NEM 3.0 Explained: What It Means for California Solar in 2026

Net Energy Metering 3.0, technically called the Net Billing Tariff, cut California solar export credits by roughly 75% when it took effect in April 2023. The solar industry has been catastrophizing about it ever since. The honest reality in 2026 is more nuanced. Solar still works in California, but the math is genuinely different, batteries are now essential, and a few critical deadlines have already passed. Here's an explanation without the industry spin.

What NEM 3.0 actually is

Net Energy Metering, or NEM, is the policy framework that determines how California solar customers get credited for the excess electricity their panels generate. When your panels produce more power than you're using, that surplus flows to the grid. NEM determines what your utility pays you for those exports.

NEM 1.0 and NEM 2.0 used a simple rule: utilities credited your exports at roughly the same rate they charged you for grid electricity. Send a kilowatt-hour to the grid at noon, get credited about $0.30. Pull a kilowatt-hour back at 7 PM, pay about $0.30. The math was nearly one-to-one, which made oversizing your solar system attractive.

NEM 3.0, which the CPUC officially calls the Net Billing Tariff (NBT), changed this fundamentally. It took effect on April 15, 2023, and applies to all new solar installations in PG&E, SCE, and SDG&E territory. Instead of crediting your exports at the retail electricity rate, NEM 3.0 credits them at an "avoided cost" rate calculated by the California Public Utilities Commission's Avoided Cost Calculator (ACC).

The shift is dramatic. Under NEM 2.0, exports averaged ~$0.30/kWh. Under NEM 3.0, exports average $0.05-$0.08/kWh blended across the year. That's roughly a 75% cut to the value of every kilowatt-hour your panels send to the grid.

The Avoided Cost Calculator (ACC) in plain English

The ACC is the mechanism that determines what your exports are worth. It's complicated, so here's the practical version.

The ACC tries to estimate what it would have cost the utility to procure that same electricity from somewhere else (the wholesale market, another power plant, energy imports) at the exact moment you exported it. Wholesale electricity prices vary by hour, day of week, and season. So the ACC produces a different export rate for every hour, weekday vs weekend, and month combination, for a total of 576 possible rates per year.

The patterns are predictable:

• Midday exports are worth the least. The sun is shining, every solar home is producing simultaneously, and the grid is flooded with cheap power. Midday export rates often dip to a few cents per kWh.
• Evening exports are worth the most. Demand peaks from 4-9 PM as households cook dinner, run AC, and charge cars. But solar production has dropped or ended by then, so few people are exporting at the right time.
• Summer evening peaks can be dramatic. During hot summer evenings, ACC export rates can briefly exceed $1.00/kWh or even spike higher. These are rare moments, not a typical condition.

The blended annual average for a typical residential system without a battery lands around $0.05-$0.07/kWh in PG&E territory, similar in SCE and SDG&E. Substantially below the $0.35-$0.55/kWh retail rate you pay to buy electricity back from the utility.

The ACC Plus adder: a partial offset

To soften the blow when NEM 3.0 launched, the CPUC included additional per-kWh credits called the ACC Plus adder. These are added on top of the standard ACC rate for residential customers in PG&E and SCE territory (SDG&E and commercial customers don't get the adder).

The catch: the adder decreases by 20% each year through 2028, when it reaches zero for new applicants. By 2026, the adder is worth roughly 40% less than it was when NEM 3.0 launched. For 2026 interconnections in PG&E territory, the standard residential adder is approximately $0.0088 per kWh, with CARE/FERA low-income customers receiving $0.036 per kWh.

The adder is locked in for 9 years from your Permission to Operate date, but only if you interconnect before the program closes at the end of 2027. After that, new solar customers receive no adder, only the base ACC rate.

The critical deadline you've already missed

If you're researching solar now, this is important: the NEM 2.0 grandfathering window has already closed.

