Breaking down the utility charges on your residential bill

Ameren Illinois

For ease of comparison, we list the Price to Compare before we break down the charges on your utility bill. Items A, B and C below reflect the order in which they appear on your Ameren Illinois bill. When you select service from a retail electric supplier, the Ameren Illinois Electric Supply and Transmission Services Charge (items B and C below) will be replaced with the charges from your new retail electric supplier. Currently, most suppliers will place their charges on your Ameren Illinois bill and some suppliers will send you a bill directly (containing Ameren Illinois' delivery service charges as well as the supplier's supply and transmission charges).

Price to Compare = Electric Supply Charges + Transmission Service Charge

Historical Prices to Compare

Combining the electric supply charges and the transmission service charge results in the current Ameren Illinois Price to Compare, which is effective January 2014 through May 2014. Electric supply charges for June 2014 - May 2015 will not be determined until May 2014.

Residential Non-Space Heating
Price to Compare (in cents per kWh)

Ameren Illinois
Rate Zone*
Non-Summer
(January 2014 – May 2014)
First 800 kWh
Non-Summer
(January 2014 – May 2014)
Usage above 800 kWh
Rate Zone I 4.863 4.863
Rate Zone I,
Metro East
(former UE)
4.863 4.18
Rate Zone II 4.8 4.8
Rate Zone III 4.803 4.803

Residential Space Heating (January 2014 – May 2014)
Price to Compare (in cents per kWh)

Ameren Illinois Rate Zone First 800kWh Usage above 800kWh
Rate Zone I 4.863 4.863
Rate Zone III 4.803 4.68

Rate Zone I = previously AmerenCIPS
Rate Zone II = previously AmerenCILCO
Rate Zone III = previously AmerenIP

If you are using more than 800 kWh of electricity during the non-summer months, your price to compare depends on your usage and includes the rate for electricity consumed below 800kWh, the rate for electricity consumed above 800kWh, as well as the transmission service charge. For example, if you are an Ameren Illinois Rate Zone I ME customer using 900kWh during a non-summer month, your price to compare is 4.81 cents per kWh ((4.863 ¢/kWh x 800 kWh + 4.418 ¢/kWh X 100 kWh) / 900 kWh) and if you are using 1200 kWh during a non-summer month your price to compare is 4.71 cents per kWh ((4.863 ¢/kWh x 800 kWh + 4.418 ¢/kWh X 400 kWh) / 1200 kWh).

If you are served under the utility's space heat provision, your price to compare depends on your usage and includes the rate for electricity consumed below 800kWh, the rate for electricity consumed above 800kWh, as well as the transmission service charge. For example, if you are an Ameren Illinois Rate Zone III customer using 900kWh during a non-summer month, your price to compare is 4.789 cents per kWh ((4.803 ¢/kWh x 800 kWh + 4.68 ¢/kWh X 100 kWh) / 900 kWh) and if you are using 1200 kWh during a non-summer month, your price to compare is 4.762 cents per kWh ((4.803 ¢/kWh x 800 kWh + 4.68 ¢/kWh X 400 kWh) / 1200 kWh).

A. Delivery Service Charges

You will pay the charges to deliver the electric supply from the transmission system to your home regardless of whether you purchase your electric supply from Ameren Illinois or a Retail Electric Supplier. On your Ameren Illinois bill, these charges are listed as DS or Delivery Service charges.

B. Electric Supply Charges

The electric supply charge is the price you pay per kWh for the amount of electricity you use in your home. The price of electric supply is determined by your choice of supplier, whether it be a Retail Electric Supplier or the electric utility. The Ameren Illinois rate for the electric supply during the summer months (June through September) is different from the utility rate during the non-summer months (October through May). The Ameren Illinois rate for electric supply during the non-summer months (October – May) may be lower if you use more than 800 kWh per month during the non-summer months if you are taking service in Rate Zone I Metro East, Rate Zone II, or if your home was previously served under space-heating provisions at the end of 2006 and you are in Rate Zone I or Rate Zone III.

