Residential customers of Ameren Illinois will see an average monthly increase of about $3.65 on natural gas bills in January, following a recent rate decision by the Illinois Commerce Commission.
The decision follows an 11-month review process in which regulators examined testimony and documents from utilities, consumer advocates, and environmental groups. The Commission approved a $73 million rate increase for Ameren and a $168 million increase for Nicor, both more than 40 percent lower than what the companies initially requested.
Ameren serves about 816,000 customers across central and southern Illinois. Nicor, the state’s largest gas utility, serves roughly 2.3 million customers in northern Illinois and the Chicago suburbs, and estimates its customers will see an average increase of less than $4.25 per month.
Both utilities are allowed to seek new rate increases annually, though in recent years they have done so every other year. The earliest customers could see another rate increase would be January 2027, or January 2028 if utilities maintain the alternate-year pattern.
Consumer advocates say the increases remain too high. Illinois PIRG policy director Abe Scarr said this marks the fifth rate increase for Nicor since 2017 and the fourth for Ameren since 2018, warning that without further intervention, gas bills will continue to rise.
Utilities earn money through infrastructure investments, not the cost of the gas itself, which is passed directly to customers without markup. Ameren officials say the company works to keep supply costs low by purchasing much of its winter gas during the summer, when prices are cheaper.
Ameren operates 12 underground natural gas storage fields across Illinois, allowing the company to buy about 60 percent of its winter supply during lower-price months. Company officials say that strategy has reduced gas supply costs by 30 percent over the past five years and helps shield customers from sudden winter price spikes.
Still, groups like the Citizens Utility Board say any increase adds pressure to already strained household budgets during the winter heating season.
