NEM 3.0: why California solar now needs a battery

If you are putting solar on a California roof in 2026, the single biggest thing that changed is how little you now get paid for sending power back to the grid. That change has a name: NEM 3.0. It is the main reason a battery has gone from a nice-to-have to nearly part of the deal.

What NEM 3.0 is

NEM 3.0 is the third version of California's Net Energy Metering rules, the framework that decides what a solar customer earns for the surplus power their panels export to the grid. It took effect for new solar interconnections starting in April 2023, under California Public Utilities Commission Decision 22-12-056 (CPUC, verified 2026). It applies to the big three investor-owned utilities: PG&E, SCE, and SDG&E.

Under the older NEM 2.0 rules, exported solar earned close to the full retail rate. You could effectively use the grid as a free battery, banking daytime surplus and pulling it back at night for nearly even credit.

What changed, and why it stings

NEM 3.0 sharply cut what new customers earn for exported power. Instead of near-retail credit, exports are now valued closer to the utility's avoided cost, which is far lower and varies by hour. In practice, the credit for sending a kWh to the grid is often a fraction of what you pay to buy that same kWh back later.

That breaks the old "grid as a battery" trick. Daytime solar surplus, exported, now earns little. The same energy, used in your home in the expensive evening hours, is worth full retail.

Why this makes a battery close to required

Here is the consequence that matters for your wallet. Under NEM 3.0, the value of solar shifts from exporting to self-consuming. A battery captures your midday surplus and lets you use it during the time-of-use evening peak instead of exporting it for pennies.

Without storage, a new NEM 3.0 solar system exports its surplus into a low-value credit and then buys expensive evening power back at retail. With a battery, that surplus stays home and offsets the priciest hours. This is why, for most new California solar in 2026, a paired battery is close to required to make the numbers work. It is not a sales upsell; it is the structure of the tariff.

What to do with this

If you are quoted solar in California, ask specifically how the proposal handles NEM 3.0 exports, and whether it assumes a battery. A solar-only NEM 3.0 quote can look worse than it should because so much of the surplus is exported cheaply. Pair it with storage and the picture changes. Our Worth It calculator reflects California's rate structure, the state's main battery rebate is covered under SGIP, and the full picture is in the California report. Always confirm current export rules with your utility, since tariffs are updated over time.