During those formative years, the major task was to link groups of towns together with transmission lines. In 1921, Central Illinois Public Service Company took an important step in expansion and experimentation. The company purchased the Farmer's Bank Building and Annex in Springfield. At the intersection of 6th and Adams Streets, this location remains the company's Springfield headquarters, though marked by a different building.

In partnership with the University of Illinois, farm organizations and manufacturers, CIPS formed the Committee on the Relations of Electricity to Agriculture to study and promote the use of electricity. One CIPS model demonstration farm was located one mile outside Macomb.

While CIPSCO continued to add generating units -- including Grand Tower Power Station and Kincaid Power Station -- and increased its transmission services, the company also explored ways to serve its customers in other ways.

Through a Personal Service Department, residential customers tested experimental furnaces and boilers used to heat homes with gas. The Commercial Department established an illuminating engineering service to design correct lighting systems for schools, factories and businesses. And a Committee on the Relation of Electricity to Agriculture studied electric use on farms to determine how to best serve the farm industry. That committee included representatives from the University of Illinois College of Agriculture, state farm organizations, the Illinois State Electric Association and manufacturers of farm and electrical equipment.

CIPSCO adds generating units with Grand Tower Power Station.

CIPSCO also continued to sell ice retail in 27 communities and wholesale in an additional 202 towns.