San Diego is one of the highest-value solar markets in the US — SDG&E consistently has some of the highest retail electricity rates in the country (~$0.35–0.45/kWh), which makes the economic case for solar-plus-storage strong even under NEM 3.0’s reduced export rates.
San Diego Solar Snapshot
NEC Edition: California Electrical Code (NEC 2020 + CA amendments) | Utility: SDG&E | Net Billing: NEM 3.0 (ACC export rates) | Permit Authority: City of San Diego DSD (city); SD County PDS (unincorporated) | SolarAPP+: City of San Diego participates
NEM 3.0 Economics in San Diego
SDG&E transitioned new solar customers to NEM 3.0 in April 2023. The economics differ significantly from NEM 2.0:
NEM 2.0 vs. NEM 3.0 for SDG&E Customers
| Parameter | NEM 2.0 | NEM 3.0 |
|---|---|---|
| Export credit | Full retail rate (~$0.40/kWh) | ACC rate (~$0.05–0.08/kWh most hours) |
| Peak export value | Same as off-peak (retail) | Higher (~$0.15–0.25/kWh in peak hours) |
| Battery storage value | Limited (already retail rate) | High (avoid retail buy, exceed ACC export) |
| System right-sizing | Export-friendly | Self-consumption-focused |
Under NEM 3.0, the priority is maximizing solar self-consumption and storage:
- Self-consumed solar = worth ~$0.40/kWh (avoided SDG&E retail rate)
- Exported solar = worth ~$0.05–0.08/kWh (ACC rate)
- Stored solar discharged in evening = worth ~$0.40/kWh (avoided retail purchase)
Avoided Cost Calculator (ACC) Export Rates
SDG&E’s ACC rates vary by time of day and season:
| Period | Approximate ACC Rate |
|---|---|
| On-peak summer afternoon | $0.15–0.25/kWh |
| Mid-peak | $0.08–0.12/kWh |
| Off-peak | $0.02–0.05/kWh |
| Overnight | $0.02–0.04/kWh |
Rates updated annually by CPUC — use the CPUC ACC calculator for current rates.
NEM 2.0 Grandfathering
SDG&E NEM 2.0 customers who interconnected before April 2023 are grandfathered on NEM 2.0 rates for 20 years from their interconnection date. Existing NEM 2.0 customers adding storage can retain NEM 2.0 status under specific CPUC rules — confirm current grandfathering conditions before adding battery to an existing system.
City of San Diego DSD Permit Process
SolarAPP+ Track
For residential systems under 15 kW meeting SolarAPP+ criteria:
- Submit to SolarAPP+ portal
- Automated approval (typically same-day)
- Apply for DSD permit with SolarAPP+ approval
- DSD issues permit (expedited)
- Install, schedule DSD inspection
- Submit to SDG&E for interconnection activation
Standard Plan Check Track
For non-SolarAPP+ projects:
- Submit application through DSD permit portal
- Upload one-line diagram, structural calculations, equipment specs
- Plan check: 7–15 business days (complex systems longer)
- Permit issued
- Install
- DSD inspection
- SDG&E interconnection activation
DSD Permit Fees
| System Type | Approximate Fee |
|---|---|
| Residential SolarAPP+ | Reduced fee (~$100–200) |
| Standard residential | $200–500 |
| Commercial (small) | $500–1,500 |
SDG&E Interconnection Process
| Step | Action | Timeline |
|---|---|---|
| 1 | Submit NEM 3.0 interconnection application online | Day 1 |
| 2 | SDG&E technical review | 10–20 business days |
| 3 | Execute NEM 3.0 interconnection agreement | After review |
| 4 | Complete installation + DSD inspection | Per schedule |
| 5 | SDG&E activates net billing | 5–10 business days post-inspection |
SDG&E requires a completed, permitted system with passed inspections before executing the final interconnection agreement. The NEM 3.0 contract start date is the interconnection activation date.
San Diego County (Unincorporated) Permitting
San Diego County Planning and Development Services (PDS) serves unincorporated county areas:
- Separate from City of San Diego DSD
- PDS portal for permit applications
- SolarAPP+ availability: confirm with PDS
- Permit fees based on county fee schedule
Unincorporated county areas include many inland communities — Santee, El Cajon, La Mesa, and Chula Vista are separate cities with their own permit departments (not City of San Diego).
San Diego Climate — Mild Derating
San Diego has the most favorable conductor derating in California’s major markets. ASHRAE max air temp: ~33°C. Effective rooftop temp: 55°C. Correction factor: 0.76. Compare to Los Angeles (0.71) and Phoenix (0.65). The mild climate reduces the conductor upgrade requirements that apply in hotter inland markets.
San Diego NEC 690.7 String Voltage
San Diego T_min = 5°C (ASHRAE), Voc = 45.0V, β_Voc = -0.28%/°C:
Factor = 1 + (5 - 25) × (-0.0028) = 1 + 0.056 = 1.056
Max modules (600V) = 600 / (45.0 × 1.056) = 12.6 → 12 modulesSDG&E NEM 3.0 + San Diego DSD Permit Packages
SurgePV models NEM 3.0 ACC export rates for SDG&E and generates San Diego DSD / SolarAPP+-compatible permit packages — NEC 2020 California, CalFire setbacks, and SDG&E interconnection documentation.
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Frequently Asked Questions
How does SDG&E NEM 3.0 affect solar economics?
NEM 3.0 pays exported solar at the Avoided Cost Calculator (ACC) rate ($0.05–0.08/kWh) rather than full retail ($0.40/kWh). Self-consumed solar avoids the retail rate — worth much more than export. Battery storage is now the standard recommendation to maximize NEM 3.0 economics in San Diego.
Does San Diego DSD use SolarAPP+?
Yes. City of San Diego DSD participates in SolarAPP+ for qualifying residential systems under 15 kW. SolarAPP+ provides same-day approval, significantly faster than standard plan check. Unincorporated county projects use SD County PDS separately.
What are the CalFire setback requirements in San Diego?
SB 1222 requires 3-foot access pathways on residential rooftop arrays. San Diego County has extensive wildland-urban interface areas — many unincorporated areas require additional clearances. Verify with DSD or County PDS for the specific project location.
