So what will the latest natural gas delivery rate hike to Ameren cost you? Ameren spokesman Leigh Morris tells the Journal Star customers in the area that used to be called Ameren CILCO will pay an additional $3.44 a month. The Illinois Commerce Commission granted a $30-million increase to Ameren, which had requested a $51-million hike. The new rate is expected to go into effect Friday. The Citizens Utility Board says it will appeal the ICC's decision.