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The European SHERPA project aims to share knowledge for energy renovation in buildings by public administrations. The EU Energy Performance in Buildings Directive (EPBD) recast, indicates the necessity of transforming EU buildings into Nearly Zero Energy Buildings (nZEB). Each Member State transposes differently the EPBD, usually based on European norms like Spain did. The generated knowledge about improving performance and transforming public buildings into nZEBs, is applied here to schools, according to the Spanish transposition. SHERPA, among other buildings, has audited four schools sited in the Valencia Region (Spain, Southern European Country). The paper starts describing, briefly, the general auditing protocol devised by SHERPA. Particularly, one school was chosen out of the four to illustrate the protocol and was converted into a nZEB. This school led to the most unexpected and outstanding results, although the trends were shared among all the audited schools. Finally, based on the results, the paper suggests some recommendations to the policy makers about the practical definition of nZEB and financial instruments to engage this nZEB challenge for schools. [ABSTRACT FROM AUTHOR]

• Shadow cast vector-based model implemented in a 2D-GIS environment. • Best statistical indicators for building height are robust mode estimators. • 3D building model and shadow model validated accurately. • Maximum error in overall, including both height and shadow models, lower than 2% • Wide range of applications, particularly in Solar Resource Assessments. This paper presents a systematic GIS-based methodology to obtain the shadow cast profile of a group of buildings on arbitrarily orientated and tilted surfaces. The model is integrated in the widely-employed 2D-GIS environment. Given its scalability, the methodology can be easily applied from a local level up to a district, city or even regional level. This work is of interest for a wide range of applications such as for instance in Solar Resource Assessments (SRA) in urban environments. The starting point is to use cadastral cartography and LiDAR altimetric data to obtain a 3D vector-based model of the buildings using high robust mode estimators. Once the geometry of the buildings is defined, analytical models are applied to calculate the shadow cast profile on any arbitrarily orientated and tilted surface of the surroundings. The model has been implemented in the R programming language. An extensive validation has been carried out for several buildings of Valencia (Spain) using CAD elevation views of the buildings and the SketchUp's shadow tool. The error of the vector-based city model is lower than 1% in all LiDAR datasets. The maximum error of the overall methodology, including both height and shadow models, is lower than 2%. [ABSTRACT FROM AUTHOR]