The proposal for Chicago to purchase Commonwealth Edison’s system franchise there after its contract expires in 1990 would affect greatly DeKalb-area residents.

In an attempt to reduce spending costs at ComEd’s Chicago system franchise, the city has been investigating alternatives. Chicago receives a franchise fee from ComEd equal to 4 percent of the utility’s city revenue.

The most recent idea was the Beck plan, a buyout proposal released by the city last week asking Chicago system customers to take on all economic responsibility for power production.

If such a plan was adopted by the city, “it would have a substantial effect on the DeKalb area,” Commonwealth Edison district manager Mario Fontana said.

For the city to purchase the proportionate share of the system, cost increases would be higher outside the city because cost of usage is averaged on the number of customers per area, he said.

The number of customers per area decreases the further the distance from the city, this would increase the amount of money needed from each customer to finance the system, Fontana said.

For the time being, however, Fontana said DeKalb-area customers have decreases to look forward to. ComEd’s lower winter rates began going into effect Sept. 15 through Oct. 14, he said.

Customer billing rates work on a system beginning with the first summer bill ending with the date on or after June 15. After the three subsequent summer-rate bills, customers begin the adjusted winter rates.

Customers pay 14.2 cents per kilowatt hour on summer rates regardless of the number of hours used. The winter rates adjust to 7.6 cents per kilowatt hour for the first 400 kilowatt hours and 4.8 cents per kilowatt hour for all usage over the inital 400 kilowatt hours.

In addition, Fontana said there might continue to be minor decreases through fuel adjustment, he said.

Fuel adjustments, which have been decreasing over the past year, are found on customer’s bills in either the form of a fuel credit, giving money back to the customer, or a fuel charge Fontana said.