate: send a kilowatt-hour at noon, pull one back at 8 p.m., and they canceled out almost one for one. That deal made California the rooftop solar capital of the world.
In April 2023, the California Public Utilities Commission replaced it for new systems with NEM 3.0, officially the Net Billing Tariff. Exports are now paid at “avoided cost” rates from the Avoided Cost Calculator, varying by hour, season, and utility across 576 combinations and averaging roughly $0.04 to $0.08 per kilowatt-hour, against the $0.30 to $0.45 many NEM 2.0 customers effectively earned. NEM 3.0 also added a monthly minimum bill of roughly $10 to $16, so new customers can no longer zero out their bills. The policy pushed new buyers toward batteries, and it worked. Our full breakdown of NEM 3.0 and batteries covers the new-customer side.
The part that matters for you: none of this applies to your existing system while you keep grandfathered status. Your credits, true-up, and rate structure stay as they were.
Your NEM 2.0 Grandfathering, Explained
When the CPUC approved NEM 3.0, it locked in existing customers. With permission to operate (PTO) under NEM 2.0, you stay on NEM 2.0 for 20 years from that PTO date. Approved in June 2021? You keep NEM 2.0 until June 2041. Approved in March 2023, just before the April 15, 2023 cutoff? Until March 2043.
Your PTO date anchors everything, so find it on your interconnection approval or utility account documents and keep it safe. Every future decision about upgrades, batteries, and home sales runs through that date. Note what grandfathering covers: the NEM tariff itself, retail-rate export credits, the annual true-up, and no new grid participation charge. It does not freeze electricity rates. Utilities can still change rate plans and time-of-use windows, which affects what your credits are worth.
What Happens at Your Annual True-Up
True-up is the once-a-year settlement reconciling 12 months of production and consumption. For NEM 2.0 customers it works as it always has: your meter tracks imports and exports per time-of-use period, exports earn credits at the retail rate for that period, and credits roll forward month to month within your 12-month cycle. At cycle end, the utility nets it out. Owe the difference if you used more than you produced; receive a small Net Surplus Compensation payment, historically 3 to 4 cents per kilowatt-hour, if you produced more, and your credits reset.
Three practical notes. Your true-up month is fixed to your PTO anniversary. You still pay monthly minimum and non-bypassable charges all year even while credits pile up. And oversizing to chase surplus payments loses money: surplus pays wholesale-ish rates for retail-priced equipment, so size to roughly 100 to 110 percent of usage. Thinking of expanding? Read our guide to the 120 percent rule on system sizing first.
NEM 2.0 vs NEM 3.0 Side by Side
| Feature | NEM 2.0 (grandfathered) | NEM 3.0 (new systems) |
|---|---|---|
| Export credit rate | Near retail ($0.30–$0.45/kWh typical) | Avoided cost (~$0.04–$0.08/kWh avg) |
| Who gets it | PTO before April 15, 2023 | Applications after April 14, 2023 |
| Duration | 20 years from original PTO | Export rates locked 9 years, then step down |
| Monthly minimum bill | Standard minimum (~$10–$12) | Grid participation charge (~$10–$16) |
| Bill near zero possible? | Yes, with well-sized system | Much harder; battery usually needed |
| Typical payback, solar only | 5–7 years | 8–11 years |
| Battery needed? | No | Effectively yes for most homes |
The table shows why NEM 2.0 systems are now a real estate selling point: a home with 15 years of grandfathering remaining carries a solar asset no new buyer can replicate. If you sell, make sure the listing agent understands this and the buyer completes the utility’s transfer correctly, because botched paperwork is one of the few ways to lose grandfathered status involuntarily. EnergySage’s net metering explainers are a good second source if you want to cross-check your utility’s tariff language.
Should You Add a Battery to a NEM 2.0 System?
Under NEM 2.0, a battery does not help your bill the way it helps a NEM 3.0 customer, because your exports already earn retail credits. The financial case rests on backup power, not savings, and in California that is a real need: Public Safety Power Shutoffs, heat-wave strain, and wildfire-season outages. A single 13.5 kWh battery, installed for roughly $9,000 to $16,000, keeps essentials running through most outages. Our Powerwall 3 vs Enphase IQ Battery 5P comparison and our look at whether home batteries are worth it can help you choose.
The critical warning: configuration matters for your NEM status. Storage paired with existing solar generally preserves NEM 2.0, but setups that charge from the grid and export can trigger reclassification, and utility rules here have changed before. Before signing, get written confirmation from both installer and utility that the proposed configuration preserves your NEM 2.0 grandfathering and original PTO date. If an installer waves this off, find another installer.
Pros
- Retail-rate export credits for up to 20 years, the best residential solar deal in the country.
- No grid participation charge and no avoided-cost math on your bill.
- A transferable asset that adds resale value no new system can match.
Cons
- Grandfathering eventually ends, and the replacement tariff is unknown.
- Utilities can still change rate plans and time-of-use windows.
- Badly handled battery additions or expansions can jeopardize your status.
What Happens When Grandfathering Ends
Twenty years sounds distant until you calculate it: a 2018 system hits the end in 2038. Then you move to whatever export tariff exists at that time. Nobody knows what that will be, but each successive version of net metering has paid less for exports than the last. Treat your grandfathered years as the prime earning period. The system will likely still be producing, since modern panels last 25 to 30 years or more, but its third-decade economics depend on future policy. Past year 10, start considering whether a later battery addition makes sense, since storage will almost certainly be part of whatever comes next.
How to Protect Your Grandfathered Status
Keep your original PTO documentation. Never let an installer submit a new interconnection application for your existing system without understanding the consequences. If you expand significantly, check whether the utility treats it as a modification or a new system, since that determines which tariff the addition falls under. When selling, use the utility’s formal transfer process and confirm the buyer lands on NEM 2.0 with your remaining term. When buying a solar home, verify the PTO date and remaining term before closing, in writing. And stay informed without anxiety: your 20-year lock is a regulatory commitment that has survived every challenge so far. For the new-buyer side of the story, see our California solar guide for 2026 and the CPUC background at energy.gov’s solar resources.
Does NEM 3.0 affect my existing NEM 2.0 system?
No. NEM 3.0 applies only to interconnection applications submitted after April 14, 2023. With PTO under NEM 2.0, you keep NEM 2.0 rates and rules for 20 years from your PTO date.
How do I find my grandfathering end date?
Add 20 years to your original permission-to-operate date, found on interconnection approval documents or in utility account records. Your utility’s solar department can look it up if paperwork is lost.
Will adding a battery void my NEM 2.0 status?
Not automatically, but configuration matters. Storage added to existing NEM 2.0 solar generally preserves status, while grid-charging export setups can trigger reclassification. Get written utility confirmation before signing.
What happens at my annual true-up?
The utility nets 12 months of imports against exports, with exports credited near retail rates. Owe the balance if you used more; receive a small per-kWh surplus payment if you produced more, and credits reset. Minimum charges apply all year.
Can I expand my grandfathered system?
Small expansions are often allowed, but large additions can be treated as a new system under NEM 3.0. Check your utility’s modification rules and confirm in writing which tariff the addition falls under.
What happens when my 20 years run out?
You transition to whatever export tariff exists then. Expect exports to be worth less than under NEM 2.0, which is why many owners plan a battery addition for the later years.
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