Optimization & techno-economic analysis of a hybrid system with thermal energy storage within a LEC

The built environment is one of the most energy-intensive actors of energy. The formation of communities, which exploit energy locally, significantly affects the energy transition process to more viable scenarios. These communities, called Local Energy Communities (LECs), mainly use their primary energy resources to cover their heating and cooling needs. Such a community is the LEC of DUTh's University campus in Xanthi, Greece. The community has installed several Renewable Energy Sources (RES) technologies to exploit the available primary energy and to cover the respective demands. However, an inability to cover the demand is observed in periods like winter or in periods of low renewable energy availability. To tackle that phenomenon, the authors investigated several optimization scenarios, which aim to mitigate the cost of investment as well as the cost of energy (levelized cost of energy -LCoE) and to maximize the thermal energy produced simultaneously - to cover the thermal energy demand - and the RES penetration in the energy mix. A multi-integer linear optimization (MILP) strategy was developed to achieve that. The results were further analyzed via a Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis. The results of the study concluded that an ideal solution for the system might be an increase in solar collector area (by 40%), the thermal energy storage system's (TESS) volume (by 213%), and the biomass boiler's capacity (by 107%) to meet the load of 1,814.48 MWhth/yr and to provide the required energy security to the community. The selected scenario provided an LCoE of 0.16 euro/kWh, which is slightly improved compared to the baselines (0.18 euro/kWh).