Energy planning in Sirnach: a case study of a Swiss-wide support tool

Switzerland's commitment to net-zero emissions by 2050 places municipalities in a key position for the energy transition. Yet many - especially small municipalities - often have limited expertise or budget for effective local energy planning. This study presents a publicly available, free online tool designed to address these challenges. Using the municipality of Sirnach (TG, CH) as an example, we demonstrate how the tool facilitates the development of local energy strategies by integrating public data and performing a quantitative scenario analysis. Various future scenarios - both policy-driven and optimized for cost or emissions - are evaluated using the mixed-integer linear programming optimization framework Calliope. These scenarios consider measures such as the replacement of fossil heating systems, the expansion of renewable energy sources, thermal and electrical storage deployment, building refurbishment, and mobility electrification. The results showcase the tool's practical value for municipalities like Sirnach in planning and prioritizing their energy transition pathways.