NEM Expansion Kit from Bright Saver

How Much Can You Save with Plug-In Solar in California?

The math on plug-in solar in California is straightforward: take some of the highest electricity rates in the country, add 260+ days of sunshine per year, and the savings add up fast.

This page shows realistic, conservative savings estimates for NEM 1.0 and NEM 2.0 customers based on actual California NEM credit rates.

How NEM Expansion Kits Save You Money

Unlike standalone plug-in solar, Bright Saver's NEM Expansion Kits work with your existing rooftop solar and net metering agreement. Every kilowatt-hour your backyard panels generate either:

  1. Powers your home directly — saving you the full retail rate (up to $0.45+/kWh)
  2. Flows back to the grid — earning you NEM credits at your existing NEM rate

Either way, you save. The conservative estimates below use NEM credit rates only, since that's the baseline value of every kWh produced.

Savings by Utility

PG&E Customers

At NEM rates of ~$0.30/kWh:

SystemPrice + Tax*Annual NEM CreditsPayback10-Year Net Savings
NEM 2-Panel$1,649$360/year4.6 years$1,951
NEM 4-Panel$2,583$660/year3.9 years$4,017

SCE Customers

At NEM rates of ~$0.32/kWh:

SystemPrice + Tax*Annual NEM CreditsPayback10-Year Net Savings
NEM 2-Panel$1,649$384/year4.3 years$2,191
NEM 4-Panel$2,583$704/year3.7 years$4,457

SDG&E Customers

At NEM rates of ~$0.36/kWh — the highest of any major California utility:

SystemPrice + Tax*Annual NEM CreditsPayback10-Year Net Savings
NEM 2-Panel$1,649$432/year3.8 years$2,671
NEM 4-Panel$2,583$792/year3.3 years$5,337

*Includes 10% estimated sales tax.*

Why the Math Gets Better Every Year

California electricity rates have been rising 5 to 8% per year consistently. Your NEM credits grow as rates increase, but your kit cost is locked in at day one.

YearPG&E NEM Rate2-Panel Credits4-Panel Credits
Year 1$0.30/kWh$360$660
Year 5$0.37/kWh$444$814
Year 10$0.47/kWh$564$1,034
Year 20$0.76/kWh$912$1,672

Over 20 years, a 2-panel kit generates over $11,000 in cumulative NEM credits on a $1,649 investment. A 4-panel kit generates over $21,000 on a $2,583 investment.

How Plug-In Solar Compares to Other Investments

InvestmentCostAnnual ReturnPayback
Plug-in solar (PG&E)$1,649$360/yr (22%)4.6 yrs
Plug-in solar (SDG&E)$1,649$432/yr (26%)3.8 yrs
High-yield savings$1,649~$74/yr (4.5%)Never
S&P 500 (hist. avg)$1,649~$165/yr (10%)Never

Plug-in solar returns 22-26% annually in avoided electricity costs — and the return grows as rates increase. Unlike financial investments, this return is tax-free (you're avoiding a cost, not earning income).

Real Scenarios

Bay Area homeowner, PG&E, NEM 2.0:

Got an EV last year, true-up bill went from $200 to $800. Added a 2-panel NEM Expansion Kit in the backyard. $360/year in additional NEM credits, offsetting about half the EV charging cost. Payback in 4.6 years, then free credits for 15+ more years.

San Diego homeowner, SDG&E, NEM 1.0:

4-panel kit in the backyard. At SDG&E's higher rates, earning $792/year in NEM credits. System pays for itself in 3.3 years. Over 20 years, $15,000+ in cumulative savings.

LA homeowner, SCE, NEM 2.0:

Added a heat pump, electricity usage jumped. 2-panel kit on the patio. $384/year in NEM credits. The kit cost less than two months of the increased electricity bill.

Self-Consumption vs. NEM Credits

When your home is using more electricity than your panels produce (common during high-use periods), the solar energy gets consumed directly. In that case, you're saving at your full retail rate — which is even higher than the NEM credit rate.

The estimates above use only the NEM credit rate ($0.30-$0.36/kWh), so your actual savings may be higher if your home consumes a significant portion of the solar output directly.

FAQ

Are these savings guaranteed? No. They depend on your NEM rate, sun exposure, panel placement, and energy usage patterns. We used conservative NEM credit rates — your actual savings may be higher. What about the NEM 3.0 / Net Billing Tariff? These kits are designed for existing NEM 1.0 and NEM 2.0 customers. The NEM expansion rule lets you add up to 1 kW or 10% of your original system size without losing your existing NEM rate. Will savings increase over time? Almost certainly. California rates have been rising 5 to 8% per year consistently. Your NEM credits grow proportionally. What about the 4-panel system clipping? The 4-panel system pairs 1,600W of panels with a 900W inverter. The inverter clips peak output on the sunniest midday hours, but annual energy lost to clipping is only about 10%. The extra panels capture significantly more energy in mornings, afternoons, and cloudy conditions.
Start saving today. Shop NEM Expansion Kits

Free pickup from our Oakland or Los Angeles warehouses. Delivery + installation support available within 50 miles of Oakland for $349.

*Bright Saver is a 501(c)(3) nonprofit. Our mission is making solar accessible to every American.*