By the SolarPayback Editorial Team · Updated June 2026 · Researched from authoritative sources. General information, not professional advice.
Net metering is the rule that decides what your solar panels are worth when they make more electricity than your home needs. It is, after the cost of the system itself, the single biggest factor in your payback. Two identical houses with identical panels can have wildly different savings simply because they sit in different utility territories with different export rules. This guide explains how net metering works, the major flavors you will encounter, and why you have to read your own utility's tariff to know what your roof is actually worth.
During the day, solar panels often generate more power than the house is using. Net metering is the policy that lets you send that surplus back onto the grid and receive a credit for it. With a traditional analog meter, the classic image is the meter literally spinning backward as power flows out; with a modern bidirectional digital meter, the utility simply tracks two numbers, the energy you imported and the energy you exported, and "nets" them out on your bill. The grid becomes a kind of battery you never had to buy: you bank excess generation by day and draw it back at night, paying only for your net consumption. The key question, and the one that varies enormously, is how much each exported kilowatt-hour (kWh) is worth.
There are three broad ways a utility can value the energy you export, and the difference between them changes the economics of solar dramatically.
| Compensation model | What you get per exported kWh | What it means for savings & batteries |
|---|---|---|
| Full-retail net metering | The same retail rate you pay to buy power (a 1-to-1 credit) | Best case. Every exported kWh offsets a future imported kWh at full value. Sizing to your full annual use makes sense; a battery is mostly for backup, not savings. |
| Net billing / avoided-cost | A lower rate, often the utility's "avoided cost" or an export-specific value well below retail | Exports are worth much less than self-consumed power. Using your own solar on-site becomes far more valuable, which is what makes a battery pay off. |
| No export compensation | Little or nothing for surplus sent to the grid | Only the energy you consume in real time has value. Oversizing wastes money; storage or load-shifting is essential to capture value. |
The shift from the first column to the second is exactly what makes recent policy changes so consequential. California's move from earlier full-retail rules to NEM 3.0 (formally the Net Billing Tariff, approved by the California Public Utilities Commission) is the headline example: exported energy is now valued using avoided-cost-style "Avoided Cost Calculator" rates that are typically far below the retail rate, rather than credited 1-to-1. The panels did not change, but the value of every exported kWh fell sharply, and overnight the financial logic tilted toward consuming your own solar and storing the rest.
Under full-retail net metering, a battery rarely pays for itself on savings alone, because the grid already credits your exports at full price; storage is mostly about backup power and resilience. Under net billing or avoided-cost rules, the calculus flips. If a kWh you export is worth only a fraction of a kWh you would otherwise buy, then storing your midday surplus in a battery and using it in the evening, instead of exporting it cheaply and buying it back expensively, captures the spread. That spread is the entire economic case for home storage in net-billing states. We cover this in depth in our battery storage guide.
Net metering is settled over time, not instantly. Many utilities run a monthly netting plus an annual true-up. Month to month, your exports offset your imports. At the annual true-up date, the utility tallies a full year and settles the balance. What happens if you produced more than you used over the year depends entirely on the tariff:
Because the cash-out rate is usually well below retail, the practical lesson is that under most modern rules you do not want to systematically generate a large annual surplus. The value is in offsetting your own usage, not in selling power to the utility.
Many solar customers are placed on, or choose, a time-of-use (TOU) rate, where the price of electricity changes by hour. This interacts powerfully with exports. If you are credited at the retail price in effect when you export, then midday solar, when rates may be lower, can be worth less than the expensive evening hours when your home draws from the grid. Under TOU plus net billing, this creates a deliberate incentive to shift solar into the peak window, typically by discharging a battery in the late afternoon and evening. Choosing the right rate schedule can meaningfully change your bill, so it is worth modeling more than one option with your utility.
Even a system that wipes out your energy charges may not zero your bill. Utilities increasingly apply fixed monthly charges, grid-access or solar-specific charges (sometimes tied to system size), and minimum bills that you pay regardless of how little net energy you consume. These exist because the grid still serves you at night and in winter. When you estimate savings, subtract these unavoidable charges, they put a floor under your bill and lengthen payback, and they are a common reason real savings come in below a back-of-envelope "rate times production" estimate.
There is no national net-metering law. In most states, the rules are set by the state Public Utilities Commission (PUC), sometimes called a Public Service Commission, and then implemented in each utility's tariff. That means compensation can differ not only from state to state but from utility to utility within the same state, and it changes over time as commissions revisit the policy. A program that offered generous full-retail credit a few years ago may have moved to net billing since. This is why no guide, including this one, can tell you your exact export rate, only your current tariff can.
Authoritative places to check include:
When you pull your utility's solar tariff, look for a short list of specifics. What is the export compensation, full retail, net billing, or an avoided-cost value? Is netting monthly, annual, or instantaneous? What happens to year-end excess, roll-over, cash-out, or forfeiture? Are you required to be on a TOU rate, and what are the peak windows? What fixed or grid-access charges and minimum bill apply? On the interconnection side, check the system-size limits, required equipment, insurance or fees, and the approval timeline, you generally cannot turn the system on until interconnection is approved.
Compensation rules should drive how big you build. Under full-retail net metering, sizing close to your full annual consumption is reasonable, because exports are credited at full value. Under net billing or avoided-cost rules, oversizing is a mistake: every kWh you export beyond your own use earns far less than it would have saved you, so a system tuned to your daytime self-consumption, paired with storage to capture the rest, usually beats a larger export-heavy array. Where there is little or no export compensation, the sizing logic is strictest of all, build for what you can use or store, not for what you can sell.
When a PUC changes net-metering policy, it commonly grandfathers existing customers, letting those who interconnected under the old rules keep the prior, often more generous, terms for a defined period (frequently a number of years). This protects people who invested based on the old economics, and it is a major reason interconnection deadlines around a policy change trigger a rush to "lock in." If you already have solar, find out what terms you are grandfathered into and for how long; if you are considering it, understand which rules you would be signing up under, since they may not be the ones available to your neighbor a year from now.
Not necessarily. Net metering can offset your energy charges, but fixed monthly charges, grid-access fees, and minimum bills often remain, and under net billing your exports are credited below retail. Many solar homes still get a small bill. Check your utility's tariff for the charges that apply even at zero net usage.
Under traditional full-retail net metering, exported energy is credited at the same rate you pay to buy power (1-to-1). Under net billing, exports are credited at a lower, export-specific or avoided-cost rate. California's NEM 3.0 is a net-billing structure. The difference sharply changes solar savings and makes batteries more valuable.
It depends on your tariff. Some programs roll credits forward, some cash out surplus at an annual true-up (usually at a low rate), and some forfeit unused credits. Because the cash-out rate is typically well below retail, it rarely pays to deliberately generate a big annual surplus. Confirm the terms in your utility's rules.
Start with your state Public Utilities Commission and your utility's published solar tariff and interconnection rules, and cross-reference DSIRE for a state-by-state summary. The DOE explains the concepts and the EIA shows regional rate trends, but only your current local tariff gives the export rate, true-up terms, and charges that determine your savings.
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