[Signal, Switch] Closing legacy net metering tariffs for Ameren Illinois and Commonwealth Edison
Summary
We're marking 21 legacy tariffs as closed across Ameren Illinois and Commonwealth Edison (ComEd). 15 of them will also change solarPvEligible from TRUE to FALSE. Our team expects to complete this exercise over the next two weeks (8/24/2026 - 09/07/2026)
What's changing
Ameren Illinois: 13 tariffs closing. Older -NEM tariffs carrying full retail-rate net metering, plus a set of No NEM tariffs left over from a short-lived 2020 policy episode.
ComEd: 8 tariffs closing. Older -NEM residential tariffs, all carrying full retail-rate net metering.
15 of the 21 also move to solarPvEligible = FALSE. These are the tariffs carrying full retail-rate net metering. Closing them wasn't enough on its own, because new solar calculations could still be run against these outdated policies.
Why we're making this change
The 2025 net metering change
Illinois net metering law changed for solar systems interconnecting on or after January 1, 2025. New systems receive net metering credit for supply charges only, and pay full delivery charges on their entire gross usage, instead of the full retail-rate credit older systems received. Systems already interconnected and receiving full retail-rate net metering before that date keep it for the life of the system.
That split is why the -NEM tariffs still exist. They remain the correct tariff for every account grandfathered into full retail-rate net metering, so we are closing them rather than removing them. New solar builds may not use the legacy net metering policy. The current, non-NEM tariff (DS-1, BES, and so on) reflects the post-2025 supply-only policy and is what new solar customers should be modeled on.
The 2020 Ameren "No NEM" episode
Ameren's No NEM tariffs are a separate, smaller story. In 2020, Ameren hit the state's 5% renewable energy threshold, which under Illinois policy at the time allowed the utility to move net metering customers off full retail-rate compensation. Ameren restricted net metering to supply charges only and billed distribution, transmission, and fixed charges as standard purchases. We modeled the No NEM tariffs to match.
In December 2020, regulators ordered Ameren to reinstate full retail-rate net metering, and the No NEM tariffs stopped applying to anyone from that point forward. We're taking this opportunity to clean them up in our database.
Tariff reference
The replacement column shows the current, non-full-retail net metering tariff for each rate class, reflecting the post-2025 policy.
Ameren Illinois
| Closing MTID | Closing tariff | Replacement MTID | Replacement tariff |
|---|---|---|---|
| 81357 | DS-1 - NEM | 3479265 | DS-1 |
| 3367007 | DS-1 - No NEM | 3479265 | DS-1 |
| 3495760 | DS-1-PSP-NEM | 3495763 | DS-1-PSP |
| 3494994 | DS-1-RTP-NEM | 3474765 | DS-1-RTP |
| 127179 | DS-2-NEM | 3494198 | DS-2 |
| 3367008 | DS-2 - No NEM | 3494198 | DS-2 |
| 3367009 | DS-2 - No NEM (Optional) | 3323797 | DS-2 (Optional) |
| 3513586 | DS-2-RTP-NEM | 3513608 | DS-2-RTP |
| 127180 | DS-3-NEM | 3494215 | DS-3 |
| 3367010 | DS-3 - No NEM | 3494215 | DS-3 |
| 127181 | DS-4-NEM | 3494211 | DS-4 |
| 3367012 | DS-4 - No NEM | 3494211 | DS-4 |
| 3475817 | DS-6-NEM | 3494201 | DS-6 |
ComEd
| Closing MTID | Closing tariff | Replacement MTID | Replacement tariff |
|---|---|---|---|
| 627 | BES - NEM (Res Single-Family) | 3479678 | BES |
| 628 | BES - NEM (Res Single-Family, Elec Heat) | 3479680 | BES-Elec-Heat |
| 84829 | BES - NEM (Res Multi-Family) | 3479679 | BES-Multi |
| 84832 | BES - NEM (Res Multi-Family, Elec Heat) | 3479681 | BES-Multi-Elec-Heat |
| 85090 | BESH - NEM (Res Single-Family, Hourly) | 3479851 | BESH |
| 85092 | BESH - NEM (Res Single-Family, Elec Heat, Hourly) | 3479853 | BESH-ELEC-HEAT |
| 85091 | BESH - NEM (Res Multi-Family, Hourly) | 3479852 | BESH-MULTI |
| 85093 | BESH - NEM (Res Multi-Family, Elec Heat, Hourly) | 3479854 | BESH-ELEC-HEAT-MULTI |
Questions?
Reach out to your Arcadia contact or our support team via [email protected] and we're happy to walk through any account-specific impact.