EXHIBIT 21.1 SUBSIDIARIES OF AQUILA ENERGY CORPORATION SUBSIDIARY STATE OR JURISDICTION OF INCORPORATION OR ORGANIZATION - ---------------------------------------- ----------------------------------- Aquila Energy Marketing Corporation Delaware Aquila Risk Management Corporation Delaware Aquila Gas Pipeline Corporation Delaware UtilCo Group Inc. Delaware Aquila Energy Resources Corporation Delaware Aquila Canada Holdings, Inc. Delaware Aquila Offshore Gas Systems Corporation Delaware Aquila Gas Storage, Inc. Delaware Aquila Technology, Inc. Delaware Aquila Energy (Bermuda) Ltd. Bermuda