Almost every line on a utility bill takes money from you. One line on a ComEd bill gives it back, and it is the largest rider on the bill.
Carbon-Free Energy Resource Adj is negative. On the two bills reconciled below it took off $11.70 and $20.40. Most people paying a ComEd bill have never noticed it, and almost nobody knows what it is paying them for.
It is the nuclear line.
What it was worth on two real bills
| Bill |
Usage |
Filed total |
Arithmetic |
Printed |
| July 2026 billing period |
953 kWh |
(1.228) cents per kWh |
953 x $0.01228 = $11.70284 |
-$11.70 |
| June 2026 billing period |
1,518 kWh |
(1.344) cents per kWh |
1,518 x $0.01344 = $20.40192 |
-$20.40 |
Brackets denote a credit, which is the tariff's own notation. The rate comes from ComEd's 47th Revised Informational Sheet No. 36.1, effective July 18, 2026.
Note the two bills carry different rates. This is one of the few rider lines that does, and the reason is in the structure below.
It is the nuclear line, and the tariff says so plainly
Rider CFRA recovers the cost of, or passes back the revenue from, procuring Carbon Mitigation Credits. The rider defines the resource that produces them in two clauses:
Carbon-Free Energy Resource (CFER) means a generating facility that: (1) is fueled by nuclear power; and (2) is interconnected to PJM Interconnection, LLC.
That is the whole definition. Not carbon-free in general, not renewables, not a portfolio standard. A nuclear plant on the PJM grid.
A Carbon Mitigation Credit is a tradable credit representing the carbon emission reduction attributes of one megawatt hour from such a facility, under subsection 1-75(d-10) of the Illinois Power Agency Act. The rider gives effect to that section and to subsection 16-108(k) of the Public Utilities Act.
Illinois has a separate renewables line on the same bill, Renewable Portfolio Standard, and a separate one for zero emission credits. This one is specifically the nuclear procurement.
Why a procurement charge is paying you
The answer is one clause in the filed equation, and it is easy to miss.
The P term is defined as the sum of "the expenditures the Company expects to incur or revenues the Company expects to receive" in connection with procuring the credits.
Read that again. The tariff contemplates, in its own arithmetic, that this programme can run as net revenue rather than net cost. When it does, P is negative, the adjustment is negative, and the line on your bill is a credit.
The filed values confirm it is running that way now. The CFR Adjustment itself is (1.466) cents per kWh, a credit before any reconciliation is applied.
What the tariff does not say is why. The contracts sit under Section 1-75(d-10) of the IPA Act, and the rider does not reproduce their pricing terms. We are not going to reconstruct them from inference. What is checkable is the direction, and the direction is money coming back.
One bill line, two numbers, two different clocks
This is the part that explains why two bills a month apart carry different rates, and it is not visible on the bill at all.
The printed line is the sum of two separately filed numbers. The filed sheet says so directly: the combined amount "must be shown as a separate line item ... designated as the Carbon-Free Energy Resource Adj."
The CFR Adjustment is the large one, set for the delivery year running June 1 to May 31, filed with the ICC by May 20 each year, and revisable mid-year when ComEd needs a better match between costs and recovery.
The CFRMR Factor is the correction. Carbon-Free Resource Monthly Reconciliation. Its job, in the rider's words, is to periodically equalise what customers were charged or credited against what the procurement actually cost, "thereby ensuring that the Company does not over or under recover". It is filed every month, by the twentieth of the month before it applies.
So the bill shows you one number that is really a yearly figure plus a monthly correction. Neither is printed. Only the sum.
The credit is scheduled to shrink, and it is already filed
ComEd has published both components through May 2027. This is the whole table.
| Billing period |
CFR Adjustment |
Monthly reconciliation |
Printed total |
| June 2026 |
(1.466) |
0.122 |
(1.344) |
| July 2026 |
(1.466) |
0.238 |
(1.228) |
| August 2026 |
(1.466) |
0.776 |
(0.690) |
| September 2026 |
(1.466) |
to be determined |
to be determined |
| October to December 2026 |
(1.057) |
to be determined |
to be determined |
| January to May 2027 |
(0.984) |
to be determined |
to be determined |
Cents per kilowatt hour, brackets denoting a credit, exactly as filed.
Two movements are working against the credit at once. The reconciliation factor is climbing hard, from 0.122 to 0.238 to 0.776 in three months, and it is a charge that eats into the credit. Separately, the base adjustment steps down twice, in October and again in January.
The practical result: the August 2026 credit is roughly half the July credit on identical usage. For a household using 1,000 kWh a month, the line goes from $13.44 back in June, to $12.28 in July, to $6.90 in August.
If your bill rose and your usage did not, this is the first line to check. It is the largest rider on the bill and it is moving faster than any other.
Who sets it and what checks it
ComEd computes both numbers and files them with the ICC for informational purposes, each time with supporting work papers.
Two correction terms sit inside the monthly factor and both carry interest at the rate the ICC sets under 83 Illinois Administrative Code Section 280.40(g):
- ABF, the Automatic Balancing Factor, the running debit or credit balance from applying past factors.
- OA, the Ordered Adjustment, an amount ordered by the ICC or determined by ComEd to correct errors in previously applied factors. It may be amortised across multiple future periods rather than returned at once.
Before each June, ComEd's internal administrative costs, operational costs and cost of working capital for the procurement must be reviewed with personnel from the Accounting Department of the ICC Staff, and the rider requires an annual audit of costs and recoveries. The money is reviewed after the fact, not just filed.
Can it be avoided?
No, and for once that is the wrong question.
Rider CFRA states that it is applicable to all retail customers, across Rates BES, BESH, BEST and RDS. It applies to each kilowatt hour delivered, so switching to a retail electric supplier does not remove it.
While it is a credit, you would not want to. The thing worth knowing is not how to avoid it but that it is scheduled to get smaller, and that when the reconciliation factor exceeds the base adjustment the line flips from a credit to a charge. On the filed numbers that has not happened yet. On the trend in the table above it is worth watching.
What this page was checked against
Both. The nuclear definition, the P term, the two component structure, the bill-line designation, the filing deadlines and the ICC Staff review are quoted from Rider CFRA, Sheets No. 388 through 392.2 of ComEd's filed Schedule of Rates. Every rate is the filed value on the 47th Revised Informational Sheet No. 36.1, and the June and July 2026 totals are confirmed to the cent by two unrelated bills.
The other lines on the same bill are covered in every line on a ComEd bill, explained, including the one that drops in August and the one that turns into a credit.
