The City of Carbondale recently announced this year’s electric rates through the aggregation program with Homefield Energy and how they compare to Ameren’s summer rates. Residents should have now received letters in the mail explaining the program and providing an opt-out of the aggregation program. Find more info on the aggregation program here: https://www.explorecarbondale.com/999/Electric-Aggregation-Program 

Ameren has shared the information below on their summer rates: 

2025/2026 AMEREN ELECTRIC SUPPLY FAQ 

MISO, the regional grid operator for the Ameren service territory, held its annual capacity auction to ensure there is sufficient electricity supply to provide power on peak days throughout the year. The auction resulted in a significant increase in summer capacity prices over current prices and will increase the overall power supply price that Central and Southern Illinois will pay this summer. 

How does the cost of power supply impact my utility bill? 

There are two components of the energy bill: Supply & Delivery 

• The main components to the energy bill are the delivery charge, which covers the costs of Ameren Illinois' wires and poles, our technology and operating systems, maintenance and modernization of the grid, and the people who do the work. As a delivery-only utility, Ameren Illinois earns a profit on energy delivery as set each year in rates approved by the Illinois Commerce Commission. 

• The other element of the bill is the power supply charge – or the cost of electricity itself. Ameren Illinois does not own generation or generate power; it is purchased for us to deliver by a state agency. The cost of electric supply accounts for more than half of a typical customer’s monthly electric bill. 

How much will customers pay for power supply? 

Beginning June 1, 2025, and ending September 30, 2025, Ameren Illinois' supply price (also known as the Price to Compare) will increase by roughly 50 percent, going from around 8 cents per kWh to around 12 cents per kWh. This will result in an approximately 18% to 22% total bill increase for the typical residential customer for the summer period, depending on their usage. This supply price increase will only be in effect for four months (June-September). Beginning on October 1, 2025, the supply rate is expected to return closer to current levels (around 8-9 cents) for the remaining eight months. 

Because of billing cycles, customers likely won't see the new rate reflected on their bills until July 2025. 

Why are power supply prices going up? 

MISO, the regional grid operator for the Ameren service territory, held its annual capacity auction to ensure there is sufficient electricity supply to provide power on peak days throughout the year. The auction showed lower available surplus capacity for the summer months, resulting in a twenty-fold increase in summer capacity prices over current prices (from $30/MW-day to $666.50/MW-day). 

How are supply prices set? 

• In Illinois’ restructured energy markets, the Illinois Power Agency (IPA) procures electricity and a portion of the electric capacity for residential and small commercial customers who have not made the switch to an alternative supplier. 

• The electricity procurement acquires the basic generation needed to meet forecasted usage through the year. Capacity is acquired to ensure that there is enough power available on days when peak usage in an hour is at its highest (like on extremely hot days) and energy usage spikes. 

• The IPA attempts to procure as much capacity as it can in advance (known as “hedging”). The remainder is procured by MISO through its annual capacity auction. 

• The supply price includes the electricity costs (IPA) and capacity costs (IPA & MISO). Ameren Illinois enters into pricing contracts with generators at the prices secured by IPA and MISO and passes the costs to customers, dollar-for-dollar without mark-up or profit. 

Is there a concern about power availability? 

Ameren Illinois is confident that there is a sufficient amount of energy to meet the needs of our residential and business customers this summer and throughout the year. Supply constraints, however, increase the risk that insufficient generation will be available during periods of extreme temperatures and high energy usage. In the unlikely event that this would occur, Ameren Illinois has a well-developed process to reduce electric load with minimal impact on residential customers. 

Are all Ameren Illinois customers subjected to the new supply rates? 

No. Only Ameren Illinois customers who elect to receive their electric supply through Ameren Illinois’ Basic Generation Service should expect to pay the new rates. 

Nearly half of Ameren Illinois customers receive their electricity from an Alternative Retail Electric Supplier (ARES). Ameren Illinois encourages all customers, including those who are supplied by an ARES under a municipal aggregation agreement, to know their supply rate and the terms of their contract. Customers can find their rate and supplier by locating the "Electric Supply" portion of their Ameren Illinois bill. 

As a delivery-only company, Ameren Illinois supports electric supply choice as another option for customers to lower their energy costs. Customers can visit the Illinois Commerce Commission website at pluginillinois.org to learn more about electric choice. 

What can customers do to save on energy costs? 

Ameren Illinois encourages its customers to begin taking steps today to prepare. Applying for financial assistance, enrolling in flexible payment programs, and implementing energy efficiency measures can help customers manage their monthly bills. 

Information on available financial assistance, flexible payment programs, and energy-saving incentives is available at www.AmerenIllinois.com/options. Ameren Illinois also offers a variety of energy efficiency programs, which can be explored at www.AmerenIllinoisSavings.com. 

 
For more information and media requests contact: 

Eva Fisher 

618-713-0711  

efisher@carbondaletourism.org