California NEM 3.0 slashed solar export credits by 75%, making solar-only systems financially unviable without batteries

In April 2023, California's Net Billing Tariff (NEM 3.0) replaced net metering with a system that pays homeowners roughly $0.04-$0.08 per kWh for exported solar electricity -- down from $0.25-$0.35 under NEM 2.0. A 10kW California system that previously earned approximately $2,000/year in export credits now earns closer to $500/year. Simultaneously, NEM 3.0 mandated time-of-use rate plans where evening peak rates hit $0.55+/kWh while midday rates (when solar produces most) drop to $0.10/kWh, creating a massive spread that only battery storage can arbitrage. This matters because California is the largest residential solar market in the country, and NEM 3.0 fundamentally broke the economics that drove millions of installations. System payback periods stretched from 5-7 years to 10-15 years for solar-only systems, and the only way to restore reasonable payback is to add a $10,000-$15,000 battery system -- doubling the upfront cost. Battery attachment rates jumped from 11% pre-2023 to nearly 70% by end of 2024, not because batteries are a great deal, but because without them the math simply doesn't work. Homeowners who installed under NEM 2.0 face a deadline: their grandfathering expires after 20 years, at which point they'll be moved to NEM 3.0 rates, retroactively undermining the financial assumptions they made when they signed their contracts. This problem persists because California utilities (PG&E, SCE, SDG&E) successfully lobbied the CPUC to shift grid maintenance costs onto solar homeowners, arguing that net metering created a cost shift from solar haves to non-solar have-nots. The policy was designed to protect utility revenue, not to optimize clean energy deployment. The California Supreme Court ordered the Court of Appeal to reconsider NEM 3.0's legality in August 2025, with a ruling expected by mid-2026, but the uncertainty itself is damaging -- homeowners don't know what rules will apply to their investment over its 25-year life. Other states are watching California and implementing similar net metering rollbacks, creating a nationwide pattern where early solar adopters get grandfathered rates while new adopters face dramatically worse economics.