Analysis of the integration of photovoltaic excess into a 5th generation district heating and cooling system for network energy storage

5th Generation District Heating and Cooling systems are promising technologies for using and storing renewable energy generation excess. An annual simulation using data of a location in the south of Spain is carried out to study this context. The novelty of this work is that a common distribution network is used as an energy storage system and integrates the PV electricity excess from the buildings into the 5GDHC system, at ultra-low temperature. The aim is to analyse if it is interesting to use 5GDHC networks, not designed initially for this purpose, to store energy. For the analysed case, it is estimated that 105 MWh of hot thermal energy and 211 MWh of cold energy are stored. This integration of renewable energy excess would reduce 30.2% of the grid electricity consumption by the 5GDHC energy hub, showing the interest of the strategy for balancing the electricity grid. On the other hand, the storage process implies an annual savings of 2.1% in the grid electricity consumption by the energy hub due to the limited thermal inertia of the network. Moreover, the system can store more energy in hours where storage capacity is still available, so its full potential is not being used. (c) 2021 Elsevier Ltd. All rights reserved.