Solar simulation and evaluation tools are essential for the design of novel energy and environmental strategies. To date, a number published studies in this area focused on the analysis of flat roofs and small urban areas. This paper presents a method, based on Geographic Information Systems (GIS), for defining the potential of photovoltaic solar energy over urban facades. The method enables the generation of 3D solar maps from two standard data sources, namely cadastral cartography and data on solar irradiance registered by the Spanish State Meteorological Agency (AEMET, for its initials in Spanish). A series of charts have been generated relating the urban and solar geometries as a result of the numerical model. The charts permit the study of the optimal parameters for the photovoltaic integration over facades. In addition, a study conducted over a representative urban area of Madrid is discussed as an example of the applicability of the discussed methodology. Finally, the adequacy of the Spanish Technical Edification Code (CTE, for its initials in Spanish), defining thresholds regarding the usability of photovoltaic energy, has been tested both theoretically and through the case study. Our study concludes that this regulation hinders the architectural integration of photovoltaic devices given the strict usability thresholds adopted. (C) 2014 Elsevier Ltd. All rights reserved.