NEM 3.0 By the Numbers: What Changed for California Solar

The Core Number: A 75% Cut in Export Value

NEM 3.0, California's current net-metering rule, cut the value of the electricity a solar system exports back to the grid by roughly 75% compared to the prior NEM 2.0 tariff, starting in April 2023. That single change reshaped the economics of a standalone, solar-only system in California, because a homeowner selling excess daytime power back to the grid now gets a fraction of what they got under the old rule.

The Grandfathering Window Just Closed

Homeowners who installed under NEM 2.0 before the 2023 cutover kept their old, higher export rate for a defined transition period. That grandfathering window closed April 15, 2026. Every California solar customer, new or previously grandfathered, is now selling power under NEM 3.0 terms. Adding to that, a California Court of Appeals upheld NEM 3.0 in March 2026 against a legal challenge, closing off the possibility that the rule gets reversed through the courts. NEM 3.0 is not a temporary or contested condition anymore, it is the fixed baseline for every California solar deal going forward.

Why Battery Storage Went From Optional to Functionally Required

Under NEM 3.0's reduced export credit, a system that just exports its excess daytime power back to the grid for a fraction of its old value performs far worse than one that stores that power and uses it later, when the household actually needs it or when a lease or PPA structure values it differently. That is why battery storage has shifted from an upsell to a functionally required part of a California system's economics. It is worth noting this alongside a national data point, not a California-specific one: the solar-plus-storage attach rate hit 45% nationally in Q1 2026, up from 38% a year earlier, a trend that runs in the same direction as what NEM 3.0 has made structurally necessary in California specifically.

What This Means for a California Appointment

A California solar or battery appointment that does not account for NEM 3.0 is not a serious appointment. Homeowner conversations, qualification criteria, and even how a system gets priced and pitched all change once export credits are worth a quarter of what they used to be. Any appointment-setting process working California should already be built around battery-attach and TPO-savvy positioning, not the same script that would work in a state that never went through this change.

Sources

The external data in this article draws on the sources below. Figures described in the text as estimates or industry triangulations are directional and are not attributed to a single dataset.

• CA Energy Savings, NEM 3.0 explained
• ca-solar.com, how NEM 3.0 is changing the California solar landscape
• SurgePV, 2026 US residential solar market trends

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