<p>This paper presents a&#xa0;data-driven study and its results for estimating the future residential battery storage potential in Austria up to 2040, including an explicit regionalization at the municipal level. The study is motivated by the increasing photovoltaic (PV) feed-in into low-voltage distribution grids, which leads to local midday peak loads, voltage limit violations, and a&#xa0;growing demand for decentralized flexibility solutions. Based on publicly available statistical and geospatial datasets, historical PV and battery storage data are harmonized and calibrated to national expansion targets using logistic PV deployment pathways. The diffusion of residential battery storage systems is modeled separately for new installations and retrofit pathways, enabling a&#xa0;realistic representation of both increasing shares of storage in newly installed PV systems and decreasing retrofit dynamics over time. In addition, storage capacity is estimated based on market shares and average usable battery capacities.</p><p>The regionalized distribution is performed using a&#xa0;GIS-based approach at municipal level and allocated proportionally to realizable PV potential areas. This results in the first municipality-level projection of future residential battery storage distribution in Austria, revealing regional differences in deployment rates and identifying regional hotspots in PV-intensive federal states. The results project approximately 1.28 million residential battery storage systems with a&#xa0;cumulative usable capacity of around 17.3 GWh by 2040. The storage share among PV installations is expected to increase from 34% to more than 80%, while the total usable storage capacity is projected to reach approximately 10 GWh by 2030. The results are provided in a&#xa0;GTIF-compatible format for an interactive web-based GIS platform and constitute a&#xa0;robust basis for spatially differentiated flexibility assessments.</p>