Ameren Illinois electric rates: fixed price, Power Smart Pricing or a supplier?

Three kinds of supply price can show up on an Ameren Illinois bill. Ameren still delivers your power and sends the bill in all three. The delivery charges are the same. Only the supply line changes.

Ameren's own rate pages are easy to misread. Its Rate Options page says its plans are not available for Illinois customers, because it describes Ameren Missouri. Its Residential Rates page opens with a $9.00 monthly charge, and that line sits in the Missouri section. Illinois delivery charges are in Ameren Illinois's DS-1 tariff, and our Ameren bill guide lists them line by line.

CUB lists two special programs for Ameren Illinois homes: Power Smart Pricing and Peak Time Rewards. Peak Time Rewards gives a bill credit when you cut use on certain hot days. It is not a rate. CUB's Peak Time Rewards sheet explains it.

Type your use in kWh. Then add an offer's price, or the average price you paid on Power Smart Pricing, or both. The test finds your bill under Ameren's two-step price and shows who wins at your use. It also shows the use level where a flat offer stops winning.

1. 1
   Type your monthly kWh.

   It is on your bill. Winter months are often near 800.

2. 2
   Add an offer's price and any monthly fee.

   Use cents per kWh, such as 11.19.

3. 3
   On Power Smart Pricing?

   Divide the Electric Supply total on a past bill by that bill's kWh. Type the answer in cents. The Commission says to compare hourly pricing this way.

4. 4
   Read the answer.

   Then check the offer's end date and exit rules.

This compares supply only. It leaves out delivery, taxes and credits. It uses Ameren's October to May price, so summer months will differ. Treat it as an estimate, not a bill or a quote.

Ameren sets its price to compare for two seasons. From October 1, 2026 to May 31, 2027 the Commission lists 10.441¢ per kWh for your first 800 kWh a month and 8.262¢ for each kWh above. We last read the Commission's page on October 25, 2026. Summer, June to September, has one flat price with no second step.

The Commission lists the supply part at 7.310¢ and 5.131¢, the transmission part at 2.765¢, and a small supply cost adjustment at 0.313¢. Do not add these up yourself. The official total is 10.441¢ for the first 800 kWh. On October 25, 2026, the parts as printed did not match it exactly. The Commission also says a monthly Purchased Electricity Adjustment is left out of the total and is expected to stay near zero.

Ameren does not earn a profit on supply. Ameren says supply charges pass through dollar for dollar. CUB blames the climb on the price of reserve power, called capacity, in grid auctions run by MISO, and on data center demand.

Past periods do not change. CUB said on September 28, 2026 that the new price was about 8 percent below summer 2026 and about 24 percent above the October before.

Power Smart Pricing (PSP) is Ameren's hourly plan. You pay the wholesale market price for each hour, set the night before, instead of the default price. Ameren posts the next day's prices after 5 p.m. You keep the same bill dates.

What the tariff says, in plain words:

• A $2.25 monthly charge on top, per Ameren's Rider PSP, in effect since Jan. 17, 2025.
• A smart meter is required. The tariff says Ameren will work to install one for people who join.
• You must buy supply from Ameren. If a supplier or town program serves you, you switch back first, says CUB.
• Leaving locks you out. You wait 12 months to rejoin an Ameren hourly rate. Ameren suggests staying a full year.

The price on the chart is not the price you pay. Ameren's hourly chart shows the energy part, and low hours can look like 2 or 3 cents. Your bill adds a capacity-based supplier charge, the transmission charge and a monthly adjustment, all named in Ameren's Rider RTP tariff. In non-summer months, that supplier charge falls on the first 800 kWh. CUB's 2021 fact sheet also said transmission for hourly customers follows your own use in the grid's busiest hour. Check your bill for how this works today.

