Photovoltaic solar power is an increasing source of energy and part of the renewable energy generation which is needed in the near future to achieve the set climate goals. When planning new photovoltaic installations, parameters which affect the design are both local conditions (e.g. weather) and system parameters such as tilt and azimuth angles. Commercial areas often have high loads during the day when solar power is available and are therefore interesting for photovoltaic installations. In order make a quick estimation of photovoltaic power potential in an area, a simulation tool which handles load profiles from multiple buildings would be desirable. The aim of this thesis project is therefore to create a tool which can simulate multiple photovoltaic systems and for each of them estimate system sizes, grid interactions, and area requirements. The simulation tool is based on Python programming with the aid of System Advisor Model, a simulation software for photovoltaic and other renewable energy tech-nologies. Optimization of orientation angles was made for clear sky with the goal of high load-generation match. Different system sizes were estimated and simulated based on different degrees of self-sufficiency, net-zero consumption, and the existing transfer capacity of the building in question. When the simulation result was compared to a detailed photovoltaic design project, some agreements between the results were found, as well as further development needs such as refining area estimation. To further develop the usability of the tool, a more user-friendly interface is needed. Other improvements could be to enable simulations of multiple direction systems and integration of the local grid structure and limitations.