Combined Production and Conversion of Energy in an Urban Integrated System

Within the framework of the European Combined Efficient Large Scale Integrated Urban Systems (CELSIUS) project, the Genoa demonstrator involves the insertion of a turbo expander (TE) to substitute the standard throttling process in a natural gas expansion station. In this way, the currently wasted mechanical energy will be recovered, while an internal combustion combined heat and power (CHP) unit will be used to meet the heating requirements of the gas before the expansion and to serve a small district heating network (DHN). Both TE and CHP are capable of delivering electric power (EP) up to 1 MW. In order to match the EP production vs demand is highly desirable to use the EP extra capacity for local EP final users, such as a nearby public school and a gas refueling station (RS). For limiting the school's consumption of fossil fuel, it is possible to use the EP surplus generated by the demonstrator to feed a heat pump in parallel to the heating conventional system. With regard to the RS, the compressors are currently driven by electric motors, with a high-energy consumption. The integrated system gives the possibility of exploiting the surplus of electricity production and of recovering heat, which would be otherwise wasted, from the intercooling of compressed gas, thus powering the DHN through a preheating system. The result expected from this strategy is a relevant energy and emissions saving due to an integrated use of the electricity generated by the Genoese demonstrator for feeding the nearby school and RS.