Which utility serves this customer?
Each Illinois utility has different net metering rules, rebate programs, and pitch angles. Selecting here loads the right calculator math and proposal template.
ComEd
ComEd / Commonwealth Edison (Exelon subsidiary) · ~4M residential customers · northern IL — Chicago metro (Cook + DuPage + Lake + Will + Kane + McHenry + Kendall counties) + Rockford / Aurora / Joliet · regulated IOU under Illinois Commerce Commission (ICC) · PJM ComEd Zone
Pre-2025 grandfather customers adding a battery face NEM 2.0 transition regardless of DG Rebate acceptance (Cohort A binary frame — new interconnection app mechanically triggers it). Post-2025 customers (Cohort C) are on supply-only NEM by default. DG Rebate $300/kW solar + $300/kWh storage available at point-of-sale via installer; requires BESH (Basic Electric Service Hourly Pricing) rate-plan switch + forfeits grandfather NM if applicable. PJM ComEd Zone — 2025/26 capacity-auction 833% spike flowing through supply-rate pass-through. CEJA preserves 1:1 retail NM for residential ≤25 kW; per-utility 8% peak-demand cap.
Lead with: Cohort A binary frame + Cohort C standard EDG + DG Rebate $300/kWh + PJM 833% rate hedge + Chicago resilience
Ameren Illinois
Ameren Illinois Company (Ameren Corporation subsidiary) · ~1.2M residential customers · central + southern IL — Peoria, Springfield, Decatur, Champaign-Urbana, Bloomington-Normal, East St. Louis fringe, Carbondale, Marion · regulated IOU under Illinois Commerce Commission (ICC) · MISO
Ameren only triggers NEM 2.0 on 100%+ capacity-increase interconnections — under-threshold battery additions do NOT mechanically destroy grandfather NM. This creates the Cohort B1 vs B2 tradeoff: B1 customers accept the DG Rebate (forfeiting grandfather + switching to Peak Time Rewards); B2 customers decline the rebate to retain grandfather + current rate plan. B1/B2 is the ONLY true rebate-vs-grandfather decision in the IL build — present both paths; customer chooses. Cohort C (post-2025) has no grandfather to lose. DG Rebate $300/kW solar + $300/kWh storage; point-of-sale via installer; requires Peak Time Rewards rate-plan switch. MISO — PJM 833% framing does NOT apply here.
Lead with: B1/B2 grandfather-vs-rebate tradeoff + DG Rebate $300/kWh + PTR battery DR + MISO rate hedge + central/southern IL resilience