Missouri's largest power company is seeking approval for a $264 million rate increase.
Ameren Missouri said Thursday the increase is needed to cover the costs for various improvements, including new equipment at some of its coal-fired and nuclear power plants and new electrical substations in the St. Louis area. Part of the increase also is due to solar power investments and customer rebates.
Ameren Missouri serves 1.2 million customers.
Company spokesman Warren Wood said the 9.7 percent rate increase would amount to an extra $10 a month for an average residential customer using 1,100 kilowatt hours of electricity.
Rate increases are subject to approval by the Missouri Public Service Commission, which often reduces the amount from the original request. The regulatory process can take up to 11 months.