State analysis · source documents checked 2026-09-24

Solar payback in Illinois (IL) — 2026

A new Illinois system has three separate cash flows: a supply-only net-metering credit, a published per-kW utility rebate, and whatever Illinois Shines REC payment the vendor passes on.

What decides the answer in Illinois

ComEd's Rider POGNM (ILL. C.C. No. 10), 5th Revised Sheet No. 298, says classifications NM1–NM4 "will not be available to a retail customer that begins taking service hereunder on or after January 1, 2025". Customers already on those classes keep them, and so does a later customer at the same premises. Sheets 298.1 and 298.2 place new applicants in NM7–NM10, or NM13/NM14 if they choose a monthly monetary credit. The classification sheets (298–298.2), sheet 301 and sheet 302.1 were effective November 15, 2022 under ICC Docket 22-0036. The other credit sheets carry their own dates: sheet 299 December 10, 2018; sheet 300 May 4, 2012; sheets 301.1 and 302 December 1, 2023. The Illinois Shines FAQ gives the result for Ameren, ComEd and MidAmerican customers: "Projects installed after 1/1/2025 operate under supply-only net metering", and "customers still pay for delivery charges on all electricity pulled from the grid." [1] [3]

For a new ComEd customer on NM7, sheet 301 gives a kWh energy credit against the Purchased Electricity Charge, the PJM Services Charge and the PEA. On NM13, sheet 302 pays a monthly monetary supply adjustment equal to those same three charges times net output. Delivery charges are not credited. For a customer who buys supply from a retail supplier (NM9, NM10 or NM14), ComEd itself gives no credit. The tariff says net output goes to that supplier, and under NM14 the monthly monetary credit comes from the supplier. So the benchmark row, which values every kWh at the delivery-inclusive 15.87-cent state average, overstates what an exported kWh is worth to a post-2025 customer. For a published reference point, the Plug In Illinois page (plugin.illinois.gov) gives ComEd's Price to Compare (Electric Supply Charge plus Transmission Services Charge) as 10.399 cents/kWh for June 1–September 30, 2026. That figure excludes the Purchased Electricity Adjustment, and the supply charge alone is 8.677 cents. It is a summer price, not the tariff's credit formula. On your bill, the supply price appears as "Electricity Supply Charge"; use your own supply and transmission prices in the worksheet. The household rows below use assumed prices, 17 cents for imports and 8 cents for exports, and neither comes from a ComEd rate component. If the 8-cent export assumption is replaced with 10.399 cents and nothing else changes, the modelled no-incentive payback is 14.9 years instead of 16.1. [1] [5]

ComEd's Rider DG Rebate pays a published rebate per kW. 1st Revised Informational Sheet No. 48, "DISTRIBUTED GENERATION REBATE AMOUNT", effective December 15, 2022 under the ICC order of August 11, 2022 in Docket No. 21-0850, lists a Resource 1B rebate of 300 dollars per kW "of nameplate generating capacity ... measured as nominal Direct Current (DC) power output". Resource 1B covers a facility "that would qualify a retail customer for net metering". Sheet 248.3 requires a Smart Inverter using the required settings "for the life of the Distributed Electric Renewable Generating Facility", and Informational Sheets 49 onward list those settings. You apply when the interconnection agreement is signed, and that value holds if the system gets permission to operate within 24 months. The rider pays the owner or operator; whether the rebate goes to you or to the installer depends on the installation contract. Sheet 248.4 adds that a Rider POGNM customer whose facility has been issued a Resource 1 rebate is eligible only for net metering under subsection (n) of Section 16-107.5 of the Public Utilities Act from the date the rebate is issued. For the modelled 7 kW array, 7 × 300 = 2,100 dollars. Taking that as cash at installation, with the no-incentive household inputs, modelled payback falls from 16.1 to 14.8 years. Adding the assumed 8,000-dollar REC pass-through at the end of year two gives 9.6 years. This note uses Sheet 48 from ComEd's 2025 ratebook; ask ComEd or the installer whether a later revision changes the amount. [4]

