Distributed multi-generation options to increase environmental efficiency in smart cities

The recent trends in social development show that in the next decades an increasing larger share of the population worldwide will live in cities. Decarbonising the energy footprint of urban areas becomes therefore a critical point in the outlook of meeting challenging environmental targets set by Governments in many Countries and eventually fighting climate change. Optimal utilization of local resources represents a strategic area to improve the environmental efficiency of cities, and integrated operation and planning of the overall urban system is needed to maximize such efficiency. Hence, while various energy vectors such as gas, electricity, heat, and so on, have been traditionally decoupled in terms of operation and planning, the need to reduce emissions and the availability of smart grid technologies represent a significant opportunity to rethink urban energy systems. The objective of this paper is to discuss the main issues relevant to interaction of urban multi-energy systems facilitated by the deployment of smart grid controls. Specific focus is set on distributed-multi generation options to integrate natural gas, electricity, heat and cooling at various decentralisation levels (with in case the option of having district energy systems). Technologies analysed include combined heat and power (CHP) and micro-CHP, electric heat pump (EHP), Photovoltaics (PV), solar thermal, storage of various forms, various types of chillers for trigeneration applications, and heat and cooling networks. Benefits, issues, enablers, and performance indicators to assess and develop optimal integrated DMG systems in urban areas from both operational and planning perspectives are discussed, supported by illustrative quantitative examples on potential environmental benefits under different conditions.