Assessing and optimizing the economic and environmental impacts of cogeneration/district energy systems using an energy equilibrium model

Energy equilibrium models can be valuable aids in energy planning and decis ion-making. In such models, supply is represented by a cost-minimizing line ar submodel and demand by a smooth vector-valued function of prices. In thi s paper, we use the energy equilibrium model to study conventional systems and cogeneration-based district energy (DE) systems for providing heating, cooling and electrical services, not only to assess the potential economic and environmental benefits of cogeneration-based DE systems, but also to de velop optimal configurations while accounting for such factors as economics and environmental impact. The energy equilibrium model is formulated and s olved with software called WATEMS, which uses sequential non-linear program ming to calculate the intertemporal equilibrium of energy supplies and dema nds. The methods of analysis and evaluation for the economic and environmen tal impacts are carefully explored. An illustrative energy equilibrium mode l of conventional and cogeneration-based DE systems is developed within WAT EMS to compare quantitatively the economic and environmental impacts of tho se systems for various scenarios. (C) 1999 Elsevier Science Ltd. All rights reserved.