Homeowners who submitted complete interconnection applications before April 15, 2023 were locked into NEM 2.0's retail-rate credits for 20 years from their Permission to Operate date. That was the grandfathering rule for systems already in flight.

April 15, 2026 was the final deadline to actually achieve Permission to Operate (PTO) on a NEM 2.0 system. Even applications submitted before April 2023 had to be installed, inspected, and granted PTO by April 15, 2026 to keep their grandfathered status. Systems still in progress after that date lost their NEM 2.0 protection and were moved to NEM 3.0.

The practical implication for 2026: new solar in PG&E, SCE, or SDG&E territory is NEM 3.0 only. There is no path to NEM 2.0 anymore. Anyone telling you otherwise is misinformed.

Why batteries became essential under NEM 3.0

The single biggest practical change from NEM 3.0 is that battery storage shifted from optional to nearly required for a financially viable solar system.

Here's the math. Under NEM 3.0:

• Midday solar export to grid: ~$0.05-$0.08/kWh
• Evening grid electricity from utility: ~$0.40-$0.55/kWh
• Gap: roughly 6-8x more valuable to use your own solar than to export and re-buy

A battery captures this gap. Instead of exporting midday solar at $0.06 and buying back evening electricity at $0.45, you store the solar in a battery and discharge it during peak hours. You effectively self-consume at the higher retail value rather than trading at the lower export value.

The numbers don't quite reach the full retail value because batteries have efficiency losses (typically 10-15% round-trip), but the economics still strongly favor storage. Industry data shows battery attachment rates on new California solar installations jumped from roughly 11% under NEM 2.0 to over 50% by 2024 and higher in 2026.

What NEM 3.0 doesn't change

Solar industry messaging often portrays NEM 3.0 as having "killed" California solar. The honest reading is more measured. Several important things didn't change:

Self-consumption is still worth full retail rate

Every kilowatt-hour your panels produce that you use directly in your home is worth the full retail electricity rate you would have paid. NEM 3.0 only affects exports, not self-consumption. For homes with daytime electricity demand (work-from-home, AC running, EV charging during the day), a substantial fraction of solar production is self-consumed and remains as valuable as it was under NEM 2.0.

California rates keep rising

PG&E's residential rates have risen steadily, and projections suggest continued increases. As retail rates rise, the value of self-consumed solar rises in lockstep. The gap between what you pay for grid electricity and what you'd otherwise pay for the same kilowatt-hour from your panels keeps widening.

The 20-year true-up math is still positive

Solar panels carry 25-year production warranties. Even with NEM 3.0's reduced exports, a well-sized solar plus battery system in PG&E or SCE territory typically generates lifetime savings of $40,000 to $100,000 in avoided utility costs, according to estimates from EnergySage and other independent sources.

SMUD and LADWP customers are unaffected

NEM 3.0 only applies to the three investor-owned utilities. SMUD and LADWP customers operate under their own net metering rules, which are typically more favorable. SMUD's customers in particular have one of the most favorable solar arrangements in California, though their lower retail rates mean smaller absolute savings than IOU customers see.

Other rule changes that matter

NEM 3.0 came with several other adjustments worth knowing:

Mandatory Time-of-Use rates

New solar customers in PG&E, SCE, and SDG&E must enroll in TOU rate plans, typically with steep peak/off-peak differentials. Peak rates (4-9 PM) can exceed $0.55/kWh while off-peak rates dip below $0.10/kWh. The wide spread is intentional: it incentivizes shifting consumption to off-peak hours and storing solar for peak-hour discharge.

Annual true-up, no cash surplus

Like NEM 2.0, NEM 3.0 uses an annual true-up. But unlike NEM 2.0, surplus credits at the end of your year expire with zero cash value. If you over-produce annually, you don't get a check. This eliminates the strategy of oversizing your system to "bank" credits.

