What changed under NEM 3.0
The official tariff is the Net Billing Tariff. PG&E calls it the Solar Billing Plan. It generally applies to solar and renewable generation customers who submitted an interconnection application after April 14, 2023.
Under the older NEM structure, excess solar exports were much closer to retail-rate credits. Under net billing, solar power you use inside the home still avoids buying energy from PG&E, but excess power sent to the grid earns Energy Export Credits that vary by time of day, day type, and season.
That makes the design problem different. The point is no longer to make as much midday solar as the roof can hold and assume the grid will bank it at a high value. The point is to use more of your own power and be deliberate about when stored energy is used or exported.
Why the battery is the load-bearing part
Solar panels make the most power in the middle of the day. Bay Area homes often use the most expensive grid power later, especially from 4 p.m. to 9 p.m. A battery moves your own solar from the low-value hours to the hours when it can offset expensive imports.
Storage also gives the system optionality. It can keep your home running during outages, reduce evening grid purchases, and preserve some ability to respond as PG&E rate plans and export values change.
This is why a small battery attached to a solar-first quote can miss the point. The battery is not just backup hardware. Under NEM 3.0, it is the financial control layer.
When solar plus battery tends to pencil
The economics are strongest when the home has a high PG&E bill, a good roof, future electric loads such as EV charging or heat pumps, and a homeowner who expects to stay long enough to care about the 10 to 25 year cost of energy.
The economics are weaker when annual usage is low, the roof is poor, the home is likely to be sold soon, or the project relies on optimistic rate and export assumptions to look good.
A serious quote should model your interval usage data, not just your monthly bill. It should also show the rate plan, battery dispatch assumptions, export-credit assumptions, backup target, and expected bill after solar.
Questions to ask before signing a solar quote
Most homeowners do not need to become tariff experts. They do need to know whether the quote in front of them was modeled for the current PG&E solar billing rules or for an older solar-only world.
- Does this model PG&E Solar Billing Plan rules, not old NEM 2.0 assumptions?
- How much of my solar production is used on-site, stored, exported, or clipped?
- What battery size is assumed, and what happens to savings if the battery is smaller?
- Which hours produce the most projected export value?
- Does the estimate include monthly billing, annual True-Up, base charges, and non-bypassable charges?
- What happens to the payback if export values fall or PG&E changes rate design again?
How Potrero approaches the design
Potrero designs the system around the battery, the smart panel, and the home loads together. For many Bay Area homes, that means more storage than a standard solar quote, because the goal is not just production. The goal is lower lifetime energy cost, resilience, and enough headroom for electrification.
If the project does not pencil under conservative assumptions, the right answer is to say that before installation. A design consultation should make the math clearer, not hide it behind a single payback number.