Renewable smart energy network: A thermoeconomic comparison between conventional lithium-ion batteries and reversible solid oxide fuel cells

Smart energy networks including renewables and energy storage systems are a promising technology for improving the sustainability of residential districts and private mobility. In this work, a smart energy network is analyzed, based on photovoltaic panels, electric energy storage systems, heat pumps and electric vehicles. The system consists of a fully electric residential district, where air-to-air heat pumps are used for space heating and cooling and air-to-water heat pumps provide domestic hot water; a photovoltaic field meets the power load of the residential district, including charging stations for electric vehicles. A district electric energy storage system is included for balancing power supply and demand: two storage technologies are considered and compared in this work: a lithium-ion battery and a reversible solid oxide fuel cell. These systems are modelled and dynamically simulated in Transient Systems Simulation Program (TRNSYS) 18. A case study is discussed, where the proposed systems exhibit promising results in terms of primary energy saving: for example, the renewable energy matches almost 74–77% of the district primary energy demand for the analyzed smart energy districts. Moreover, both the proposed systems achieve very profitable results with a payback period of 3.5–4.4 years. Both the analyzed layouts achieve very similar results.