The short version
- Under PG&E's current solar billing plan, solar you use yourself is worth far more than solar you send to the grid.
- A battery stores cheap midday solar and uses it in the expensive 4–9 p.m. peak, which is where most of today's savings come from.
- Size your system for your future use, including an EV or heat pump you're planning, not just last year's bill.
- Your bill won't reach $0: PG&E's fixed monthly charge can't be offset by solar.
How PG&E pays for solar now
New PG&E solar customers are on the Solar Billing Plan (also called net billing or "NEM 3.0"). The key idea: solar you use in your home saves you the full price of electricity, but solar you send to the grid earns a much smaller export credit, often just a few cents per kWh in the middle of the day.
Meanwhile, electricity is most expensive during the 4–9 p.m. peak, right when solar production fades. That gap is the whole story of modern solar.
Why batteries matter more now
A battery captures extra solar in the middle of the day, when it would earn little as an export, and uses it in the evening when grid power costs the most. It turns a low-value export into a high-value saving.
That's why a solar-only system and a solar-plus-battery system can have very different savings. The Solar & Battery Savings calculator shows both side by side for your home. A battery also keeps your essentials running during outages; the Battery Backup Planner covers that side.
Sizing: plan for your future, not your past
The most common sizing mistake is designing for last year's bill. If you're planning an EV, a heat pump or a heat pump water heater in the next few years, your electricity use could rise a lot. Adding panels later usually costs more per panel than including them from the start.
On the other hand, making far more solar than you use doesn't pay off under the current rules: extra credits at the end of the year are worth very little. The goal is a system sized to what you'll actually use.
What your bill looks like with solar
Even with solar, you'll still have PG&E's Base Services Charge, a fixed monthly charge of about $24 for most customers that solar credits can't offset. Solar customers also settle up once a year at true-up, when a year of charges and credits is added together. See Understanding your PG&E bill for more.
Paying for it
The 30% federal tax credit for homeowner-owned solar and batteries ended for systems installed after 2025, so older quotes and articles that include it are out of date. Compare cash, loan, lease and power purchase agreement (PPA) options on the total cost over the life of the system, not just the monthly payment. California's SGIP program may still offer battery rebates for some households; ask what applies to you.
Check your roof first
Panels last 25 years or more. If your roof has less than about ten years left, it's usually cheaper to replace it before solar goes on than to remove and reinstall the panels later. Shade matters too: a real shade analysis beats a satellite estimate.
Questions to ask your contractor
- What is the production estimate based on?Ask whether it uses an on-site shade analysis.
- What electricity use did you design for?Tell them about any EV or heat pump plans.
- What rate plan and export credits did you assume for savings?Savings claims should reflect today's PG&E rules.
- How much would I save with and without a battery?
- How will the battery be set up to operate?Savings, backup, or both, and which circuits are backed up.
- Does my electrical panel need work to connect the system?
- Who handles warranties and service, and for how long?Panels, inverters, battery and workmanship can differ.
- Is my roof in good enough shape for 25 years of panels?
Common mistakes to avoid
- Sizing only for last year's bill. Plan for the EV or heat pump you're adding.
- Trusting savings from old rules. Quotes should reflect the current Solar Billing Plan.
- Oversizing. Extra credits at true-up are worth very little.
- Comparing monthly payments only. Look at total cost over the life of the system.
- Ignoring the roof. Reroofing under panels later is expensive.
Run the numbers for your home
This guide is general education, not advice for your specific home. Equipment, rebates and PG&E rates change; confirm details with a qualified professional. Unfamiliar term? See the glossary. Have a question it didn't answer? Ask Robert.