Illinois Shines' FAQ says REC incentives "are paid to participating AVs and savings may be passed on to customers"; one REC is one MWh. The Illinois Power Agency's final REC prices for the Program Year starting June 1, 2026 pay 70.37 dollars per REC in Group A and 80.77 dollars in Group B for distributed generation of 0–10 kW AC, the tier for a 7 kW DC array whose inverter is rated 10 kW AC or less. The 2026-27 Program Guidebook puts Ameren, MidAmerican, Mt. Carmel and MISO-area cooperatives and municipal utilities in Group A, and ComEd and PJM-area cooperatives and municipal utilities in Group B. It says "All projects approved by the Commission after June 1, 2026, use the new 2026 REC Contracts", under which small distributed generation has a 15-year term and is paid "50% upfront payment at Energization and the remainder ratably over the subsequent 6 years". The utility makes those payments to the Approved Vendor, not to the homeowner. The program's REC Payments Calculator counts 15 years of production with 0.5% annual degradation and rounds down. Applied to this page's modelled first-year production of 9,187.27 kWh, that gives 133 RECs, so an estimated contract value paid to the vendor of 9,359.21 dollars in Group A or 10,742.41 dollars in Group B. A customer-owned small project can also get a 20-dollar-per-REC adder, if the vendor requests it and the project "has not received or will not receive an ITC or residential clean energy tax credit"; with the adder the estimate is 12,019.21 or 13,402.41 dollars. The vendor's own REC count comes from PVWatts with its roof inputs and the inverter's AC rating, so it will differ. How much of that value reaches you, as a lower price or a payment, is set by the contract and Disclosure Form, not by the program. The 8,000-dollar receipt in the rows below is an assumed net homeowner pass-through, not a program price. Timing depends on capacity: when a category is full, projects are waitlisted, and "New capacity is released for all Program categories at the start of each Program Year, which occurs annually in June." The Block Capacity Dashboard's table of final 2026-27 block sizes gives Small DG 236.71 MW of opening capacity (a 180.00 MW block plus uncontracted 2025-26 capacity) and a 2025-26 waitlist of 0.00 MW. The page describes its interactive chart as "Up-to-date data" on allocated, submitted and available capacity; check it, or ask the vendor, before counting on a 2026-27 award. Get the Disclosure Form, the vendor's deductions and the contractual payout milestone. [2] [9] [10] [11] [8]

The two REC rows put the assumed receipt at the end of year one or year two. Both print 11.0 years, because the model does not discount future dollars and both receipts arrive before break-even; each row's own text lists its cumulative cash year by year, which is where the timing difference shows. A later receipt would move payback: the same 8,000 dollars paid at the end of year 12 gives a modelled 12.0 years. Under the 2026 contract the vendor itself is paid half at energization and the rest over six years, so ask when your share is paid. [2] [10]

Ameren Illinois is a separate utility, and none of the rows is an Ameren bill. Ameren's solar page says that for applications after January 1, 2025, "excess generation will be credited to the bill's Supply section". Its Rider NMOS bills residential (DS-1) customers who start after January 1, 2025 under Methodology C (Sheet No. 31.004, effective August 14, 2026). Under that methodology, credits for customers initiating net metering on or after January 1, 2025 "are not subject to expiration at the end of the Annual Period", for both non-time-of-use and time-of-use supply (Sheet No. 31.009, effective November 29, 2024, and Sheet No. 31.010, effective August 14, 2026). The same page lists a residential (DS-1) smart-inverter rebate of 300 dollars per kW-DC for generators. No Ameren case is modelled, and Ameren's supply price is not used on this page. MidAmerican, municipal and cooperative territories are not covered here. Sunlight also varies within the state. PVWatts v8, with the settings used for the state input (listed on the methodology page and in the PVWatts source below), returns 4.51 kWh/m²/day for Chicago (41.8781, −87.6298) and 4.86 for Springfield (39.7817, −89.6501), against the 4.61 used here. With the no-incentive household inputs, those give a modelled 16.4 and 15.4 years. [6] [7] [12]

How Illinois pays for an exported kilowatt-hour

Export value differs from the full retail bill. For systems installed after January 1, 2025 in Ameren, ComEd and MidAmerican territory, exports earn supply-only credit, so the retail-value benchmark overstates export value. The household rows use an assumed 8-cent export value. Lower export credits lengthen payback, while a real REC payment or DG rebate shortens it; those effects do not reliably cancel.

