Operational optimisation of a complex trigeneration system connected to a district heating and cooling network

The combined production of electricity, heat and cold by polygeneration systems ensures maximum utilization of resources by reducing emissions and energy losses during distribution. Polygeneration systems are highly integrated systems characterized by the simultaneously production of different services (electricity, heating, cooling) by means of several technologies using fossil and renewable fuels that operates together to obtain a higher efficiency than that of an equivalent conventional system. The high number of distribution technologies available to produce electricity, heating and cooling and the different levels of integration make it difficult to select of the optimal configuration. Moreover, the high variability in the energy demand renders difficult the selection of the optimal operational strategy. Optimization methodologies are usually applied for the selection of the optimal configuration and operation of energy supply systems. This paper presents a scenario analysis using optimization models to perform an economic, energetic and environmental assessment of a new polygeneration system in Cerdanyola del Vallès (Spain) in the framework of the Polycity project of the European Concerto Program. This polygeneration system comprise high-efficiency natural gas cogeneration engines with thermal cooling facilities and it will provide electricity, heating and cooling for a new area in growth known as Alba park including a Synchrotron Light Facility and a Science and Technological park through a district heating and cooling network of four tubes. The results of the scenario analysis show that the polygeneration plant is an efficient way to reduce the primary energy consumption and CO2 emissions (up to 24%).