If you’ve been thinking about adding solar to your Southern California home — or already have solar and are wondering whether to add a battery — there’s one piece of policy you need to understand: Net Energy Metering 3.0 (NEM 3.0).
NEM 3.0 changed the math on residential solar in California. It’s not bad news, exactly. But it’s different news, and most homeowners don’t fully understand it. Here’s the plain-English version.
What is Net Energy Metering, in 30 seconds?
When your solar panels produce more electricity than your home is using, the excess flows back to the grid. Net Energy Metering is the policy that decides what you get paid for that excess.
Under the old policies (NEM 1.0 and NEM 2.0), California paid solar owners roughly the same retail rate they were buying electricity for. Send a kilowatt-hour to the grid at noon, get a credit equal to what you’d pay for one at noon. Pretty fair — and very generous compared to most states.
NEM 3.0 (officially called the Net Billing Tariff, or NBT) changed that. Now your excess solar production is paid at a much lower rate — closer to the wholesale rate, around 25-30% of what you pay to buy back.
Why the change?
The California Public Utilities Commission rationale: as more homeowners adopted solar under NEM 2.0, the cost-shift to non-solar customers grew. Utilities argued they were still maintaining the grid that solar customers depended on, but solar customers were paying very little for that maintenance.
You can debate whether the new rates are fair (a lot of people do), but the policy is in effect for all new solar interconnections in SoCal Edison, PG&E, and SDG&E territory.
What it means for new solar
Under NEM 3.0, if you install solar without a battery:
- Your daytime overproduction (which is most homes — solar peaks midday when no one is home) earns you very little credit.
- You’ll pay full retail rates for the electricity you import in the evening (5pm-9pm peak hours).
- Your payback period gets longer — typically 9-12 years instead of the 5-7 years that was common under NEM 2.0.
Solar still works. But the economics are weaker than they used to be.
Why batteries change everything under NEM 3.0
Here’s the key insight: under NEM 3.0, the value of your solar is much higher when you use it yourself rather than send it to the grid.
That’s where a battery — like a Tesla Powerwall — completely flips the math.
Without a battery: solar production at noon → sold to grid for ~$0.08/kWh → grid sells it back to you at 5pm for $0.45/kWh. You’re effectively giving away $0.37/kWh of value.
With a battery: solar production at noon → stored in your Powerwall → discharged at 5pm to power your own home. You avoid buying that same kilowatt-hour at $0.45/kWh.
That’s not a small difference. For a typical SoCal home using 25 kWh/day, the difference between solar-only and solar+battery under NEM 3.0 can be $1,500-$3,000 per year in savings.
The payback math, real numbers
Let’s run a realistic example for a Newbury Park home with a 7 kW solar system:
Solar only (NEM 3.0):
- System cost: ~$20,000 installed
- Annual savings: $1,400
- Payback: ~14 years
Solar + Powerwall (NEM 3.0):
- System cost: ~$32,000 installed
- Annual savings: $2,800
- Payback: ~11 years
Those are gross numbers. Through 2025 you would have subtracted a 30% federal credit from both, which is why you still see shorter paybacks quoted all over the internet. That credit is gone — see below — so we quote what you actually pay.
The battery still shortens payback, and it does it for a reason that has nothing to do with incentives: under NEM 3.0 your daytime export is worth a fraction of what you pay at night, so storing your own production and using it after sunset is worth far more than selling it. The backup power is on top of that.
What about existing solar customers?
If your solar system was interconnected under NEM 1.0 or NEM 2.0, you’re grandfathered into your existing tariff for 20 years from your original interconnection date. You don’t have to switch to NEM 3.0.
But here’s a nuance: if you make significant changes to your system (like adding panels or upgrading equipment), you may trigger a transition to NEM 3.0. Adding a Powerwall to an existing NEM 2.0 system does NOT trigger this transition. You can keep your NEM 2.0 rates and add battery storage.
This is actually a great move for grandfathered customers: you keep the favorable solar rates AND gain backup + time-of-use arbitrage.
What if I have a Time-of-Use rate plan?
If you’re on SoCal Edison’s TOU-D-PRIME or similar time-of-use rate plan (most newer SoCal customers are), the difference between peak and off-peak rates is large — often $0.25-$0.35/kWh. This makes battery arbitrage valuable even without solar:
- Charge battery from grid at off-peak rates (typically 9am-4pm or overnight, depending on plan)
- Discharge battery during peak (4pm-9pm) to avoid expensive grid usage
- Net savings even before considering solar
Adding solar makes this work harder, but the battery has value either way under TOU rates.
What about the federal tax credit and SGIP?
This is the part that changed, and it changed badly. If another installer is still quoting you “30% back,” they are working from last year’s rules.
Federal Investment Tax Credit (Section 25D): gone. The 30% residential clean energy credit for solar and battery does not apply to any installation completed after December 31, 2025. There was no phase-down — it stopped. The IRS ties eligibility to when installation is completed, not when you pay, so a deposit written in 2025 against a system finished in 2026 does not qualify.
The federal EV charger credit (Section 30C): also gone, for equipment placed in service after June 30, 2026.
California SGIP: mostly closed. The general-market residential budget stopped accepting new applicants at the end of 2025. An income-qualified budget still exists, but it is heavily oversubscribed and new applications join a waitlist that only moves as earlier projects drop out. We check eligibility for your address at consultation, because the rules turn on income, utility and fire-threat district. Do not build your budget around it.
So the honest version: the incentives that used to cover 35-50% of a Powerwall are not there for most homeowners anymore. Paybacks are longer than they were in 2025. That is exactly why the rate-arbitrage math above matters more now than it did then — the savings have to come from the rate plan rather than from Washington.
The honest summary
NEM 3.0 made solar-only less compelling than it used to be in California. But it made solar + battery more compelling than ever — because the policy now rewards self-consumption over grid export.
For homeowners considering solar in 2026, going straight to solar + Powerwall is the right move 90% of the time. For homeowners who already have NEM 1.0 or 2.0 solar, adding Powerwall is an even bigger no-brainer — you keep your favorable rates AND gain battery benefits.
Want us to run the numbers for your home? We do free consultations across Southern California — we’ll look at your electric bills, your roof, your panel, and your goals, then design a system that actually makes financial sense for you.
Get a free consultation or call (805) 296-4122.
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