System sizing rules changed

Under NEM 3.0, system sizing is allowed up to 150% of your historical annual usage if you're planning to electrify (adding an EV, heat pump, induction range, or similar). This is more generous than NEM 2.0's 100% sizing rule, and reflects California's policy push toward whole-home electrification.

No "solar tax" monthly fee

An earlier NEM 3.0 proposal included a monthly Grid Participation Charge of $14-$16. After significant public opposition, this was removed from the final policy. Standard non-bypassable charges still apply to imported electricity, but there's no fixed monthly fee specific to solar customers.

Does solar still make sense in California under NEM 3.0?

For most California homeowners with home Level 2 charging access and high retail electricity rates, yes. The math is genuinely tighter than it was under NEM 2.0, especially since the federal 30% tax credit also expired at the end of 2025. But the case is still positive over a 25-year system lifetime.

Realistic payback timelines for cash purchases in 2026, with battery, in IOU territory:

Solar plus battery generally pays back faster than solar alone under NEM 3.0, which is the opposite of what was true under NEM 2.0. This is the inversion that NEM 3.0 created intentionally.

What about the ongoing lawsuits and policy reviews?

NEM 3.0 has been litigated since it took effect. In August 2025, the California Supreme Court ordered the case back to the Court of Appeal for reconsideration, with briefs re-filed in November 2025. As of mid-2026, the policy remains in effect with no immediate changes expected.

Separately, the CPUC is required to conduct a three-year review of NEM 3.0 starting after April 2026, which could result in modifications to export rates, the adder structure, or other elements. Any changes from this review would likely not take effect until 2027 at earliest.

For homeowners considering solar now: waiting for the lawsuit or the review to change the rules is generally not a winning strategy. The ACC Plus adder decreases every year you delay, the federal credit is already gone, and California rates continue to rise. Acting under current rules while modeling the math honestly is the practical approach.

What to ask installers in 2026

If you're getting solar quotes in California, a few questions specific to NEM 3.0 economics that separate good installers from bad ones:

1. Are you modeling my system under NEM 3.0 export rates? Any quote that uses NEM 2.0 retail-rate exports for a new 2026 install is wrong.
2. What's the production-export-self-consumption breakdown for my home? The installer should be able to estimate hourly production, hourly load, and what fraction of your solar will be self-consumed vs. exported.
3. Does the quote include a battery? If not, why not? For most California IOU customers in 2026, the math heavily favors including a battery. An installer recommending solar-only should have a specific reason.
4. What's the battery sized for? A right-sized battery covers your evening peak hours (4-9 PM) for typical usage. Undersized batteries leave you buying expensive peak electricity. Oversized batteries cost more without proportional benefit.
5. Are you including the ACC Plus adder in projections? If you're in PG&E or SCE territory, this matters. SDG&E customers don't get the adder.
6. What happens to my projections if rates increase 5% per year vs 3% per year? The case for solar is more sensitive to rate trajectory now than it was under NEM 2.0. A reasonable installer should show you both scenarios.

The honest summary

NEM 3.0 made California solar harder, not impossible. The dramatic export rate cut means every kilowatt-hour you export to the grid is worth roughly a quarter of what it would have been worth under NEM 2.0. But the policy also intentionally rewards self-consumption, which means batteries went from optional to essential.

For a typical California IOU customer with high electricity bills and high evening usage, a properly sized solar plus battery system in 2026 still produces meaningful long-term savings. Payback is in the 7-10 year range for IOU customers, and lifetime savings remain substantial.

The window for getting onto NEM 2.0 has closed. New solar customers in 2026 enroll in NEM 3.0, the federal credit is gone, and the ACC Plus adder is decreasing each year. None of this kills the case for solar, but it does mean the math is tighter and the equipment choices matter more.

For a personalized estimate using your specific utility, current rates, and a proper NEM 3.0 model, run the solar savings calculator. It accounts for the post-credit landscape and treats exports at realistic ACC values rather than the inflated NEM 2.0 assumptions some online calculators still use.