The 20-Year NEM Clock: When Your NEM 1.0 or 2.0 Legacy Period Ends — and What To Do

Most of the noise about California solar owners "losing net metering" is misinformation — we've debunked the AB 942 version of it here. But underneath the noise sits a real, quiet deadline that was built into the rules from the start: your NEM 1.0 or NEM 2.0 protection is a 20-year term, measured from the date your system got permission to operate (PTO). It doesn't renew. And for California's earliest solar adopters — systems interconnected in the mid-2000s — those terms are ending now, exactly on schedule.

No one is coming to take your tariff early. But when the term ends, your account moves automatically to the current successor tariff — today's net billing plan, where exported power is credited at roughly 75% less than the retail-rate credits you've enjoyed for two decades. Same panels, same sun, meaningfully different bill.

Find your date (it takes five minutes)

Your expiration date is your PTO date plus 20 years. The PTO letter from your utility is the definitive source; if you can't find it, your original interconnection paperwork, your installer's records, or a call to your utility's NEM department will produce it. Rough map of where the wave is: systems interconnected 2006 hit expiration in 2026 — that's now; 2010 systems roll off in 2030; the last NEM 1.0 systems (interconnected up to mid-2016) run through roughly 2036; and NEM 2.0 systems (mid-2016 through April 2023) expire between about 2036 and 2043 — that 20-year commitment was written into the CPUC's order.

Two important notes while you're checking: your legacy term belongs to the system, not to you — it survives a home sale for its remaining years. And be careful with expansions: enlarging a legacy system beyond the allowed threshold (roughly 10% or 1 kW) can move the whole system to current rules early. Adding a battery does not.

What actually changes when the term ends

Under NEM 1.0/2.0, the grid has effectively been your free battery: export at midday for near-retail credit, draw it back at night. Under the successor net billing rules, midday exports earn hourly avoided-cost rates — often just a few cents — while the electricity you buy back in the evening costs full retail on time-of-use plans where 4–9 PM is the expensive window.

The result: a system that zeroed out your bill can leave a substantial one, not because it produces less, but because exports stopped paying. The economics flip from "export everything" to "use everything yourself" — the same self-consumption logic that governs all new NEM 3.0 systems.

The 18-month playbook

You don't need to do anything the day you find your date — you need a sequence. 12–18 months out: model your post-expiration bill honestly (your utility's NEM department can tell you the successor rates; we model it from your actual usage). If the number is small, relax. 6–12 months out: if the number is real, this is the battery window — storing your midday production and discharging it across the evening peak recovers most of what the export cut takes away, and it's precisely why batteries became standard on post-2023 systems.

Doing it before expiration means you never experience the bad-bill year. The natural repower question: a system hitting year 20 usually has an inverter at or past end-of-life and panels producing 85–90% of their original rating. Sometimes the right answer is battery-plus-keep; sometimes it's a refresh of aging equipment while the crew is already there. An honest system health check — production audit, inverter diagnostics, warranty inventory — tells you which case you're in before anyone quotes anything.

One more Southern California wrinkle: this entire page describes the CPUC utilities (SCE, PG&E, SDG&E). LADWP, Pasadena, and Riverside customers are on municipal programs with their own rules and timelines — check your utility's page before assuming any of these dates apply to you.

Frequently asked questions

How do I find out exactly when my NEM 1.0 or 2.0 period expires?

Take your permission-to-operate (PTO) date and add 20 years. The PTO letter, your interconnection agreement, or your utility's NEM department will confirm the date. Don't rely on the install date or contract date — the clock runs from PTO.

What happens to my bill when the legacy period ends?

Your account moves to the current net billing tariff automatically. Exports drop from near-retail credit to hourly avoided-cost rates (roughly 75% lower on average), while evening purchases stay at full time-of-use retail. Production doesn't change; compensation does.

Will adding a battery now void my remaining NEM 1.0/2.0 years?

No — adding storage doesn't affect legacy status. What can end it early is expanding the solar array beyond roughly 10% or 1 kW of original size, so get expansion designs reviewed against the grandfathering rules before work starts.

Is it worth replacing a 20-year-old system entirely?

Sometimes. Year-20 systems typically have an end-of-life inverter and panels at 85–90% output, so a battery retrofit on aging equipment isn't always the best money. A production audit and inverter diagnostic first, then decide between battery-plus-keep and a repower — the math differs house by house.