Solar in California After the Net Metering Shake-Up

For two decades, California solar ran on a simple bargain: every kilowatt-hour your panels pushed to the grid canceled one you bought back later, at full retail price. Under that regime — net energy metering, or NEM — the grid behaved as a perfect battery and the winning strategy was blunt. Cover 100% of your annual usage, let the meter do the accounting, and don’t overthink it. That bargain ended for new residential customers of the state’s three big investor-owned utilities in 2023, when NEM gave way to what regulators call net billing, widely known as NEM 3. Solar in California still makes sense for a great many homes. What changed is how it makes sense — and the homeowners who end up disappointed are almost always the ones still running the old playbook against the new rules.

What net billing changed, and what it didn’t

The structural change is easy to state and consequential to live with: imports and exports are now priced differently. Electricity you buy from the utility still costs the retail rate, which in California is among the highest in the nation. Electricity you export is credited at values derived from the utility’s avoided costs, which vary by hour and season and are, for most daylight hours, dramatically lower than retail. A common shorthand is that typical midday exports earn something on the order of a quarter or less of the retail rate, while a narrow band of summer evening hours — when the grid is genuinely strained and additional supply is valuable — credits far more. Treat those proportions as the shape of the system rather than quotable numbers; the exact values live in published tables that get updated, and any specific figure you memorize will be stale before long. Two consequences fall straight out of that structure and reshape everything downstream. First, a kilowatt-hour consumed the moment it’s generated is worth full retail, while a kilowatt-hour exported usually is not — so self-consumption went from an irrelevant detail under the old bargain to the central variable in California solar economics. Second, when you export matters nearly as much as how much: midday surplus is close to worthless, evening delivery is valuable, and hardware that can shift solar energy from noon to 7 p.m. — a battery — went from luxury add-on to the default design assumption. One important carve-out keeps this from being universal. Homeowners who interconnected under the earlier NEM tariffs generally keep those terms for a fixed period measured from their original interconnection date, so if you bought a house with existing solar, the system’s tariff status is a genuinely valuable and checkable attribute that can be worth real money. Customers of municipal utilities outside the big three operate under their own rules entirely, which may still resemble the old bargain, so nothing here applies uniformly across the state — your utility’s current tariff is the controlling document, full stop.

It would be easy to read the export haircut as “California killed solar,” and the offsetting facts are substantial enough to retire that reaction quickly. California retail electricity rates are extraordinarily high and carry a long history of climbing, which makes every self-consumed solar kilowatt-hour more valuable here than almost anywhere in the country — the very thing net billing rewards, California has in abundance. The solar resource is excellent, with much of the state seeing on the order of 5 to 5.5 peak sun hours, so the panels produce plentifully. A mature, competitive installer market keeps per-watt pricing reasonable. And the 30% federal Residential Clean Energy Credit applies to both solar and battery storage, which matters more here than in most states precisely because batteries have become central to the design. Put plainly, the state pairs some of the nation’s best reasons to generate your own power with some of the nation’s worst compensation for giving it away. That combination doesn’t argue against solar — it argues against oversized, battery-less solar, which is a very different conclusion. The broad question of which factors move solar payback in any market, of which export compensation is only one, is worked through in the payback factors guide; California is simply the sharpest current example of export rules overriding sunshine in the final math.

The new design playbook: self-consumption, timing, and batteries

Under the old rules, systems were sized to annual usage and that was the end of the design conversation. Under net billing, three shifts follow directly from the arithmetic, and together they define how a well-configured California system now gets built. The first is sizing closer to what you can actually consume or store, because every kilowatt of capacity whose output routinely exports at midday earns pennies on the retail dollar. Systems now get sized against daytime consumption plus battery capacity rather than against the annual bill alone, which for many homes means a somewhat smaller array than the old playbook would have specified — unless a battery raises the amount of production the home can keep for itself. The second shift is that batteries moved from add-on to core component. A battery converts near-worthless midday exports into full-retail evening self-consumption, and it can also discharge to the grid during those high-value evening windows when export credits briefly spike. This is the rare market where storage improves the investment case rather than merely adding backup resilience — a genuine reversal of the usual guidance in is a solar battery worth it, which in most states treats a battery as a resilience purchase that rarely pays for itself. The mechanics of how a battery intercepts and time-shifts solar production are laid out in how home solar batteries work, and the solar battery calculator will size one against your specific evening loads.