Ameren says savings vary, and participation is no guarantee. CUB's 2021 fact sheet said participants saved about 10 percent on supply on average. That is five years old, and prices have moved a lot since. The only test that counts is your own bill. Add up three months of the Electric Supply total, divide by the kWh, and put that average in the tool above. If you have solar, read our Ameren net metering guide first and ask Ameren how hourly billing treats your credits.

To enroll or leave, use Ameren's Power Smart Pricing page or call 1.888.596.5498, Monday to Friday, 8 a.m. to 5 p.m. The hourly price line is 1.877.655.6028. The hourly prices change every hour, so this page does not copy them.

Ameren Illinois has three rate zones. The Commission keeps one offer list for each. A person read all three on October 25, 2026. It is a snapshot, not a live feed, because the Commission's own site does not allow robots to read it.

Compare each lowest fixed price with Ameren's first-800 price of 10.441¢. On October 25, 2026, the lowest one-month intro price on a variable plan was 9.499¢. After the month ends, a variable price can change with no cap. Do not sign for the intro and ignore what follows.

Flat offers also face a catch the lists hide. Ameren's price falls above 800 kWh, so an offer that looks close at 800 kWh gets worse as your use grows. A flat offer a little under Ameren's first-800 price stops winning once your use climbs well past 800 kWh. The tool above finds that use level for your price and fee.

Offers change daily. The Commission's list is the official record, so check it for your zone at Plug In Illinois. A plan finder can show plans for your ZIP in one place. Coverage differs by ZIP, and some Ameren towns will show none.

Many Ameren towns voted to buy power as a group. If you did not opt out, you are signed up, and a supplier named in your letter sets your supply price. The state's list on October 25, 2026 showed 259 Ameren-area programs with a supplier chosen. 1 of them were priced below Ameren's first-800 price. The median was 11.78¢. Homefield Energy held 188 of them.

Compare each price in the table with Ameren's first-800 price of 10.441¢. CUB reached the same view in a review on Aug. 26, 2026: more than 9 in 10 community offers in Ameren territory were money-losers. If your price is higher, you can opt out and return to Ameren without an exit fee, says CUB. Call the supplier on your bill. For the full Peoria story, read Peoria electric companies.

Steps to check your own town:

1. 1
   Find the supplier name on your Ameren bill.

   It prints beside the supply charge.

2. 2
   Look up your town

   on the Commission's municipal aggregation list.

3. 3
   Type the price into the tool above.

   The tool shows the monthly gap and the winning stretch.

4. 4
   Opt out only after you see a better choice.

   Your letter or the supplier sets the date.

The price to compare is set for two seasons a year, and a few other charges move on their own dates.

1. Now to May 31, 2027Ameren's price is 10.441¢ for the first 800 kWh and 8.262¢ above.
2. Each JanuaryThe transmission charge resets, so the price to compare will move.
3. The day after the current price endsThe next price starts. Summer, June to September, has one flat price.
4. Check for a rulingOn September 28, 2026, CUB said Ameren was asking regulators for about $65 million more for delivery, a separate part of your bill.

Hourly prices change every hour. A fixed supplier price does not move until its term ends. Write the end date on your calendar before the offer rolls to a new price.

Plug In Illinois lists these protections for Ameren and ComEd homes:

• You can cancel within 10 days. The clock starts when Ameren processes the enrollment, and Ameren sends you a letter naming the supplier.
• Nobody may switch you without your approval. Share your account number only when you decide to switch.
• Ask about exit fees and the term before you agree. The contract sets them.
• Add your name to Ameren's Do Not Market List to cut sales calls. Call 800-755-5000.
• File a complaint with the Illinois Commerce Commission at (800) 524-0795 if a supplier fails to deliver what it promised.

CUB warns that suppliers face the same costly market as Ameren and that your utility is likely your best bet. It estimates Illinois households lost about $2.3 billion to alternative suppliers since 2015. That is CUB's figure, not ours. If the numbers say a supplier does win for your use, the finder button below shows plans for your ZIP.