AmerenIP and AmerenCILCO customers could see their utility bills grow more than 17 percent between 2007 and 2008, meaning they could eventually pay about $11 more each month.
The utility company Tuesday asked the Illinois Commerce Commission to increase Ameren's delivery surcharge to customers. To ease the impact, Ameren proposed to phase in the increase over two years beginning in 2007.
The company also asked for a smaller monthly increase ranging from 27 cents to $5.19 for AmerenCIPS customers. That would be a one-time hike, with the higher fees closer to St. Louis, and would go into effect in 2007.
St. Louis-based Ameren contracts outside companies to deliver electricity to customers through power lines. The rate increases would help ease the rising costs of those contracts, said Ameren spokeswoman Susan Gallagher.
"It's been so many years since we had an increase in this area and our costs have gone up," she said. "We have invested to improve our lines and infrastructure. To continue investing we need to adjust these rates."
Because each Ameren Corp. subsidiary's expenses differ, delivery charges would be slightly higher for AmerenIP customers. They would pay an average of $7.08 extra beginning in 2007, or a 9.3 percent increase.
An AmerenCILCO customer would pay an average of $6.84 a month, a 9.8 percent increase.
In 2008, the charge would increase again.
So in 2008, AmerenIP customers would pay an additional $4.49 a month, an 8.5 percent increase, while AmerenCILCO customers would pay an extra 7.5 percent, or $3.87 more each month.
After the two years, average AmerenIP customers could pay $11.57 more than they are now, and AmerenCILCO customers could pay $10.71 more per month.
"It's mostly so we don't hit somebody with this all in one year," Gallagher said.
All costs are based on the average customer who consumes 866 kilowatt-hours a month.
AmerenIP and AmerenCIPS haven't raised delivery charges since 1992. AmerenCILCO hasn't raised its rate since 1982.
The ICC has 11 months to act on the request, so a ruling may not be made until next November.
AmerenIP serves the Bloomington-Normal area, while AmerenCILCO serves Logan and Tazewell counties and the communities of Stanford, McLean and Heyworth in McLean County.
AmerenCIPS serves Ford and Iroquois counties, and parts of eastern McLean, southern Livingston and northern Champaign counties.