Solar Feed-in Tariff Calculator (U.S. Net Metering)

How the calculator works

The Solar Feed-in Tariff Calculator estimates the annual dollar value a residential solar system generates from two streams: self-consumption (offsetting imports at your retail rate) and exports (paid at your utility’s net metering or FIT rate). It is built around four locale-specific defaults — system size, peak sun hours, retail rate, and export rate — that match U.S. averages out of the box and can be overridden for your exact utility.

Plug in six numbers and the tool returns annual production (kWh), annual exported kWh, annual export revenue, self-consumption savings, total annual value, and your blended $/kWh:

1. System size (kW) — DC nameplate of your array. National average residential install is 7.5 kW per EnergySage H2 2025 marketplace data. Use the how many solar panels do I need calculator to size for your bill first.
2. Peak sun hours/day — your local NSRDB average. Pull the exact value from PVWatts (pvwatts.nrel.gov). Phoenix 6.5, Los Angeles 5.5, Dallas 5.0, Atlanta 4.7, Boston 4.0, Seattle 3.5.
3. Annual usage (kWh) — your last 12 months. Average U.S. residential customer uses 10,791 kWh/yr per EIA 2024 data; AZ/TX/FL run 13,000–15,000, while CA/NY/WA run 6,000–9,000.
4. Retail electricity rate ($/kWh) — your blended rate. EIA Form 826 Feb 2026 national residential average is $0.165/kWh; PG&E E-TOU-C blends to $0.42, AEP Texas 12-month $0.135, Hawaiian Electric residential $0.42.
5. Export rate ($/kWh) — under NEM 1.0/2.0 set this equal to retail. Under NEM 3.0 California, average $0.05–$0.08. Under sell-all/buy-all, use the utility’s avoided cost.
6. Self-consumption (%) — 25–40% without battery, 60–85% with battery.

How the math works

The calculator runs the following equations:

annual_kWh_produced  = system_kW × peak_sun_hours × 365 × 0.77
self_consumed_kWh    = min(annual_use_kWh, annual_kWh_produced × self_pct/100)
exported_kWh         = annual_kWh_produced - self_consumed_kWh
self_consume_value   = self_consumed_kWh × retail_rate
export_revenue       = exported_kWh × export_rate
total_annual_value   = self_consume_value + export_revenue
blended_$_per_kWh    = total_annual_value / annual_kWh_produced

The 0.77 multiplier is the IEC 61724 system performance ratio, accounting for inverter losses (3–4%), wire losses (1–2%), soiling (2–5%), high-temperature derating (5–8%), and module mismatch (1–2%). NREL PVWatts uses 0.86 as its DC-to-AC default but applies temperature and soiling separately. Our integrated 0.77 is the conservative number U.S. installers use in proposals.

Worked example: 7 kW system in Sacramento under NEM 3.0

• System: 7 kW DC, 5.4 PSH (Sacramento average per NSRDB)
• Annual production: 7 × 5.4 × 365 × 0.77 = 10,632 kWh/yr
• Annual use: 9,000 kWh, retail rate $0.30/kWh (PG&E E-TOU-C blended)
• NEM 3.0 average export rate $0.07/kWh
• Self-consumption 35% without battery → 3,721 kWh self-consumed × $0.30 = $1,116
• Exported: 10,632 − 3,721 = 6,911 kWh × $0.07 = $484
• Total annual value: $1,600/yr — blended $0.150/kWh

Now add a 13.5 kWh Tesla Powerwall:

• Self-consumption climbs to 85% → 8,037 kWh × $0.30 = $2,411
• Exported drops to 2,595 kWh × $0.07 = $182
• Total annual value: $2,593/yr — blended $0.244/kWh

The battery is worth nearly $1,000/yr extra under NEM 3.0 because it shifts $0.07 exports into $0.30 self-consumption value. That changes the lifetime ROI math entirely.

State-by-state net metering snapshot (Q1 2026)

The biggest driver of your export value is your state’s current NEM policy. Synthesis from DSIRE, NREL, and state PUC orders:

Reference: DSIRE (dsireusa.org), individual state PUC orders, utility tariff sheets. Update one tier above your default before running the calculator if your state matches.

NEM 1.0 vs NEM 2.0 vs NEM 3.0 — what to enter

NEM 1.0 (most U.S. states through ~2018): every exported kWh credited at full retail rate. Excess credits roll forward indefinitely or true up at retail. Enter your retail rate as the export rate.

NEM 2.0 (California 2016–2023): retail-rate credit but with non-bypassable charges ($0.02–$0.03/kWh) subtracted on import side, plus mandatory TOU rate. Enter retail rate minus $0.02 as export rate for closest match.

NEM 3.0 (California from April 2023, and increasingly the model for new state revisions): exports priced at avoided cost using a CPUC-published Avoided Cost Calculator (ACC) lookup table. Annual average lands at $0.05–$0.08. Peak-hour summer evening exports can hit $0.50+/kWh but represent under 5% of annual generation. Enter $0.07 as a reasonable annual blended export rate.

Sell-all / buy-all (Hawaii CGS+, some IOUs): you sell every kWh produced to the utility at the FIT rate, then buy back every kWh consumed at the retail rate. Set self-consumption to 0% and enter the FIT rate as export rate.

Federal incentives that change the math

The federal Investment Tax Credit (Section 25D) at 30% knocks down your system cost — modeled in our solar panel tax credit calculator. On a $21,000 7 kW system, the ITC returns $6,300 on your following year’s federal taxes, bringing net cost to $14,700. Combined with $1,600/yr value, simple payback drops from 13 years to 9 years.

The Inflation Reduction Act extended Section 25D at 30% through 2032, dropping to 26% in 2033 and 22% in 2034 before sunsetting in 2035. New solar installations contracted in 2026 lock in 30% so long as the system is installed and operational before December 31, 2032. Section 25D applies to total system cost including labor, permits, monitoring, and battery storage if rated 3+ kWh — battery storage qualifies under the IRA’s storage provision even if installed years after the PV array.

Time-of-use export tariffs in 2026

Under NEM 3.0 California, the avoided-cost table varies by hour. Summer weekday 5pm–9pm exports earn $0.30–$0.50 — roughly retail rate. Midday spring/fall exports earn under $0.04. The annual average works out to $0.07 because most production happens midday when the grid is oversupplied. A south-facing fixed array exports 70%+ of generation between 10am and 3pm, dragging the blended export rate down. West-facing or southwest-tilted arrays shift generation later — gaining 8–15% in export value per kWh under NEM 3.0 at the cost of 5–8% lower total production.

If your utility is in a NEM 3.0 or NBT framework, the calculator’s blended $/kWh output is your best summary metric. Compare it against your retail rate: any gap is the value a battery could recapture by shifting exports into self-consumption.

Sources

• U.S. Energy Information Administration, Form 826 February 2026 retail rate release.
• Database of State Incentives for Renewables & Efficiency (DSIRE), N.C. Clean Energy Technology Center.
• National Renewable Energy Laboratory, PVWatts Calculator and NSRDB.
• California Public Utilities Commission, NEM 3.0 / Net Billing Tariff Decision D.22-12-056.
• EnergySage Solar Marketplace Intel Report H2 2025.
• Internal Revenue Service Section 25D Residential Clean Energy Credit (Form 5695 instructions, 2025 tax year).