Add to ORKG"This paper discusses how steady state models are being used in the process industry to perform online energy optimization of steam and electrical systems. It presents process demands commonly found in the processing industry in terms of steam and electricity. It further discusses the methods of providing this energy for refineries, petrochemical plants, and other processing plants - chemical, paper, and metal. A typical system flow diagram is used to highlight the energy system network and describe areas where steady-state models are used. The types of models used are discussed, and a scheme for putting the models together to provide total process plant energy optimization is summarized. The types of optimization which can be implemented i...