No federal residential credit is applied by default in any calculator or state benchmark on this site (Section 25D expired at the end of 2025), and the mechanics of export regimes are covered in the net metering guide.

Sources for the Illinois section above

ComEd tariff book — Rider POGNM — Legacy/successor classification boundary and supply-only energy credit components for post-2025 classes.
Document: ILL. C.C. No. 10, Rider POGNM sheets 298–302.1. Effective/source period: Sheets 298–298.2, 301 and 302.1 November 15, 2022 (ICC 22-0036); sheet 299 December 10, 2018; sheet 300 May 4, 2012; sheets 301.1 and 302 December 1, 2023.
Applies to: ComEd net-metered retail customers; NM classification and supply arrangement matter. Relevant passage: “classifications NM1, NM2, NM3, or NM4 will not be available”.
Illinois Shines consumer FAQs — Vendor receives program incentive; homeowner pass-through depends on contract; capacity released each June.
Document: Consumer FAQs: incentive payments; waitlist and Program Year capacity. Effective/source period: Incentive FAQ marked updated July 2026; capacity FAQs marked updated January 2026.
Applies to: Illinois Shines distributed-generation customers contracting with Approved Vendors. Relevant passage: “The incentives are paid to participating AVs”.
Illinois Shines FAQ — net metering — Exports are credited against supply, not delivery, for post-2025 projects.
Document: What is net metering? (for customers in Ameren, ComEd, or MidAmerican service territories). Effective/source period: FAQ marked updated January 2026; applies to projects installed after January 1, 2025.
Applies to: Ameren, ComEd and MidAmerican customers; not municipal, cooperative or Mt. Carmel territories. Relevant passage: “Projects installed after 1/1/2025 operate under supply-only net metering”.
ComEd tariff book — Rider DG Rebate — Published Resource 1B rebate per kW DC, smart-inverter condition and legacy net-metering consequence.
Document: 1st Revised Informational Sheet No. 48; Rider DG Rebate sheets 248.2–248.4; Informational Sheet No. 49. Effective/source period: December 15, 2022; ICC order August 11, 2022, Docket No. 21-0850.
Applies to: Owners or operators of qualifying facilities with Smart Inverters; Resource 1B for net-metering-eligible facilities. Relevant passage: “DISTRIBUTED GENERATION REBATE AMOUNT”.
Plug In Illinois — ComEd Price to Compare — Published supply-plus-transmission reference price; not the net-metering credit formula.
Document: Price to Compare - ComEd. Effective/source period: Summer (June 1, 2026 - September 30, 2026).
Applies to: ComEd residential customers on utility supply; excludes the Purchased Electricity Adjustment. Relevant passage: “effective June 1, 2026 is 10.399 cents per kWh”.
Ameren Illinois — solar and net metering — Supply-only crediting and smart-inverter rebate amount for Ameren Illinois.
Document: Excess Generation Credits; Rebates. Effective/source period: Applications after January 1, 2025; retrieved September 24, 2026.
Applies to: Ameren Illinois customers; rebate amounts shown for DS-1 and DS-2. Relevant passage: “excess generation will be credited to the bill's Supply section”.
Ameren Illinois Rider NMOS — Carryover of post-2025 supply and transmission credits.
Document: Ill. C. C. No. 1, Rider NMOS – Net Metering for On-Site Generation, Sheet Nos. 31.004, 31.009 and 31.010 (Methodology C). Effective/source period: Sheet 31.004 and 31.010 August 14, 2026; Sheet 31.009 November 29, 2024.
Applies to: Ameren Illinois DS-1 and DS-2 customers initiating net metering on or after January 1, 2025. Relevant passage: “These credits are not subject to expiration at the end of the Annual Period”.
Illinois Shines Block Capacity Dashboard — Small DG opening capacity of 236.71 MW for 2026-27 and a 0.00 MW 2025-26 waitlist; the capacity still open is in the interactive chart.
Document: Block Capacity Dashboard: Final Block Sizes for the 2026-2027 Program Year (Small DG row); interactive capacity chart; project waitlists. Effective/source period: 2026-27 Program Year final block sizes; retrieved September 24, 2026.
Applies to: Illinois Shines project categories, including Small Distributed Generation. Relevant passage: “The Final Block Sizes for the 2026-2027 Program Year”.
Illinois Shines — Final 2026-27 REC Prices — 70.37 and 80.77 dollars per REC for 0–10 kW AC distributed generation, and the 20-dollar-per-REC customer-owned Small DG adder.
Document: Final 2026-27 REC Prices Applicable for the Program Year starting June 1, 2026 (section J, REC Pricing), pp. 1–2. Effective/source period: 2026-27 Program Year, starting June 1, 2026.
Applies to: Distributed generation projects of 0–10 kW AC, Group A and Group B; customer-owned Small DG adder conditions. Relevant passage: “REC Pricing for 2026-27 Program Year”.
Illinois Shines 2026-27 Program Guidebook — Group A/B territories, 15-year Small DG contract and 50%-upfront payment schedule to the Approved Vendor.
Document: Program Guidebook, version released April 17, 2026 for the 2026-27 Program Year: Group A/B definitions (p. 20), 2026 REC Contracts (p. 115), invoicing schedule (pp. 138–139). Effective/source period: 2026-27 Program Year; projects approved by the Commission after June 1, 2026.
Applies to: Illinois Shines Approved Vendors and their Small DG projects. Relevant passage: “All projects approved by the Commission after June 1, 2026, use the new 2026 REC Contracts”.
Illinois Shines REC Payments Calculator 2026-2027 — 15-year REC count formula, rounded down, used for the 133-REC estimate.
Document: REC Payments Calculator 2026-2027 (Excel), Calculator sheet. Effective/source period: 2026-27 Program Year prices.
Applies to: Distributed generation and Public Schools projects; estimate only. Relevant passage: “Degradation is assumed at 0.5%”.
NLR PVWatts v8 API documentation — Sunlight values for Chicago and Springfield.
Document: PVWatts V8 (GET /api/pvwatts/v8), output field solrad_annual; queries with system_capacity=1, module_type=0, losses=14, array_type=1, tilt=20, azimuth=180, dataset=nsrdb at Chicago (41.8781, −87.6298) and Springfield (39.7817, −89.6501); the state-input request is published in /data/state-insolation-pvwatts.json. Effective/source period: PVWatts version 8.5.0 responses, retrieved September 24, 2026.
Applies to: A 1 kW "Fixed - Roof Mounted" array at 20° tilt and 180° azimuth; not a specific roof. Relevant passage: “Annual solar radiation values. (kWh/m2/day)”.

