Illinois Home Battery Payback Calculator (2026)
Priced on Commonwealth Edison (northern IL) Standard (flat; Hourly Pricing / TOD optional) rates and below-retail export rules. No federal tax credit is assumed — Section 25D ended 2025-12-31.
Why Illinois is different
Illinois is the rebate state. Since January 2025, systems installed under CEJA's revised rules are compensated for exports at the supply portion only — roughly 7 cents against an all-in ComEd rate near 18 cents — which finally makes self-consumption worth real money (about 11 cents per stored kWh). More importantly, the ComEd / Ameren distributed-generation rebate pays about $300 per kWh of storage: roughly $4,050 on a 13.5 kWh system, the strongest immediate incentive in our ten-state set (a smart inverter is required, and ComEd's channel expects enrollment in Hourly Pricing — confirm on the official program page). Even with that rebate, payback at typical installed prices runs past two decades on bill savings alone. Summer storms and PJM price volatility add outage value the model does not count.
Rate structure
| Rate | Value | Notes |
|---|---|---|
| Peak rate (discharge window) | $0.18/kWh · flat rate — same price every hour (Hourly Pricing opt-in) | |
| Off-peak rate (charging) | $0.18/kWh | |
| Export credit | $0.07/kWh · Supply-only credit (CEJA, post-2025 NEM) | |
| Average residential retail | $0.183/kWh · EIA statewide residential average 18.31¢ (2026-07); the ComEd PTC is supply + transmission only (10.103¢ from 2026-10 to 2027-05), with delivery adding about 5–6¢ |
Verification status: Sourced. Flat modelling on the EIA statewide average by default; ComEd's voluntary Hourly Pricing (BESH) and TOD options exist, but the official all-in TOU tables are unverified and will be modelled once M1 adds the links
Export mechanism: below-retail export
Illinois credits new solar exports below retail (Supply-only credit (CEJA, post-2025 NEM)). Energy you store and use yourself avoids the peak purchase but gives up the export credit, so its value is peak minus export — about $0.11/kWh. That gap is what a battery monetises.
Incentives and VPP
| Program | Status | What it means for a battery |
|---|---|---|
| ComEd/Ameren DG rebate | Verify | Battery storage rebate of about $300/kWh (requires a smart inverter, and the ComEd channel requires enrolment in Hourly Pricing); 13.5 kWh ≈ $4,050 — confirm against the official programme page |
| Virtual power plant (VPP) | verify | CRGA (signed 2026-01) is building a VPP with a reported dispatch floor of $10/kW; Storage for All targets low-income households — enrolment details pending |
Outage context
Summer storms and PJM capacity price spikes drive rate volatility and outage risk
Typical payback in Illinois
Precomputed with the same model as the calculator, at the Illinois rates above and the reference installed cost of $13,000 (13.5 kWh usable, pre-incentive). Your numbers move with your bill, your quote and your rate plan.
| Scenario | Year-1 savings | Simple payback | 10-year net |
|---|---|---|---|
| Have solar · $200/mo bill · 13.5 kWh · $13,000 installed | $400 | 32.5 years | −$8,434 |
| Have solar · larger bill · $600/mo bill · 13.5 kWh · $13,000 installed | $501 | 25.9 years | −$7,282 |
| Battery only · $200/mo bill · 13.5 kWh · $13,000 installed | $0 | — | −$13,000 |
Estimates only — not financial, tax, or installation advice. Backup value and program payments are shown separately and never folded into the payback ratio.
State data pack
| Field | Value |
|---|---|
| Default utility | Commonwealth Edison (northern IL) |
| Rate plan modelled | Standard (flat; Hourly Pricing / TOD optional) |
| Average residential retail | $0.183/kWh |
| Verification status | Sourced |
| Data as of | 2026-10-18 |
| Official sources | Citizens Utility Board fact sheet (ComEd/Ameren rates Oct 2026–May 2027) (2026-10-18) · Illinois supply-only net metering & DG rebate guide (CEJA 2025 change) (2026-10-18) · Illinois CRGA VPP & Storage for All program overview (2026-10-18) · EIA Electric Power Monthly Table 5.6.A (IL residential average) (2026-10-18) · Database of State Incentives for Renewables & Efficiency (Illinois) (2026-10-18) |
Frequently asked questions
How much can a battery actually save on my Illinois bill?
At the rates above, each self-consumed kWh is worth the peak rate minus the export credit ($0.18 − $0.07 = $0.11). The model caps discharge at how much of your usage actually falls in the evening peak, so the reference scenarios above are the honest range — your bill, your quote and your rate plan move them.
Does Illinois pay for home batteries?
Battery storage rebate of about $300/kWh (requires a smart inverter, and the ComEd channel requires enrolment in Hourly Pricing); 13.5 kWh ≈ $4,050 — confirm against the official programme page Program terms change mid-cycle — verify on the program's own page before counting on any rebate.
Is a battery worth it in Illinois without the federal tax credit?
Section 25D ended 2025-12-31, so every result on this site assumes no federal credit. That makes the break-even installed price the most useful number on the results screen: it is the price at which the ten-year arithmetic stops working at your assumptions. Compare every quote against it, and read the outage context above — backup is real value, just not a cash flow.
Calculate with Illinois data →
Keep reading
| All state guides — ten states, ten different answers | Directory |
| Data & method — every constant with its source and verification date | Data |
| Full guide — how to read a payback number and the mistakes that inflate it | Article |
| How the model works — included, excluded, and a worked example | Method |
This page is educational. It is not financial, tax, or installation advice. Data as of 2026-10-18.