US-based gas utility Nicor has announced that the Illinois Commerce Commission has approved a base rate increase for its natural gas distribution company, Nicor Gas, which will add about $2.50 to an average monthly residential customer bill beginning in April 2009.

The company claims that, even under the new rates approved by the Illinois Commerce Commission’s (ICC) order, it will continue to have the lowest rates of any major natural gas utility in Illinois and among the lowest in the entire US.

It said that the rate increase would not apply to the cost of the gas itself, which Nicor Gas purchases on the wholesale market and passes along to consumers without any mark-up. The increase would only apply to what Nicor Gas charges to deliver the gas to homes and businesses, typically between 15% and 20% of a customer’s annual bill.

The commission’s order provides for a $69 million increase in Nicor Gas’s base revenues. The order also approves Nicor Gas’s request for an energy efficiency rider.

Russ Strobel, chairman, president and CEO of Nicor Gas, said: The ICC decision, which will increase an average residential customer’s bill by only about $2.50 per month, is a necessary step to enabling Nicor to continue its tradition of being a high-value, low-cost provider.