Abstract Energy recovery within processes via heat exchanger network (HEN) to minimise the external utilities has been well established. Due to the close energy interactions between HEN and the utility system, it is important to synthesise these two elements simultaneously. In this work, a novel systematic approach for synthesis of HEN with utility systems is presented. Multiple cascades automated targeting is applied to determine minimum total operating cost of the trigeneration system, minimum hot and cold utility targets for heat integration prior to detailed design. Besides, the selection and allocation of utilities, distribution of steam, and potential power generation can also be determined. Meanwhile, the types of boiler fuel for the trigeneration utility system is also identified. An illustrative example with two scenarios is solved to illustrate the proposed approach.