Net Metering Savings Calculator

Net metering is a utility billing arrangement that allows solar homeowners to send excess electricity back to the grid and receive a credit on their bill. When your panels produce more than you consume, the surplus flows outward; when you need more than your panels produce (at night or on cloudy days), you draw from the grid. Your bill reflects the net difference — hence "net metering." Most US states require utilities to offer some form of net metering.

NEM 3.0 — officially the Net Billing Tariff (NBT) — is the compensation structure approved by the California Public Utilities Commission (CPUC) in December 2022 and effective for new solar installations from April 15, 2023. Unlike NEM 1.0 and NEM 2.0, which credited exports at the full retail rate, NEM 3.0 compensates exports at an "avoided cost" rate that averages roughly 25% of the retail rate (approximately $0.03–$0.05/kWh). The goal was to reduce the "cost shift" to non-solar customers, but it significantly lengthened solar payback periods for California homeowners without battery storage.

Your retail electricity rate determines the value of self-consumed solar energy. If you pay $0.15/kWh, each kWh your panels produce and you use directly saves $0.15. Under traditional NEM, exported kWh are credited at the same $0.15. Under NEM 3.0, that same exported kWh earns only about $0.04. This is why self-consumption rate matters so much in NEM 3.0 states — maximizing on-site use before exporting dramatically improves the financial outcome.

Traditional NEM (used in most US states including TX, FL, NY, MA, and many others) credits every exported kWh at the full retail electricity rate. Your bill is literally the net of what you consumed minus what you exported at the same price. NEM 3.0 (California new installations since April 2023) uses a time-varying "avoided cost" export rate that averages about 25% of the retail rate. The practical result: a system that earns $500/year in export credits under traditional NEM might earn only $125/year in California under NEM 3.0, with the same production and export profile.

Under traditional NEM, modest oversizing (exporting 10–20% of annual production) can make sense because export credits equal the retail rate. Under NEM 3.0 in California, oversizing beyond your consumption is rarely economical — the export rate is so low that additional panels primarily generate low-value exported energy rather than high-value self-consumed savings. For NEM 3.0 homeowners, the smarter investment is pairing a right-sized system with a battery (like a Powerwall) to store and self-consume excess production instead of exporting it.

California NEM 1.0 and NEM 2.0 customers are grandfathered under their existing rate structures for 20 years from their original interconnection date. If you installed solar before April 15, 2023 and are on NEM 2.0, you continue to receive retail-rate export credits until your grandfathering period expires. This is a significant financial benefit worth preserving — avoid system modifications that could trigger a re-enrollment under NEM 3.0 without consulting your utility.

Most US states require investor-owned utilities (IOUs) to offer some form of net metering for residential customers, but the specific policies vary widely by state, utility type, and customer class. Municipal utilities and rural electric cooperatives often have their own rules and are not always bound by state mandates. Some utilities — particularly in deregulated markets like Texas — replace net metering entirely with a 'buy-all, sell-all' or net billing arrangement that credits exports at a wholesale rate. The DSIRE database (dsireusa.org) and your utility's published tariff sheet are the authoritative sources for confirming your local policy before you sign a solar contract.

Year-end credit treatment varies significantly by state and utility. Most traditional net metering programs roll unused kWh credits forward month to month indefinitely, while others reset the balance annually — typically on your interconnection anniversary or on April 1 — and pay out any remaining credits at the wholesale (avoided-cost) rate, which is often 70–90% lower than retail. A few jurisdictions historically allowed credits to roll forever; under California NEM 3.0 those rules change. Right-sizing your system to roughly match annual consumption is the simplest way to avoid losing value at year-end true-up settlements.

Net metering credits you at the retail electricity rate for every kWh you export — your meter effectively spins backward. Net billing (used in California NEM 3.0 and Arizona's Resource Comparison Proxy program) credits exports at a separate, usually lower, 'avoided cost' or time-of-export rate. Under net billing you effectively sell your excess solar at wholesale prices while still buying grid power at retail prices. The gap between buy and sell rates makes battery storage far more economically attractive in net billing states than under traditional net metering, where exports already earn the full retail rate.

In most net metering states, adding a battery to an existing solar system does not trigger re-enrollment under newer (and often less favorable) policies, as long as you do not increase your solar PV capacity. California is the most documented example: NEM 2.0 customers can typically add batteries while preserving their 20-year grandfathered rate, provided no panels are added. Always confirm with your utility in writing before installation — some interconnection-agreement amendments can inadvertently reset your enrollment date. Consult your installer and utility account representative before signing any change orders.

For most residential homeowners, bill credits received under net metering are not treated as taxable income because they offset your own electricity consumption rather than constituting a cash payment. However, when a utility issues a cash payout for excess year-end credits, the IRS may treat that payment as taxable income — particularly if it exceeds a de minimis threshold. State tax treatment can also differ from federal rules. This is a fact-specific determination that depends on your filing situation; consult a licensed tax professional or CPA before relying on any specific treatment of net metering payments on your tax return.