IL Regulators Slash Nicor, Ameren Rate Hikes

(CHICAGO, IL – November 19, 2025) Utility regulators at the Illinois Commerce Commission (ICC) sharply reduced rate increases sought by suburban gas utility Nicor and downstate utility Ameren, approving substantially smaller increases than the companies proposed. Pending a review of the written order, the five-person commission appears to have cut both rate hikes by over 50%. Nicor requested $314 million and requested $129 million. Commissioners lowered the rate increase primarily by rejecting excessive infrastructure spending and cutting authorized profit rates.

At the end of Nicor and Ameren’s last rate cases in 2023, ICC Chair Doug Scott warned that as Illinois moves toward a 100 percent clean energy economy, the “gas system’s operations will not continue to exist in its current form.” In this year’s rate case, Illinois PIRG and Environmental Defense Fund argued that the utilities ignored that clear direction from the ICC in their infrastructure spending plans. In its final decisions Wednesday, the ICC agreed – significantly paring back both companies’ gas system investments.

Lower authorized profit rates also drove down the approved rate increases. The ICC reduced Nicor’s proposed return on equity from 10.35% to 9.60%. It also lowered Ameren’s return on equity. Additional highlights of the Commission’s decisions include:

• Studying line extension allowances. The Commission ordered staff to issue a report on gas utility line extension allowances, in which existing customers subsidize the costs to connect new customers to the gas system. Multiple states have recently ended the practice.
• Ending Nicor’s TotalGreen pilot program. Regulators discontinued the program, which charged customers a premium for carbon offsets and “renewable natural gas” credits that offered questionable environmental value.
• Rejecting Ameren’s “renewable natural gas” interconnection proposal. Ameren failed to show the project would reduce carbon emissions or provide a cost-effective climate benefit. 

Final written orders are not available yet. Illinois PIRG and EDF will provide further analysis once the orders are released.

In response to Wednesday's decisions by the ICC, Curt Stokes, Senior Attorney, Environmental Defense Fund, made the following statement:

“The Commission’s order makes meaningful progress on energy affordability and climate progress. By rejecting exorbitantly priced biomethane projects – such as Nicor’s TotalGreen, which would have charged customers thousands for virtually no emissions benefit – the Commission put customers first. Just as importantly, it set strong guardrails that push utilities to pursue cleaner, more affordable alternatives instead of doubling down on yesterday’s gas infrastructure.”

In response to Wednesday's decisions by the ICC, Illinois PIRG Director Abe Scarr made the following statement:

“We applaud the Commission’s clear and consistent message to Illinois gas utilities: stop the excessive spending that has driven up rates over the past decade. We hope the utilities respond in good faith, including Peoples Gas which has announced its plan to file a rate increase early in 2026. It’s time to embrace alternatives to business-as-usual investments in fossil-fuel infrastructure.

“While we’re pleased regulators lowered the size of these rate hikes, they are still the 5th increase for Nicor since 2017 and the 4th increase for Ameren since 2018. Without intervention, gas bills will continue to rise. Illinois urgently needs to pursue a managed transition to safer, cleaner energy to heat our homes.”