Key Takeaways
- NEM 3.0 (officially the Net Billing Tariff) took effect April 15, 2023, for California’s three IOUs
- Export compensation dropped roughly 75% compared to NEM 2.0 retail-rate credits
- Compensation is based on the “Avoided Cost Calculator” — values vary by hour, month, and utility
- Battery storage became economically essential to maximize self-consumption
- Existing NEM 1.0 and NEM 2.0 customers are grandfathered for 20 years from their original interconnection
- Solar-plus-storage payback periods under NEM 3.0 range from 6–10 years depending on usage
What Is NEM 3.0?
NEM 3.0, officially called the Net Billing Tariff (NBT), is California’s updated compensation structure for new solar installations interconnected on or after April 15, 2023. It replaced the NEM 2.0 framework under a decision by the California Public Utilities Commission (CPUC Decision 22-12-056).
The fundamental change: exported solar electricity is no longer credited at the retail rate. Instead, exports receive compensation based on the “Avoided Cost Calculator” (ACC), which values energy based on what the utility would have paid for that power from other sources at that specific hour. During midday hours when solar production is highest, ACC values are low (often $0.04–$0.08/kWh). During evening peak hours, values can reach $0.20–$0.35/kWh.
NEM 3.0 fundamentally changed solar economics in California. Accurate TOU and export rate modeling in solar design software is no longer optional — it is the difference between a proposal that makes financial sense and one that doesn’t.
How NEM 3.0 Works
The Net Billing Tariff operates differently from traditional net metering:
Real-Time Export Valuation
Every kWh exported to the grid is valued at the ACC rate for that specific hour and month. These rates are published annually by the CPUC and vary by utility territory (PG&E, SCE, SDG&E).
Import at Full Retail Rate
Electricity imported from the grid is still billed at the full retail TOU rate. This creates a large spread between what you pay for grid power and what you receive for exports, incentivizing self-consumption.
Monthly Netting Within TOU Periods
Exports and imports are netted within each TOU period (on-peak, mid-peak, off-peak) within a billing month. Credits from one TOU period cannot offset charges in a higher-value period within the same month.
Annual True-Up
At the end of the 12-month billing cycle, any remaining net export credits are paid out at the Net Surplus Compensation rate (approximately $0.02–$0.05/kWh), not at retail value.
Electrification and Storage Adders
NEM 3.0 includes a temporary “adder” for low-income customers and those who install battery storage, providing additional per-kWh compensation on exports during the first nine years.
Monthly Bill = (Imported kWh × TOU Retail Rate) − (Exported kWh × ACC Hourly Rate) + Fixed ChargesNEM 3.0 vs. NEM 2.0
Understanding the differences between NEM 2.0 and NEM 3.0 is critical for accurate solar proposals in California.
NEM 2.0 (Before April 2023)
Exported kWh credited at full retail TOU rate (typically $0.25–$0.50/kWh). Monthly netting across all TOU periods. Minimal non-bypassable charges. Solar-only systems had 5–7 year payback periods. Grid essentially served as a free battery.
NEM 3.0 / Net Billing Tariff
Exported kWh credited at ACC rates (typically $0.04–$0.08/kWh midday, $0.20–$0.35/kWh evening peak). No cross-TOU-period netting. Higher non-bypassable charges. Solar-only payback periods extended to 9–12+ years. Batteries are now economically justified.
NEM 1.0 (Legacy)
Full retail-rate 1:1 credits for all exports, no TOU differentiation. Customers interconnected before specific utility deadlines (2016–2017) are grandfathered for 20 years. The most favorable compensation structure, no longer available for new systems.
NEM 3.0 + Battery Storage
Adding a battery to a NEM 3.0 system allows homeowners to store midday solar for evening self-consumption, avoiding low export values and high evening import rates. Solar-plus-storage achieves 6–9 year payback, comparable to NEM 2.0 solar-only economics.
Under NEM 3.0, system sizing strategy changed completely. Instead of sizing to offset 100%+ of annual consumption, the optimal approach is to size solar for high self-consumption and add a battery to shift excess generation to evening peak. Use solar software with hourly TOU modeling to find the sweet spot.
Key Metrics & Calculations
NEM 3.0 financial modeling requires more granular data than previous net metering policies:
| Metric | NEM 2.0 Value | NEM 3.0 Value | Impact |
|---|---|---|---|
| Midday Export Credit | $0.25–$0.40/kWh | $0.04–$0.08/kWh | 75–85% reduction |
| Evening Peak Export | $0.35–$0.55/kWh | $0.20–$0.35/kWh | 30–50% reduction |
| Solar-Only Payback | 5–7 years | 9–12+ years | Near doubling |
| Solar+Storage Payback | N/A (not economical) | 6–9 years | Now cost-effective |
| Optimal Self-Consumption | 30–40% (acceptable) | 70–85% (target) | Requires battery |
| Annual Savings (7kW solar) | $1,800–$2,400/year | $800–$1,200/year | 50–60% reduction |
Battery Value = (Shifted kWh × Peak Import Rate) − (Shifted kWh × Midday ACC Rate) − Battery LossesPractical Guidance
NEM 3.0 requires a different approach from every solar professional:
- Model hourly production and consumption. Annual or even monthly averages are insufficient under NEM 3.0. Use solar design software with hourly interval modeling to accurately capture TOU export values and self-consumption ratios.
- Size batteries for peak-hour shifting. The primary value of a battery under NEM 3.0 is shifting midday solar to evening peak consumption. A 10–13.5 kWh battery covers most residential evening loads for 4–6 hours.
- Consider west-facing panels. West-facing arrays produce more during late afternoon when TOU rates transition to peak. This may generate more financial value than a south-facing array with higher total kWh.