The third shift costs nothing and is the most overlooked: load timing became a lever you can pull with zero additional hardware. Dishwashers, laundry, pool pumps, EV charging, and pre-cooling the house can all migrate into the solar window, and a household that shifts even a few kilowatt-hours a day from evening to midday captures retail value it would otherwise have exported for pennies. Time-of-use rate plans, which are standard for California solar customers, reward exactly the same behavior from the consumption side of the meter, so the incentive points the same direction for both your own solar production and the grid power you still buy. What ties these three shifts together is that they all chase the same objective — keeping more of your own generation for yourself instead of handing it to the grid at a discount. The old playbook was indifferent to that objective because the grid paid full retail for surplus; the new one is organized entirely around it. A homeowner who internalizes just that single reframing — self-consumption is now the goal, not annual offset — will make better decisions about array size, battery capacity, and daily habits than one who arrives with a proposal built on the assumption that exports still pay retail. And it’s worth being clear that none of this makes California a bad solar state; it makes it a state where the design has to be right, and where the penalty for getting the design wrong is larger than almost anywhere else.

The practical upshot for hardware is that a California system now gets designed as an integrated whole rather than a panel count. The array, the battery’s usable capacity, and the inverter that ties them together are sized against the shape of a household’s daily load curve — how much power it draws at 8 a.m. versus 8 p.m. — instead of against a single annual kilowatt-hour figure. That is a subtler exercise, and it is why two homes with identical yearly usage can rationally end up with quite different systems: the one that runs a pool pump and cooks with gas at midday needs less storage than the one that arrives home at six and switches on an electric range and an EV charger. Oversizing the array without the storage to hold its output is the specific error the new rules punish hardest, since those extra midday kilowatt-hours pour onto the grid for pennies. Getting the balance right is where a good installer earns the fee, and where a proposal that simply scales up an old-NEM design quietly leaves money on the table.

Running the numbers, and what to check before signing

A stylized comparison shows why the playbook changed rather than merely asserting it. Assume a home using 9,600 kWh per year at an average retail rate of $0.35 per kWh, considering a 6 kW system that produces about 9,500 kWh annually — every figure here an assumption to be replaced with your own tariff and usage. Configured as solar only with 35% self-consumption, the system offsets roughly 3,325 kWh at retail, worth about $1,160, plus 6,175 kWh exported at an assumed average of $0.06 per kWh, worth about $370 — call it $1,530 a year. Add a battery that raises effective self-consumption to 85%, and the same system now keeps roughly 8,075 kWh at retail, worth about $2,825, with only 1,425 kWh exported for about $85 — around $2,910 a year. The battery nearly doubles annual savings in this illustration, which is the crux of why it moved to the center of the design. Notice, too, what those high retail rates do to the absolute numbers: even the battery-less configuration saves over $1,500 a year, more than the same system would save in most low-rate states with generous net metering. California’s rates are high enough that a merely decent capture rate still throws off serious dollars, so the export haircut changes the optimum rather than the opportunity. Whether the battery doubles the return as cleanly as it doubles the annual savings depends on what the battery costs after the federal credit and how long it lasts — the honest answer is that solar-plus-storage in California typically shows a longer payback than bare solar did under old NEM, but a considerably better one than bare solar under net billing. The solar ROI calculator is built for exactly the substitution of your real numbers into that frame.

The net billing era rewards diligence on a handful of specific points, and each one maps to a way proposals go wrong. Ask which tariff the proposal models, and insist that the savings projection reflect hourly export values rather than a flat retail credit — a projection that quietly assumes old-NEM economics is the single biggest red flag in California proposals today, because it inflates savings using rules that no longer apply to you, and it inflates them most for exactly the oversized, battery-less configurations the new rules punish. Confirm whether the battery is folded into the payback math or presented as a separate resilience purchase, since blending the two hides whether the storage actually earns its cost. If you’re buying a home with existing panels, verify the system’s interconnection date and its remaining grandfathered term, because that older tariff can be worth thousands over its remaining life and it transfers with the house. And if your utility is a municipal one rather than one of the big three, set all of this aside and read its actual rules, where you may be pleasantly surprised to find the old bargain still largely intact. California hasn’t stopped being a solar state. It has become a solar-design state, where the gap between a well-configured system and a naively configured one is wider than anywhere else in the country — and where the homeowner who understands that gap captures most of the value the state’s high rates and strong sun still make available.