Ameren Illinois
Rate Zone
Non-Summer
(January 2014 – May 2014)
First 800kWh
Non-Summer
(January 2014 – May 2014)
Usage above 800kWh
Rate Zone I 4.271 cents per kWh 4.271 cents per kWh
Rate Zone I,
Metro East
(former UE)
4.271 cents per kWh 3.826 cents per kWh
Rate Zone II 4.271 cents per kWh 4.271 cents per kWh
Rate Zone III 4.271 cents per kWh 4.271 cents per kWh

Over the course of a year, your average utility rate per kWh is likely somewhere between the summer rate and the non-summer rate. Whether your average electricity supply charge for a 12-month period is closer to the summer rate or closer to the non-summer rate depends on how much electricity you use and during which months you use it. Please take a look at your electric bill or log in to your Ameren Illinois account here to see how much electricity you typically use over the course of a year and when you use it.

Attention Electric Space Heating Customers

If you are using electricity to heat your home and your home was served under the utility's space heating rate in 2006, your rate for electricity consumed above 800 kWh is discounted as shown in the chart below. The space-heat provision is automatically available if your home was previously served under space-heating tariff provisions at the end of 2006. The space heat pricing stays with the premises and not with the customer, and the pricing is not available to new premises. Also, while the chart below shows that there is no special electric space heating rate for Rate Zone I, Metro East (former UE) customers and Rate Zone II customers, please keep in mind that there are lower rates for usage above 800 kWh during the non-summer months for all of the residential Ameren Illinois customers in those service territories. The chart above shows those rates.

Non-Summer (January 2014 – May 2014)

Ameren Illinois Rate Zone First 800kWh Usage above 800kWh
Rate Zone I 4.271 cents per kWh 4.271 cents per kWh
Rate Zone III 4.271 cents per kWh 4.148 cents per kWh

The Electric Supply charge section on your Ameren Illinois bill includes a Supply Cost Adjustment, shown as "Rider PER Supply Cost Adj." The Supply Cost Adjustment is designed to allow the utility to recover costs associated with procurement, working capital and uncollectible charges. The Supply Cost Adjustment is largely a fixed charge that changes only when the ICC makes changes to Ameren Illinois' delivery service rates, after an annual power supply procurement update, or pursuant to other Commission Orders. The currently effective fixed Supply Cost Adjustment is at 0.029 cents per kWh for Ameren Illinois rate Zone I customers, -0.033 cents per kWh for Ameren Rate Zone II customers, and -0.032 cents per kWh for Ameren Rate Zone III customers. When calculating the utility's electric supply price for Ameren Illinois' Price to Compare, we do include the Supply Cost Adjustment.

You will also notice on your bill a monthly "Purchased Electricity Adjustment" that causes the electric supply charges to fluctuate above or below the established electric supply rate from one month to the next. The purpose of the Purchased Electric Adjustment is to "true-up" any difference (over or under) between what Ameren Illinois previously paid to acquire electric supply and what Ameren Illinois previously charged its customers for that electric supply. Ameren Illinois expects that for the remainder of the planning year (through May 2014), the Purchased Electricity Adjustment will be a credit of about 0.5 cents/kWh. When calculating the utility's electric supply price for Ameren Illinois' Price to Compare, We do not include a value for the Purchased Electricity Adjustment. You will not be subject to the Purchased Electricity Adjustment when you switch to a Retail Electricity Supplier.

Attention Residential Power Smart Pricing Customers

To make a meaningful comparison between variable Power Smart Pricing rates and RES offers, customers should compare their past supply cost savings, provided by their Power Smart Pricing provider, with a supply cost savings estimate provided by RESs. Competitive supplier savings estimates are often calculated on a percentage savings compared to the utility's Price to Compare. Alternatively, customers can compute their average real-time price in cents per kWh to compare with RES offers posted in cents per kWh. Customer should bear in mind, however, that since Power Smart Pricing rates vary over time, past savings do not predict future savings, but only serve as a guide to compare past performance.

C. Transmission Service Charge

Also included in the Electric Supply Section on your Ameren Illinois bill is the Transmission Service Charge. The transmission service charge is designed to allow the utility to recover costs associated with transmission service. The transmission charge is set annually by the Federal Energy Regulatory Commission (FERC). Ameren Illinois determines its transmission charge annually for prices effective each June through the following May.

The currently effective transmission service charge that we include in the Ameren Illinois Price to Compare is 0.563 cents per kWh for Ameren Illinois Rate Zone I customers, 0.562 cents per kWh for Ameren Illinois Rate Zone II customers and 0.564 cents per kWh for Ameren Rate Zone III customers.