Techno-Economic Assessment of Thermal and Battery Storage in a Residential Heating System: A Case Study in Parma

The growing adoption of renewable energy sources, particularly photovoltaic generation, has made energy storage a key element for increasing self-consumption and mitigating production intermittency in residential energy systems. Lithium-based batteries are currently the most widespread solution, but they present several drawbacks, including high investment costs, limited lifetime, and dependence on critical materials. Thermal energy storage, especially in the form of hot-water tanks, has emerged as a promising alternative in systems where the final energy demand is mainly thermal, such as space heating. This paper presents a techno-economic comparison of two domestic heating systems applied to a case study in Parma, Italy: a photovoltaic system coupled with a heat pump and a lithium-ion battery, and a photovoltaic system coupled with a heat pump and a hot-water thermal storage tank. A system-sizing model was developed using data from installers in Northern Italy and national technical and economic databases, enabling optimal sizing for each configuration while ensuring full coverage of thermal demand. For each system, several configurations were evaluated, and the optimal technical solution was first identified and then assessed through a net present value analysis over a 10-year horizon. The results show that the thermal storage configuration provides a higher economic benefit, with a saving of €2,506.18 compared to the battery- based system. Furthermore, thermal storage does not involve certain replacement costs at the end of the period, unlike lithium-ion batteries.