California NEM 3.0: The 2023 Net Metering Change That Reshaped Residential Solar
No single policy decision affected more residential solar installers in 2023 than California's transition to the Net Billing Tariff (NBT), widely known as NEM 3.0. Implemented on April 15, 2023, the change slashed the value of exported solar energy and fundamentally altered the economics of rooftop solar in the nation's largest residential market. For contractors, distributors, and homeowners alike, NEM 3.0 marked the end of one era and the beginning of a battery-first one.
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What the CPUC Decided
The California Public Utilities Commission (CPUC) adopted Decision 22-12-056 on December 15, 2022, establishing the Net Billing Tariff as the successor to NEM 2.0, according to the CPUC's official Net Billing Tariff page. The tariff applies to any customer submitting an interconnection application on or after April 15, 2023, while existing NEM 1.0 and 2.0 customers retained their legacy rates.
The CPUC later refined implementation details through Resolution E-5301 in November 2023 and Decision 23-11-068, which established a virtual net billing tariff and an aggregation subtariff for customers submitting applications after February 14, 2024, per the CPUC NEM Revisit Proceeding page.
The Core Change: A 75% Cut in Export Value
Under NEM 2.0, exported solar electricity was credited at close to the retail rate. Under NEM 3.0, export compensation is instead based on the hourly "Avoided Cost Calculator" (ACC) value — what the utility would otherwise have paid for that power on the wholesale market. This structural shift reduced the average value of exported solar energy by approximately 75%, according to industry analysis of the CPUC's NEM 3.0 fact sheet.
| Feature | NEM 2.0 | NEM 3.0 / Net Billing Tariff |
|---|---|---|
| Export compensation basis | Near-retail rate | Hourly avoided-cost value |
| Average export value reduction | — | ~75% lower than NEM 2.0 |
| Netting interval | Interval/monthly netting | Instantaneous netting |
| Rate lock-in period | 20 years | 9 years (ACC values lock in, then float) |
| Effective date | Legacy | April 15, 2023 |
Additional five-year "adders" were made available to PG&E and Southern California Edison customers who enrolled early, while SDG&E customers were excluded from the adder, according to SEIA's Net Billing summary for residential California customers.
Solar-Plus-Storage Adoption Surged
Attachment Rates Before and After NEM 3.0
The most dramatic market response to NEM 3.0 was the explosion in battery storage attachment rates. Under the old NEM 2.0 structure, only about 10% of new residential solar installations in California included a battery. Under the new Net Billing Tariff, that figure jumped to roughly 60% by the end of 2023, according to a Lawrence Berkeley National Laboratory technical brief on NEM 3.0's early market effects.
The logic is straightforward: since exporting to the grid now pays a fraction of what it once did, storing self-generated power for evening use — when it directly offsets high retail rates — became far more valuable than selling it back to the utility. U.S. Energy Information Administration data confirmed the trend, showing that the share of new California residential solar systems paired with batteries rose from just over 20% in October 2023 to more than 50% by April 2024. Installers sourcing solar batteries for California jobs should expect storage to be the default configuration rather than an add-on.
How Installer Business Models Shifted
NEM 3.0 forced a rapid strategic pivot across California's installer base:
- Sales pitches changed — Installers moved from selling "bill savings via export credits" to selling "self-consumption and backup resilience via storage."
- System sizing changed — Oversized systems designed to maximize export credits became less attractive; right-sizing to match on-site consumption, paired with storage, became the norm.
- Financing and attach-rate targets shifted — Companies reported internally targeting battery attachment rates of 80-95% on new California proposals, according to Solar Power World's coverage of installer adaptation to NEM 3.0.
- Backlog effects — A surge of pre-April 2023 NEM 2.0 applications created an interconnection backlog that kept installation volumes elevated through mid-to-late 2023, even as new sales under NEM 3.0 slowed initially, per SEIA's Q4 2023 Solar Market Insight Report.
Market-Wide Impact
Despite the export rate cut, California still accounted for 35% of national installed solar capacity in 2023 and grew installations 34% year-over-year, per PV Tech's coverage of the SEIA/Wood Mackenzie 2023 Year in Review — largely due to the pre-NBT application backlog working through the interconnection queue. However, SEIA projected a 36% decline in California solar deployment for 2024 as that backlog cleared and the underlying economics of NEM 3.0 took full effect, according to the same report.
How Other States Compare
California's shift accelerated a broader national trend. States including Arizona, Nevada, and others had already moved toward time-of-use or reduced export compensation structures in prior years, but California's market size made its transition the most closely watched in the industry. Nationally, residential storage attachment rates rose to about 12% by 2023 from a much lower base, but remained far below California's post-NBT rate, according to Berkeley Lab's Tracking the Sun report. Hawaii remains the outlier, with residential storage attachment near 95% under its own long-standing net billing structure.
What Installers Should Stock and Recommend
- Prioritize battery storage systems sized for whole-home or critical-load backup as a standard line item on every California proposal.
- Evaluate hybrid inverters capable of managing PV, storage, and backup loads in a single unit to simplify system design under net billing.
- Educate customers early that export credits are no longer the primary financial driver — self-consumption and resilience now are.
PES Supply ships qualifying inverter and battery orders within 7-10 business days, helping installers keep NEM 3.0-driven storage installations on schedule.
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