“Source documents checked 2026-09-24” means each linked document was retrieved on that date and the passage quoted under it is the text the claims in this section rely on. The date covers only those claims. It is not a household eligibility decision or a guarantee that a tariff is still current, so check the linked live documents before signing a contract, and report corrections via the contact page.

Common retail-value benchmark — not a household forecast

No incentives; every modeled kWh is valued at the historical state-average retail price. The household scenarios below separate assumed import/export prices, consumption share, cash cost and receipt timing.

How Illinois compares with the other 50 records in this dataset
Measure	Illinois	Dataset median	Rank of 51
Avg residential rate	15.87¢/kWh	14.91¢/kWh	19th highest
NSRDB daily sunlight (one location per state)	4.6 kWh/m²/day	4.9 kWh/m²/day	38th highest
Retail benchmark payback	13.2 years	13.0 years	29th fastest on this benchmark
Household scenarios below (range)	11.0 years to 18.7 years	—	Not ranked across states

The rank compares every state on the same full-retail basis; it is a benchmark, not a forecast for a new Illinois customer. The household scenarios below, each with its own stated import price, export credit, cost and incentive timing, give 11.0 years to 18.7 years; that range leaves out the illustrative 20% lower and higher production rows, which change only production.

Rate: Calendar year 2024 annual average, from the EIA. Sunlight is NSRDB data via NLR PVWatts v8 at each state's 2020 Census center of population, one location per state (request settings and the values PVWatts returned are in state-insolation-pvwatts.json). Ranks and medians are computed across the 50 states and DC in this dataset. Every input behind the payback figure is printed in the assumptions block below, and the full 51-row table is at /states.

