In this system, the facade of a building was retrofitted with photovoltaic modules.
In addition to producing electricity, the solar modules also serve to shade the window surfaces in summer to protect the office space from overheating.
In this solar system, some of the electricity generated by the solar panels is used directly in the building to reduce electricity costs for the office. The excess electricity is fed into the public power grid and remunerated by the local power grid operator at a fixed rate.