Do Solar Panels Work at Night? California Guide

Short answer: no. Solar panels do not produce electricity at night. Solar photovoltaic (PV) cells need sunlight to generate current, and without sunlight they sit idle. But that's not the end of the story — homes with solar still run electricity through the night, either from a battery that stored the day's solar production, or from the utility grid.

Here's exactly how it works in California and how NEM 3.0 changes the calculation.

This page is one part of our guide to solar cost and payback.

How Solar Panels Actually Produce Power

A solar panel works by the photovoltaic effect — photons from sunlight knock electrons loose from silicon atoms in the cells, creating an electrical current. No sunlight, no photons, no current. This is why solar production follows the sun's path: zero at sunrise, peak around noon, zero again at sunset.

On a cloudless day in California, a typical residential system produces 4-6 hours of "full" output, with partial production for a few hours on either side.

Moonlight produces a tiny amount of measurable current in very sensitive lab conditions, but it's thousands of times weaker than sunlight — not useful for household electricity.

So How Do Solar Homes Run at Night?

Two options: battery storage, or the grid.

Grid-tied solar (no battery). During the day, your panels produce electricity. Your home uses what it needs in real time; excess goes to the grid. At night, your home pulls from the grid like any non-solar house. You pay the utility for that evening grid consumption. Under NEM 2.0 (pre-April 2023), the export credits roughly balanced evening consumption.

Under NEM 3.0, exports are credited at a much lower rate, so evening grid consumption is essentially a full-retail charge against a smaller export credit.

This is the same two-way exchange the U.S. Department of Energy describes for any grid-connected home system: when the system generates more than the home needs, the excess is exported to the grid, and "when the homeowner's electricity needs exceed the capacity of the system, the home draws energy from the grid as usual" — which is what happens every night, with or without NEM 3.0.

No battery is required for this baseline exchange; it's how a grid-tied system is wired to behave by default.

Solar + battery. During the day, your panels produce electricity. Your home uses what it needs; excess charges a battery on your wall. At sunset, the battery begins discharging into your home, covering evening use until it runs out. If the battery empties, you fall back to the grid.

A properly sized solar + battery system can cover 80-95% of a typical California household's consumption, including the evening, without touching the grid.

Why This Matters More Under NEM 3.0

Under the Net Billing Tariff, PG&E, SCE and SDG&E don't credit your exported solar at one fixed rate.

Each calculates it hourly from the CPUC's Avoided Cost Calculator, and the CPUC states that value "is usually lower than the retail rate... but can rise above the retail rate on late summer evenings." What you pay to import power at night is a separate, and separately set, number — your time-of-use plan's price for that hour.

As one example: SCE places Net Billing Tariff customers on TOU-D-Prime, where published summer-weekday pricing runs 59¢/kWh on-peak against 26¢/kWh off-peak. PG&E and SDG&E price their own peak windows on their own plans. See What is NEM 3.0 in California? for the full export-versus-import mechanics, and PG&E, SCE or SDG&E for current time-of-use pricing by utility.

Why the 4-9 p.m. window is the real cost driver

PG&E, SCE and SDG&E each set their highest time-of-use price for the same stretch — 4 to 9 p.m. daily, according to each utility's own rate page (checked September 22, 2026). That's not a coincidence relative to your panels: by 4 p.m. production is already tapering off, and by 9 p.m. most California homes are past sunset. The hours your system stops covering your home directly are largely the same hours your utility charges the most to fill the gap — whether that gap gets covered by a battery discharging, by solar exported earlier in the day, or by a straight grid import at the on-peak rate.

Translation: a NEM 3.0 solar system without a battery exports most of its production at the low credit rate, then buys electricity back at the high on-peak rate at night. A NEM 3.0 solar + battery system stores the production and uses it at night, displacing that on-peak grid purchase. That's why battery storage moved from "nice to have" to "essentially required" under NEM 3.0. More detail in our NEM 3.0 worth-it analysis.

The peak window is on each utility's own rate pages. PG&E's E-TOU-C charges its peak price from 4 to 9 p.m. every day (PG&E residential rates table). SCE's TOU-D-4-9PM plan has its highest rates on summer weekdays from 4 to 9 p.m. (SCE). SDG&E's TOU-DR1 has peak pricing between 4 p.m. and 9 p.m. (SDG&E). All checked September 24, 2026.

On the export side, the CPUC says Net Billing credits are based on its Avoided Cost Calculator values, “usually lower than import rates” (CPUC, Net Energy Metering and Net Billing, checked September 24, 2026).

What Happens During a Power Outage at Night?

A common misconception: if the grid goes down at night and you have solar, you'll have power. Actually, a grid-tied solar system without a battery shuts off during outages for safety (to prevent backfeeding the grid while utility crews are working on lines). It's the battery that keeps your home running during an outage — day or night.

California homeowners in high-fire-risk areas subject to Public Safety Power Shutoffs (PSPS) lean heavily on battery storage for this reason. When the utility cuts power for wildfire safety, a solar + battery system keeps critical loads running for hours to days, depending on battery capacity and load management.

Does a Battery "Solve" the Nighttime Problem?

Mostly, yes. A typical 13.5 kWh residential battery (Tesla Powerwall, Enphase IQ, FranklinWH) stores enough energy to cover roughly 12-18 hours of typical California household consumption. Properly sized solar with one battery handles nightly cycling and still covers most mid-size outages. Larger homes or all-electric households (EV charging + heat pump + induction cooktop) often need two batteries.

Multi-day outages or winter storms with reduced solar production over consecutive cloudy days will eventually drain even a large battery. In those cases the grid (when it's up) fills the gap — which is why most California residential solar systems are grid-tied with battery backup rather than fully off-grid.

Shifting stored solar into that 4-9 p.m. window instead of importing at the on-peak rate is the specific problem a battery is sized to solve under NEM 3.0.

For sizing guidance built from your own panel and usage, see the home battery hub; for utility-by-utility payback math on pairing a battery with NEM 3.0, see battery payback under NEM 3.0.

Frequently Asked Questions

Do solar panels work at all at night?

No, they need sunlight to produce electricity. They sit idle from sunset to sunrise.

How do I use solar electricity at night then?

Either via a battery that stored the day's production, or by pulling from the grid at night and letting the daytime solar export offset part of that cost on your bill.

Do solar panels work when there's a power outage at night?

A grid-tied solar system without a battery shuts off during outages. Only a solar + battery system keeps your home powered through a nighttime outage. See our outage-specific guide.

How big does my battery need to be to cover my nights?

For a typical California household, one 13.5 kWh battery (like Tesla Powerwall 3) covers most overnight consumption. Larger homes or all-electric setups usually need two batteries. Our system sizing guide covers the math.

Does moonlight work?

Moonlight is reflected sunlight. It produces a tiny trickle of measurable current in lab conditions but is far too weak for household electricity. Functionally, the answer is no. The same is true of streetlights and other nighttime artificial lighting: the intensity is a small fraction of daylight, and household panels aren't built to register it as usable output. Functionally, neither moonlight nor streetlight will run your home.

Is "free nights and solar days" available in California?

Not as a named plan. None of PG&E's, SCE's or SDG&E's own rate pages publishes a plan under that name (checked September 22, 2026). What California's investor-owned utilities offer instead is standard time-of-use pricing — a cheaper off-peak stretch (PG&E's Electric Home plan, for example, prices off-peak from midnight to 3 p.m.) paired with a 4-9 p.m. on-peak window, not a literal free period.