Vertical flat-panel photobioreactors for microalgae culture can be integrated into building facades. On top of providing the large solar illuminated surfaces needed for microalgae production, this original combination opens various optimization opportunities, such as the possibility to create mutual benefits for both systems with appropriate and efficient integration. For example, microalgal photosynthesis can be used to fix the CO2 contained in flue gas emitted from the building (in a factory set-up) or to significantly reduce energy consumption for thermal regulation of both photobioreactors and building. Here we report the results of a theoretical modelling-based investigation designed to define how the specific building integration conditions affect photobioreactor operation. Expected biomass production and light attenuation conditions encountered in the culture volume were determined for the green microalgae Chlorella vulgaris for a location based in Nantes (France). Results were compared to figures from the more conventional systems such as horizontal or ideally-inclined microalgal culture systems. We conclude with an energetic analysis that underlines the relevance of optimizing thermal exchanges between microalgal culture and building. (C) 2015 Elsevier B.V. All rights reserved.