From solar to storage: Case study for assessing massive use of small-scale lithium-ion batteries in residential sector

Urban photovoltaic (PV) systems enhance energy production. Still, widespread adoption can lead to fluctuations in energy prices (at different seasons and times), which drop during sunny periods and rise when solar power is unavailable. Nevertheless, using energy storage systems does not necessarily depend on the costs. Still, because of the random nature of primary (solar) energy, storage is required for PV generation systems to become an alternative solution to classic generation systems. While integrating energy storage systems can mitigate these fluctuations and enhance system reliability, high investment costs often challenge their implementation. The economic viability of battery systems in urban areas, including the residential sector, deviates from the trend observed in photovoltaic systems. This discrepancy can be attributed to the generally unprofitable nature of such systems from an economic standpoint. This study provides a methodology for assessing the use of massive lithium-ion battery systems in the residential sector. The methodology is applied to Valencia City but adaptable to other locations, employing tools such PVGIS to obtain the energy demand of the city, HOMER to carry out the economic analysis, PVGIs to estimate the solar resources, and QGis to estimate the available rooftop. The results reveal that Valencia’s residential rooftops offer 392 MW of PV and 469 MWh of storage potential, covering 66 % of demand. Mid-rise buildings (5–8 floors) dominate capacity, while low-rise buildings (2–3 floors) achieve 95 % energy self-sufficiency. High-rise buildings cover only 36 %. Payback periods range from 4–14 years, with IRRs of 17–23 %. LCOE varies from 13 to 25 c€/kWh, with low-rise and high-rise buildings facing higher costs due to scale and space limitations.