PG&E ADU Solar: Title 24, NEM 3.0 & Interconnection Guide

Pacific Gas & Electric (PG&E) serves more than 16 million customers across Northern and Central California — the largest service territory of any California utility. If you're building an ADU in a PG&E zone, here's exactly how Title 24 solar, NEM 3.0 net billing, and PG&E's interconnection process affect your project.

Does PG&E Require Solar on New ADUs?

PG&E itself doesn't write building code, but California's Title 24 Building Energy Efficiency Standards apply to every new ADU in PG&E territory. That means almost every detached ADU permitted in 2024–2026 must include a properly sized rooftop solar PV system at the time of construction.

Local jurisdictions inside PG&E's footprint — San Francisco, Oakland, San Jose, Sacramento, Fresno, and hundreds more — enforce Title 24 at plan check. Plans without solar are rejected unless an exemption is documented.

PG&E NEM 3.0 (Net Billing) for ADUs

Since April 15, 2023, all new PG&E solar customers — including ADU systems — interconnect under NEM 3.0, officially called the Net Billing Tariff (NBT). Export rates fell roughly 75% from NEM 2.0, which makes self-consumption (using your solar in real time) far more valuable than exporting to the grid.

For ADU owners, NEM 3.0 changes the optimal system design: pair smaller solar arrays with a battery (Tesla Powerwall 3, Enphase IQ Battery 5P) to capture mid-day production for evening tenant use.

  • Average PG&E daytime export rate under NEM 3.0: ~$0.05–$0.08/kWh
  • Average PG&E retail rate (E-TOU-C peak): $0.40–$0.55/kWh
  • Solar + battery payback in PG&E territory: typically 7–10 years
  • Solar-only payback in PG&E territory under NEM 3.0: typically 11–14 years

PG&E Interconnection Process for ADU Solar

After installation and final building inspection, PG&E requires Permission to Operate (PTO) before you can legally turn on your solar system. The interconnection application is filed online via PG&E's Your Project Tool.

Current PG&E PTO timelines run 4–8 weeks after submission. Your installer handles the paperwork — you just need to provide your PG&E account number and signed interconnection agreement.

ADU Solar Cost in PG&E Territory

Title 24-compliant ADU solar packages in PG&E territory range from $4,000 (Standard, cash) to $15,000 (Premium with battery). HDM financing reduces effective cost ~40% via commercial ITC pass-through. Cities with higher labor costs (San Francisco, San Jose, Berkeley) sit at the upper end.

FAQs

Can I use my main house's PG&E solar to cover an ADU?

In limited cases yes — under aggregated net metering — but Title 24 still requires the ADU to be permitted with its own dedicated solar system unless an exemption applies.

Does PG&E charge an interconnection fee for ADU solar?

For standard residential systems under 30 kW (which covers all ADUs), PG&E does not charge an interconnection fee. PTO is free.

How long does PG&E take to approve ADU solar?

Permission to Operate typically arrives 4–8 weeks after your installer submits the interconnection application post-inspection.

Is the PG&E solar billing credit cash or rollover?

Under NEM 3.0, exports are credited at avoided-cost rates that vary hourly. Credits roll month-to-month and any net surplus is cashed out annually at a low wholesale rate.

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