- Update ACC rates annually. The Avoided Cost Calculator values change each year. Using outdated ACC rates produces inaccurate savings projections.
- Prepare for battery installations on most jobs. Under NEM 3.0, the majority of California residential solar proposals include battery storage. Ensure your crews are trained on battery installation, commissioning, and the additional permitting requirements.
- Verify the interconnection application specifies NEM 3.0. If a customer’s application was submitted before April 15, 2023, and they received Permission to Operate under NEM 2.0, they remain on NEM 2.0 for 20 years. Confirm the tariff assignment.
- Configure monitoring for TOU optimization. Set up inverter and battery monitoring to show the customer their self-consumption ratio, export patterns, and TOU period performance.
- Stock battery-ready equipment. Even if a customer starts with solar-only, install a hybrid inverter and battery-ready infrastructure. The economics of adding a battery later are strong.
- Lead with solar-plus-storage proposals. Under NEM 3.0, solar-only proposals show longer payback periods that can be off-putting. Solar-plus-storage proposals show 6–9 year payback — much more compelling.
- Sell energy independence, not just bill savings. With reduced export credits, the value proposition shifts from “selling power to the grid” to “using your own power and reducing dependence on utility rate increases.”
- Show the rate escalation advantage. NEM 3.0 export values are low today but are projected to increase as grid avoided costs rise. Show customers how their savings improve over 25 years as utility rates climb.
- Address the “solar is dead in California” narrative directly. Solar is not dead — the economics changed. Solar-plus-storage under NEM 3.0 achieves comparable payback to NEM 2.0 solar-only. The savings are real; the system design is different.
Model NEM 3.0 Economics Accurately
SurgePV includes hourly ACC rate modeling, TOU optimization, and battery dispatch simulation for California NEM 3.0 proposals — no spreadsheets needed.
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Real-World Examples
Residential: Solar-Only Under NEM 3.0
A homeowner in San Diego installed a 7 kW solar-only system under NEM 3.0. Annual production is 10,500 kWh, with 65% exported during midday (average ACC credit: $0.05/kWh) and 35% self-consumed. Year-one savings totaled $1,050, yielding a 13.3-year payback on the $14,000 system cost. Under NEM 2.0, the same system would have saved $2,200/year with a 6.4-year payback.
Residential: Solar + Battery Under NEM 3.0
The same homeowner added a 13.5 kWh battery for $9,000 additional cost ($23,000 total before ITC). The battery shifts 5,500 kWh of midday solar to evening peak consumption, increasing self-consumption to 82%. Year-one savings rose to $2,350. After the 30% ITC, the net cost is $16,100, yielding a 6.9-year payback — competitive with NEM 2.0 solar-only economics.
Commercial: TOU Optimization
A small business in the PG&E territory installed 50 kW solar with 100 kWh battery storage. The battery is programmed to charge during midday solar overproduction and discharge during the 4–9 PM peak demand period. This strategy reduces demand charges by $450/month in addition to energy savings, achieving a combined payback period of 5.2 years.
Impact on System Design
NEM 3.0 fundamentally changed how California solar systems should be designed using solar software:
| Design Decision | NEM 2.0 Approach | NEM 3.0 Approach |
|---|---|---|
| System Size | 100–120% of annual usage | 80–100% of annual usage |
| Battery | Optional / Backup only | Standard on most projects |
| Panel Orientation | South (max kWh) | South/West blend (max financial value) |
| Self-Consumption Target | 30–40% acceptable | 70–85% target |
| Financial Modeling | Annual average rates | Hourly TOU + ACC rates |
When modeling NEM 3.0 proposals, always show the customer three scenarios: solar-only, solar + one battery, and solar + two batteries. Many customers find that the second battery pushes self-consumption from 80% to 92%, which provides enough additional savings to justify the cost in high-usage households.
Frequently Asked Questions
Is solar still worth it under NEM 3.0 in California?
Yes, but the optimal system design changed. Solar-plus-storage under NEM 3.0 achieves 6–9 year payback periods, comparable to solar-only under NEM 2.0. The key is maximizing self-consumption through battery storage rather than relying on export credits. With California’s high and rising electricity rates ($0.35–$0.65/kWh), solar still provides substantial savings over 25 years.
What is the difference between NEM 2.0 and NEM 3.0?
The biggest difference is export compensation. NEM 2.0 credited exports at the full retail TOU rate ($0.25–$0.50/kWh). NEM 3.0 credits exports at the Avoided Cost Calculator rate, which averages $0.04–$0.08/kWh during midday. NEM 3.0 also eliminated cross-TOU-period netting, added higher fixed charges, and introduced storage adders for customers who install batteries.
Are existing NEM 2.0 customers affected by NEM 3.0?
No. Existing NEM 1.0 and NEM 2.0 customers are grandfathered under their original tariff for 20 years from their interconnection date. However, if a NEM 2.0 customer significantly modifies their system (increases capacity beyond 10% of original nameplate), they may be required to transition to NEM 3.0 for the entire system. Adding a battery without increasing solar capacity does not trigger transition.
About the Contributors
CEO & Co-Founder · SurgePV
Keyur Rakholiya is CEO & Co-Founder of SurgePV and Founder of Heaven Green Energy Limited, where he has delivered over 1 GW of solar projects across commercial, utility, and rooftop sectors in India. With 10+ years in the solar industry, he has managed 800+ project deliveries, evaluated 20+ solar design platforms firsthand, and led engineering teams of 50+ people.
Content Head · SurgePV
Rainer Neumann is Content Head at SurgePV and a solar PV engineer with 10+ years of experience designing commercial and utility-scale systems across Europe and MENA. He has delivered 500+ installations, tested 15+ solar design software platforms firsthand, and specialises in shading analysis, string sizing, and international electrical code compliance.