Reproduce the Illinois household comparisons

These are hypothetical households, not customer results or offers. All start from an assumed 7 kW array producing 9187.27 kWh in year one; any row that changes production (a battery or a production-stress row) says so. The sunlight input is NSRDB data via PVWatts v8 for one location per state (request and response in state-insolation-pvwatts.json; see the methodology), not a production estimate for your roof. No federal credit is applied. No loan, income-tax effect on incentive revenue, battery replacement or future tariff change is modeled.

The benchmark row prices every kWh at the EIA average cited above. Where another row applies a published figure (for example a tariff or rider rate or charge, a program incentive rate, a statutory fee schedule, or a tax credit's rate, cap or carryforward period), that figure comes from a document in the sources list above. Every other price, consumption share, cost, fee, receipt date and amount of tax a household can use in a year is assumed. Eligibility remains conditional. The annual split does not reproduce monthly netting, time-of-use periods, credit caps, curtailment or minimum bills. Annual fees represent incremental solar costs, not charges you would pay with or without solar.

Production degrades by assumed 0.5% per year. The main result increases both import and export prices by assumed 3% per year; the flat-price column sets that to zero. Neither escalation is a tariff forecast. Fixed fees and scheduled receipts do not escalate. Energy savings accrue uniformly within a year for interpolation; incentives arrive only at year end.

Download exact scenario inputs and all 25 yearly results (JSON)

Modeled results, not guarantees. No break-even means no crossing inside 25 years, not a calculated date beyond year 25.
Scenario	Initial cash cost	Year 1 energy value	Year 1 net cash incl. receipts	Payback	Flat-price payback	25-year net cash after cost
Common retail-value benchmark — no incentives	$22,400.00	$1,458.02	$1,458.02	13.2 years	15.9 years	Modeled $27,306.05
Hypothetical household — no incentives	$22,400.00	$1,148.41	$1,148.41	16.1 years	20.5 years	Modeled $16,750.95
Illustrative higher cash price — no incentives	$26,880.00	$1,148.41	$1,148.41	18.7 years	24.8 years	Modeled $12,270.95
Illustrative 75% self-use — no incentives	$22,400.00	$1,355.12	$1,355.12	14.0 years	17.2 years	Modeled $23,798.12
Conditional vendor REC payment in year 1	$22,400.00	$1,148.41	$9,148.41	11.0 years	12.9 years	Modeled $24,750.95
Conditional vendor REC payment in year 2	$22,400.00	$1,148.41	$1,148.41	11.0 years	12.9 years	Modeled $24,750.95
Conditional ComEd DG rebate (2,100 dollars) — no REC payment	$22,400.00	$1,148.41	$3,248.41	14.8 years	18.5 years	Modeled $18,850.95
Export credit at ComEd's summer 2026 Price to Compare (10.399 cents) — no incentives	$22,400.00	$1,258.61	$1,258.61	14.9 years	18.6 years	Modeled $20,507.87
Illustrative 20% lower production — no incentives	$22,400.00	$918.73	$918.73	19.3 years	no break-even inside 25 years	Modeled $8,920.76
Illustrative 20% higher production — no incentives	$22,400.00	$1,378.09	$1,378.09	13.8 years	16.9 years	Modeled $24,581.14

Inputs, receipts and annual arithmetic: Common retail-value benchmark — no incentives

Historical state-average import value for ALL production; only a comparison, not an address-specific tariff.

Assumed initial cash cost $22,400.00, not reduced by any upfront credit or rebate; any receipt is listed below and arrives at year end. Import 15.870¢/kWh; export 15.870¢/kWh; self-use 100%; incremental fixed annual cost $0.00.

Year-one modeled energy value = 9187.27 × [(100/100 × 15.87/100) + ((1 − 100/100) × 15.87/100)] = $1,458.02. Subtract the annual fixed cost and add only that year's receipts for net cash. Display rounds cents; the downloadable calculation retains full precision.

Incentive basis: None; no eligibility or benefit assumed. Modeled total receipts inside 25 years: $0.00. These are not subtracted from initial cash cost.